kdd.c: Add support for initial handshake in KD protocol for Win 7, 8 and 10 (64 bit)
Current implementation of find_os is based on the hard-coded values for
different Windows version. It uses the value for get the address to
start looking for DOS header in the given specified range. However, this
is not scalable to all version of Windows as it will require us to keep
adding new entries and also due to KASLR, chances of not hitting the PE
header is significant. We implement a way for 64-bit systems to use IDT
entry to get a valid exception/interrupt handler and then move back into
the memory to find the valid DOS header. Since IDT entries are protected
by PatchGuard, we think our assumption that IDT entries will not be
corrupted is valid for our purpose. Once we have the image base, we
search for the DBGKD_GET_VERSION64 structure type in .data section to
get information required for handshake.
Currently, this is a work in progress feature and current patch only
supports the handshake and memory read/write on 64-bit systems.
NOTE: This is the Updated version of the previous patch submitted
NOTE: This has currently been only tested when debugging was not enabled
on the guest Windows.
Signed-off-by: Jenish Rakholiya <rjenish@cmu.edu> Signed-off-by: Julian Tuminaro <jtuminar@andrew.cmu.edu> Reviewed-by: Tim Deegan <tim@xen.org> Reviewed-by: Paul Durrant <paul@xen.org> Acked-by: Wei Liu <wl@xen.org>
Anthony PERARD [Fri, 15 Nov 2019 13:18:16 +0000 (14:18 +0100)]
x86: fix race to build arch/x86/efi/relocs-dummy.o
With $(TARGET).efi depending on efi/relocs-dummy.o, arch/x86/Makefile
will attempt to build that object. This may result in a dependency file
being generated that has relocs-dummy.o depending on efi/relocs-dummy.S.
Then, when arch/x86/efi/Makefile tries to build relocs-dummy.o, well
efi/relocs-dummy.S doesn't exist.
Have only one makefile responsible for building relocs-dummy.o.
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Release-acked-by: Juergen Gross <jgross@suse.com>
Jan Beulich [Fri, 15 Nov 2019 13:17:26 +0000 (14:17 +0100)]
AMD/IOMMU: restore DTE fields in amd_iommu_setup_domain_device()
Commit 1b00c16bdf ("AMD/IOMMU: pre-fill all DTEs right after table
allocation") moved ourselves into a more secure default state, but
didn't take sufficient care to also undo the effects when handing a
previously disabled device back to a(nother) domain. Put the fields
that may have been changed elsewhere back to their intended values
(some fields amd_iommu_disable_domain_device() touches don't
currently get written anywhere else, and hence don't need modifying
here).
Reported-by: Sander Eikelenboom <linux@eikelenboom.it> Signed-off-by: Jan Beulich <jbeulich@suse.com> Tested-by: Igor Druzhinin <igor.druzhinin@citrix.com> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> Release-acked-by: Juergen Gross <jgross@suse.com>
Jan Beulich [Fri, 15 Nov 2019 13:15:31 +0000 (14:15 +0100)]
x86emul: 16-bit XBEGIN does not truncate rIP
SDM rev 071 points out this fact explicitly.
Signed-off-by: Jan Beulich <jbeulich@suse.com> Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com> Release-acked-by: Juergen Gross <jgross@suse.com>
Andrew Cooper [Wed, 13 Nov 2019 18:11:17 +0000 (18:11 +0000)]
xen/sched: Render sibling/core masks with %pbl to improve 'r' debugkey
For system with large numbers of CPUs, the 'r' debugkey is unwieldy. Sibling
and core masks are a single block of adjacent bits, so are vastly shorter to
render with %pbl.
Andrew Cooper [Wed, 13 Nov 2019 13:19:36 +0000 (13:19 +0000)]
AMD/IOMMU: Fix crash in 'V' debugkey
c/s bb038f31168 "AMD/IOMMU: replace INTREMAP_ENTRIES" introduces a call to
intremap_table_entries() in dump_intremap_table() before tbl.ptr is checked
for NULL.
intremap_table_entries() internally uses virt_to_page() which falls over
ASSERT(va >= XEN_VIRT_START);
in __virt_to_page().
Reported-by: Igor Druzhinin <igor.druzhinin@citrix.com> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Release-acked-by: Juergen Gross <jgross@suse.com>
Andrew Cooper [Wed, 13 Nov 2019 13:04:43 +0000 (13:04 +0000)]
xen/passthrough: Render domains with %pd in the 'Q' debug handler
IOMMUs are owned by DOM_XEN, and with XSA-302, DOM_IO is used for
quarantined devices. Use %pd in the printk to render the system
domains more intelligently.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Release-acked-by: Juergen Gross <jgross@suse.com>
Andrew Cooper [Wed, 19 Jun 2019 17:16:03 +0000 (18:16 +0100)]
x86/tsx: Introduce tsx= to use MSR_TSX_CTRL when available
To protect against the TSX Async Abort speculative vulnerability, Intel have
released new microcode for affected parts which introduce the MSR_TSX_CTRL
control, which allows TSX to be turned off. This will be architectural on
future parts.
Introduce tsx= to provide a global on/off for TSX, including its enumeration
via CPUID. Provide stub virtualisation of this MSR, as it is not exposed to
guests at the moment.
VMs may have booted before microcode is loaded, or before hosts have rebooted,
and they still want to migrate freely. A VM which booted seeing TSX can
migrate safely to hosts with TSX disabled - TSX will start unconditionally
aborting, but still behave in a manner compatible with the ABI.
The guest-visible behaviour is equivalent to late loading the microcode and
setting the RTM_DISABLE bit in the course of live patching.
This is part of XSA-305 / CVE-2019-11135
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
Andrew Cooper [Fri, 8 Nov 2019 16:36:50 +0000 (16:36 +0000)]
x86/vtx: Allow runtime modification of the exec-sp setting
See patch for details.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Reviewed-by: George Dunlap <george.dunlap@citrix.com>
Andrew Cooper [Thu, 20 Dec 2018 17:25:29 +0000 (17:25 +0000)]
x86/vtx: Disable executable EPT superpages to work around CVE-2018-12207
CVE-2018-12207 covers a set of errata on various Intel processors, whereby a
machine check exception can be generated in a corner case when an executable
mapping changes size or cacheability without TLB invalidation. HVM guest
kernels can trigger this to DoS the host.
To mitigate, in affected hardware, all EPT superpages are marked NX. When an
instruction fetch violation is observed against the superpage, the superpage
is shattered to 4k and has execute permissions restored. This prevents the
guest kernel from being able to create the necessary preconditions in the iTLB
to exploit the vulnerability.
This does come with a workload-dependent performance overhead, caused by
increased TLB pressure. Performance can be restored, if guest kernels are
trusted not to mount an attack, by specifying ept=exec-sp on the command line.
This is part of XSA-304 / CVE-2018-12207
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Acked-by: George Dunlap <george.dunlap@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
Andrew Cooper [Thu, 24 Oct 2019 13:09:01 +0000 (14:09 +0100)]
x86/vtd: Hide superpage support for SandyBridge IOMMUs
Something causes SandyBridge IOMMUs to choke when sharing EPT pagetables, and
an EPT superpage gets shattered. The root cause is still under investigation,
but the end result is unusable in combination with CVE-2018-12207 protections.
This is part of XSA-304 / CVE-2018-12207
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
Dario Faggioli [Tue, 12 Nov 2019 17:03:49 +0000 (17:03 +0000)]
sched: fix dom0less boot with the null scheduler
In a dom0less configuration, if the null scheduler is used, the system
may fail to boot, because the loop in null_unit_wake() never exits.
Bisection showed that this behavior occurs since commit d545f1d6 ("xen:
sched: deal with vCPUs being or becoming online or offline") but the
real problem is that, in this case, pick_res() always return the same
CPU.
Fix this by only deal with the simple case, i.e., the vCPU that is
coming online can be assigned to a sched. resource right away, in
null_unit_wake().
If it can't, just add it to the waitqueue, and we will deal with it in
null_schedule(), being careful about not racing with vcpu_wake().
If an error were to happen before the last step, for example the
domain_configuration is missing, the error wouldn't be checked by the
_end callback.
Fix that, also initialise `lock' to NULL because the exit path checks
it.
The issue shows up when there's a stubdom, and running `xl list -l`
aborts. Instead, with this patch, `xl list -l` will not list stubdom,
probably like before.
Reported-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com> Fixes: 61563419257ed40278938db2cce7d697aed44f5d Signed-off-by: Anthony PERARD <anthony.perard@citrix.com> Tested-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com> Acked-by: Wei Liu <wl@xen.org> Release-acked-by: Juergen Gross <jgross@suse.com>
Andrew Cooper [Mon, 11 Nov 2019 20:46:08 +0000 (20:46 +0000)]
AMD/IOMMU: Fix passthrough following c/s d7cfeb7c13e
"AMD/IOMMU: don't blindly allocate interrupt remapping tables" introduces a
call at runtime from amd_iommu_add_device() to amd_iommu_set_intremap_table()
which is still marked as __init.
On one AMD Rome machine we have, this results in a crash the moment we try to
use an SR-IOV VF in a VM.
Reported-by: Jennifer Herbert <jennifer.herbert@citrix.com> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Release-acked-by: Juergen Gross <jgross@suse.com>
Paul Durrant [Fri, 8 Nov 2019 09:42:33 +0000 (09:42 +0000)]
tools/hotplug: only attempt to call 'ip route' if there is valid command
The vif-route script should only call 'ip route' when 'ipcmd' has been
set, otherwise it will fail due to an incorrect command string.
This patch also adds routes for 'tap' (i.e. emulated) devices as well as
'vif' (i.e. PV) devices. Empirically offline/online commands relate to
'vif' devices, and add/remove commands relate to 'tap' devices. However,
this patch treats them equally and uses ${type_if} to distinguish. By
adding cases for add/remove the command list becomes exhaustive and hence
'ipcmd' is guaranteed to be set.
