Anthony PERARD [Thu, 1 Dec 2022 15:14:59 +0000 (16:14 +0100)]
tools/include: fix clean and rework COPYING for installed Xen public header
Use actual include directory used to install the public header in
COPYING file.
Also, move the input file out of "tools/include/xen/" because that
directory is removed on `make clean`.
We can't used ./configure because $includedir contain another
variable, so the change is done in Makefile.
Fixes: 4ea75e9a9058 ("Rework COPYING installed in /usr/include/xen/, due to several licences") Signed-off-by: Anthony PERARD <anthony.perard@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
Michal Orzel [Fri, 18 Nov 2022 11:45:54 +0000 (12:45 +0100)]
docs/misc/arm: Update references to Linux kernel docs
Some time ago, Linux switched the format of docs to ReST and the format
of device-tree bindings to json-schema.
Signed-off-by: Michal Orzel <michal.orzel@amd.com> Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Andrew Cooper [Thu, 24 Nov 2022 02:50:40 +0000 (10:50 +0800)]
Changelog: Add __ro_after_init and CET
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Signed-off-by: Henry Wang <Henry.Wang@arm.com> Reviewed-by: Roger Pau Monné <roger.pau@citrix.com> Reviewed-by: Julien Grall <jgrall@amazon.com>
Andrew Cooper [Mon, 21 Nov 2022 12:46:39 +0000 (12:46 +0000)]
xen/flask: Wire up XEN_DOMCTL_{get,set}_paging_mempool_size
These were overlooked in the original patch, and noticed by OSSTest which does
run some Flask tests.
Fixes: 22b20bd98c02 ("xen: Introduce non-broken hypercalls for the paging mempool size") Suggested-by: Daniel Smith <dpsmith@apertussolutions.com> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Jason Andryuk <jandryuk@gmail.com> Acked-by: Daniel P. Smith <dpsmith@apertussolutions.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Andrew Cooper [Fri, 18 Nov 2022 16:53:45 +0000 (16:53 +0000)]
tools/libxl: Fixes to libxl__domain_set_paging_mempool_size()
The error message accidentally printed the bytes value as if it were kB.
Furthermore, both b_info.shadow_memkb and shadow_mem are uint64_t, meaning
there is a risk of overflow if the user specified a stupidly large value in
the vm.cfg file. Check and reject such a condition.
Fixes: 7c3bbd940dd8 ("xen/arm, libxl: Revert XEN_DOMCTL_shadow_op; use p2m mempool hypercalls") Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Anthony PERARD <anthony.perard@citrix.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Commit 34990446ca91 started to overwrite the `rc` value from
libxl__arch_domain_create(), thus error aren't propagated anymore.
Check `rc` value before doing the next thing.
Fixes: 34990446ca91 ("libxl: don't ignore the return value from xc_cpuid_apply_policy") Reported-by: Andrew Cooper <andrew.cooper3@citrix.com> Signed-off-by: Anthony PERARD <anthony.perard@citrix.com> Reviewed-by: Jason Andryuk <jandryuk@gmail.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Roger Pau Monné [Mon, 21 Nov 2022 11:21:51 +0000 (12:21 +0100)]
efifb: ignore frame buffer with invalid configuration
On one of my boxes when the HDMI cable is not plugged in the
FrameBufferBase of the EFI_GRAPHICS_OUTPUT_PROTOCOL_MODE structure is
set to 0 by the firmware (while some of the other fields looking
plausible).
Such (bogus address) ends up mapped in vesa_init(), and since it
overlaps with a RAM region the whole system goes down pretty badly,
see:
(XEN) vesafb: framebuffer at 0x0000000000000000, mapped to 0xffff82c000201000, using 35209k, total 35209k
(XEN) vesafb: mode is 0x37557x32, linelength=960, font 8x16
(XEN) vesafb: Truecolor: size=8:8:8:8, shift=24:0:8:16
(XEN) (XEN) (XEN) (XEN) (XEN) (XEN) (XEN) (XEN) �ERROR: Class:0; Subclass:0; Operation: 0
ERROR: No ConOut
ERROR: No ConIn
Do like Linux and prevent using the EFI Frame Buffer if the base
address is 0. This is inline with the logic in Linuxes
fb_base_is_valid() function at drivers/video/fbdev/efifb.c v6.0.9.
Andrew Cooper [Thu, 20 Oct 2022 11:14:30 +0000 (12:14 +0100)]
xen/arm: Correct the p2m pool size calculations
Allocating or freeing p2m pages doesn't alter the size of the mempool; only
the split between free and used pages.
Right now, the hypercalls operate on the free subset of the pool, meaning that
XEN_DOMCTL_get_paging_mempool_size varies with time as the guest shuffles its
physmap, and XEN_DOMCTL_set_paging_mempool_size ignores the used subset of the
pool and lets the guest grow unbounded.
This fixes test-pagign-mempool on ARM so that the behaviour matches x86.
This is part of XSA-409 / CVE-2022-33747.
Fixes: cbea5a1149ca ("xen/arm: Allocate and free P2M pages from the P2M pool") Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Julien Grall <jgrall@amazon.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
First of all, with ARM borrowing x86's implementation, the logic to set the
pool size should have been common, not duplicated. Introduce
libxl__domain_set_paging_mempool_size() as a shared implementation, and use it
from the ARM and x86 paths. It is left as an exercise to the reader to judge
how libxl/xl can reasonably function without the ability to query the pool
size...
Remove ARM's p2m_domctl() infrastructure now the functioanlity has been
replaced with a working and unit tested interface.
This is part of XSA-409 / CVE-2022-33747.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> Reviewed-by: Anthony PERARD <anthony.perard@citrix.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Andrew Cooper [Thu, 20 Oct 2022 11:13:46 +0000 (12:13 +0100)]
tools/tests: Unit test for paging mempool size
Exercise some basic functionality of the new
xc_{get,set}_paging_mempool_size() hypercalls.
This passes on x86, but fails currently on ARM. ARM will be fixed up in
future patches.
This is part of XSA-409 / CVE-2022-33747.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Acked-by: Jan Beulich <jbeulich@suse.com> Acked-by: Anthony PERARD <anthony.perard@citrix.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Andrew Cooper [Fri, 21 Oct 2022 13:13:00 +0000 (14:13 +0100)]
xen: Introduce non-broken hypercalls for the paging mempool size
The existing XEN_DOMCTL_SHADOW_OP_{GET,SET}_ALLOCATION have problems:
* All set_allocation() flavours have an overflow-before-widen bug when
calculating "sc->mb << (20 - PAGE_SHIFT)".
* All flavours have a granularity of 1M. This was tolerable when the size of
the pool could only be set at the same granularity, but is broken now that
ARM has a 16-page stopgap allocation in use.
* All get_allocation() flavours round up, and in particular turn 0 into 1,
meaning the get op returns junk before a successful set op.
* The x86 flavours reject the hypercalls before the VM has vCPUs allocated,
despite the pool size being a domain property.
