Andrew Cooper [Sun, 29 Dec 2024 14:46:34 +0000 (14:46 +0000)]
x86: Drop the vm86 segments selectors from struct cpu_user_regs
The data segment registers are part of the on-stack IRET frame when
interrupting Virtual 8086 mode, but this ceased being relevant for Xen in
commit 5d1181a5ea5e ("xen: Remove x86_32 build target.") in 2012.
With all other cleanup in place, delete the fields so we can introduce FRED
support which uses this space for different data.
Everywhere which used the es field as an offset in cpu_user_regs needs
adjusting. However, they'll change again for FRED, so no cleanup is performed
at this juncture.
This also undoes the OoB Read workaround in show_registers(), which can now
switch back to being simple structure copy.
No functional change, but a lot of rearranging of stack and struct layout
under the hood.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
--- CC: Jan Beulich <JBeulich@suse.com> CC: Roger Pau Monné <roger.pau@citrix.com>
Andrew Cooper [Sun, 29 Dec 2024 17:40:54 +0000 (17:40 +0000)]
x86/public: Split the struct cpu_user_regs type
In order to support FRED, we're going to have to remove the {ds..gs} fields
from struct cpu_user_regs, meaning that it is going to have to become a
different type to the structure embedded in vcpu_guest_context_u.
struct cpu_user_regs is a name used in common Xen code (i.e. needs to stay
using this name), so renaming the public struct to be guest_user_regs in Xen's
view only.
Introduce a brand hew cpu-user-regs.h, currently containing a duplicate
structure. This removes the need for current.h to include public/xen.h, and
highlights a case where the emulator was picking up cpu_user_regs
transitively.
No functional change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
--- CC: Jan Beulich <JBeulich@suse.com> CC: Roger Pau Monné <roger.pau@citrix.com>
Jan: Is this what you intended?
cpu_user_regs_t and the guest handle don't seem to be used anywhere. I'm
tempted to exclude them from Xen builds.
Andrew Cooper [Mon, 30 Dec 2024 11:49:14 +0000 (11:49 +0000)]
x86/domctl: Stop using XLAT_cpu_user_regs()
In order to support FRED, we're going to have to remove the {ds..gs} fields
from struct cpu_user_regs, meaning that it is going to have to become a
different type to the structure embedded in vcpu_guest_context_u.
In both arch_{get,set}_info_guest(), expand the memcpy()/XLAT_cpu_user_regs()
to copy the fields individually. This will allow us to eventually make them
different types.
No practical change. The compat cases are identical, while the non-compat
cases no longer copy _pad fields.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
--- CC: Jan Beulich <JBeulich@suse.com> CC: Roger Pau Monné <roger.pau@citrix.com>
Should we really be copying error_code/entry_vector? They're already listed
as explicitly private fields, and I don't think anything good can come of
providing/consuming them.
The discussed "proper fix" has now been implemented, and the #DF path no
longer writes out-of-bounds. Restore the proper #DF IST pointer.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
--- CC: Jan Beulich <JBeulich@suse.com> CC: Roger Pau Monné <roger.pau@citrix.com>
Only 5 years late...
Andrew Cooper [Sun, 29 Dec 2024 19:06:10 +0000 (19:06 +0000)]
x86/traps: Avoid OoB accesses to print the data selectors
_show_registers() prints the data selectors from struct cpu_user_regs, but
these fields are sometimes out-of-bounds. See commit 6065a05adf15
("x86/traps: 'Fix' safety of read_registers() in #DF path").
There are 3 callers of _show_registers():
1. vcpu_show_registers(), which always operates on a scheduled-out vCPU,
where v->arch.user_regs (or aux_regs on the stack) is always in-bounds.
2. show_registers() where regs is always an on-stack frame. regs is copied
into a local variable first (which is an OoB read for constructs such as
WARN()), before being modified (so no OoB write).
3. do_double_fault(), where regs is adjacent to the stack guard page, and
written into directly. This is an out of bounds read and write, with a
bodge to avoid the writes hitting the guard page.
Include the data segment selectors in struct extra_state, and use those fields
instead of the fields in regs. This resolves the OoB write on the #DF path.
Resolve the OoB read in show_registers() by doing a partial memcpy() rather
than full structure copy. This is temporary until we've finished untangling
the vm86 fields fully.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
--- CC: Jan Beulich <JBeulich@suse.com> CC: Roger Pau Monné <roger.pau@citrix.com>
Andrew Cooper [Sun, 29 Dec 2024 19:23:03 +0000 (19:23 +0000)]
x86/traps: Rework register state printing to use a struct
... in preference to the crs[8] array. This avoids abusing crs[5..7] for the
fs/gs bases, giving them proper named fields instead, and avoids storage for
cr1 which is unused in the x86 architecture.
In show_registers(), remove a redundant read_cr2(). read_registers() already
did the same, and it is only the PV path which needs to override with
arch_get_cr2().
In vcpu_show_registers(), express the gsb/gss decision using SWAP(). The
determination is going to get even more complicated under FRED.