Routes for 'tap' and 'vif' devices are distinguished by a route metric.
Emulated devices are used by HVM guests until they are unplugged, at which
point the PV device becomes active. Thus 'tap' devices should get a higher
priority (i.e. lower numbered) metric than 'vif' devices.
There is also one small whitespace fix.
Signed-off-by: Paul Durrant <pdurrant@amazon.com> Acked-by: Wei Liu <wl@xen.org> Release-acked-by: Juergen Gross <jgross@suse.com>
Anthony PERARD [Mon, 4 Nov 2019 15:30:47 +0000 (15:30 +0000)]
libxl: Fix setting vncpasswd to empty string
Before 93dcc22, error from setting the vnc password to an empty
string, when QEMU wasn't expected a password, never prevented the creation
of a guest, and only logged an error message.
Reported-by: Roger Pau Monné <roger.pau@citrix.com> Fixes: 93dcc22fe798c9fa5ce117f1ed6db0d8bd779020 Signed-off-by: Anthony PERARD <anthony.perard@citrix.com> Acked-by: Wei Liu <wl@xen.org> Release-acked-by: Juergen Gross <jgross@suse.com>
Juergen Gross [Tue, 12 Nov 2019 10:09:11 +0000 (11:09 +0100)]
sched: fix a potential issue with core scheduling
cpupool_online_cpumask() is used by credit and rt scheduler. It returns
all the cpus of a cpupool or all online cpus in case no cpupool is
specified.
The "no cpupool" case can be dropped, as no scheduler other than the
init scheduler will ever work on cpus not associated with any cpupool.
As the individual schedulers should only ever work on scheduling
resources instead of individual cpus, their cpupool_online_cpumask()
use should be replaced by cpupool->res_valid.
Note that only with core scheduling active this might result in
potential problems, as with cpu scheduling both masks are identical.
Jan Beulich [Tue, 12 Nov 2019 10:08:34 +0000 (11:08 +0100)]
AMD/IOMMU: don't needlessly trigger errors/crashes when unmapping a page
Unmapping a page which has never been mapped should be a no-op (note how
it already is in case there was no root page table allocated). There's
in particular no need to grow the number of page table levels in use,
and there's also no need to allocate intermediate page tables except
when needing to split a large page.
Signed-off-by: Jan Beulich <jbeulich@suse.com> Reviewed-by: Paul Durrant <paul@xen.org> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> Release-acked-by: Juergen Gross <jgross@suse.com>
Roger Pau Monné [Tue, 12 Nov 2019 10:07:40 +0000 (11:07 +0100)]
x86/ioapic: fix clear_IO_APIC_pin write of raw entries
clear_IO_APIC_pin can be called after the iommu has been enabled, and
using raw reads and writes to modify IO-APIC entries that have been
setup to use interrupt remapping can lead to issues as some of the
fields have different meaning when the IO-APIC entry is setup to point
to an interrupt remapping table entry.
The following ASSERT in AMD IOMMU code triggers afterwards as a result
of the raw changes to IO-APIC entries performed by clear_IO_APIC_pin.
(XEN) [ 10.082154] ENABLING IO-APIC IRQs
(XEN) [ 10.087789] -> Using new ACK method
(XEN) [ 10.093738] Assertion 'get_rte_index(rte) == offset' failed at iommu_intr.c:328
Fix this by making sure that modifications to entries are performed in
non raw mode when fields are affected which may either have changed
meaning with interrupt remapping, or which may need mirroring into
IRTEs.
Reported-by: Sergey Dyasli <sergey.dyasli@citrix.com> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
xen/arm: entry: Ensure the guest state is synced when receiving a vSError
When a SError/Asynchronous Abort generated by the guest has been
consumed, we will skip the handling of the initial exception.
This includes the calls to enter_hypervisor_from_guest{, _noirq} that
is used to synchronize part of the guest state with the internal
representation and re-enable workarounds (e.g. SSBD). However, we still
call leave_hypervisor_to_guest() which is used for preempting the guest
and synchronizing back part of the guest state.
enter_hypervisor_from_guest{, _noirq} works in pair with
leave_hypervisor_to_guest(), so skipping the first two may result
in a loss of some part of guest state.
An example is the new vGIC which will save the state of the LRs on exit
from the guest and rewrite all of them on entry to the guest.
A more worrying example is SSBD workaround may not be re-enabled. If
leave_hypervisor_to_guest() is rescheduling the vCPU, then we may end to
run a lot of code with SSBD workaroud disabled.
For now, calling leave_hypervisor_to_guest() is not necessary when
injecting a vSError to the guest. But it would still be good to give an
opportunity to reschedule. So both enter_hypervisor_from_guest() and
leave_hypervisor_to_guest() are called.
Note that on arm64, the return value for check_pending_vserror is now
stored in x19 instead of x0. This is because we want to keep the value
across call to C-functions (x0, unlike x19, will not be saved by the
callee).
Take the opportunity to rename check_pending_vserror() to
check_pending_guest_serror() as the function is dealing with host SError
and *not* virtual SError. The documentation is also updated accross
Arm32 and Arm64 to clarify how Xen is dealing with SError generated by
the guest.
Julien Grall [Mon, 7 Oct 2019 12:57:00 +0000 (13:57 +0100)]
xen/arm: Update the ASSERT() in SYNCHRONIZE_SERROR()
The macro SYNCHRONIZE_SERROR() has an assert to check whether it will
be called with Abort interrupt unmasked. However, this is only done if
a given cap is not enabled.
None of the callers will treat the abort interrupt differently
depending on a feature. Furthermore, it makes more difficult to check
whether SYNCHRONIZE_SERROR() is going to be called with abort interrupt
unmasked.
Therefore, we now require the abort interrupt to be unmasked regardless
the state of the cap.
Mark Rutland [Tue, 24 Sep 2019 11:25:47 +0000 (12:25 +0100)]
xen/arm: alternative: add auto-nop infrastructure
In some cases, one side of an alternative sequence is simply a number of
NOPs used to balance the other side. Keeping track of this manually is
tedious, and the presence of large chains of NOPs makes the code more
painful to read than necessary.
To ameliorate matters, this patch adds a new alternative_else_nop_endif,
which automatically balances an alternative sequence with a trivial NOP
sled.
In many cases, we would like a NOP-sled in the default case, and
instructions patched in in the presence of a feature. To enable the NOPs
to be generated automatically for this case, this patch also adds a new
alternative_if, and updates alternative_else and alternative_endif to
work with either alternative_if or alternative_endif.
The alternative infrastructure was originally ported from Linux. So this
is pretty much a straight backport from commit 792d47379f4d "arm64:
alternative: add auto-nop infrastructure". The only difference is the
nops macro added as not yet existing in Xen.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
[will: use new nops macro to generate nop sequences] Signed-off-by: Will Deacon <will.deacon@arm.com>
[julien: Add nops and port to Xen] Signed-off-by: Julien Grall <julien.grall@arm.com> Reviewed-by: Volodymyr Babchuk <volodymyr_babchuk@epam.com> Acked-by: Stefano Stabellini <sstabellini@kernel.org> Release-acked-by: Juergen Gross <jgross@suse.com>
A follow-up patch will require to include insn.h from assembly code. So
we need to protect any C-specific definition to avoid compilation
errors when used in assembly code.
xen/arm: alternative: Remove unused parameter for alternative_if_not_cap
The macro alternative_if_not_cap is taking two parameters. The second
parameter is never used and it is hard to see how this can be used
correctly as it is only protecting the alternative section magic.
xen/arm: Ensure the SSBD workaround is re-enabled right after exiting a guest
At the moment, SSBD workaround is re-enabled for Xen after interrupts
are unmasked. This means we may end up to execute some part of the
hypervisor if an interrupt is received before the workaround is
re-enabled.
Each trap may require to unmask different interrupts.
As the rest of enter_hypervisor_from_guest() does not require to have
interrupts masked, the function is now split in two parts:
1) enter_hypervisor_from_guest_preirq() called with interrupts
masked.
2) enter_hypervisor_from_guest() called with interrupts unmasked.
Note that while it might be possible to avoid spliting the function in
two parts, it requires a bit more work than I can currently invest to
avoid using indirect branch.
Furthermore, the function name is rather generic as there might be more
work to dob before interrupts are unmasked in the future.
Julien Grall [Wed, 30 Oct 2019 11:24:59 +0000 (11:24 +0000)]
xen/arm32: entry: Rename save_guest_regs()
The function save_guest_regs() is doing more than saving guest
registers. It also restore the vectors table and consume any pending
SErrors generated by the guest. So rename the function to
prepare_context_from_guest().
Take the opportunity to use ENDPROC() for the benefits of static
analizer and the reader.
Julien Grall [Thu, 31 Oct 2019 15:09:12 +0000 (15:09 +0000)]
xen/arm: traps: Rework entry/exit from the guest path
At the moment, enter_hypervisor_head() and leave_hypervisor_tail() are
used to deal with actions to be done before/after any guest request is
handled.
While they are meant to work in pair, the former is called for most of
the traps, including traps from the same exception level (i.e.
hypervisor) whilst the latter will only be called when returning to the
guest.
As pointed out, the enter_hypervisor_head() is not called from all the
traps, so this makes potentially difficult to extend it for the dealing
with same exception level.
Furthermore, some assembly only path will require to call
enter_hypervisor_tail(). So the function is now directly call by
assembly in for guest vector only. This means that the check whether we
are called in a guest trap can now be removed.
Take the opportunity to rename enter_hypervisor_tail() and
leave_hypervisor_tail() to something more meaningful and document them.
This should help everyone to understand the purpose of the two
functions.
Note that enter_hypervisor_tail() does not take any parameters anymore
as after the rework, the code does not use them anymore.