* Even the hypercall names are long-obsolete.
Implement a better interface, which can be first used to unit test the
behaviour, and subsequently correct a broken implementation. The old
interface will be retired in due course.
The unit of bytes (as opposed pages) is a deliberate API/ABI improvement to
more easily support multiple page granularities.
This is part of XSA-409 / CVE-2022-33747.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> Reviewed-by: Jan Beulich <jbeulich@suse.com> Acked-by: Anthony PERARD <anthony.perard@citrix.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Andrew Cooper [Mon, 14 Nov 2022 21:47:59 +0000 (21:47 +0000)]
x86/hvm: Revert per-domain APIC acceleration support
I was really hoping to avoid this, but its now too late in the 4.17 freeze and
we still don't have working fixes.
The in-Xen calculations for assistance capabilities are buggy. For the
avoidance of doubt, the original intention was to be able to control every
aspect of a APIC acceleration so we could comprehensively test Xen's support,
as it has proved to be buggy time and time again.
Even after a protracted discussion on what the new API ought to mean, attempts
to apply it to the existing logic have been unsuccessful, proving that the
API/ABI is too complicated for most people to reason about.
leaving in place the non-APIC specific changes (minimal as they are).
This takes us back to the behaviour of Xen 4.16 where APIC acceleration is
configured on a per system basis.
This work will be revisted in due course.
Fixes: 2ce11ce249a3 ("x86/HVM: allow per-domain usage of hardware virtualized APIC") Fixes: 6b2b9b340509 ("x86: report Interrupt Controller Virtualization capabilities") Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Acked-by: Jan Beulich <jbeulich@suse.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Anthony PERARD [Thu, 3 Nov 2022 11:52:04 +0000 (11:52 +0000)]
xen: Used SPDX identifier in public headers
The text of the licence has been check to be the same as the one at
https://spdx.org/licenses/MIT.html, except we don't have "(including
the next paragraph)".
Mecanical change done with a script.
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com> Reviewed-by: Juergen Gross <jgross@suse.com> Acked-by: Jan Beulich <jbeulich@suse.com> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Anthony PERARD [Thu, 3 Nov 2022 11:52:03 +0000 (11:52 +0000)]
Rework COPYING installed in /usr/include/xen/, due to several licences
The notice in the COPYING file in "xen/include/public/COPYING" doesn't
really apply to the files that ultimately are been install at
"/usr/include/xen". The issue are headers in the "sys/" subdirectory
that comes from other projects such as Linux or FreeBSD.
The main issue is that there are two headers that have a different
licence than the MIT licence:
- xen-sys/Linux/gntalloc.h (installed as "sys/gntalloc.h") is public
domain.
- xen-sys/FreeBSD/gntdev.h (installed as "sys/gntdev.h") is BSD-2.
To clarify this, we'll install a COPYING file with a different notice.
Reported-by: Andrew Cooper <Andrew.Cooper3@citrix.com> Signed-off-by: Anthony PERARD <anthony.perard@citrix.com> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Anthony PERARD [Thu, 3 Nov 2022 11:52:02 +0000 (11:52 +0000)]
xen: Add licence header to device_tree_defs.h
This header have been created by moving code from other part of the
project and miss a licence header. The original source code was some
version of GPL or LGPL but we intend to have the public header to be
MIT so they can be included easily in other projects.
Part of device_tree_defs.h were moved from libxl_arm.c which is
LGPL-2.1-only. And part were moved from device_tree.h that is
GPL-2.0-only.
Part of the original code were added by Julien Grall @ Linaro in
commits c3ba52a84dd8 and 405c167f0ec9 and 886f34045bf0. The other part
were added by Ian Campbell @ Citrix, with commit 0c64527e7fc9.
Resolves: xen-project/xen#35 Fixes: 1c898a9fec7e ("xen/arm: move a few DT related defines to public/device_tree_defs.h") Reported-by: Andrew Cooper <Andrew.Cooper3@citrix.com> Signed-off-by: Anthony PERARD <anthony.perard@citrix.com> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> [Citrix relicensing] Acked-by: Grant Likely <grant.likely@linaro.org> [Linaro relicensing] Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Anthony PERARD [Thu, 3 Nov 2022 11:52:01 +0000 (11:52 +0000)]
tools/include/xen-foreign: Add SPDX identifier to generated headers
The headers install in "/usr/include/xen/foreign/" are missing a
licence header. This patch adds a SPDX identifier to clarify that
the MIT licence is used.
The script now check that the licence of the input file is also MIT,
by checking for the presence of the SPDX identifier.
Also add information about which files are used to generate the
headers.
Reported-by: Andrew Cooper <Andrew.Cooper3@citrix.com> Signed-off-by: Anthony PERARD <anthony.perard@citrix.com> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Anthony PERARD [Thu, 3 Nov 2022 11:52:00 +0000 (11:52 +0000)]
xen: Used SPDX identifier in some public headers
The script "tools/include/xen-foreign/mkheader.py" is going to do a
sanity check on the licences of these headers. To ease this, we will
replace the verbatim copy of the MIT licence by its SPDX identifier
equivalent.
The text of the licence has been check to be the same as the one at
https://spdx.org/licenses/MIT.html, except we don't have "(including
the next paragraph)". The text is also the same as the one in
"xen/include/public/COPYING".
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com> Acked-by: Jan Beulich <jbeulich@suse.com> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Anthony PERARD [Thu, 3 Nov 2022 11:51:59 +0000 (11:51 +0000)]
xen: Add licence information to public/errno.h
Fixes: 81f559e97974 ("make error codes a formal part of the ABI") Reported-by: Andrew Cooper <Andrew.Cooper3@citrix.com> Signed-off-by: Anthony PERARD <anthony.perard@citrix.com> Acked-by: Jan Beulich <jbeulich@suse.com> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Andrew Cooper [Mon, 14 Nov 2022 21:41:08 +0000 (21:41 +0000)]
x86/spec-ctrl: Fill in whitepaper URL
... now that we a link available.
Fixes: 9deaf2d932f0 ("x86/spec-ctrl: Enable Zen2 chickenbit") Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Acked-by: Jan Beulich <jbeulich@suse.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
We use CC-BY-4.0 for many of the documents under docs/ so we should have
a copy of the license.
Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Roger Pau Monne [Tue, 15 Nov 2022 13:26:56 +0000 (14:26 +0100)]
amd: remove VIRT_SC_MSR_HVM synthetic feature
With the previous bugfix, X86_FEATURE_VIRT_SC_MSR_HVM is no longer
needed and can be replaced with an __initdata variable. This also
leaves asm/cpufeatures.h as it was in 4.16 which will simplify
backports.
No functional change intended.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Rewrite commit message. Move amd_virt_spec_ctrl into __initdata.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Roger Pau Monne [Tue, 15 Nov 2022 13:26:55 +0000 (14:26 +0100)]
amd/virt_ssbd: set SSBD at vCPU context switch
This fixes an issue with running C code in a GIF=0 region, that's
problematic when using UBSAN or other instrumentation techniques.