No functional change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
--- CC: Jan Beulich <JBeulich@suse.com> CC: Roger Pau Monné <roger.pau@citrix.com>
Jan Beulich [Tue, 11 Mar 2025 08:55:47 +0000 (09:55 +0100)]
x86/P2M: don't include MMIO_DM in p2m_is_valid()
MMIO_DM specifically marks pages which aren't valid, much like INVALID
does. Dropping the type from the predicate
- (conceptually) corrects _sh_propagate(), where the comment says that
"something valid" is needed (the only call path not passing in RAM_RW
would pass in INVALID_GFN along with MMIO_DM),
- is benign to the use in sh_page_fault(), where the subsequent
mfn_valid() check would otherwise cause the same bail-out code path to
be taken,
- is benign to all three uses in p2m_pt_get_entry(), as MMIO_DM entries
will only ever yield non-present entries, which are being checked for
earlier,
- is benign to sh_unshadow_for_p2m_change(), for the same reason,
- is benign to gnttab_transfer() with EPT not in use, again because
MMIO_DM entries will only ever yield non-present entries, and
INVALID_MFN is returned for those anyway by p2m_pt_get_entry().
- for gnttab_transfer() with EPT in use (conceptually) corrects the
corner case of a page first being subject to XEN_DMOP_set_mem_type
converting a RAM type to MMIO_DM (which retains the MFN in the entry),
and then being subject to GNTTABOP_transfer, except that steal_page()
would later make the operation fail unconditionally anyway.
While there also drop the unused (and otherwise now redundant)
p2m_has_emt().
Signed-off-by: Jan Beulich <jbeulich@suse.com> Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Jan Beulich [Tue, 11 Mar 2025 08:55:20 +0000 (09:55 +0100)]
x86/P2M: correct old entry checking in p2m_remove_entry()
Using p2m_is_valid() isn't quite right here. It expanding to RAM+MMIO,
the subsequent p2m_mmio_direct check effectively reduces its use to
RAM+MMIO_DM. Yet MMIO_DM entries, which are never marked present in the
page tables, won't pass the mfn_valid() check. It is, however, quite
plausible (and supported by the rest of the function) to permit
"removing" hole entries, i.e. in particular to convert MMIO_DM to
INVALID. Which leaves the original check to be against RAM (plus MFN
validity), while HOLE then instead wants INVALID_MFN to be passed in.
Further more grant and foreign entries (together with RAM becoming
ANY_RAM) as well as BROKEN want the MFN checking, too.
All other types (i.e. MMIO_DIRECT and POD) want rejecting here rather
than skipping, for needing handling / accounting elsewhere.
Signed-off-by: Jan Beulich <jbeulich@suse.com> Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Jan Beulich [Tue, 11 Mar 2025 08:54:19 +0000 (09:54 +0100)]
PCI: drop pci_segments_init()
Have callers invoke pci_add_segment() directly instead: With radix tree
initialization moved out of the function, its name isn't quite
describing anymore what it actually does.
On x86 move the logic into __start_xen() itself, to reduce the risk of
re-introducing ordering issues like the one which was addressed by 26fe09e34566 ("radix-tree: introduce RADIX_TREE{,_INIT}()").
Signed-off-by: Jan Beulich <jbeulich@suse.com> Reviewed-by: Roger Pau Monné <roger.pau@citrix.com> Acked-by: Julien Grall <jgrall@amazon.com>
Roger Pau Monne [Mon, 10 Mar 2025 17:41:57 +0000 (18:41 +0100)]
automation/cirrus-ci: store xen/.config as an artifact
Always store xen/.config as an artifact, renamed to xen-config to match
the naming used in the Gitlab CI tests.
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com> Acked-by: Stefano Stabellini <sstabellini@kernel.org>
Juergen Gross [Thu, 6 Mar 2025 07:47:52 +0000 (08:47 +0100)]
docs: fix INTRODUCE description in xenstore.txt
The description of the Xenstore INTRODUCE command is still referencing
xend. Fix that.
The <evtchn> description is starting with a grammatically wrong
sentence. Fix that.
While at it, make clear that the Xenstore implementation is allowed
to ignore the specified gfn and use the Xenstore reserved grant id
GNTTAB_RESERVED_XENSTORE instead.
Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Andrew Cooper [Fri, 7 Mar 2025 14:24:42 +0000 (14:24 +0000)]
xen/watchdog: Identify which domain watchdog fired
When a watchdog fires, the domain is crashed and can't dump any state.
Xen allows a domain to have two separate watchdogs. Therefore, for a
domain running multiple watchdogs (e.g. one based around network, one
for disk), it is important for diagnostics to know which watchdog
fired.
As the printk() is in a timer callback, this is a bit awkward to
arrange, but there are 12 spare bits in the bottom of the domain
pointer owing to its alignment.
Reuse these bits to encode the watchdog id too, so the one which fired
is identified when the domain is crashed.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Reviewed-by: Juergen Gross <jgross@suse.com>
Andrew Cooper [Fri, 7 Mar 2025 16:38:26 +0000 (16:38 +0000)]
xen/domain: Initialise the domain handle before inserting into the domlist
As soon as the the domain is in the domlist, it can be queried via various
means, ahead of being fully constructed. Ensure it has the toolstack-given
UUID prior to becoming visible.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
Andrew Cooper [Fri, 7 Mar 2025 15:16:29 +0000 (15:16 +0000)]
CI: Drop the now-obsolete 11-riscv64.dockerfile
Fixes: bd9bda50553b ("automation: drop debian:11-riscv64 container") Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Acked-by: Stefano Stabellini <sstabellini@kernel.org>
Jiqian Chen [Mon, 24 Feb 2025 03:24:33 +0000 (11:24 +0800)]
vpci: Add resizable bar support
Some devices, like AMDGPU, support resizable bar capability,
but vpci of Xen doesn't support this feature, so they fail
to resize bars and then cause probing failure.