Julien Grall [Thu, 31 Oct 2019 15:09:11 +0000 (15:09 +0000)]
xen/arm64: entry: Check if an SError is pending when receiving a vSError
At the moment, when we receive an SError exception from the guest, we
don't check if there are any other pending. For hardening the code, we
should ensure any pending SError are accounted to the guest before
executing any code with SError unmasked.
The recently introduced macro 'guest_vector' could used to generate the
two vectors and therefore take advantage of any change required in the
future.
Julien Grall [Thu, 31 Oct 2019 15:09:10 +0000 (15:09 +0000)]
xen/arm64: entry: Introduce a macro to generate guest vector and use it
Most of the guest vectors are using the same pattern. This makes fairly
tedious to alter the pattern and risk introducing mistakes when updating
each path.
A new macro is introduced to generate the guest vectors and now use it
in the one that use the open-code version.
Julien Grall [Thu, 31 Oct 2019 15:09:08 +0000 (15:09 +0000)]
xen/arm: traps: Update the correct PC when inject a virtual SError to the guest
When injecting a virtual Abort to the guest, we want to update the guest
PC so it can re-execute the HVC/SMC once it has handled the SError.
This is unfortunately not the case when the SError is synchronized on
entry from the guest. As the SError will be received while running in
hypervisor context, we will update the PC of hypervisor context (i.e
the trap).
Rework inject_vabt_exception so it uses the guest context rather than
the current one.
Julien Grall [Thu, 31 Oct 2019 15:09:07 +0000 (15:09 +0000)]
docs/misc: xen-command-line: Rework documentation of the option 'serrors'
The current documentation is misleading for a few reasons:
1) The synchronization happens on all exit/entry from/to the guest.
This includes from EL0 (i.e userspace).
2) Trusted guest can also generate SErrors (e.g. memory failure)
3) Without RAS support, SErrors are IMP DEFINED. Unless you have a
complete TRM in hand, you can't really make a decision.
4) The documentation is written around performance when this is not
the first concern.
The documentation is now reworked to focus on the consequences of using
serrors="panic" and avoid to go in details on the exact implementation.
The documentation on top of __do_serror() is trying to describe all the
possibilities to receive an SErrors.
The description of type#2 is quite misleading because receiving an
SError in EL2 after unmasking SError interrupt ({PSTATE, CPSR}.A) does
not necessarily imply the SError were generated by the guest. You also
need to be in a special window (see abort_guest_exist_{guest, end}).
However, for the context of the function it does not matter how we
categorize the interrupts. What matter is to know whether this is a
guest-generated SError.
All the documentation of __do_serror() is now reworked to avoid
misleading information.
Take the opportunity to simplify the code after the forward option has
been dropped.
Julien Grall [Thu, 31 Oct 2019 15:09:05 +0000 (15:09 +0000)]
xen/arm: Remove serrors=forward
Per the Arm ARM (D4.5 in ARM DDI 0487E.a), SError may be precise or
imprecise.
Imprecise means the state presented to the exception handler is not
guaranteed to be consistent with any point in the excution stream from
which the exception was taken. In other words, they are likely to be
fatal as you can't return safely from them.
Without the RAS extension, the Arm architecture does not provide a way
to differentiate between imprecise and precise SError. Furthermore Xen
has no support for RAS yet. So from a software POV, there is not much
we can do.
More generally, forwarding blindly SErrors to the guest is likely to be
the wrong thing to do. Indeed, Xen is not able to know what is the
content of the SError. This may be a critical device used by the
hypervisor that is about to fail.
In a nutshell, the option serrors=forward is not safe to use in any
environment with the current state of Xen. Therefore the option and any
code related to it are completely removed.
Take the opportunity to rework the comment in do_trap_data_abort() as
all SErrors/External Abort generated by the hypervisor will result in
a crash of the system no matter what the user passed on the command
line.
Julien Grall [Thu, 31 Oct 2019 15:09:04 +0000 (15:09 +0000)]
docs/misc: xen-command-line: Remove wrong statement from serrors=diverse
When serrors=diverse is selected by the user, we will only synchronize
the pending SErrors on entry to hypervisor from guest context and exit
from guest to hypervisor context.
We don't need synchronize SErrors between guest context switch as they
would be categorized to Hypervisor generated SErrors in any case.
x86/hvm: Update code in HVMOP_altp2m_set_suppress_ve
Originally the gfn and altp2m_idx are assigned from the a.u.mem_access union.
This works because it's the same memory used. This patch addresses this
issue by changing the mem_access union with the suppress_ve union for
consistency.
Signed-off-by: Alexandru Isaila <aisaila@bitdefender.com> Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com> Release-acked-by: Juergen Gross <jgross@suse.com>
Andrew Cooper [Thu, 31 Oct 2019 19:38:08 +0000 (19:38 +0000)]
x86/pv: Fix !CONFIG_PV build following XSA-299
PTF_* are declared within CONFIG_PV, and used outside:
mm.c: In function ‘_put_page_type’:
mm.c:2819:32: error: ‘PTF_preemptible’ undeclared (first use in this function)
bool preemptible = flags & PTF_preemptible;
^~~~~~~~~~~~~~~
mm.c:2819:32: note: each undeclared identifier is reported only once for each
function it appears in
mm.c:2842:24: error: ‘PTF_partial_set’ undeclared (first use in this function)
if ( !(flags & PTF_partial_set) )
^~~~~~~~~~~~~~~
mm.c: In function ‘put_page_type_preemptible’:
mm.c:3090:33: error: ‘PTF_preemptible’ undeclared (first use in this function)
return _put_page_type(page, PTF_preemptible, NULL);
^~~~~~~~~~~~~~~
mm.c: In function ‘put_old_guest_table’:
mm.c:3108:25: error: ‘PTF_preemptible’ undeclared (first use in this function)
PTF_preemptible |
^~~~~~~~~~~~~~~
mm.c:3110:27: error: ‘PTF_partial_set’ undeclared (first use in this function)
PTF_partial_set : 0 ),
^~~~~~~~~~~~~~~
mm.c: In function ‘put_page_type_preemptible’:
mm.c:3091:1: error: control reaches end of non-void function
[-Werror=return-type]
}
^
cc1: all warnings being treated as errors
Re-position the definitions to be outside of the #ifdef CONFIG_PV
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Wei Liu <wl@xen.org> Release-acked-by: Juergen Gross <jgross@suse.com>
Julien Grall [Mon, 7 Oct 2019 17:10:56 +0000 (18:10 +0100)]
xen/arm64: Don't blindly unmask interrupts on trap without a change of level
Some of the traps without a change of the level (i.e. hypervisor ->
hypervisor) will unmask interrupts regardless the state of them in the
interrupted context.
One of the consequences is IRQ will be unmasked when receiving a
synchronous exception (used by WARN*()). This could result to unexpected
behavior such as deadlock (if a lock was shared with interrupts).
In a nutshell, interrupts should only be unmasked when it is safe to
do. Xen only unmask IRQ and Abort interrupts, so the logic can stay
simple:
- hyp_error: All the interrupts are now kept masked. SError should
be pretty rare and if ever happen then we most likely want to
avoid any other interrupts to be generated. The potential main
"caller" is during virtual SError synchronization on the exit
path from the guest (see check_pending_vserror).
- hyp_sync: The interrupts state is inherited from the interrupted
context.
- hyp_irq: All the interrupts but IRQ state are inherited from the
interrupted context. IRQ is kept masked.
Julien Grall [Fri, 11 Oct 2019 16:49:28 +0000 (17:49 +0100)]
xen/arm32: Don't blindly unmask interrupts on trap without a change of level
Exception vectors will unmask interrupts regardless the state of them in
the interrupted context.
One of the consequences is IRQ will be unmasked when receiving an
undefined instruction exception (used by WARN*) from the hypervisor.
This could result to unexpected behavior such as deadlock (if a lock was
shared with interrupts).
In a nutshell, interrupts should only be unmasked when it is safe to do.
Xen only unmask IRQ and Abort interrupts, so the logic can stay simple.
As vectors exceptions may be shared between guest and hypervisor, we now
need to have a different policy for the interrupts.
On exception from hypervisor, each vector will select the list of
interrupts to inherit from the interrupted context. Any interrupts not
listed will be kept masked.
On exception from the guest, the Abort and IRQ will be unmasked
depending on the exact vector.
The interrupts will be kept unmasked when the vector cannot used by
either guest or hypervisor.
Note that each vector is not anymore preceded by ALIGN. This is fine
because the alignment is already bigger than what we need.
Julien Grall [Tue, 1 Oct 2019 12:15:48 +0000 (13:15 +0100)]
xen/arm32: entry: Fold the macro SAVE_ALL in the macro vector
Follow-up rework will require the macro vector to distinguish between
a trap from a guest vs while in the hypervisor.
The macro SAVE_ALL already has code to distinguish between the two and
it is only called by the vector macro. So fold the former into the
latter. This will help to avoid duplicating the check.
Julien Grall [Tue, 1 Oct 2019 12:07:53 +0000 (13:07 +0100)]
xen/arm32: entry: Split __DEFINE_ENTRY_TRAP in two
The preprocessing macro __DEFINE_ENTRY_TRAP is used to generate trap
entry function. While the macro is fairly small today, follow-up patches
will increase the size signicantly.
In general, assembly macros are more readable as they allow you to name
parameters and avoid '\'. So the actual implementation of the trap is
now switched to an assembly macro.
Paul Durrant [Fri, 18 Oct 2019 16:41:44 +0000 (17:41 +0100)]
passthrough: quarantine PCI devices
When a PCI device is assigned to an untrusted domain, it is possible for
that domain to program the device to DMA to an arbitrary address. The
IOMMU is used to protect the host from malicious DMA by making sure that
the device addresses can only target memory assigned to the guest. However,
when the guest domain is torn down the device is assigned back to dom0,
thus allowing any in-flight DMA to potentially target critical host data.
