The only locking required here is that between checking d->target and
setting it. To avoid the need for an explicit lock, use cmpxchgptr() to
update d->target.
Move the handling not only ahead of acquiring the lock, but also ahead
of the XSM check, leveraging that the sub-op has its own hook.
This is part of XSA-492.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Daniel P. Smith <dpsmith@apertussolutions.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
(cherry picked from commit 4a93d1fb4f)
Integrate the checking with xsm_domctl(). As a positive side effect,
permissions are then checked at the same early point with and without
Flask. As the DT device path needs fetching earlier (but must not be
double fetched), cache it in a private field of the public interface
struct.
This is part of XSA-492.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Daniel P. Smith <dpsmith@apertussolutions.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
(cherry picked from commit eab54f074f)
iommu_get_device_group() uses its own locking. Thus, with caller side
locking irrelevant, it can as well be called with the domctl lock not
held.
Move the handling not only ahead of acquiring the lock, but also ahead
of the XSM check, leveraging that the sub-op has its own hook.
This is part of XSA-492.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Daniel P. Smith <dpsmith@apertussolutions.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
(cherry picked from commit 471b377747)
Integrate the checking with xsm_domctl(), now that it has the full op
struct passed. As a positive side effect, permissions are then checked at
the same early point with and without Flask.
This is part of XSA-492.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Daniel P. Smith <dpsmith@apertussolutions.com>
(cherry picked from commit d9d2758622)
Integrate the checking with xsm_domctl(), now that it has the full op
struct passed. As a positive side effect, permissions are then checked at
the same early point with and without Flask.
This is part of XSA-492.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Daniel P. Smith <dpsmith@apertussolutions.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
(cherry picked from commit 3ba374d388)
Subsequently some sub-ops will want to inspect their sub-sub-ops. Plus
this way we don't need to pass SSIDref separately anymore for
domain_create.
This is part of XSA-492.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Daniel P. Smith <dpsmith@apertussolutions.com>
(cherry picked from commit 83f0e11ed1)
Integrate the checking with xsm_domctl(). Care needs to be taken with the
GET_VERSION sub-op, which may be invoked with DOMID_INVALID, and which has
been (and continues to be) bypassing XSM checking.
Since the latter two parameters were unused, monitor_domctl() invoking the
hook was actually redundant with the earlier xsm_domctl() (as can be seen
nicely from the hunks changing xsm/flask/hooks.c).
As a positive side effect, permissions are then checked at the same early
point with and without Flask.
While folding XEN_DOMCTL_monitor_op and XEN_DOMCTL_vm_event_op in
flask_domctl(), also fold in XEN_DOMCTL_set_access_required.
This is part of XSA-492.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Daniel P. Smith <dpsmith@apertussolutions.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
(cherry picked from commit b4a7c17146)
With dedicated locking added, the domctl lock isn't required here anymore.
As the GSI handling is in arch-specific code (x86 only), no code is being
moved there; the 2nd invocation of arch_do_domctl() is re-used. Move the
re-purposed (XSM_HOOK -> XSM_PRIV, as xsm_domctl() is now bypassed)
dedicated XSM checks as early as possible.
This is part of XSA-492.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Daniel P. Smith <dpsmith@apertussolutions.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
(cherry picked from commit 6b71151cd8)
With dedicated locking added, the domctl lock isn't required here anymore.
As the I/O port handling is in arch-specific code (x86 only), no code is
being moved, but the 2nd invocation of arch_do_domctl() is re-used. Move
the re-purposed dedicated XSM checks as early as possible.
This is part of XSA-492.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Daniel P. Smith <dpsmith@apertussolutions.com>
(cherry picked from commit 9f54e10bf3)
With dedicated locking added, the domctl lock isn't required here anymore.
(It also already isn't used when pt_irq_{create,destroy}_bind() are
invoked for PVH Dom0.) As the handling is in arch-specific code, no code
is being moved, but the 2nd (extensible to other sub-ops like the ones
here) invocation of arch_do_domctl() is being re-used.
This is part of XSA-492.
Fixes: fda49f9b3f ("Add build option to allow more hypercalls from stubdoms")
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Daniel P. Smith <dpsmith@apertussolutions.com>
Acked-by: Julien Grall <julien@xen.org>
(cherry picked from commit e263eeaf71)
With dedicated locking added, the domctl lock isn't required here anymore.
As the handling is in arch-specific code (x86 only), almost no code is
being moved, but a 2nd (extensible to other sub-ops) invocation of
arch_do_domctl() is being added. Move just the re-purposed dedicated XSM
check as early as possible.
In flask_domctl() don't put #ifdef around the moved case label.
This is part of XSA-492.
Fixes: fda49f9b3f ("Add build option to allow more hypercalls from stubdoms")
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Daniel P. Smith <dpsmith@apertussolutions.com>
(cherry picked from commit 9ac94138a5)
With dedicated locking added, the domctl lock isn't required here anymore.
Move the re-purposed dedicated XSM check as early as possible.
Minimal "modernization": Switch "add" to bool and use %pd in log messages.