According to PCIe spec, each bar that supports resizing has
two registers, PCI_REBAR_CAP and PCI_REBAR_CTRL. So, add
handlers to support resizing the size of BARs.
Note that Xen will only trap PCI_REBAR_CTRL, as PCI_REBAR_CAP
is read-only register and the hardware domain already gets
access to it without needing any setup.
tools/hvmloader: Replace LAPIC_ID() with cpu_to_apicid[]
Replace uses of the LAPIC_ID() macro with accesses to the
cpu_to_apicid[] lookup table. This table contains the APIC IDs of each
vCPU as probed at runtime rather than assuming a predefined relation.
Moved smp_initialise() ahead of apic_setup() in order to initialise
cpu_to_apicid ASAP and avoid using it uninitialised. Note that bringing
up the APs doesn't need the APIC in hvmloader becasue it always runs
virtualized and uses the PV interface.
Signed-off-by: Alejandro Vallejo <alejandro.vallejo@cloud.com> Acked-by: Jan Beulich <jbeulich@suse.com>
tools/hvmloader: Retrieve APIC IDs from the APs themselves
Make it so the APs expose their own APIC IDs in a lookup table (LUT). We
can use that LUT to populate the MADT, decoupling the algorithm that
relates CPU IDs and APIC IDs from hvmloader.
Modified the printf to also print the APIC ID of each CPU, as well as
fixing a (benign) wrong specifier being used for the vcpu id.
Signed-off-by: Alejandro Vallejo <alejandro.vallejo@cloud.com> Acked-by: Jan Beulich <jbeulich@suse.com>
Andrew Cooper [Thu, 28 Nov 2024 00:47:37 +0000 (00:47 +0000)]
x86/vlapic: Drop vlapic->esr_lock
The exact behaviour of LVTERR interrupt generation is implementation
specific.
* Newer Intel CPUs generate an interrupt when pending_esr becomes
nonzero.
* Older Intel and all AMD CPUs generate an interrupt when any
individual bit in pending_esr becomes nonzero.
Neither vendor documents their behaviour very well. Xen implements
the per-bit behaviour and has done since support was added.
Importantly, the per-bit behaviour can be expressed using the atomic
operations available in the x86 architecture, whereas the
former (interrupt only on pending_esr becoming nonzero) cannot.
With vlapic->hw.pending_esr held outside of the main LAPIC register page,
it's much easier to use atomic operations.
Use xchg() in vlapic_reg_write(), and *set_bit() in vlapic_error().
The only interesting change is that vlapic_error() now needs to take a
single bit only, rather than a mask, but this fine for all current
callers and forseable changes.
No change from a guests perspective.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
Andrew Cooper [Thu, 28 Nov 2024 00:47:36 +0000 (00:47 +0000)]
x86/vlapic: Fix handling of writes to APIC_ESR
Xen currently presents APIC_ESR to guests as a simple read/write register.
This is incorrect. The SDM states:
The ESR is a write/read register. Before attempt to read from the ESR,
software should first write to it. (The value written does not affect the
values read subsequently; only zero may be written in x2APIC mode.) This
write clears any previously logged errors and updates the ESR with any
errors detected since the last write to the ESR.
Introduce a new pending_esr field in hvm_hw_lapic.
Update vlapic_error() to accumulate errors here, and extend vlapic_reg_write()
to discard the written value and transfer pending_esr into APIC_ESR. Reads
are still as before.
Importantly, this means that guests no longer destroys the ESR value it's
looking for in the LVTERR handler when following the SDM instructions.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
Andrew Cooper [Tue, 25 Jun 2024 16:23:12 +0000 (17:23 +0100)]
x86/vmx: Rewrite vmx_sync_pir_to_irr() to be more efficient
There are two issues. First, pi_test_and_clear_on() pulls the cache-line to
the CPU and dirties it even if there's nothing outstanding, and second,
bitmap_for_each() is O(256) when O(8) would do, and would avoid multiple
atomic updates to the same IRR word.
Rewrite it from scratch, explaining what's going on at each step.
Bloat-o-meter reports 177 -> 145 (net -32), but real improvement is the
removal of calls to __find_{first,next}_bit() hidden behind bitmap_for_each().
No functional change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
Andrew Cooper [Tue, 18 Feb 2025 23:01:11 +0000 (23:01 +0000)]
xen/domain: Annotate struct domain as page aligned
struct domain is always a page aligned allocation. Update it's type to
reflect this, so we can safely reuse the lower bits in the pointer for
auxiliary information.
No functional change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Andrew Cooper [Fri, 3 Jan 2025 15:16:45 +0000 (15:16 +0000)]
x86/IDT: Don't rewrite bsp_idt[] at boot time
Now that bsp_idt[] is constructed at build time, we do not need to manually
initialise it in init_idt_traps() and trap_init().
When swapping the early pagefault handler for the normal one, switch to using
_update_gate_addr_lower() as we do on the kexec path for NMI and #MC.
This in turn allows us to drop set_{intr,swint}_gate() and the underlying
infrastructure. It also lets us drop autogen_entrypoints[] and that
underlying infrastructure.