This patch introduces a 'quarantine' for PCI devices using dom_io. When
the toolstack makes a device assignable (by binding it to pciback), it
will now also assign it to DOMID_IO and the device will only be assigned
back to dom0 when the device is made unassignable again. Whilst device is
assignable it will only ever transfer between dom_io and guest domains.
dom_io is actually only used as a sentinel domain for quarantining purposes;
it is not configured with any IOMMU mappings. Assignment to dom_io simply
means that the device's initiator (requestor) identifier is not present in
the IOMMU's device table and thus any DMA transactions issued will be
terminated with a fault condition.
In addition, a fix to assignment handling is made for VT-d. Failure
during the assignment step should not lead to a device still being
associated with its prior owner. Hand the device to DomIO temporarily,
until the assignment step has completed successfully. Remove the PI
hooks from the source domain then earlier as well.
Failure of the recovery reassign_device_ownership() may not go silent:
There e.g. may still be left over RMRR mappings in the domain assignment
to which has failed, and hence we can't allow that domain to continue
executing.
NOTE: This patch also includes one printk() cleanup; the
"XEN_DOMCTL_assign_device: " tag is dropped in iommu_do_pci_domctl(),
since similar printk()-s elsewhere also don't log such a tag.
This is XSA-302.
Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Signed-off-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Julien Grall [Tue, 15 Oct 2019 16:10:42 +0000 (17:10 +0100)]
xen/arm: p2m: Don't check the return of p2m_get_root_pointer() with BUG_ON()
It turns out that the BUG_ON() was actually reachable with well-crafted
hypercalls. The BUG_ON() is here to prevent catch logical error, so
crashing Xen is a bit over the top.
While all the holes should now be fixed, it would be better to downgrade
the BUG_ON() to something less fatal to prevent any more DoS.
The BUG_ON() in p2m_get_entry() is now replaced by ASSERT_UNREACHABLE()
to catch mistake in debug build and return INVALID_MFN for production
build. The interface also requires to set page_order to give an idea of
the size of "hole". So 'level' is now set so we report a hole of size of
the an entry of the root page-table. This stays inline with what happen
when the GFN is higher than p2m->max_mapped_gfn.
The BUG_ON() in p2m_resolve_translation_fault() is now replaced by
ASSERT_UNREACHABLE() to catch mistake in debug build and just report a
fault for producion build.
Julien Grall [Tue, 15 Oct 2019 16:10:41 +0000 (17:10 +0100)]
xen/arm: p2m: Avoid off-by-one check on p2m->max_mapped_gfn
The code base is using inconsistently the field p2m->max_mapped_gfn.
Some of the useres expect that p2m->max_guest_gfn contain the highest
mapped GFN while others expect highest + 1.
p2m->max_guest_gfn is set as highest + 1, because of that the sanity
check on the GFN in p2m_resolved_translation_fault() and
p2m_get_entry() can be bypassed when GFN == p2m->max_guest_gfn.
p2m_get_root_pointer(p2m->max_guest_gfn) may return NULL if it is
outside of address range supported and therefore the BUG_ON() could be
hit.
The current value hold in p2m->max_mapped_gfn is inconsistent with the
expectation of the common code (see domain_get_maximum_gpfn()) and also
the documentation of the field.
Rather than changing the check in p2m_translation_fault() and
p2m_get_entry(), p2m->max_mapped_gfn is now containing the highest
mapped GFN and the callers assuming "highest + 1" are now adjusted.
Take the opportunity to use 1UL rather than 1 as page_order could
theoritically big enough to overflow a 32-bit integer.
Lastly, the documentation of the field max_guest_gfn to reflect how it
is computed.
Julien Grall [Tue, 15 Oct 2019 16:10:40 +0000 (17:10 +0100)]
xen/arm: p2m: Avoid aliasing guest physical frame
The P2M helpers implementation is quite lax and will end up to ignore
the unused top bits of a guest physical frame.
This effectively means that p2m_set_entry() will create a mapping for a
different frame (it is always equal to gfn & (mask unused bits)). Yet
p2m->max_mapped_gfn will be updated using the original frame.
At the moment, p2m_get_entry() and p2m_resolve_translation_fault()
assume that p2m_get_root_pointer() will always return a non-NULL pointer
when the GFN is smaller than p2m->max_mapped_gfn.
Unfortunately, because of the aliasing described above, it would be
possible to set p2m->max_mapped_gfn high enough so it covers frame that
would lead p2m_get_root_pointer() to return NULL.
As we don't sanity check the guest physical frame provided by a guest, a
malicious guest could craft a series of hypercalls that will hit the
BUG_ON() and therefore DoS Xen.
To prevent aliasing, the function p2m_get_root_pointer() is now reworked
to return NULL If any of the unused top bits are not zero. The caller
can then decide what's the appropriate action to do. Since the two paths
(i.e. P2M_ROOT_PAGES == 1 and P2M_ROOT_PAGES != 1) are now very
similarly, take the opportunity to consolidate them making the code a
bit simpler.
With this change, p2m_get_entry() will not try to insert a mapping as
the root pointer is invalid.
Note that root_table is now switch to unsigned long as unsigned int is
not enough to hold part of a GFN.
George Dunlap [Thu, 10 Oct 2019 16:57:50 +0000 (17:57 +0100)]
x86/mm: Don't drop a type ref unless you held a ref to begin with
Validation and de-validation of pagetable trees may take arbitrarily
large amounts of time, and so must be preemptible. This is indicated
by setting the PGT_partial bit in the type_info, and setting
nr_validated_entries and partial_flags appropriately. Specifically,
if the entry at [nr_validated_entries] is partially validated,
partial_flags should have the PGT_partial_set bit set, and the entry
should hold a general reference count. During de-validation,
put_page_type() is called on partially validated entries.
Unfortunately, there are a number of issues with the current algorithm.
First, doing a "normal" put_page_type() is not safe when no type ref
is held: there is nothing to stop another vcpu from coming along and
picking up validation again: at which point the put_page_type may drop
the only page ref on an in-use page. Some examples are listed in the
appendix.
The core issue is that put_page_type() is being called both to clean
up PGT_partial, and to drop a type count; and has no way of knowing
which is which; and so if in between, PGT_partial is cleared,
put_page_type() will drop the type ref erroneously.
What is needed is to distinguish between two states:
- Dropping a type ref which is held
- Cleaning up a page which has been partially de/validated
Fix this by telling put_page_type() which of the two activities you
intend.
When cleaning up a partial de/validation, take no action unless you
find a page partially validated.
If put_page_type() is called without PTF_partial_set, and finds the
page in a PGT_partial state anyway, then there's certainly been a
misaccounting somewhere, and carrying on would almost certainly cause
a security issue, so crash the host instead.
In put_page_from_lNe, pass partial_flags on to _put_page_type().
old_guest_table may be set either with a fully validated page (when
using the "deferred put" pattern), or with a partially validated page
(when a normal "de-validation" is interrupted, or when a validation
fails part-way through due to invalid entries). Add a flag,
old_guest_table_partial, to indicate which of these it is, and use
that to pass the appropriate flag to _put_page_type().
While here, delete stray trailing whitespace.
This is part of XSA-299.
Reported-by: George Dunlap <george.dunlap@citrix.com> Signed-off-by: George Dunlap <george.dunlap@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
-----
Appendix:
Suppose page A, when interpreted as an l3 pagetable, contains all
valid entries; and suppose A[x] points to page B, which when
interpreted as an l2 pagetable, contains all valid entries.
P1: PIN_L3_TABLE
A -> PGT_l3_table | 1 | valid
B -> PGT_l2_table | 1 | valid
P1: UNPIN_TABLE
> Arrange to interrupt after B has been de-validated
B:
type_info -> PGT_l2_table | 0
A:
type_info -> PGT_l3_table | 1 | partial
nr_validated_enties -> (less than x)
P2: mod_l4_entry to point to A
> Arrange for this to be interrupted while B is being validated
B:
type_info -> PGT_l2_table | 1 | partial
(nr_validated_entires &c set as appropriate)
A:
type_info -> PGT_l3_table | 1 | partial
nr_validated_entries -> x
partial_pte = 1
P3: mod_l3_entry some other unrelated l3 to point to B:
B:
type_info -> PGT_l2_table | 1
P1: Restart UNPIN_TABLE
At this point, since A.nr_validate_entries == x and A.partial_pte !=
0, free_l3_table() will call put_page_from_l3e() on pl3e[x], dropping
its type count to 0 while it's still being pointed to by some other l3
A similar issue arises with old_guest_table. Consider the following
scenario:
Suppose A is a page which, when interpreted as an l2, has valid entries
until entry x, which is invalid.
V1: PIN_L2_TABLE(A)
<Validate until we try to validate [x], get -EINVAL>
A -> PGT_l2_table | 1 | PGT_partial
V1 -> old_guest_table = A
<delayed>
V2: PIN_L2_TABLE(A)
<Pick up where V1 left off, try to re-validate [x], get -EINVAL>
A -> PGT_l2_table | 1 | PGT_partial
V2 -> old_guest_table = A
<restart>
put_old_guest_table()
_put_page_type(A)
A -> PGT_l2_table | 0
George Dunlap [Thu, 10 Oct 2019 16:57:49 +0000 (17:57 +0100)]
x86/mm: Fix nested de-validation on error
If an invalid entry is discovered when validating a page-table tree,
the entire tree which has so far been validated must be de-validated.
Since this may take a long time, alloc_l[2-4]_table() set current
vcpu's old_guest_table immediately; put_old_guest_table() will make
sure that put_page_type() will be called to finish off the
de-validation before any other MMU operations can happen on the vcpu.
The invariant for partial pages should be:
* Entries [0, nr_validated_ptes) should be completely validated;
put_page_type() will de-validate these.
* If [nr_validated_ptes] is partially validated, partial_flags should
set PTF_partiaL_set. put_page_type() will be called on this page to
finish off devalidation, and the appropriate refcount adjustments
will be done.
alloc_l[2-3]_table() indicates partial validation to its callers by
setting current->old_guest_table.