The current logic for AMD SSBD context switches it on every
vm{entry,exit} if the Xen and guest selections don't match. This is
expensive when not using SPEC_CTRL, and hence should be avoided as
much as possible.
When SSBD is not being set from SPEC_CTRL on AMD don't context switch
at vm{entry,exit} and instead only context switch SSBD when switching
vCPUs. This has the side effect of running Xen code with the guest
selection of SSBD, the documentation is updated to note this behavior.
Also note that then when `ssbd` is selected on the command line guest
SSBD selection will not have an effect, and the hypervisor will run
with SSBD unconditionally enabled when not using SPEC_CTRL itself.
As a result of no longer running the code to set SSBD in a GIF=0
region the locking of amd_set_legacy_ssbd() can be done using normal
spinlocks, and some more checks can be added to assure it works as
intended.
Finally it's also worth noticing that since the guest SSBD selection
is no longer set on vmentry the VIRT_SPEC_MSR handling needs to
propagate the value to the hardware as part of handling the wrmsr.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
Extend the msrs->virt_spec_ctrl context switching comment.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
xen/arm: vGICv3: Restore the interrupt state correctly
As "spin_lock_irqsave(&v->arch.vgic.lock, flags)" saves the current interrupt
state in "flags", "spin_unlock_irqrestore(&v->arch.vgic.lock, flags)" should be
used to restore the saved interrupt state.
Fixes: fe7fa1332dabd9ce4 ("ARM: vGICv3: handle virtual LPI pending and property tables") Signed-off-by: Ayan Kumar Halder <ayankuma@amd.com> Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com> Reviewed-by: Andre Przywara <andre.przywara@arm.com> Acked-by: Julien Grall <jgrall@amazon.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Luca Fancellu [Wed, 9 Nov 2022 14:04:20 +0000 (14:04 +0000)]
arm: fix Kconfig symbol dependency on arm features
The commit 3c2a14ea81c7 is introducing some unsupported arm features
that by default are disabled and are used for the cpufeature.c code.
As they are disabled by default, a typo in the Kconfig symbol they
depend on has landed in the codebase unnoticed, instead of depending
on ARM64 which does not exist, fix the code to depend on ARM_64 that
is the intended symbol.
Fixes: 3c2a14ea81c7 ("arm: Define kconfig symbols used by arm64 cpufeatures") Signed-off-by: Luca Fancellu <luca.fancellu@arm.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com> Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com>
Jan Beulich [Mon, 7 Nov 2022 15:09:13 +0000 (16:09 +0100)]
kexec: restore hypercall 1st arg's type
This reverts a small part of 7e21b25059ed ("xen: harmonize return types
of hypercall handlers"). The change from "unsigned long" to "unsigned
int" for the native handler function meant that previously invalid
values became valid. While perhaps not a significant issue, strictly
speaking that's still a change to the ABI. Don't go as far as restoring
the compat entry point's type though: That one can't have values passed
which don't fit in 32 bits.
Note that as a side effect this fixes the invocation of
hypercall_create_continuation(), which by mistake wasn't adjusted by the
earlier change.
Also take the opportunity and correct the respective comment in the
public header. (The way it was it really supports that it probably was
pointless to use "long", but that's the way the hypercall was
introduced.)
Requested-by: Andrew Cooper <andrew.cooper3@citrix.com> Signed-off-by: Jan Beulich <jbeulich@suse.com> Reviewed-by: Juergen Gross <jgross@suse.com> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
The dumping of stacks for HVM guests is problematic, since it requires
taking the p2m lock in order to walk the guest page tables and the p2m.
The suggested solution to the issue is to introduce and use a lockless p2m
walker, that relies on being executed with interrupts disabled in order to
prevent any p2m pages from being freed while doing the walk.
Note that modifications of p2m entries are already done atomically in order
to prevent the hardware walker from seeing partially updated values.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Juergen Gross [Wed, 9 Nov 2022 09:48:59 +0000 (10:48 +0100)]
tools/hotplug: fix systemd unit dependencies
Commit 1283af6465cd ("tools/xenstore: remove XEN_LIB_STORED and
XENSTORED_ROOTDIR") removed the systemd file var-lib-xenstored.mount
without removing dependencies to this file.
Fixes: 1283af6465cd ("tools/xenstore: remove XEN_LIB_STORED and XENSTORED_ROOTDIR") Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Anthony PERARD <anthony.perard@citrix.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Edwin Török [Wed, 9 Nov 2022 09:48:33 +0000 (10:48 +0100)]
tools/ocaml/xenstored/store.ml: fix build error
Building with Dune in release mode fails with:
```
File "ocaml/xenstored/store.ml", line 464, characters 13-32:
Warning 18: this type-based record disambiguation is not principal.
File "ocaml/xenstored/store.ml", line 1:
Error: Some fatal warnings were triggered (1 occurrences)
```
This is a warning to help keep the code futureproof, quoting from its
documentation:
> Check information path during type-checking, to make sure that all types are
> derived in a principal way. When using labelled arguments and/or polymorphic
> methods, this flag is required to ensure future versions of the compiler will
> be able to infer types correctly, even if internal algorithms change. All
> programs accepted in -principal mode are also accepted in the default mode with
> equivalent types, but different binary signatures, and this may slow down type
> checking; yet it is a good idea to use it once before publishing source code.
Fixes: db471408edd46 "tools/ocaml/xenstored: Fix quota bypass on domain shutdown" Signed-off-by: Edwin Török <edvin.torok@citrix.com> Acked-by: Christian Lindig <christian.lindig@citrix.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Andrew Cooper [Tue, 14 Jun 2022 15:18:36 +0000 (16:18 +0100)]
x86/spec-ctrl: Mitigate IBPB not flushing the RSB/RAS
Introduce spec_ctrl_new_guest_context() to encapsulate all logic pertaining to
using MSR_PRED_CMD for a new guest context, even if it only has one user
presently.
Introduce X86_BUG_IBPB_NO_RET, and use it extend spec_ctrl_new_guest_context()
with a manual fixup for hardware which mis-implements IBPB.
This is part of XSA-422 / CVE-2022-23824.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Acked-by: Jan Beulich <jbeulich@suse.com>
Wei Chen [Fri, 4 Nov 2022 10:07:32 +0000 (18:07 +0800)]
xen/arm: add iounmap after initrd has been loaded in domain_build
domain_build use ioremap_wc to map a new non-cacheable virtual
address for initrd. After Xen copy initrd from this address to
guest, this new allocated virtual address has not been unmapped.
So in this patch, we add an iounmap to the end of domain_build,
after Xen loaded initrd to guest memory.