No functional change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
Andrew Cooper [Fri, 3 Jan 2025 14:44:19 +0000 (14:44 +0000)]
x86/IDT: Generate bsp_idt[] at build time
... rather than dynamically at boot time. Aside from less runtime overhead,
this approach is less fragile than the preexisting autogen stubs mechanism.
We can manage this with some linker calculations. See patch comments for full
details.
For simplicity, we create a new set of entry stubs here, and clean up the old
ones in the subsequent patch. bsp_idt[] needs to move from .bss to .data.
No functional change yet; the boot path still (re)writes bsp_idt[] at this
juncture.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
Andrew Cooper [Thu, 2 Jan 2025 17:17:30 +0000 (17:17 +0000)]
x86/IDT: Rename idt_table[] to bsp_idt[]
Having variables named idt_table[] and idt_tables[] is not ideal.
Use X86_IDT_VECTORS and remove IDT_ENTRIES. State the size of bsp_idt[] in
idt.h so that load_system_tables() and cpu_smpboot_alloc() can use sizeof()
rather than opencoding the calculation.
Move the variable into a new traps-setup.c, to make a start at splitting
traps.c in half.
No functional change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Acked-by: Jan Beulich <jbeulich@suse.com>
Juergen Gross [Fri, 7 Mar 2025 10:11:41 +0000 (11:11 +0100)]
xen/events: fix global virq handling
VIRQs are split into "global" and "per vcpu" ones. Unfortunately in
reality there are "per domain" ones, too.
send_global_virq() and set_global_virq_handler() make only sense for
the real "global" ones, so replace virq_is_global() with a new
function get_virq_type() returning one of the 3 possible types (global,
domain, vcpu VIRQ).
To make its intended purpose more clear, also rename
send_guest_global_virq() to send_guest_domain_virq().
Fixes: 980822c5edd1 ("xen/events: allow setting of global virq handler only for unbound virqs") Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Jan Beulich <jbeulich@suse.com> Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Juergen Gross [Thu, 6 Mar 2025 16:23:36 +0000 (17:23 +0100)]
xen/events: fix get_global_virq_handler() usage without hardware domain
Some use cases of get_global_virq_handler() didn't account for the
case of running without hardware domain.
Fix that by testing get_global_virq_handler() returning NULL where
needed (e.g. when directly dereferencing the result).
Fixes: 980822c5edd1 ("xen/events: allow setting of global virq handler only for unbound virqs") Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
Jan Beulich [Thu, 6 Mar 2025 14:21:52 +0000 (15:21 +0100)]
XSM: correct xsm_get_domain_state()
Add the missing first parameter and move it next to a close relative.
Fixes: 3ad3df1bd0aa ("xen: add new domctl get_domain_state") Signed-off-by: Jan Beulich <jbeulich@suse.com> Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Juergen Gross [Thu, 6 Mar 2025 13:03:37 +0000 (14:03 +0100)]
xen/public: remove some unused defines from xs_wire.h
xs_wire.h contains some defines XS_WRITE_* which seem to be leftovers
from some decades ago. They haven't been used in the Xen tree since at
least Xen 2.0 and they make no sense anyway.
Remove them, as they seem not to be related to any Xen interface we
have today.
Signed-off-by: Juergen Gross <jgross@suse.com> Acked-by: Jan Beulich <jbeulich@suse.com>
Supported ISA extensions are specified in the device tree within the CPU
node, using two properties: `riscv,isa-extensions` and `riscv,isa`.
Currently, Xen does not support the `riscv,isa-extensions` property and
will be added in the future.
The `riscv,isa` property is parsed for each CPU, and the common extensions
are stored in the `host_riscv_isa` bitmap.
This bitmap is then used by `riscv_isa_extension_available()` to check
if a specific extension is supported.
The current implementation is based on Linux kernel v6.12-rc3
implementation with the following changes:
- Drop unconditional setting of {RISCV_ISA_EXT_ZICSR,
RISCV_ISA_EXT_ZIFENCEI, RISCV_ISA_EXT_ZICNTR, RISCV_ISA_EXT_ZIHPM} because
Xen is going to run on hardware produced after the aforementioned
extensions were split out of "i".
- Remove saving of the ISA for each CPU, only the common available ISA is
saved.
- Remove ACPI-related code as ACPI is not supported by Xen.
- Drop handling of elf_hwcap, since Xen does not provide hwcap to
userspace.
- Replace of_cpu_device_node_get() API, which is not available in Xen,
with a combination of dt_for_each_child_node(), dt_device_type_is_equal(),
and dt_get_cpuid_from_node() to retrieve cpuid and riscv,isa in
riscv_fill_hwcap_from_isa_string().
- Rename arguments of __RISCV_ISA_EXT_DATA() from _name to ext_name, and
_id to ext_id for clarity.
- Replace instances of __RISCV_ISA_EXT_DATA with RISCV_ISA_EXT_DATA.
- Replace instances of __riscv_isa_extension_available with
riscv_isa_extension_available for consistency. Also, update the type of
`bit` argument of riscv_isa_extension_available().
- Redefine RISCV_ISA_EXT_DATA() to work only with ext_name and ext_id,
as other fields are not used in Xen currently. Also RISCV_ISA_EXT_DATA()
is reworked in the way to take only one argument `ext_name`.
- Add check of first 4 letters of riscv,isa string to
riscv_isa_parse_string() as Xen doesn't do this check before so it is
necessary to check correctness of riscv,isa string. ( it should start with
rv{32,64} with taking into account upper and lower case of "rv").