This is part of XSA-492.
Fixes: fda49f9b3f ("Add build option to allow more hypercalls from stubdoms")
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Daniel P. Smith <dpsmith@apertussolutions.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
(cherry picked from commit 5a81fb873c)
It's used twice in entirely different situations. The use in do_domctl()
wants to become an ordinary XSM_DM_PRIV invocation, while the one in vPCI
code need to remain XSM_HOOK (it may plausibly become XSM_TARGET). For
Flask, the same backing function will continue to be used for the time
being.
This is part of XSA-492.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Daniel P. Smith <dpsmith@apertussolutions.com>
(cherry picked from commit 6bb83b1aa0)
In order to be able to pull at least the XEN_DOMCTL_{,un}bind_pt_irq
handling out of the domctl-locked region, a separate (per-domain) lock is
needed to synchronize in particular with XEN_DOMCTL_{irq,gsi}_permission.
Locking is added only as far as domctl-s are affected. Uses presently
outside of the domctl lock may want dealing with subsequently (perhaps
limited to non-__init code).
This is part of XSA-492.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Julien Grall <julien@xen.org>
(cherry picked from commit 329edc090d)
In order to be able to pull at least the XEN_DOMCTL_ioport_mapping
handling out of the domctl-locked region, the new separate (per-domain)
lock is used to synchronize in particular with
XEN_DOMCTL_ioport_permission.
Locking is added only as far as domctl-s are affected. Uses presently
outside of the domctl lock may want dealing with subsequently (perhaps
limited to non-__init code).
This is part of XSA-492.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
(cherry picked from commit c9f4586766)
In order to be able to pull at least the XEN_DOMCTL_iomem_mapping handling
out of the domctl-locked region, a separate (per-domain) lock is needed to
synchronize in particular with XEN_DOMCTL_iomem_permission.
Locking is added only as far as domctl-s are affected. Uses presently
outside of the domctl lock may want dealing with subsequently (perhaps
limited to non-__init code).
This is part of XSA-492.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
(cherry picked from commit 960713dfd4)
get_domain_state() uses its own locking. Thus, with caller side locking
irrelevant, it can as well be called with the domctl lock not held.
Move the handling not only ahead of acquiring the lock, but also ahead
of the XSM check, leveraging that the sub-op has its own hook.
This is part of XSA-492.
Fixes: 3ad3df1bd0 ("xen: add new domctl get_domain_state")
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Daniel P. Smith <dpsmith@apertussolutions.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
(cherry picked from commit eedff4bcd3)
When DOMID_INVALID is passed, the dom exec handler lock is being taken
without any check that the domain is even allowed to take the lock. This
allows for an unauthorized domain to DoS the get_domain_state domctl op.
Move to consider the op effectively being called against the hypervisor.
Thus it is the target of the call being invoked to identify the last
domain with a state change. The subsequent check of whether the source
domain is allowed the state of the last domain to change state is still
relevant.
This is part of XSA-492.
Signed-off-by: Daniel P. Smith <dpsmith@apertussolutions.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
(cherry picked from commit 5154fdda11)
getdomaininfo() is not called under consistently the same lock. Thus,
with caller side locking irrelevant, it can as well be called with the
domctl lock not held. (Callers not pausing the domain they want to
retrieve information for already need to be aware that not all of the
data returned can be relied on as being consistent; most data will also
be stale by the time the caller gets to look at it.)
Move the handling not only ahead of acquiring the lock, but also ahead
of the XSM check, leveraging that the sub-op has its own hook.
While moving, convert an assignment to an assertion: The domain in
question was determined from the field which previously was "updated".
This is part of XSA-492.
Fixes: 5513bd0b46 ("add xenstore domain flag to hypervisor")
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Daniel P. Smith <dpsmith@apertussolutions.com>
(cherry picked from commit 784bd4dc0b)
Subsequently XEN_DOMCTL_getdomaininfo will want to invoke the function
without holding a lock, thus allowing parallel execution of potentially
many instances. As was learned from 228ab9992f ("domctl: improve
locking during domain destruction"), reverted by d0887cc6b1, such
parallelism can result in severe lock contention on any (previously)
inner lock. To avoid taking that risk replace the use of the scheduler
lock in vcpu_runstate_get() by a newly introduced sequence counter.
Convert the "no lock if current" property to "use a local counter
instance", thus guaranteeing the loop to exit after the first iteration.
Skeleton and commentary of the seqcount implementation based on /
derived from Linux 6.11-rc.
To have runstate_seq placed next to runstate in struct vcpu, without
introducing a new obvious padding hole, yet while keeping the latter
adjacent to runstate_guest{,_area} as well, move runstate down a little.
This is part of XSA-492.
Requested-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
(cherry picked from commit 1dc4d5d818)
XEN_DOMCTL_ioport_mapping is usable by DM stubdoms, and hence we can't
assume the list to be left unaltered while the guest (really: the
hypervisor on behalf of the guest) is accessing it.
This is XSA-491 / CVE-2026-42487.