Unfortunately, this is mishandled.
Take the case where validating lNe[x] returns an error.
First, alloc_l3_table() doesn't check old_guest_table at all; as a
result, partial_flags is not set when it should be. nr_validated_ptes
is set to x; and since PFT_partial_set clear, de-validation resumes at
nr_validated_ptes-1. This means that the l2 page at pl3e[x] will not
have put_page_type() called on it when de-validating the rest of the
l3: it will be stuck in the PGT_partial state until the domain is
destroyed, or until it is re-used as an l2. (Any other page type will
fail.)
Worse, alloc_l4_table(), rather than setting PTF_partial_set as it
should, sets nr_validated_ptes to x+1. When de-validating, since
partial is 0, this will correctly resume calling put_page_type at [x];
but, if the put_page_type() is never called, but instead
get_page_type() is called, validation will pick up at [x+1],
neglecting to validate [x]. If the rest of the validation succeeds,
the l4 will be validated even though [x] is invalid.
Fix this in both cases by setting PTF_partial_set if old_guest_table
is set.
While here, add some safety catches:
- old_guest_table must point to the page contained in
[nr_validated_ptes].
- alloc_l1_page shouldn't set old_guest_table
If we experience one of these situations in production builds, it's
safer to avoid calling put_page_type for the pages in question. If
they have PGT_partial set, they will be cleaned up on domain
destruction; if not, we have no idea whether a type count is safe to
drop. Retaining an extra type ref that should have been dropped may
trigger a BUG() on the free_domain_page() path, but dropping a type
count that shouldn't be dropped may cause a privilege escalation.
This is part of XSA-299.
Reported-by: George Dunlap <george.dunlap@citrix.com> Signed-off-by: George Dunlap <george.dunlap@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
George Dunlap [Thu, 10 Oct 2019 16:57:49 +0000 (17:57 +0100)]
x86/mm: Properly handle linear pagetable promotion failures
In order to allow recursive pagetable promotions and demotions to be
interrupted, Xen must keep track of the state of the sub-pages
promoted or demoted. This is stored in two elements in the page
struct: nr_entries_validated and partial_flags.
The rule is that entries [0, nr_entries_validated) should always be
validated and hold a general reference count. If partial_flags is
zero, then [nr_entries_validated] is not validated and no reference
count is held. If PTF_partial_set is set, then [nr_entries_validated]
is partially validated, and a general reference count is held.
Unfortunately, in cases where an entry began with PTF_partial_set set,
and get_page_from_lNe() returns -EINVAL, the PTF_partial_set bit is
erroneously dropped. (This scenario can be engineered mainly by the
use of interleaving of promoting and demoting a page which has "linear
pagetable" entries; see the appendix for a sketch.) This means that
we will "leak" a general reference count on the page in question,
preventing the page from being freed.
Fix this by setting page->partial_flags to the partial_flags local
variable.
This is part of XSA-299.
Reported-by: George Dunlap <george.dunlap@citrix.com> Signed-off-by: George Dunlap <george.dunlap@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
-----
Appendix
Suppose A and B can both be promoted to L2 pages, and A[x] points to B.
V1: MOD_L3_ENTRY pointing something to A.
In the process of validating A[x], grab an extra type / ref on B:
B.type_count = 2 | PGT_validated
B.count = 3 | PGC_allocated
A.type_count = 1 | PGT_validated
A.count = 2 | PGC_allocated
V1: MOD_L3_ENTRY removing the reference to A.
De-validate A, down to A[x], which points to B.
Drop the final type on B. Arrange to be interrupted.
B.type_count = 1 | PGT_partial
B.count = 2 | PGC_allocated
A.type_count = 1 | PGT_partial
A.nr_validated_entries = x
A.partial_pte = -1
V2: MOD_L3_ENTRY adds a reference to A.
At this point, get_page_from_l2e(A[x]) tries
get_page_and_type_from_mfn(), which fails because it's the wrong type;
and get_l2_linear_pagetable() also fails, because B isn't validated as
an l2 anymore.
George Dunlap [Thu, 10 Oct 2019 16:57:49 +0000 (17:57 +0100)]
x86/mm: Collapse PTF_partial_set and PTF_partial_general_ref into one
...now that they are equivalent. No functional change intended.
Reported-by: George Dunlap <george.dunlap@citrix.com> Signed-off-by: George Dunlap <george.dunlap@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
George Dunlap [Thu, 10 Oct 2019 16:57:49 +0000 (17:57 +0100)]
x86/mm: Always retain a general ref on partial
In order to allow recursive pagetable promotions and demotions to be
interrupted, Xen must keep track of the state of the sub-pages
promoted or demoted. This is stored in two elements in the page struct:
nr_entries_validated and partial_flags.
The rule is that entries [0, nr_entries_validated) should always be
validated and hold a general reference count. If partial_flags is
zero, then [nr_entries_validated] is not validated and no reference
count is held. If PTF_partial_set is set, then [nr_entries_validated]
is partially validated.
At the moment, a distinction is made between promotion and demotion
with regard to whether the entry itself "holds" a general reference
count: when entry promotion is interrupted (i.e., returns -ERESTART),
the entry is not considered to hold a reference; when entry demotion
is interrupted, the entry is still considered to hold a general
reference.
PTF_partial_general_ref is used to distinguish between these cases.
If clear, it's a partial promotion => no general reference count held
by the entry; if set, it's partial demotion, so a general reference
count held. Because promotions and demotions can be interleaved, this
value is passed to get_page_and_type_from_mfn and put_page_from_l*e,
to be able to properly handle reference counts.
Unfortunately, because a refcount is not held, it is possible to
engineer a situation where PFT_partial_set is set but the page in
question has been assigned to another domain. A sketch is provided in
the appendix.
Fix this by having the parent page table entry hold a general
reference count whenever PFT_partial_set is set. (For clarity of
change, keep two separate flags. These will be collapsed in a
subsequent changeset.)
This has two basic implications. On the put_page_from_lNe() side,
this mean that the (partial_set && !partial_ref) case can never happen,
and no longer needs to be special-cased.
Secondly, because both flags are set together, there's no need to carry over
existing bits from partial_pte.
(NB there is still another issue with calling _put_page_type() on a
page which had PGT_partial set; that will be handled in a subsequent
patch.)
On the get_page_and_type_from_mfn() side, we need to distinguish
between callers which hold a reference on partial (i.e.,
alloc_lN_table()), and those which do not (new_cr3, PIN_LN_TABLE, and
so on): pass a flag if the type should be retained on interruption.
NB that since l1 promotion can't be preempted, that get_page_from_l2e
can't return -ERESTART.
This is part of XSA-299.
Reported-by: George Dunlap <george.dunlap@citrix.com> Signed-off-by: George Dunlap <george.dunlap@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
-----
* Appendix: Engineering PTF_partial_set while a page belongs to a
foreign domain
Suppose A is a page which can be promoted to an l3, and B is a page
which can be promoted to an l2, and A[x] points to B. B has
PGC_allocated set but no other general references.
V1: PIN_L3 A.
A is validated, B is validated.
A.type_count = 1 | PGT_validated | PGT_pinned
B.type_count = 1 | PGT_validated
B.count = 2 | PGC_allocated (A[x] holds a general ref)
V1: UNPIN A.
A begins de-validation.
Arrange to be interrupted when i < x
V1->old_guest_table = A
V1->old_guest_table_ref_held = false
A.type_count = 1 | PGT_partial
A.nr_validated_entries = i < x
B.type_count = 0
B.count = 1 | PGC_allocated
V2: MOD_L4_ENTRY to point some l4e to A.
Picks up re-validation of A.
Arrange to be interrupted halfway through B's validation
B.type_count = 1 | PGT_partial
B.count = 2 | PGC_allocated (PGT_partial holds a general ref)
A.type_count = 1 | PGT_partial
A.nr_validated_entries = x
A.partial_pte = PTF_partial_set
V3: MOD_L3_ENTRY to point some other l3e (not in A) to B.
Validates B.
B.type_count = 1 | PGT_validated
B.count = 2 | PGC_allocated ("other l3e" holds a general ref)
V3: MOD_L3_ENTRY to clear l3e pointing to B.
Devalidates B.
B.type_count = 0
B.count = 1 | PGC_allocated
V3: decrease_reservation(B)
Clears PGC_allocated
B.count = 0 => B is freed
B gets assigned to a different domain
V1: Restarts UNPIN of A
put_old_guest_table(A)
...
free_l3_table(A)
Now since A.partial_flags has PTF_partial_set, free_l3_table() will
call put_page_from_l3e() on A[x], which points to B, while B is owned
by another domain.
If A[x] held a general refcount for B on partial validation, as it does
for partial de-validation, then B would still have a reference count of
1 after PGC_allocated was freed; so B wouldn't be freed until after
put_page_from_l3e() had happend on A[x].
George Dunlap [Thu, 10 Oct 2019 16:57:49 +0000 (17:57 +0100)]
x86/mm: Have alloc_l[23]_table clear partial_flags when preempting
In order to allow recursive pagetable promotions and demotions to be
interrupted, Xen must keep track of the state of the sub-pages
promoted or demoted. This is stored in two elements in the page
struct: nr_entries_validated and partial_flags.
The rule is that entries [0, nr_entries_validated) should always be
validated and hold a general reference count. If partial_flags is
zero, then [nr_entries_validated] is not validated and no reference
count is held. If PTF_partial_set is set, then [nr_entries_validated]
is partially validated.
At the moment, a distinction is made between promotion and demotion
with regard to whether the entry itself "holds" a general reference
count: when entry promotion is interrupted (i.e., returns -ERESTART),
the entry is not considered to hold a reference; when entry demotion
is interrupted, the entry is still considered to hold a general
reference.
PTF_partial_general_ref is used to distinguish between these cases.