Additionally, check also that 'i' goes after 'rv{32,64}' to be sure that
`out_bitmap` can't be empty.
- Drop an argument of riscv_fill_hwcap() and riscv_fill_hwcap_from_isa_string()
as it isn't used, at the moment.
- Update the comment message about QEMU workaround.
- Apply Xen coding style.
- s/pr_info/printk.
- Drop handling of uppercase letters of riscv,isa in riscv_isa_parse_string() as
Xen checks that riscv,isa should be in lowercase according to the device tree
bindings.
- Update logic of riscv_isa_parse_string(): now it stops parsing of riscv,isa
if illegal symbol was found instead of ignoring them.
Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com> Acked-by: Jan Beulich <jbeulich@suse.com>
Extensions 'f' and 'd' aren't really needed for Xen, and allowing floating
point registers to be used can lead to crashes.
Extensions 'i', 'm', 'a', 'zicsr', and 'zifencei' are necessary for the
operation of Xen, which is why they are used explicitly (unconditionally)
in -march.
Drop "Base ISA" choice from riscv/Kconfig as it is always empty.
Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
There are two reasons for that:
1. In the README, GCC baseline is chosen to be 12.2, whereas Debian 11
uses GCC 10.2.1.
2. Xen requires mandatory some Z extensions, but GCC 10.2.1 does not
support Z extensions in -march, causing the compilation to fail.
Jan Beulich [Thu, 6 Mar 2025 12:57:21 +0000 (13:57 +0100)]
VMX: convert vmx_basic_msr
... to a struct field, which is then going to be accompanied by other
capability/control data presently living in individual variables. As
this structure isn't supposed to be altered post-boot, put it in
.data.ro_after_init right away.
Suggested-by: Roger Pau Monné <roger.pau@citrix.com> Signed-off-by: Jan Beulich <jbeulich@suse.com> Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Jan Beulich [Thu, 6 Mar 2025 12:56:49 +0000 (13:56 +0100)]
VMX: drop vmcs_revision_id
It's effectively redundant with vmx_basic_msr. For the #define
replacement to work, struct vmcs_struct's respective field name also
needs to change: Drop the not really meaningful "vmcs_" prefix from it.
Signed-off-by: Jan Beulich <jbeulich@suse.com> Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Jan Beulich [Thu, 6 Mar 2025 12:56:21 +0000 (13:56 +0100)]
x86/HVM: improve CET-IBT pruning of ENDBR
__init{const,data}_cf_clobber can have an effect only for pointers
actually populated in the respective tables. While not the case for SVM
right now, VMX installs a number of pointers only under certain
conditions. Hence the respective functions would have their ENDBR purged
only when those conditions are met. Invoke "pruning" functions after
having copied the respective tables, for them to install any "missing"
pointers.
Signed-off-by: Jan Beulich <jbeulich@suse.com> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Juergen Gross [Thu, 6 Mar 2025 12:54:55 +0000 (13:54 +0100)]
tools/xenstored: use new stable interface instead of libxenctrl
Replace the current use of the unstable xc_domain_getinfo_single()
interface with the stable domctl XEN_DOMCTL_get_domain_state call
via the new libxenmanage library.
This will remove the last usage of libxenctrl by Xenstore, so update
the library dependencies accordingly.
For now only do a direct replacement without using the functionality
of obtaining information about domains having changed the state.
Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>
Juergen Gross [Thu, 6 Mar 2025 12:52:38 +0000 (13:52 +0100)]
xen: add new domctl get_domain_state
Add a new domctl sub-function to get data of a domain having changed
state (this is needed by Xenstore).
The returned state just contains the domid, the domain unique id,
and some flags (existing, shutdown, dying).
In order to enable Xenstore stubdom being built for multiple Xen
versions, make this domctl stable. For stable domctls the
interface_version is always 0.
Signed-off-by: Juergen Gross <jgross@suse.com> Acked-by: Daniel P. Smith <dpsmith@apertussolutions.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
Juergen Gross [Thu, 6 Mar 2025 12:52:14 +0000 (13:52 +0100)]
xen: add bitmap to indicate per-domain state changes
Add a bitmap with one bit per possible domid indicating the respective
domain has changed its state (created, deleted, dying, crashed,
shutdown).
Registering the VIRQ_DOM_EXC event will result in setting the bits for
all existing domains and resetting all other bits.
As the usage of this bitmap is tightly coupled with the VIRQ_DOM_EXC
event, it is meant to be used only by a single consumer in the system,
just like the VIRQ_DOM_EXC event.
Resetting a bit will be done in a future patch.
This information is needed for Xenstore to keep track of all domains.
Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
Juergen Gross [Thu, 6 Mar 2025 12:51:55 +0000 (13:51 +0100)]
xen/events: allow setting of global virq handler only for unbound virqs
XEN_DOMCTL_set_virq_handler will happily steal a global virq from the
current domain having bound it and assign it to another domain. The
former domain will just never receive any further events for that
virq without knowing what happened.
Change the behavior to allow XEN_DOMCTL_set_virq_handler only if the
virq in question is not bound by the current domain allowed to use it.
Currently the only user of XEN_DOMCTL_set_virq_handler in the Xen code
base is init-xenstore-domain, so changing the behavior like above will
not cause any problems.