Signed-off-by: Wei Chen <wei.chen@arm.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com> Acked-by: Julien Grall <jgrall@amazon.com>
xen/arm: vGICv3: Emulate properly 32-bit access on GICR_PENDBASER
If a guest is running in 32 bit mode and it tries to access
"GICR_PENDBASER + 4" mmio reg, it will be trapped to Xen. vreg_reg64_extract()
will return the value stored "v->arch.vgic.rdist_pendbase + 4".
This will be stored in a 64bit cpu register.
So now we have the top 32 bits of GICR_PENDBASER (a 64 bit MMIO register) stored
in the lower 32 bits of the 64bit cpu register.
This 64bit cpu register is then modified bitwise with a mask (ie
GICR_PENDBASER_PTZ, it clears the 62nd bit). But the PTZ (which is bit 30 in the
64 bit cpu register) is not cleared as expected by the specification.
The correct thing to do here is to store the value of
"v->arch.vgic.rdist_pendbase" in a temporary 64 bit variable. This variable is
then modified bitwise with GICR_PENDBASER_PTZ mask. It is then passed to
vreg_reg64_extract() which will extract 32 bits from the given offset.
Also, we have removed spin_lock_irqsave()/spin_unlock_irqrestore() to protect
v->arch.vgic.rdist_pendbase in __vgic_v3_rdistr_rd_mmio_read(). The reason
being v->arch.vgic.rdist_pendbase is now being read in an atomic manner.
Similarly in __vgic_v3_rdistr_rd_mmio_write(), we have used read_atomic(),
write_atomic() to read/write v->arch.vgic.rdist_pendbase.
Fixes: fe7fa1332dabd9ce4 ("ARM: vGICv3: handle virtual LPI pending and property tables") Signed-off-by: Ayan Kumar Halder <ayankuma@amd.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com> Reviewed-by: Andre Przywara <andre.przywara@arm.com> Reviewed-by: Julien Grall <jgrall@amazon.com>
Juergen Gross [Fri, 4 Nov 2022 08:03:23 +0000 (09:03 +0100)]
xen/sched: migrate timers to correct cpus after suspend
Today all timers are migrated to cpu 0 when the system is being
suspended. They are not migrated back after resuming the system again.
This results (at least) to visible problems with the credit scheduler,
as the timer isn't handled on the cpu it was expected to occur, which
will result in an ASSERT() triggering. Other more subtle problems, like
uninterrupted elongated time slices, are probable. The least effect
will be worse performance on cpu 0 resulting from most scheduling
related timer interrupts happening there after suspend/resume.
Add migrating the scheduling related timers of a specific cpu from cpu
0 back to its original cpu when that cpu has gone up when resuming the
system.
Fixes: 0763cd268789 ("xen/sched: don't disable scheduler on cpus during suspend") Signed-off-by: Juergen Gross <jgross@suse.com> Tested-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com> Acked-by: Dario Faggioli <dfaggioli@suse.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Juergen Gross [Fri, 4 Nov 2022 07:54:57 +0000 (08:54 +0100)]
xen: fix generated code for calling hypercall handlers
The code generated for the call_handlers_*() macros needs to avoid
undefined behavior when multiple handlers share the same priority.
The issue is the hypercall number being unverified fed into the macros
and then used to set a mask via "mask = 1ULL << <hypercall-number>".
Avoid a shift amount of more than 63 by setting mask to zero in case
the hypercall number is too large.
Fixes: eca1f00d0227 ("xen: generate hypercall interface related code") Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
drivers/char: suspend handling in XHCI console driver
Similar to the EHCI driver - save/restore relevant BAR and command
register, re-configure DbC on resume and stop/start timer.
On resume trigger sending anything that was queued in the meantime.
Save full BAR value, instead of just the address part, to ease restoring
on resume.
Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com> Acked-by: Jan Beulich <jbeulich@suse.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
IOMMU/VT-d: wire common device reserved memory API
Re-use rmrr= parameter handling code to handle common device reserved
memory.
Move MAX_USER_RMRR_PAGES limit enforcement to apply only to
user-configured ranges, but not those from internal callers.
Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com> Reviewed-by: Kevin Tian <kevin.tian@intel.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Juergen Gross [Wed, 2 Nov 2022 11:08:22 +0000 (12:08 +0100)]
tools/xenstore: call remove_domid_from_perm() for special nodes
When destroying a domain, any stale permissions of the domain must be
removed from the special nodes "@...", too. This was not done in the
fix for XSA-322.
Fixes: 496306324d8d ("tools/xenstore: revoke access rights for removed domains") Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Julien Grall <jgrall@amazon.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Juergen Gross [Wed, 2 Nov 2022 11:07:57 +0000 (12:07 +0100)]
tools/xenstore: remove XEN_LIB_STORED and XENSTORED_ROOTDIR
XEN_LIB_STORED is serving no real purpose, as it is a mount point for
a tmpfs, so it can be replaced easily by XEN_RUN_STORED.
XENSTORED_ROOTDIR is basically unused already, there is just a single
reference in xs_daemon_rootdir() with a fallback to XEN_LIB_STORED,
and a .gdbinit file setting it.
Remove the .gdbinit file, as it is not known having been used since
ages, and make xs_daemon_rootdir() an alias of xs_daemon_rundir().
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com> Signed-off-by: Juergen Gross <jgross@suse.com> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Roger Pau Monné [Wed, 2 Nov 2022 11:06:37 +0000 (12:06 +0100)]
hvm/msr: load VIRT_SPEC_CTRL
Add MSR_VIRT_SPEC_CTRL to the list of MSRs handled by
hvm_load_cpu_msrs(), or else it would be lost.
Fixes: 8ffd5496f4 ('amd/msr: implement VIRT_SPEC_CTRL for HVM guests on top of SPEC_CTRL') Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
tools/xenstore: harden transaction finalization against errors
When finalizing a transaction, any error occurring after checking for
conflicts will result in the transaction being performed only
partially today. Additionally accounting data will not be updated at
the end of the transaction, which might result in further problems
later.
Avoid those problems by multiple modifications:
- free any transaction specific nodes which don't need to be committed
as they haven't been written during the transaction as soon as their
generation count has been verified, this will reduce the risk of
out-of-memory situations
- store the transaction specific node name in struct accessed_node in
order to avoid the need to allocate additional memory for it when
finalizing the transaction
- don't stop the transaction finalization when hitting an error
condition, but try to continue to handle all modified nodes
- in case of a detected error do the accounting update as needed and
call the data base checking only after that
- if writing a node in a transaction is failing (e.g. due to a failed
quota check), fail the transaction, as prior changes to struct
accessed_node can't easily be undone in that case
In case a node has been created in a transaction and it is later
deleted in the same transaction, the transaction will be terminated
with an error.
As this error is encountered only when handling the deleted node at
transaction finalization, the transaction will have been performed
partially and without updating the accounting information. This will
enable a malicious guest to create arbitrary number of nodes.
Edwin Török [Wed, 12 Oct 2022 18:13:05 +0000 (19:13 +0100)]
tools/ocaml: Ensure packet size is never negative
Integers in Ocaml have 63 or 31 bits of signed precision.