If clear, it's a partial promotion => no general reference count held
by the entry; if set, it's partial demotion, so a general reference
count held. Because promotions and demotions can be interleaved, this
value is passed to get_page_and_type_from_mfn and put_page_from_l*e,
to be able to properly handle reference counts.
Unfortunately, when alloc_l[23]_table check hypercall_preempt_check()
and return -ERESTART, they set nr_entries_validated, but don't clear
partial_flags.
If we were picking up from a previously-interrupted promotion, that
means that PTF_partial_set would be set even though
[nr_entries_validated] was not partially validated. This means that
if the page in this state were de-validated, put_page_type() would
erroneously be called on that entry.
Perhaps worse, if we were racing with a de-validation, then we might
leave both PTF_partial_set and PTF_partial_general_ref; and when
de-validation picked up again, both the type and the general ref would
be erroneously dropped from [nr_entries_validated].
In a sense, the real issue here is code duplication. Rather than
duplicate the interruption code, set rc to -EINTR and fall through to
the code which already handles that case correctly.
Given the logic at this point, it should be impossible for
partial_flags to be non-zero; add an ASSERT() to catch any changes.
This is part of XSA-299.
Reported-by: George Dunlap <george.dunlap@citrix.com> Signed-off-by: George Dunlap <george.dunlap@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
Make it easier to read by declaring the conditions in which we will
retain the ref, rather than the conditions under which we release it.
The only way (page == current->arch.old_guest_table) can be true is if
preemptible is true; so remove this from the query itself, and add an
ASSERT() to that effect on the opposite path.
No functional change intended.
NB that alloc_lN_table() mishandle the "linear pt failure" situation
described in the comment; this will be addressed in a future patch.
This is part of XSA-299.
Reported-by: George Dunlap <george.dunlap@citrix.com> Signed-off-by: George Dunlap <george.dunlap@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
George Dunlap [Thu, 10 Oct 2019 16:57:49 +0000 (17:57 +0100)]
x86/mm: Use flags for _put_page_type rather than a boolean
This is in mainly in preparation for _put_page_type taking the
partial_flags value in the future. It also makes it easier to read in
the caller (since you see a flag name rather than `true` or `false`).
No functional change intended.
This is part of XSA-299.
Reported-by: George Dunlap <george.dunlap@citrix.com> Signed-off-by: George Dunlap <george.dunlap@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
George Dunlap [Thu, 10 Oct 2019 16:57:49 +0000 (17:57 +0100)]
x86/mm: Separate out partial_pte tristate into individual flags
At the moment, partial_pte is a tri-state that contains two distinct bits
of information:
1. If zero, the pte at index [nr_validated_ptes] is un-validated. If
non-zero, the pte was last seen with PGT_partial set.
2. If positive, the pte at index [nr_validated_ptes] does not hold a
general reference count. If negative, it does.
To make future patches more clear, separate out this functionality
into two distinct, named bits: PTF_partial_set (for #1) and
PTF_partial_general_ref (for #2).
Additionally, a number of functions which need this information also
take other flags to control behavior (such as `preemptible` and
`defer`). These are hard to read in the caller (since you only see
'true' or 'false'), and ugly when many are added together. In
preparation for adding yet another flag in a future patch, collapse
all of these into a single `flag` variable.
NB that this does mean checking for what was previously the '-1'
condition a bit more ugly in the put_page_from_lNe functions (since
you have to check for both partial_set and general ref); but this
clause will go away in a future patch.
Also note that the original comment had an off-by-one error:
partial_flags (like partial_pte before it) concerns
plNe[nr_validated_ptes], not plNe[nr_validated_ptes+1].
No functional change intended.
This is part of XSA-299.
Reported-by: George Dunlap <george.dunlap@citrix.com> Signed-off-by: George Dunlap <george.dunlap@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
George Dunlap [Thu, 10 Oct 2019 16:57:49 +0000 (17:57 +0100)]
x86/mm: Don't re-set PGT_pinned on a partially de-validated page
When unpinning pagetables, if an operation is interrupted,
relinquish_memory() re-sets PGT_pinned so that the un-pin will
pickedup again when the hypercall restarts.
This is appropriate when put_page_and_type_preemptible() returns
-EINTR, which indicates that the page is back in its initial state
(i.e., completely validated). However, for -ERESTART, this leads to a
state where a page has both PGT_pinned and PGT_partial set.
This happens to work at the moment, although it's not really a
"canonical" state; but in subsequent patches, where we need to make a
distinction in handling between PGT_validated and PGT_partial pages,
this causes issues.
Move to a "canonical" state by:
- Only re-setting PGT_pinned on -EINTR
- Re-dropping the refcount held by PGT_pinned on -ERESTART
In the latter case, the PGT_partial bit will be cleared further down
with the rest of the other PGT_partial pages.
While here, clean up some trainling whitespace.
This is part of XSA-299.
Reported-by: George Dunlap <george.dunlap@citrix.com> Signed-off-by: George Dunlap <george.dunlap@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
George Dunlap [Thu, 10 Oct 2019 16:57:49 +0000 (17:57 +0100)]
x86/mm: L1TF checks don't leave a partial entry
On detection of a potential L1TF issue, most validation code returns
-ERESTART to allow the switch to shadow mode to happen and cause the
original operation to be restarted.
However, in the validation code, the return value -ERESTART has been
repurposed to indicate 1) the function has partially completed
something which needs to be undone, and 2) calling put_page_type()
should cleanly undo it. This causes problems in several places.
For L1 tables, on receiving an -ERESTART return from alloc_l1_table(),
alloc_page_type() will set PGT_partial on the page. If for some
reason the original operation never restarts, then on domain
destruction, relinquish_memory() will call free_page_type() on the
page.
Unfortunately, alloc_ and free_l1_table() aren't set up to deal with
PGT_partial. When returning a failure, alloc_l1_table() always
de-validates whatever it's validated so far, and free_l1_table()
always devalidates the whole page. This means that if
relinquish_memory() calls free_page_type() on an L1 that didn't
complete due to an L1TF, it will call put_page_from_l1e() on "page
entries" that have never been validated.
For L2+ tables, setting rc to ERESTART causes the rest of the
alloc_lN_table() function to *think* that the entry in question will
have PGT_partial set. This will cause it to set partial_pte = 1. If
relinqush_memory() then calls free_page_type() on one of those pages,
then free_lN_table() will call put_page_from_lNe() on the entry when
it shouldn't.
Rather than indicating -ERESTART, indicate -EINTR. This is the code
to indicate that nothing has changed from when you started the call
(which is effectively how alloc_l1_table() handles errors).
mod_lN_entry() shouldn't have any of these types of problems, so leave
potential changes there for a clean-up patch later.
This is part of XSA-299.
Reported-by: George Dunlap <george.dunlap@citrix.com> Signed-off-by: George Dunlap <george.dunlap@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
Jan Beulich [Thu, 31 Oct 2019 15:08:16 +0000 (16:08 +0100)]
x86/PV: check GDT/LDT limits during emulation
Accesses beyond the LDT limit originating from emulation would trigger
the ASSERT() in pv_map_ldt_shadow_page(). On production builds such
accesses would cause an attempt to promote the touched page (offset from
the present LDT base address) to a segment descriptor one. If this
happens to succeed, guest user mode would be able to elevate its
privileges to that of the guest kernel. This is particularly easy when
there's no LDT at all, in which case the LDT base stored internally to
Xen is simply zero.
Also adjust the ASSERT() that was triggering: It was off by one to
begin with, and for production builds we also better use
ASSERT_UNREACHABLE() instead with suitable recovery code afterwards.
This is XSA-298.
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com> Signed-off-by: Jan Beulich <jbeulich@suse.com> Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Andrew Cooper [Thu, 31 Oct 2019 15:07:11 +0000 (16:07 +0100)]
xen/hypercall: Don't use BUG() for parameter checking in hypercall_create_continuation()
Since c/s 1d429034 "hypercall: update vcpu_op to take an unsigned vcpuid",
which incorrectly swapped 'i' for 'u' in the parameter type list, guests have
been able to hit the BUG() in next_args()'s default case.
Correct these back to 'i'.
In addition, make adjustments to prevent this class of issue from occurring in
the future - crashing Xen is not an appropriate form of parameter checking.
Capitalise NEXT_ARG() to catch all uses, to highlight that it is a macro doing
non-function-like things behind the scenes, and undef it when appropriate.
Implement a bad_fmt: block which prints an error, asserts unreachable, and
crashes the guest.
On the ARM side, drop all parameter checking of p. It is asymmetric with the
x86 side, and akin to expecting memcpy() or sprintf() to check their src/fmt
parameter before use. A caller passing "" or something other than a string
literal will be obvious during code review.
This is XSA-296.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Acked-by: Julien Grall <julien.grall@arm.com>
Ross Lagerwall [Thu, 4 Feb 2016 16:40:56 +0000 (16:40 +0000)]
x86/livepatch: Fail the build if duplicate symbols exist
The binary diffing algorithm used by xen-livepatch depends on having unique
symbols.
The livepatch loading algorithm used by Xen resolves relocations by symbol
name, and thus also depends on having unique symbols.
Introduce CONFIG_ENFORCE_UNIQUE_SYMBOLS to control failing the build if
duplicate symbols are found, and disable it in the RANDCONFIG build.
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Release-acked-by: Juergen Gross <jgross@suse.com>
Andrew Cooper [Tue, 15 Oct 2019 08:57:31 +0000 (09:57 +0100)]
x86/nospec: Rename and rework l1tf-barrier as branch-harden
l1tf-barrier is an inappropriate name, and came about because of restrictions
on could be discussed publicly when the patches were proposed.
In practice, it is for general Spectre v1 mitigations, and is necessary in all
cases. An adversary which can control speculation in Xen can leak data in
cross-core (BCBS, etc) or remote (NetSpectre) scenarios - the problem is not
limited to just L1TF with HT active.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Release-acked-by: Juergen Gross <jgross@suse.com>
Just as with CONFIG_SPECULATIVE_HARDEN_ARRAY, branch hardening should be
configurable at compile time.