Juergen Gross [Thu, 6 Mar 2025 12:51:35 +0000 (13:51 +0100)]
xen/events: don't allow binding a global virq from any domain
Today Xen will happily allow binding a global virq by a domain which
isn't configured to receive it. This won't result in any bad actions,
but the bind will appear to have succeeded with no event ever being
received by that event channel.
Instead of allowing the bind, error out if the domain isn't set to
handle that virq. Note that this check is inside the write_lock() on
purpose, as a future patch will put a related check into
set_global_virq_handler() with the addition of using the same lock.
Frediano Ziglio [Thu, 6 Mar 2025 12:51:01 +0000 (13:51 +0100)]
EFI: Avoid crash calling PrintErrMesg() from efi_multiboot2()
Although code is compiled with -fpic option data is not position
independent. This causes data pointer to become invalid if
code is not relocated properly which is what happens for
efi_multiboot2 which is called by multiboot entry code.
Code tested adding
PrintErrMesg(L"Test message", EFI_BUFFER_TOO_SMALL);
in efi_multiboot2 before calling efi_arch_edd (this function
can potentially call PrintErrMesg).
After the patch:
Booting `XenServer (Serial)'Booting `XenServer (Serial)'
Test message: Buffer too small
BdsDxe: loading Boot0000 "UiApp" from Fv(7CB8BDC9-F8EB-4F34-AAEA-3EE4AF6516A1)/FvFile(462CAA21-7614-4503-836E-8AB6F4662331)
BdsDxe: starting Boot0000 "UiApp" from Fv(7CB8BDC9-F8EB-4F34-AAEA-3EE4AF6516A1)/FvFile(462CAA21-7614-4503-836E-8AB6F4662331)
Similar to commit (d736b6eb451b, "xen/arm: mpu: Define Xen start address for
MPU systems"), one needs to add a build assertion to ensure that the page size
is 4KB on arm32 based systems as well.
The existing build assertion is moved under "xen/arch/arm/mpu" as it applies
for both arm64 and arm32 based systems.
xen/arm: mpu: Move some of the definitions to common file
For AArch32, refer to ARM DDI 0568A.c ID110520.
MPU_REGION_SHIFT is same between AArch32 and AArch64 (HPRBAR).
Also, NUM_MPU_REGIONS_SHIFT is same between AArch32 and AArch64
(HMPUIR).
Andrew Cooper [Fri, 13 Dec 2024 14:34:00 +0000 (14:34 +0000)]
x86/ucode: Perform extra SHA2 checks on AMD Fam17h/19h microcode
Collisions have been found in the microcode signing algorithm used by AMD
Fam17h/19h CPUs, and now anyone can sign their own.
For more details, see:
https://bughunters.google.com/blog/5424842357473280/zen-and-the-art-of-microcode-hacking
https://www.amd.com/en/resources/product-security/bulletin/amd-sb-7033.html
As a stopgap mitigation, check the digest of patches against a table of blobs
with known provenance. These are all Fam17h and Fam19h blobs included in
linux-firwmare at the time of writing, specifically:
Andrew Cooper [Fri, 13 Dec 2024 14:34:00 +0000 (14:34 +0000)]
xen/lib: Introduce SHA2-256
A future change will need to calculate SHA2-256 digests. Introduce an
implementation in lib/, derived from Trenchboot which itself is derived from
Linux.
In order to be useful to other architectures, it is careful with endianness
and misaligned accesses as well as being more MISRA friendly, but is only
wired up for x86 in the short term.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Juergen Gross [Wed, 5 Mar 2025 15:37:37 +0000 (16:37 +0100)]
tools/xl: fix channel configuration setting
Channels work differently than other device types: their devid should
be -1 initially in order to distinguish them from the primary console
which has the devid of 0.
So when parsing the channel configuration, use
ARRAY_EXTEND_INIT_NODEVID() in order to avoid overwriting the devid
set by libxl_device_channel_init().
Fixes: 3a6679634766 ("libxl: set channel devid when not provided by application") Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>
x86/xstate: Create map/unmap primitives for xsave areas
Add infrastructure to simplify ASI handling. With ASI in the picture
we'll have several different means of accessing the XSAVE area of a
given vCPU, depending on whether a domain is covered by ASI or not and
whether the vCPU is question is scheduled on the current pCPU or not.
Having these complexities exposed at the call sites becomes unwieldy
very fast. These wrappers are intended to be used in a similar way to
map_domain_page() and unmap_domain_page(); The map operation will
dispatch the appropriate pointer for each case in a future patch, while
unmap will remain a no-op where no unmap is required (e.g: when there's
no ASI) and remove the transient maping if one was required.
Follow-up patches replace all uses of raw v->arch.xsave_area by this
mechanism in preparation to add the beforementioned dispatch logic to be
added at a later time.
Signed-off-by: Alejandro Vallejo <alejandro.vallejo@cloud.com> Acked-by: Jan Beulich <jbeulich@suse.com>
Penny Zheng [Wed, 5 Mar 2025 14:45:10 +0000 (15:45 +0100)]
xen/cpufreq: abstract Energy Performance Preference value
Intel's hwp Energy Performance Preference value is compatible with
CPPC's Energy Performance Preference value, so this commit abstracts
the value and re-place it in common header file cpufreq.h, to be
used not only for hwp in the future.
Signed-off-by: Penny Zheng <Penny.Zheng@amd.com> Acked-by: Jan Beulich <jbeulich@suse.com>
Extensions 'f' and 'd' aren't really needed for Xen, and allowing floating
point registers to be used can lead to crashes.