On 64-bit builds of Ocaml, this is fine because a C uint32_t always fits
within a 63-bit signed integer.
In 32-bit builds of Ocaml, this goes wrong. The C uint32_t is truncated
first (loses the top bit), then has a unsigned/signed mismatch.
A "negative" value (i.e. a packet on the ring of between 1G and 2G in size)
will trigger an exception later in Bytes.make in xb.ml, and because the packet
is not removed from the ring, the exception re-triggers on every subsequent
query, creating a livelock.
Fix both the source of the exception in Xb, and as defence in depth, mark the
domain as bad for any Invalid_argument exceptions to avoid the risk of
livelock.
This is XSA-420 / CVE-2022-42324.
Signed-off-by: Edwin Török <edvin.torok@citrix.com> Acked-by: Christian Lindig <christian.lindig@citrix.com>
Edwin Török [Wed, 12 Oct 2022 18:13:06 +0000 (19:13 +0100)]
tools/ocaml/xenstored: Fix quota bypass on domain shutdown
XSA-322 fixed a domid reuse vulnerability by assigning Dom0 as the owner of
any nodes left after a domain is shutdown (e.g. outside its /local/domain/N
tree).
However Dom0 has no quota on purpose, so this opened up another potential
attack vector. Avoid it by deleting these nodes instead of assigning them to
Dom0.
This is part of XSA-419 / CVE-2022-42323.
Fixes: c46eff921209 ("tools/ocaml/xenstored: clean up permissions for dead domains") Signed-off-by: Edwin Török <edvin.torok@citrix.com> Acked-by: Christian Lindig <christian.lindig@citrix.com>
tools/xenstore: make the internal memory data base the default
Having a file backed data base has the only advantage of being capable
to dump the contents of it while Xenstore is running, and potentially
using less swap space in case the data base can't be kept in memory.
It has the major disadvantage of a huge performance overhead: switching
to keep the data base in memory only speeds up live update of xenstored
with 120000 nodes from 20 minutes to 11 seconds. A complete tree walk
of this configuration will be reduced from 7 seconds to 280 msecs
(measured by "xenstore-control check").
So make the internal memory data base the default and enhance the
"--internal-db" command line parameter to take an optional parameter
allowing to switch the internal data base back to the file based one.
tools/xenstore: remove nodes owned by destroyed domain
In case a domain is removed from Xenstore, remove all nodes owned by
it per default.
This tackles the problem that nodes might be created by a domain
outside its home path in Xenstore, leading to Xenstore hogging more
and more memory. Domain quota don't work in this case if the guest is
rebooting in between.
Since XSA-322 ownership of such stale nodes is transferred to dom0,
which is helping against unintended access, but not against OOM of
Xenstore.
As a fallback for weird cases add a Xenstore start parameter for
keeping today's way to handle stale nodes, adding the risk of Xenstore
hitting an OOM situation.
This is part of XSA-419 / CVE-2022-42322.
Fixes: 496306324d8d ("tools/xenstore: revoke access rights for removed domains") Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Julien Grall <jgrall@amazon.com>
check_store() is using a hash table for storing all node names it has
found via walking the tree. Additionally it using another hash table
for all children of a node to detect duplicate child names.
Simplify that by dropping the second hash table as the first one is
already holding all the needed information.
Add a generic function to walk the complete node tree. It will start
at "/" and descend recursively into each child, calling a function
specified by the caller. Depending on the return value of the user
specified function the walk will be aborted, continued, or the current
child will be skipped by not descending into its children.
tools/xenstore: don't let remove_child_entry() call corrupt()
In case of write_node() returning an error, remove_child_entry() will
call corrupt() today. This could result in an endless recursion, as
remove_child_entry() is called by corrupt(), too:
Today chk_domain_generation() is being used to check whether a node
permission entry is still valid or whether it is referring to a domain
no longer existing. This is done by comparing the node's and the
domain's generation count.
In case no struct domain is existing for a checked domain, but the
domain itself is valid, chk_domain_generation() assumes it is being
called due to the first node created for a new domain and it will
return success.
This might be wrong in case the checked permission is related to an
old domain, which has just been replaced with a new domain using the
same domid.
Fix that by letting chk_domain_generation() fail in case a struct
domain isn't found. In order to cover the case of the first node for
a new domain try to allocate the needed struct domain explicitly when
processing the related SET_PERMS command. In case a referenced domain
isn't existing, flag the related permission to be ignored right away.
tools/xenstore: don't use conn->in as context for temporary allocations
Using the struct buffered data pointer of the current processed request
for temporary data allocations has a major drawback: the used area (and
with that the temporary data) is freed only after the response of the
request has been written to the ring page or has been read via the
socket. This can happen much later in case a guest isn't reading its
responses fast enough.
As the temporary data can be safely freed after creating the response,
add a temporary context for that purpose and use that for allocating
the temporary memory, as it was already the case before commit cc0612464896 ("xenstore: add small default data buffer to internal
struct").
Some sub-functions need to gain the "const" attribute for the talloc
context.
This is XSA-416 / CVE-2022-42319.
Fixes: cc0612464896 ("xenstore: add small default data buffer to internal struct") Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Julien Grall <jgrall@amazon.com>
SUPPORT.md: clarify support of untrusted driver domains with oxenstored
Add a support statement for the scope of support regarding different
Xenstore variants. Especially oxenstored does not (yet) have security
support of untrusted driver domains, as those might drive oxenstored
out of memory by creating lots of watch events for the guests they are
servicing.
Add a statement regarding Live Update support of oxenstored.
This is part of XSA-326.
Signed-off-by: Juergen Gross <jgross@suse.com> Acked-by: George Dunlap <george.dunlap@citrix.com> Acked-by: Julien Grall <jgrall@amazon.com> Reviewed-by: Christian Lindig <christian.lindig@citrix.com>
Edwin Török [Wed, 12 Oct 2022 18:13:04 +0000 (19:13 +0100)]
tools/ocaml: Limit maximum in-flight requests / outstanding replies
Introduce a limit on the number of outstanding reply packets in the xenbus
queue. This limits the number of in-flight requests: when the output queue is
full we'll stop processing inputs until the output queue has room again.
To avoid a busy loop on the Unix socket we only add it to the watched input
file descriptor set if we'd be able to call `input` on it. Even though Dom0
is trusted and exempt from quotas a flood of events might cause a backlog
where events are produced faster than daemons in Dom0 can consume them, which
could lead to an unbounded queue size and OOM.
Therefore the xenbus queue limit must apply to all connections, Dom0 is not
exempt from it, although if everything works correctly it will eventually
catch up.
This prevents a malicious guest from sending more commands while it has
outstanding watch events or command replies in its input ring. However if it
can cause the generation of watch events by other means (e.g. by Dom0, or
another cooperative guest) and stop reading its own ring then watch events
would've queued up without limit.