The previous CONFIG_HVM was a consequence of what could be discussed publicly
at the time the patches were submitted, and wasn't actually correct. Later
patches will make further corrections.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Release-acked-by: Juergen Gross <jgross@suse.com>
Andrew Cooper [Tue, 15 Oct 2019 09:14:51 +0000 (10:14 +0100)]
x86/nospec: Use always_inline to fix code gen for evaluate_nospec
evaluate_nospec() is incredibly fragile, and this is one giant bodge.
To correctly protect jumps, the generated code needs to be of the form:
cmp/test <cond>
jcc 1f
lfence
...
1: lfence
...
Critically, the lfence must be at the head of both basic blocks, later in the
instruction stream than the conditional jump in need of protection.
When the compiler chooses to out-of-line the condition calculation (e.g. by
not inlining a predicate), the code layout can end up as:
pred:
lfence
<calculate cond>
ret
call pred
cmp $0, %eax
jcc 1f
...
1: ...
which breaks the speculative safety, as the lfences are earlier in the
instruction stream than the jump in need of protection.
Any use of evaluate_nospec() needs all static inline predicates which use it
to be declared always_inline to prevent the optimiser having the flexibility
to generate unsafe code.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Acked-by: Jan Beulich <jbeulich@suse.com> Release-acked-by: Juergen Gross <jgross@suse.com>
Andrew Cooper [Thu, 24 Oct 2019 14:46:13 +0000 (15:46 +0100)]
x86/vtx: Fixes to Haswell/Broadwell LBR TSX errata
Cross reference and list all errata, now that they are published.
These errata are specific to Haswell/Broadwell. They should have model and
vendor checks, as Intel isn't the only vendor to implement VT-x.
All affected models use the same MSR indicies, so these can be hard coded
rather than looking up and storing constant values.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Reviewed-by: Kevin Tian <kevin.tian@intel.com> Release-acked-by: Juergen Gross <jgross@suse.com>
Andrew Cooper [Thu, 24 Oct 2019 14:40:42 +0000 (15:40 +0100)]
x86/vtx: Corrections to BDF93 errata workaround
At the time of fixing c/s 20f1976b44, no obvious errata had been published,
and BDF14 looked like the most obvious candidate. Subsequently, BDF93 has
been published and it is obviously this.
The erratum states that LER_TO_LIP is the only affected MSR. The provisional
fix in Xen adjusted LER_FROM_LIP, but this is not correct. The FROM MSRs are
intended to have TSX metadata, and for steppings with TSX enabled, it will
corrupt the value the guest sees, while for parts with TSX disabled, it is
redundant with FIXUP_TSX. Drop the LER_FROM_LIP adjustment.
Replace BDF14 references with BDF93, drop the redundant 'bdw_erratum_' prefix,
and use an Intel vendor check, as other vendors implement VT-x.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Reviewed-by: Kevin Tian <kevin.tian@intel.com> Release-acked-by: Juergen Gross <jgross@suse.com>
Petre Pircalabu [Mon, 28 Oct 2019 16:38:42 +0000 (18:38 +0200)]
tools/ocaml: Fix build error with Arch Linux
gcc (GCC) 9.2.0 complains:
xentoollog_stubs.c: In function ‘stub_xtl_ocaml_vmessage’:
xentoollog_stubs.c:93:16: error: initialization discards ‘const’ qualifier from pointer target type [-Werror=discarded-qualifiers]
93 | value *func = caml_named_value(xtl->vmessage_cb) ;
| ^~~~~~~~~~~~~~~~
This patch constifies the pointer returned by caml_named_value in order
to the accommodate newer versions of OCaml.
In OCaml >= 4.09 the return value pointer of caml_named_value is
declared const.
Previously, defaulting and checking of some aspects of the domain
config was skipped for stub dms. This has been the case forever.
In ad011ad08843 "libxl/xl: Overhaul passthrough setting logic" some
defaulting that was needed for stub dms was moved from
libxl__domain_create_info_setdefault to .._config_setdefault with the
result that for stub dms, libxl__domain_make fails with this
assertion:
xl: libxl_create.c:582: libxl__domain_make: Assertion
`info->passthrough != LIBXL_PASSTHROUGH_DEFAULT' failed.
Fix this by properly doing all defaulting and all checking for stub
dms. This is more correct, but (especially at this stage of the
release) it is necessary to more closely evaluate the effects by
reviewing the body of _config_setdefault. The changes are as follows:
One actual functional change:
* The new passthrough defaulting is properly done. This is what we
are trying to actually fix here.
And a lot of things that make no difference:
* shadow_memkb would now be set. Whether this would be correct is not
entirely clear. It seems better to make this patch (whose purpose
is to fix the passthrough defaulting) *not* include that semantic
change, so here I have included a hunk to explicitly override this.
* FLASK ssid_label is processed. But the actual ssidref is copied
from the guest domain by spawn_stub_dm, and ssid_label is set to
NULL. So no change.
* We set iommu_memkb. But to 0 since passthrough is disabled.
* cpuid pool_name is processed. But this is not set by
spawn_stub_dm. (Arguably this is a bug: stub dms should inherit the
parent cpupool.) The effect is to leave poolid set to 0 and call
libxl_cpupoolid_is_valid but that always succeeds for 0. So no
change.
* Various extra checks are done: reject PCI passthrough for HVM with
POD (stub dm is PV); reject pod + vnuma, or PV + vnuma (stub dm has
no vnuma); reject nested HVM or pod, with alt2pm-hvm (again, stub dm
is PV). So these checks will always pass.
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com> Release-acked-by: Juergen Gross <jgross@suse.com> Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
Ian Jackson [Mon, 28 Oct 2019 12:04:04 +0000 (12:04 +0000)]
libxl: domain_config_setdefault: Document use of domid
We are going to want to call this from a site which has a domid which
is good for logging but not the domid of the domain we are creating
(namely, the stub device domain).
Consequently, add the same comment to
libxl__arch_passthrough_mode_setdefault.
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com> Release-acked-by: Juergen Gross <jgross@suse.com> Acked-by: Anthony PERARD <anthony.perard@citrix.com>
xen/arm: platform: fix Raspberry Pi compatible string
Both upstream [1] and downstream [2] Linux kernels use "brcm,bcm2711"
as the compatible string for Raspberry Pi 4. Add this string to our
platform compatible list.
The brcm,bcm2838 convention is abandoned. Remove it.
Rename the variables within the file to a rpi4_* prefix since the file
is meant to cover the Raspberry Pi 4 platform.
If you are using a device tree with the old compatible string
brcm,bcm2838, you will need to upgrade your device tree to one that has
the new brcm,bcm2711 compatible string.
efi: use directmap to access runtime services table
Do not require switching page tables to access (static) information in
the runtime services table itself, use directmap for this. This allows
exiting early from XEN_EFI_query_capsule_capabilities,
XEN_EFI_update_capsule and XEN_EFI_query_variable_info (in case of not
supported call) without all the impact of page table switch.
Suggested-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Release-acked-by: Juergen Gross <jgross@suse.com>
Some UEFI implementations are not happy about lack of
SetVirtualAddressMap() call. Likely abuse the address map change
notification to do things beyond the necessary ConvertPointer() calls.
Specifically, wihtout the SetVirtualAddressMap() call, some access
EfiBootServices{Code,Data}, or even totally unmapped areas. Example
crash of GetVariable() call on Thinkpad W540:
****************************************
Panic on CPU 0:
FATAL PAGE FAULT
[error_code=0002]
Faulting linear address: ffffffff858483a1
****************************************
Fix this by calling SetVirtualAddressMap() runtime service, giving it
1:1 map for areas marked as needed during runtime. The address space in
which EFI runtime services are called is unchanged, but UEFI view of it
may be.
Since it's fairly late in Xen 4.13 development cycle, disable it
by default and hide behind EXPERT.
Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Release-acked-by: Juergen Gross <jgross@suse.com>
efi: remove old SetVirtualAddressMap() arrangement
Remove unused (#ifdef-ed out) code. Reviving it in its current shape
won't fly because:
- SetVirtualAddressMap() needs to be called with 1:1 mapping, which
isn't the case at this time
- it uses directmap, which may go away soon
- it uses directmap, which is mapped with NX, breaking EfiRuntimeServicesCode
No functional change.
Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> Acked-by: Jan Beulich <jbeulich@suse.com> Release-acked-by: Juergen Gross <jgross@suse.com>
Andrew Cooper [Thu, 24 Oct 2019 17:19:20 +0000 (18:19 +0100)]
x86/VT-d: Misc initialisation cleanup
* Initialise all spinlock fields together
* No need for an atomic set_bit() to initialise domid_bitmap
* Avoid using partial-line printk()'s.
* Style fixes (too many, and too few spaces)
No functional change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Kevin Tian <kevin.tian@intel.com> Release-acked-by: Juergen Gross <jgross@suse.com>
Roger Pau Monné [Fri, 25 Oct 2019 14:03:32 +0000 (16:03 +0200)]
iommu: translate IO-APIC pins when enabling interrupt remapping
On Intel hardware there's currently no translation of already enabled
IO-APIC pins when interrupt remapping is enabled on the IOMMU, hence
introduce a logic similar to the one used in x2apic_bsp_setup in order
to save and mask all IO-APIC pins, and then translate and restore them
after interrupt remapping has been enabled.
With this change the AMD specific logic to deal with enabled pins
(amd_iommu_setup_ioapic_remapping) can be removed, thus unifying the
handling of IO-APIC when enabling interrupt remapping regardless of
the IOMMU vendor.
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Release-acked-by: Juergen Gross <jgross@suse.com>
Roger Pau Monné [Fri, 25 Oct 2019 14:00:10 +0000 (16:00 +0200)]
x2APIC: translate IO-APIC entries when enabling the IOMMU
When interrupt remapping is enabled as part of enabling x2APIC the
IO-APIC entries also need to be translated to the new format and added
to the interrupt remapping table.