Extensions 'i', 'm', 'a', 'zicsr', and 'zifencei' are necessary for the
operation of Xen, which is why they are used explicitly (unconditionally)
in -march.
Drop "Base ISA" choice from riscv/Kconfig as it is always empty.
Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
xen/README: add compiler and binutils versions for RISCV-64
Considering that the Zbb extension is supported since GCC version 12 [1]
and that older GCC versions do not support Z extensions in -march (I haven't
faced this issue for GCC >=11.2), leading to compilation failures,
the baseline version for GCC is set to 12.2 and for GNU binutils to 2.39.
The GCC version is set to 12.2 instead of 12.1 because Xen's GitLab CI uses
Debian 12, which includes GCC 12.2 and GNU binutils 2.39.
Denis Mukhin [Wed, 5 Mar 2025 14:42:49 +0000 (15:42 +0100)]
xen/console: introduce console_{get,put}_domain()
console_input_domain() takes an RCU lock to protect domain structure.
That implies call to rcu_unlock_domain() after use.
Introduce a pair of console_get_domain() / console_put_domain() to highlight
the correct use of the call within the code interacting with Xen console
driver.
The new calls used in __serial_rx(), which also fixed console forwarding to
late hardware domains which run with domain IDs different from 0.
While moving the guest_printk() invocation also drop the redundant _G infix.
Jan Beulich [Wed, 5 Mar 2025 14:42:12 +0000 (15:42 +0100)]
x86/HVM: drop redundant access splitting
With all paths into hvmemul_linear_mmio_access() coming through
linear_{read,write}(), there's no need anymore to split accesses at
page boundaries there. Leave an assertion, though.
Signed-off-by: Jan Beulich <jbeulich@suse.com> Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Jan Beulich [Wed, 5 Mar 2025 14:41:14 +0000 (15:41 +0100)]
x86/HVM: slightly improve CMPXCHG16B emulation
Using hvmemul_linear_mmio_write() directly (as fallback when mapping the
memory operand isn't possible) won't work properly when the access
crosses a RAM/MMIO boundary. Use linear_write() instead, which splits at
such boundaries as necessary.
Signed-off-by: Jan Beulich <jbeulich@suse.com> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Roger Pau Monne [Wed, 12 Feb 2025 10:37:50 +0000 (11:37 +0100)]
x86/dom0: be less restrictive with the Interrupt Address Range
Xen currently prevents dom0 from creating CPU or IOMMU page-table mappings
into the interrupt address range [0xfee00000, 0xfeefffff]. This range has
two different purposes. For accesses from the CPU is contains the default
position of local APIC page at 0xfee00000. For accesses from devices
it's the MSI address range, so the address field in the MSI entries
(usually) point to an address on that range to trigger an interrupt.
There are reports of Lenovo Thinkpad devices placing what seems to be the
UCSI shared mailbox at address 0xfeec2000 in the interrupt address range.
Attempting to use that device with a Linux PV dom0 leads to an error when
Linux kernel maps 0xfeec2000:
Remove the restrictions to create mappings in the interrupt address range
for dom0. Note that the restriction to map the local APIC page is enforced
separately, and that continues to be present. Additionally make sure the
emulated local APIC page is also not mapped, in case dom0 is using it.
Note that even if the interrupt address range entries are populated in the
IOMMU page-tables no device access will reach those pages. Device accesses
to the Interrupt Address Range will always be converted into Interrupt
Messages and are not subject to DMA remapping.
There's also the following restriction noted in Intel VT-d:
> Software must not program paging-structure entries to remap any address to
> the interrupt address range. Untranslated requests and translation requests
> that result in an address in the interrupt range will be blocked with
> condition code LGN.4 or SGN.8. Translated requests with an address in the
> interrupt address range are treated as Unsupported Request (UR).
Similarly for AMD-Vi:
> Accesses to the interrupt address range (Table 3) are defined to go through
> the interrupt remapping portion of the IOMMU and not through address
> translation processing. Therefore, when a transaction is being processed as
> an interrupt remapping operation, the transaction attribute of
> pretranslated or untranslated is ignored.
>
> Software Note: The IOMMU should
> not be configured such that an address translation results in a special
> address such as the interrupt address range.
However those restrictions don't apply to the identity mappings possibly
created for dom0, since the interrupt address range is never subject to DMA
remapping, and hence there's no output address after translation that
belongs to the interrupt address range.
Roger Pau Monne [Fri, 14 Feb 2025 09:39:29 +0000 (10:39 +0100)]
x86/iommu: account for IOMEM caps when populating dom0 IOMMU page-tables
The current code in arch_iommu_hwdom_init() kind of open-codes the same
MMIO permission ranges that are added to the hardware domain ->iomem_caps.
Avoid this duplication and use ->iomem_caps in arch_iommu_hwdom_init() to
filter which memory regions should be added to the dom0 IOMMU page-tables.
Note the IO-APIC and MCFG page(s) must be set as not accessible for a PVH
dom0, otherwise the internal Xen emulation for those ranges won't work.
This requires adjustments in dom0_setup_permissions().
The call to pvh_setup_mmcfg() in dom0_construct_pvh() must now strictly be
done ahead of setting up dom0 permissions, so take the opportunity to also
put it inside the existing is_hardware_domain() region.