The xenstore protocol doesn't have a back-pressure mechanism, and doesn't
allow dropping watch events. In fact, dropping watch events is known to break
some pieces of normal functionality. This leaves little choice to safely
implement the xenstore protocol without exposing the xenstore daemon to
out-of-memory attacks.
Implement the fix as pipes with bounded buffers:
* Use a bounded buffer for watch events
* The watch structure will have a bounded receiving pipe of watch events
* The source will have an "overflow" pipe of pending watch events it couldn't
deliver
Items are queued up on one end and are sent as far along the pipe as possible:
source domain -> watch -> xenbus of target -> xenstore ring/socket of target
If the pipe is "full" at any point then back-pressure is applied and we prevent
more items from being queued up. For the source domain this means that we'll
stop accepting new commands as long as its pipe buffer is not empty.
Before we try to enqueue an item we first check whether it is possible to send
it further down the pipe, by attempting to recursively flush the pipes. This
ensures that we retain the order of events as much as possible.
We might break causality of watch events if the target domain's queue is full
and we need to start using the watch's queue. This is a breaking change in
the xenstore protocol, but only for domains which are not processing their
incoming ring as expected.
When a watch is deleted its entire pending queue is dropped (no code is needed
for that, because it is part of the 'watch' type).
There is a cache of watches that have pending events that we attempt to flush
at every cycle if possible.
Introduce 3 limits here:
* quota-maxwatchevents on watch event destination: when this is hit the
source will not be allowed to queue up more watch events.
* quota-maxoustanding which is the number of responses not read from the ring:
once exceeded, no more inputs are processed until all outstanding replies
are consumed by the client.
* overflow queue on the watch event source: all watches that cannot be stored
on destination are queued up here, a single command can trigger multiple
watches (e.g. due to recursion).
The overflow queue currently doesn't have an upper bound, it is difficult to
accurately calculate one as it depends on whether you are Dom0 and how many
watches each path has registered and how many watch events you can trigger
with a single command (e.g. a commit). However these events were already
using memory, this just moves them elsewhere, and as long as we correctly
block a domain it shouldn't result in unbounded memory usage.
Note that Dom0 is not excluded from these checks, it is important that Dom0 is
especially not excluded when it is the source, since there are many ways in
which a guest could trigger Dom0 to send it watch events.
This should protect against malicious frontends as long as the backend follows
the PV xenstore protocol and only exposes paths needed by the frontend, and
changes those paths at most once as a reaction to guest events, or protocol
state.
The queue limits are per watch, and per domain-pair, so even if one
communication channel would be "blocked", others would keep working, and the
domain itself won't get blocked as long as it doesn't overflow the queue of
watch events.
Similarly a malicious backend could cause the frontend to get blocked, but
this watch queue protects the frontend as well as long as it follows the PV
protocol. (Although note that protection against malicious backends is only a
best effort at the moment)
This is part of XSA-326 / CVE-2022-42318.
Signed-off-by: Edwin Török <edvin.torok@citrix.com> Acked-by: Christian Lindig <christian.lindig@citrix.com>
Edwin Török [Wed, 12 Oct 2022 18:13:03 +0000 (19:13 +0100)]
tools/ocaml/xb: Add BoundedQueue
Ensures we cannot store more than [capacity] elements in a [Queue]. Replacing
all Queue with this module will then ensure at compile time that all Queues
are correctly bound checked.
Each element in the queue has a class with its own limits. This, in a
subsequent change, will ensure that command responses can proceed during a
flood of watch events.
No functional change.
This is part of XSA-326.
Signed-off-by: Edwin Török <edvin.torok@citrix.com> Acked-by: Christian Lindig <christian.lindig@citrix.com>
Edwin Török [Wed, 12 Oct 2022 18:13:07 +0000 (19:13 +0100)]
tools/ocaml: GC parameter tuning
By default the OCaml garbage collector would return memory to the OS only
after unused memory is 5x live memory. Tweak this to 120% instead, which
would match the major GC speed.
This is part of XSA-326.
Signed-off-by: Edwin Török <edvin.torok@citrix.com> Acked-by: Christian Lindig <christian.lindig@citrix.com>
Edwin Török [Thu, 28 Jul 2022 16:08:15 +0000 (17:08 +0100)]
tools/ocaml/xenstored: Check for maxrequests before performing operations
Previously we'd perform the operation, record the updated tree in the
transaction record, then try to insert a watchop path and the reply packet.
If we exceeded max requests we would've returned EQUOTA, but still:
* have performed the operation on the transaction's tree
* have recorded the watchop, making this queue effectively unbounded
It is better if we check whether we'd have room to store the operation before
performing the transaction, and raise EQUOTA there. Then the transaction
record won't grow.
This is part of XSA-326 / CVE-2022-42317.
Signed-off-by: Edwin Török <edvin.torok@citrix.com> Acked-by: Christian Lindig <christian.lindig@citrix.com>
Edwin Török [Wed, 12 Oct 2022 18:13:01 +0000 (19:13 +0100)]
tools/ocaml/xenstored: Synchronise defaults with oxenstore.conf.in
We currently have 2 different set of defaults in upstream Xen git tree:
* defined in the source code, only used if there is no config file
* defined in the oxenstored.conf.in upstream Xen
An oxenstored.conf file is not mandatory, and if missing, maxrequests in
particular has an unsafe default.
Resync the defaults from oxenstored.conf.in into the source code.
This is part of XSA-326 / CVE-2022-42316.
Signed-off-by: Edwin Török <edvin.torok@citrix.com> Acked-by: Christian Lindig <christian.lindig@citrix.com>
tools/xenstore: add control command for setting and showing quota
Add a xenstore-control command "quota" to:
- show current quota settings
- change quota settings
- show current quota related values of a domain
Note that in the case the new quota is lower than existing one,
Xenstored may continue to handle requests from a domain exceeding the
new limit (depends on which one has been broken) and the amount of
resource used will not change. However the domain will not be able to
create more resource (associated to the quota) until it is back to below
the limit.
Add the memory accounting for Xenstore nodes. In order to make this
not too complicated allow for some sloppiness when writing nodes. Any
hard quota violation will result in no further requests to be accepted.
When a socket connection is destroyed, the associated watches are
removed, too. In order to keep memory accounting correct the watches
must be removed explicitly via a call of conn_delete_all_watches() from
destroy_conn().
tools/xenstore: add memory accounting for responses
Add the memory accounting for queued responses.
In case adding a watch event for a guest is causing the hard memory
quota of that guest to be violated, the event is dropped. This will
ensure that it is impossible to drive another guest past its memory
quota by generating insane amounts of events for that guest. This is
especially important for protecting driver domains from that attack
vector.
tools/xenstore: add infrastructure to keep track of per domain memory usage
The amount of memory a domain can consume in Xenstore is limited by
various quota today, but even with sane quota a domain can still
consume rather large memory quantities.
Add the infrastructure for keeping track of the amount of memory a
domain is consuming in Xenstore. Note that this is only the memory a
domain has direct control over, so any internal administration data
needed by Xenstore only is not being accounted for.