This prevents IOMMU interrupt remapping faults when booting on
hardware that has unmasked IO-APIC pins.
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Release-acked-by: Juergen Gross <jgross@suse.com>
Roger Pau Monné [Fri, 25 Oct 2019 13:59:34 +0000 (15:59 +0200)]
x2APIC: simplify resume
There's no need to save and restore the IO-APIC entries, the entries
prior to suspension have already been saved by ioapic_suspend, and
will be restored by ioapic_resume. Note that at the point where
resume_x2apic gets called the IO-APIC has not yet resumed, and hence
all entries should be masked.
Note this shouldn't introduce any functional change.
Suggested-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Tested-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Release-acked-by: Juergen Gross <jgross@suse.com>
Jan Beulich [Fri, 25 Oct 2019 08:40:12 +0000 (10:40 +0200)]
MAINTAINERS: correct description of M:
Let's reflect reality, its use by add_maintainers.pl / get_maintainer.pl,
as well as what
https://wiki.xenproject.org/wiki/Submitting_Xen_Project_Patches says.
Signed-off-by: Jan Beulich <jbeulich@suse.com> Acked-by: George Dunlap <george.dunlap@citrix.com> Acked-by: Wei Liu <wl@xen.org> Release-acked-by: Juergen Gross <jgross@suse.com>
Jan Beulich [Fri, 25 Oct 2019 08:38:58 +0000 (10:38 +0200)]
x86: fix off-by-one in is_xen_fixed_mfn()
__2M_rwdata_end marks the first byte after the Xen image, not its last
byte. Subtract 1 to obtain the upper bound to compare against. (Note
that instead switching from <= to < is less desirable, as in principle
__pa() might return rubbish for addresses outside of the Xen image.)
Since the & needs to be dropped from the line in question, also drop it
from the adjacent one.
Reported-by: Julien Grall <julien.grall@arm.com> Signed-off-by: Jan Beulich <jbeulich@suse.com> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> Release-acked-by: Juergen Gross <jgross@suse.com>
Ian Jackson [Mon, 7 Oct 2019 16:59:15 +0000 (17:59 +0100)]
libxl/xl: Overhaul passthrough setting logic
LIBXL_PASSTHROUGH_UNKNOWN (aka "ENABLED" in an earlier uncommitted
version of this code) is doing double duty. We actually need all of
the following to be specifiable:
* "default": enable PT iff we have devices to
pass through specified in the initial config file.
* "enabled" (and fail if the platform doesn't support it).
* "disabled" (and reject future PT hotplug).
* "share_pt"/"sync_pt": enable PT and set a specific PT mode.
Defaulting and error checking should be done in libxl. So, we make
several changes here.
We introduce "enabled", and rename "unknown" to "default".
We move all of the error checking and defaulting code from xl into
libxl. Now, libxl__domain_config_setdefault has all of the necessary
information to get this right. So we can do it all there. Choosing
the specific mode is arch-specific.
We can also arrange to have only one place each which calculates
(i) whether passthrough needs to be enabled because pt devices were
specified (ii) whether pt_share can be used (for each arch).
xl now only has to parse the enum in the same way as it parses all
other enums.
This change fixes a regression from earlier 4.13-pre: until recent
changes, passthrough was only enabled by default if passthrough
devices were specified. We restore this behaviour.
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com> CC: Stefano Stabellini <sstabellini@kernel.org> CC: Julien Grall <julien@xen.org> CC: Volodymyr Babchuk <Volodymyr_Babchuk@epam.com> CC: Andrew Cooper <Andrew.Cooper3@citrix.com> CC: Paul Durrant <pdurrant@gmail.com> CC: Jan Beulich <jbeulich@suse.com> Release-acked-by: Juergen Gross <jgross@suse.com> Acked-by: Anthony PERARD <anthony.perard@citrix.com>
Ian Jackson [Fri, 11 Oct 2019 16:16:44 +0000 (17:16 +0100)]
libxl: Move domain_create_info_setdefault earlier
We need this before we start to figure out the passthrough mode.
I have checked that nothing in libxl__domain_create_info_setdefault
nor the two implementations of ..._arch_... accesses anything else,
other than (i) the domain type (which this function is responsible for
setting and nothing before it looks at) (ii) c_info->ssidref (which is
defaulted by flask code near the top of
libxl__domain_config_setdefault and not accessed afterwards).
So no functional change.
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com> Acked-by: Anthony PERARD <anthony.perard@citrix.com> Release-acked-by: Juergen Gross <jgross@suse.com>
Ian Jackson [Fri, 4 Oct 2019 14:36:59 +0000 (15:36 +0100)]
libxl: Remove/deprecate libxl_get_required_*_memory from the API
These are now redundant because shadow_memkb and iommu_memkb are now
defaulted automatically by libxl_domain_need_memory and
libxl_domain_create etc. Callers should not now call these; instead,
they should just let libxl take care of it.
libxl_get_required_shadow_memory was introduced in f89f555827a6
"remove late (on-demand) construction of IOMMU page tables"
We can freely remove it because it was never in any release.
libxl_get_required_shadow_memory has been in libxl approximately
forever. It should probably not have survived the creation of
libxl_domain_create, but it seems the API awkwardnesses we see in
recent commits prevented this. So we have to keep it. It remains
functional but we can deprecate it. Hopefully we can get rid of it
completely before we find the need to change the calculation to use
additional information which its arguments do not currently supply.
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com> Acked-by: Anthony PERARD <anthony.perard@citrix.com> Release-acked-by: Juergen Gross <jgross@suse.com>
Ian Jackson [Fri, 4 Oct 2019 10:45:59 +0000 (11:45 +0100)]
libxl: Move shadow_memkb and iommu_memkb defaulting into libxl
Defaulting is supposed to be done by libxl. So these calculations
should be here in libxl. libxl__domain_config_setdefault has all the
necessary information including the values of max_memkb and max_vcpus.
The overall functional effect depends on the caller:
For xl, no change. The code moves from xl to libxl.
For callers who set one or both shadow_memkb and iommu_memkb (whether
from libxl_get_required_shadow_memory or otherwise) before calling
libxl_domain_need_memory (any version): the new code will leave their
setting(s) unchanged.
For callers who do not call libxl_domain_need_memory at all, and who
fail to set one of these memory values: now they are both are properly
set. The shadow and iommu memory to be properly accounted for as
intended.
For callers which call libxl_domain_need_memory and request the
current API (4.13) or which track libxl, the default values are also
now right and everything works as intended.
For callers which call libxl_domain_need_memory, and request an old
pre-4.13 libxl API, and which leave one of these memkb settings unset,
we take special measures to preserve the old behaviour.
This means that they don't get the additional iommu memory and are at
risk of the domain running out of memory as a result of f89f555827a6
"remove late (on-demand) construction of IOMMU page tables". But this
is no worse than the state just after f89f555827a6, which already
broke such callers in that way. This is perhaps justifiable because
of the API stability warning next to libxl_domain_need_memory.
An alternative would be to drop the special-casing of these callers.
That would cause a discrepancy between libxl_domain_need_memory and
libxl_domain_create: the former would not include the iommu memory and
the latter would. That seems worse, but it's debateable.
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com> Reviewed-by: Anthony PERARD <anthony.perard@citrix.com> Release-acked-by: Juergen Gross <jgross@suse.com>
Ian Jackson [Thu, 3 Oct 2019 15:58:32 +0000 (16:58 +0100)]
libxl: libxl_domain_need_memory: Make it take a domain_config
This should calculate the extra memory needed for shadow and iommu,
the defaults for which depend on values in c_info. So we need this to
have the complete domain config available.
And the defaults should actually be updated and stored. So make it
non-const.
We provide the usual kind of compatibility function for callers
expecting 4.12 and earlier. This function becomes responsible for the
clone-and-modify of the b_info.
No overall functional change for external libxl callers which use the
API version system to request a particular API version.
Other external libxl callers will need to update their calling code,
and will then find that the new version of this function fills in most
of the defaults in d_config. Because libxl__domain_config_setdefault
doesn't quite do all of the defaults, that's only partial. For
present purposes that doesn't matter because none of the missing
settings are used by the memory calculations. It does mean we need to
document in the API spec that the defaulting is only partial.
This lack of functional change is despite the fact that
numa_place_domain now no longer calls
libxl__domain_build_info_setdefault (via libxl_domain_need_memory).
That is OK because it's idempotent and numa_place_domain's one call
site is libxl__build_pre which is called from libxl__domain_build
which is called from domcreate_bootloader_done, well after the
defaults are set by initiate_domain_create.
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com> Reviewed-by: Anthony PERARD <anthony.perard@citrix.com> Release-acked-by: Juergen Gross <jgross@suse.com>
Ian Jackson [Thu, 3 Oct 2019 16:31:15 +0000 (17:31 +0100)]
libxl: libxl__domain_config_setdefault: New function
Break out this into a new function. We are going to want to call it
from a new call site.
Unfortunately not all of the defaults can be moved into the new
function without changing the order in which things are done. That
does not seem wise at this stage of the release. The effect is that
additional calls to libxl__domain_config_setdefault (which are going
to be introduced) do not quite set everything. But they will do what
is needed. After Xen 4.13 is done, we should move those settings into
the right order.
No functional change.
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com> Reviewed-by: Anthony PERARD <anthony.perard@citrix.com> Release-acked-by: Juergen Gross <jgross@suse.com>
Ian Jackson [Thu, 3 Oct 2019 16:06:43 +0000 (17:06 +0100)]
xl: Pass libxl_domain_config to freemem(), instead of b_info
We are going to change the libxl API in a moment and this change will
make it simpler.
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com> Reviewed-by: Anthony PERARD <anthony.perard@citrix.com> Release-acked-by: Juergen Gross <jgross@suse.com>
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