Also the special casing of E820_UNUSABLE regions no longer needs to be done
in arch_iommu_hwdom_init(), as those regions are already blocked in
->iomem_caps and thus would be removed from the rangeset as part of
->iomem_caps processing in arch_iommu_hwdom_init(). The E820_UNUSABLE
regions below 1Mb are not removed from ->iomem_caps, that's a slight
difference for the IOMMU created page-tables, but the aim is to allow
access to the same memory either from the CPU or the IOMMU page-tables.
Since ->iomem_caps already takes into account the domain max paddr, there's
no need to remove any regions past the last address addressable by the
domain, as applying ->iomem_caps would have already taken care of that.
Suggested-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
Roger Pau Monne [Tue, 18 Feb 2025 16:57:49 +0000 (17:57 +0100)]
x86/dom0: correctly set the maximum ->iomem_caps bound for PVH
The logic in dom0_setup_permissions() sets the maximum bound in
->iomem_caps unconditionally using paddr_bits, which is not correct for HVM
based domains. Instead use domain_max_paddr_bits() to get the correct
maximum paddr bits for each possible domain type.
Switch to using PFN_DOWN() instead of PAGE_SHIFT, as that's shorter.
Fixes: 53de839fb409 ('x86: constrain MFN range Dom0 may access') Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
Roger Pau Monne [Thu, 13 Feb 2025 09:58:45 +0000 (10:58 +0100)]
x86/dom0: attempt to fixup p2m page-faults for PVH dom0
When building a PVH dom0 Xen attempts to map all (relevant) MMIO regions
into the p2m for dom0 access. However the information Xen has about the
host memory map is limited. Xen doesn't have access to any resources
described in ACPI dynamic tables, and hence the p2m mappings provided might
not be complete.
PV doesn't suffer from this issue because a PV dom0 is capable of mapping
into it's page-tables any address not explicitly banned in d->iomem_caps.
Introduce a new command line options that allows Xen to attempt to fixup
the p2m page-faults, by creating p2m identity maps in response to p2m
page-faults.
This is aimed as a workaround to small ACPI regions Xen doesn't know about.
Note that missing large MMIO regions mapped in this way will lead to
slowness due to the VM exit processing, plus the mappings will always use
small pages.
The ultimate aim is to attempt to bring better parity with a classic PV
dom0.
Note such fixup rely on the CPU doing the access to the unpopulated
address. If the access is attempted from a device instead there's no
possible way to fixup, as IOMMU page-fault are asynchronous.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Acked-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
---
Only slightly tested on my local PVH dom0 deployment.
---
Changes since v1:
- Make the fixup function static.
- Print message in case mapping already exists.
Roger Pau Monne [Thu, 13 Feb 2025 08:08:01 +0000 (09:08 +0100)]
x86/emul: dump unhandled memory accesses for PVH dom0
A PV dom0 can map any host memory as long as it's allowed by the IO
capability range in d->iomem_caps. On the other hand, a PVH dom0 has no
way to populate MMIO region onto it's p2m, so it's limited to what Xen
initially populates on the p2m based on the host memory map and the enabled
device BARs.
Introduce a new debug build only printk that reports attempts by dom0 to
access addresses not populated on the p2m, and not handled by any emulator.
This is for information purposes only, but might allow getting an idea of
what MMIO ranges might be missing on the p2m.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Acked-by: Jan Beulich <jbeulich@suse.com>
Andrew Cooper [Wed, 1 Jan 2025 15:43:20 +0000 (15:43 +0000)]
x86/IDT: Collect IDT related content idt.h
Logic concerning the IDT is somewhat different to the other system tables, and
in particular ought not to be in asm/processor.h. Collect it together a new
header.
While doing so, make a few minor adjustments:
* Make set_ist() use volatile rather than ACCESS_ONCE(), as
_write_gate_lower() already does, removing the need for xen/lib.h.
* Move the BUILD_BUG_ON() from subarch_percpu_traps_init() into mm.c's
build_assertions(), rather than including idt.h into x86_64/traps.c.
* Drop UL from IST constants.
No functional change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Acked-by: Jan Beulich <jbeulich@suse.com>
Andrew Cooper [Mon, 30 Dec 2024 06:41:46 +0000 (06:41 +0000)]
xen: Don't cast away const-ness in vcpu_show_registers()
The final hunk is `(struct vcpu *)v` in disguise, expressed using a runtime
pointer chase through memory and a technicality of the C type system to work
around the fact that get_hvm_registers() strictly requires a mutable pointer.
For anyone interested, this is one reason why C cannot optimise any reads
across sequence points, even for a function purporting to take a const object.
Anyway, have the function correctly state that it needs a mutable vcpu. All
callers have a mutable vCPU to hand, and it removes the runtime pointer chase
in x86.
Make one style adjustment in ARM while adjusting the parameter type.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Acked-by: Jan Beulich <jbeulich@suse.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Nicola Vetrini [Tue, 4 Mar 2025 17:49:36 +0000 (18:49 +0100)]
automation/eclair: Reduce verbosity of ECLAIR logs.
While activating verbose logging simplifies debugging, this causes
GitLab logs to be truncated, preventing the links to the ECLAIR
analysis database to be shown.
Andrew Cooper [Mon, 3 Mar 2025 14:06:55 +0000 (14:06 +0000)]
CHANGELOG.md: Set release date for 4.20
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Acked-by: Roger Pau Monné <roger.pau@citrix.com> Acked-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
projects / people / andrewcoop / xen.git / log