There are two quotas defined: a soft quota which will result in a
warning issued via syslog() when it is exceeded, and a hard quota
resulting in a stop of accepting further requests or watch events as
long as the hard quota would be violated by accepting those.
Setting any of those quotas to 0 will disable it.
As default values use 2MB per domain for the soft limit (this basically
covers the allowed case to create 1000 nodes needing 2kB each), and
2.5MB for the hard limit.
tools/xenstore: limit max number of nodes accessed in a transaction
Today a guest is free to access as many nodes in a single transaction
as it wants. This can lead to unbounded memory consumption in Xenstore
as there is the need to keep track of all nodes having been accessed
during a transaction.
In oxenstored the number of requests in a transaction is being limited
via a quota maxrequests (default is 1024). As multiple accesses of a
node are not problematic in C Xenstore, limit the number of accessed
nodes.
In order to let read_node() detect a quota error in case too many nodes
are being accessed, check the return value of access_node() and return
NULL in case an error has been seen. Introduce __must_check and add it
to the access_node() prototype.
tools/xenstore: simplify and fix per domain node accounting
The accounting of nodes can be simplified now that each connection
holds the associated domid.
Fix the node accounting to cover nodes created for a domain before it
has been introduced. This requires to react properly to an allocation
failure inside domain_entry_inc() by returning an error code.
Especially in error paths the node accounting has to be fixed in some
cases.
A guest not reading its Xenstore response buffer fast enough might
pile up lots of Xenstore watch events buffered. Reduce the generated
load by dropping new events which already have an identical copy
pending.
The special events "@..." are excluded from that handling as there are
known use cases where the handler is relying on each event to be sent
individually.
Add another quota for limiting the number of outstanding requests of a
guest. As the way to specify quotas on the command line is becoming
rather nasty, switch to a new scheme using [--quota|-Q] <what>=<val>
allowing to add more quotas in future easily.
Set the default value to 20 (basically a random value not seeming to
be too high or too low).
A request is said to be outstanding if any message generated by this
request (the direct response plus potential watch events) is not yet
completely stored into a ring buffer. The initial watch event sent as
a result of registering a watch is an exception.
Note that across a live update the relation to buffered watch events
for other domains is lost.
Use talloc_zero() for allocating the domain structure in order to have
all per-domain quota zeroed initially.
A future modification will limit the number of outstanding requests
for a domain, where "outstanding" means that the response of the
request or any resulting watch event hasn't been consumed yet.
In order to avoid a malicious guest being capable to block other guests
by not reading watch events, add a timeout for watch events. In case a
watch event hasn't been consumed after this timeout, it is being
deleted. Set the default timeout to 20 seconds (a random value being
not too high).
In order to support to specify other timeout values in future, use a
generic command line option for that purpose:
When removing a watched node outside of a transaction, two watch events
are being produced instead of just a single one.
When finalizing a transaction watch events can be generated for each
node which is being modified, even if outside a transaction such
modifications might not have resulted in a watch event.
This happens e.g.:
- for nodes which are only modified due to added/removed child entries
- for nodes being removed or created implicitly (e.g. creation of a/b/c
is implicitly creating a/b, resulting in watch events for a, a/b and
a/b/c instead of a/b/c only)
Avoid these additional watch events, in order to reduce the needed
memory inside Xenstore for queueing them.
This is being achieved by adding event flags to struct accessed_node
specifying whether an event should be triggered, and whether it should
be an exact match of the modified path. Both flags can be set from
fire_watches() instead of implying them only.
tools/xenstore: add helpers to free struct buffered_data
Add two helpers for freeing struct buffered_data: free_buffered_data()
for freeing one instance and conn_free_buffered_data() for freeing all
instances for a connection.
This is avoiding duplicated code and will help later when more actions
are needed when freeing a struct buffered_data.
tools/xenstore: Fail a transaction if it is not possible to create a node
Commit f2bebf72c4d5 "xenstore: rework of transaction handling" moved
out from copying the entire database everytime a new transaction is
opened to track the list of nodes changed.
The content of all the nodes accessed during a transaction will be
temporarily stored in TDB using a different key.
The function create_node() may write/update multiple nodes if the child
doesn't exist. In case of a failure, the function will revert any
changes (this include any update to TDB). Unfortunately, the function
which reverts the changes (i.e. destroy_node()) will not use the correct
key to delete any update or even request the transaction to fail.
This means that if a client decide to go ahead with committing the
transaction, orphan nodes will be created because they were not linked
to an existing node (create_node() will write the nodes backwards).
Once some nodes have been partially updated in a transaction, it is not
easily possible to undo any changes. So rather than continuing and hit
weird issue while committing, it is much saner to fail the transaction.
This will have an impact on any client that decides to commit even if it
can't write a node. Although, it is not clear why a normal client would
want to do that...
Lastly, update destroy_node() to use the correct key for deleting the
node. Rather than recreating it (this will allocate memory and
therefore fail), stash the key in the structure node.
tools/xenstore: create_node: Don't defer work to undo any changes on failure
XSA-115 extended destroy_node() to update the node accounting for the
connection. The implementation is assuming the connection is the parent
of the node, however all the nodes are allocated using a separate context
(see process_message()). This will result to crash (or corrupt) xenstored
as the pointer is wrongly used.
In case of an error, any changes to the database or update to the
accounting will now be reverted in create_node() by calling directly
destroy_node(). This has the nice advantage to remove the loop to unset
the destructors in case of success.
Take the opportunity to free the nodes right now as they are not
going to be reachable (the function returns NULL) and are just wasting
resources.
Andrew Cooper [Wed, 24 Aug 2022 13:16:44 +0000 (14:16 +0100)]
x86/vmx: Revert "VMX: use a single, global APIC access page"
The claim "No accesses would ever go to this page." is false. A consequence
of how Intel's APIC Acceleration works, and Xen's choice to have per-domain
P2Ms (rather than per-vCPU P2Ms) means that the APIC page is fully read-write
to any vCPU which is not in xAPIC mode.
Igor Druzhinin [Fri, 28 Oct 2022 13:49:33 +0000 (15:49 +0200)]
x86/pv-shim: correct ballooning down for compat guests
From: Igor Druzhinin <igor.druzhinin@citrix.com>
The compat layer for multi-extent memory ops may need to split incoming
requests. Since the guest handles in the interface structures may not be
altered, it does so by leveraging do_memory_op()'s continuation
handling: It hands on non-initial requests with a non-zero start extent,
with the (native) handle suitably adjusted down. As a result
do_memory_op() sees only the first of potentially several requests with
start extent being zero. In order to be usable as overall result, the
function accumulates args.nr_done, i.e. it initialized the field with
the start extent. Therefore non-initial requests resulting from the
split would pass too large a number into pv_shim_offline_memory().
Address that breakage by always calling pv_shim_offline_memory()
regardless of current hypercall preemption status, with a suitably
adjusted first argument. Note that this is correct also for the native
guest case: We now simply "commit" what was completed right away, rather
than at the end of a series of preemption/re-start cycles. In fact this
improves overall preemption behavior: There's no longer a potentially
big chunk of work done non-preemptively at the end of the last
"iteration".
Fixes: b2245acc60c3 ("xen/pvshim: memory hotplug") Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com> Signed-off-by: Jan Beulich <jbeulich@suse.com> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Igor Druzhinin [Fri, 28 Oct 2022 13:48:50 +0000 (15:48 +0200)]
x86/pv-shim: correct ballooning up for compat guests
From: Igor Druzhinin <igor.druzhinin@citrix.com>
The compat layer for multi-extent memory ops may need to split incoming
requests. Since the guest handles in the interface structures may not be
altered, it does so by leveraging do_memory_op()'s continuation
handling: It hands on non-initial requests with a non-zero start extent,
with the (native) handle suitably adjusted down. As a result
do_memory_op() sees only the first of potentially several requests with
start extent being zero. It's only that case when the function would
issue a call to pv_shim_online_memory(), yet the range then covers only
the first sub-range that results from the split.
Address that breakage by making a complementary call to
pv_shim_online_memory() in compat layer.
Fixes: b2245acc60c3 ("xen/pvshim: memory hotplug") Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com> Signed-off-by: Jan Beulich <jbeulich@suse.com> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Mem-op requests may have zero extents. Such requests need treating as
no-ops. pv_shim_online_memory(), however, would have tried to take 2³²-1
order-sized pages from its balloon list (to then populate them),
typically ending when the entire set of ballooned pages of this order
was consumed.
Note that pv_shim_offline_memory() does not have such an issue.
Fixes: b2245acc60c3 ("xen/pvshim: memory hotplug") Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com> Signed-off-by: Jan Beulich <jbeulich@suse.com> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Roger Pau Monné [Fri, 28 Oct 2022 09:40:45 +0000 (11:40 +0200)]
vpci: refuse BAR writes only if the BAR is mapped
Writes to the BARs are ignored if memory decoding is enabled for the
device, and the same happen with ROM BARs if the write is an attempt
to change the position of the BAR without disabling it first.
The reason of ignoring such writes is a limitation in Xen, as it would
need to unmap the BAR, change the address, and remap the BAR at the
new position, which the current logic doesn't support.
Some devices however seem to (wrongly) have the memory decoding bit
hardcoded to enabled, and attempts to disable it don't get reflected
on the command register.
This causes issues for well behaved domains that disable memory
decoding and then try to size the BARs, as vPCI will think memory
decoding is still enabled and ignore the write.
Since vPCI doesn't explicitly care about whether the memory decoding
bit is disabled as long as the BAR is not mapped in the domain p2m use
the information in the vpci_bar to check whether the BAR is mapped,
and refuse writes only based on that information. This workarounds
the issue, and allows domains to size and reposition the BARs properly.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Roger Pau Monné [Fri, 28 Oct 2022 09:40:00 +0000 (11:40 +0200)]
pci: do not disable memory decoding for devices
Commit 75cc460a1b added checks to ensure the position of the BARs from
PCI devices don't overlap with regions defined on the memory map.
When there's a collision memory decoding is left disabled for the
device, assuming that dom0 will reposition the BAR if necessary and
enable memory decoding.
While this would be the case for devices being used by dom0, devices
being used by the firmware itself that have no driver would usually be
left with memory decoding disabled by dom0 if that's the state dom0
found them in, and thus firmware trying to make use of them will not
function correctly.
The initial intent of 75cc460a1b was to prevent vPCI from creating
MMIO mappings on the dom0 p2m over regions that would otherwise
already have mappings established. It's my view now that we likely
went too far with 75cc460a1b, and Xen disabling memory decoding of
devices (as buggy as they might be) is harmful, and reduces the set of
hardware on which Xen works.
This commits reverts most of 75cc460a1b, and instead adds checks to
vPCI in order to prevent misplaced BARs from being added to the
hardware domain p2m. Signaling on whether BARs are mapped is tracked
in the vpci structure, so that misplaced BARs are not mapped, and thus
Xen won't attempt to unmap them when memory decoding is disabled.
This restores the behavior of Xen for PV dom0 to the state it was
previous to 75cc460a1b, while also introducing a more contained fix
for the vPCI BAR mapping issues.
Fixes: 75cc460a1b ('xen/pci: detect when BARs are not suitably positioned') Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Jan Beulich [Fri, 28 Oct 2022 09:38:32 +0000 (11:38 +0200)]
common: map_vcpu_info() wants to unshare the underlying page
Not passing P2M_UNSHARE to get_page_from_gfn() means there won't even be
an attempt to unshare the referenced page, without any indication to the
caller (e.g. -EAGAIN). Note that guests have no direct control over
which of their pages are shared (or paged out), and hence they have no
way to make sure all on their own that the subsequent obtaining of a
writable type reference can actually succeed.
Signed-off-by: Jan Beulich <jbeulich@suse.com> Reviewed-by: Roger Pau Monné <roger.pau@citrix.com> Acked-by: Julien Grall <jgrall@amazon.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Jan Beulich [Thu, 27 Oct 2022 09:50:47 +0000 (11:50 +0200)]
Arm32: prune (again) ld warning about mismatched wchar_t sizes
The name change (stub.c -> common-stub.c) rendered the earlier
workaround (commit a4d4c541f58b ["xen/arm32: avoid EFI stub wchar_t size
linker warning"]) ineffectual.
Fixes: bfd3e9945d1b ("build: fix x86 out-of-tree build without EFI") Signed-off-by: Jan Beulich <jbeulich@suse.com> Acked-by: Julien Grall <jgrall@amazon.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Jan Beulich [Thu, 27 Oct 2022 09:49:09 +0000 (11:49 +0200)]
x86: also zap secondary time area handles during soft reset
Just like domain_soft_reset() properly zaps runstate area handles, the
secondary time area ones also need discarding to prevent guest memory
corruption once the guest is re-started.
Signed-off-by: Jan Beulich <jbeulich@suse.com> Reviewed-by: Roger Pau Monné <roger.pau@citrix.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Patch b4f211606011 ("vpci/msix: fix PBA accesses") introduced call to
iounmap(), but not added corresponding include.
Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@epam.com> Reviewed-by: Roger Pau Monné <roger.pau@citrix.com> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Andrew Cooper [Wed, 26 Oct 2022 12:39:06 +0000 (13:39 +0100)]
CI: Drop more TravisCI remnants
This was missed from previous attempts to remove Travis.
Fixes: e0dc9b095e7c ("CI: Drop TravisCI") Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Acked-by: Jan Beulich <jbeulich@suse.com> Acked-by: Stefano Stabellini <sstabellini@kernel.org> Release-acked-by: Henry Wang <Henry.Wang@arm.com>
projects / people / dwmw2 / xen.git / log