Fixes: 192c4dabc3 ("domctl and p2m changes for PCI passthru")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
(cherry picked from commit 7787f8e939)
When netbooting a unified Xen kernel image (via GRUB chainloader),
the resulting loaded_image->DeviceHandle does not support
SIMPLE_FILE_SYSTEM_PROTOCOL.
Instead of crashing via noreturn PrintErrMesg() in get_parent_handle(),
we defer calling this function until filesystem access is needed.
This way when booting UKI, get_parent_handle() is not called at all.
Suggested-by: Andrew Cooper <andrew.cooper3@citrix.com>
Suggested-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Signed-off-by: Szymon Acedański <accek@invisiblethingslab.com>
Acked-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
xen/efi: Use blexit() instead of BUG_ON() in read_file()
Follow-up to 880e40b187, which added a BUG_ON() guard in read_file().
But as Jan pointed out, before ExitBootServices BUG_ON()
is not functional. It results in a hang with no message.
On the other hand blexit() prints a message and returns back
to the bootloader.
Fixes: 880e40b187 ("xen/efi: Fix boot from a device without a file system")
Reported-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Szymon Acedański <accek@invisiblethingslab.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
master commit: 880e40b187
master date: 2026-05-28 16:19:16 +0100
master commit: 7e11543c53
master date: 2026-06-03 08:17:56 +0200
In FRED mode, the SYSCALL instruction does not modify %rcx/%r11. All current
software using SYSCALL expects the pre-FRED behaviour and spills %rcx/%r11
around the invocation, which is why FRED not doing this goes largely
unnoticed.
However, consider the following migration scenario:
* VM suspends. Hypercall, so SYSCALL, %rcx/%r11 left unmodified
* VM moves to a non-FRED system
* Xen resumes the VM with a real SYSRET instruction
Instead of resuming at the instruction following the SYSCALL instruction, the
VM is resumed at whatever dead value was in %rcx.
In FRED mode, manually adjust %rcx/%r11 when SYSCALL is used and when SYSRET
would have been used.
Regarding the choice of instructions in eretu_exit_to_guest(), a branch would
be a context dependent 50/50 split (i.e. increased chance of mispredict), and
only saves one instruction. The CMOVs read the same cacheline that ERETU is
about to process, so are as close to free as we can reasonably get.
Fixes: 76193ef47d ("x86/pv: System call handling in FRED mode")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: c5a4b9125b
master date: 2026-05-28 16:19:16 +0100
__{put,get}_guest() returns -EFAULT on access faults which causes
the injected CR2 to be off by 14 bytes (as EFAULT is 14) which is
incorrect.
Fix the computation by relying on __copy_{from,to}_guest_pv() which
reports the number of remaining bytes instead of a negative errno,
such that we can compute the offset properly.
Fixes: 70ad570b27 ("x86/64: paravirt 32-on-64 call gate support")
Signed-off-by: Teddy Astie <teddy.astie@vates.tech>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 03878fba4a
master date: 2026-05-22 14:33:44 +0100
Move first read of gt->gt_version inside the critical region of the
rwlock, otherwise concurrent gnttab operations (silly as they would be)
may get mutually confused as to the actual current version.
Fixes: c1488502c949("grant-tables: do not fail attempts to...")
Reported-by: Oleksandr Tyshchenko <Oleksandr_Tyshchenko@epam.com>
Signed-off-by: Alejandro Vallejo <alejandro.garciavallejo@amd.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: c0e548d920
master date: 2026-05-22 13:32:44 +0200
Starting with Zen4, AMD CPUs can virtualise NMIs for a guest. On older
hardware, determining when an NMI is safe to deliver is a challenge and Xen
does not handle all corner cases correctly.
With vNMI, there is an enablement bit and two new bits of state in the VMCB; a
pending bit, and a blocked bit. These directly map to the CPU state for
handling NMIs, and are maintained by hardware during the running of the vCPU.
When vNMI is enabled, have svm_{get,set}_interrupt_shadow() work in terms of
the vnmi_blocking bit rather than the IRET intercept. This allows an emulated
IRET instruction to re-enable NMIs.
When injecting a new NMI, simply set the vnmi_pending bit; hardware will
deliver the NMI to the guest at the next suitable juncture.
One complication is that, when delivering a second NMI before the first has
completed, the mix between common HVM logic and SVM specific logic will try to
open an NMI window, malfunctioning as it does so. When vNMI is enabled, short
circuit this to not consider NMIs blocked.
Signed-off-by: Abdelkareem Abdelsaamad <abdelkareem.abdelsaamad@citrix.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Teddy Astie <teddy.astie@vates.tech>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 86a203ab8d
master date: 2026-05-21 16:43:01 +0100
PV console doesn't require Xen to be running as a shim and only
requires CONFIG_XEN_GUEST and running as a Xen guest. Update the
documentation accordingly.
Fixes: 4f6609d6a6 ("x86/guest: use PV console for Xen/Dom0 I/O")
Signed-off-by: Teddy Astie <teddy.astie@vates.tech>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: f47c2e96ab
master date: 2026-05-21 09:13:42 +0200
Introduce the cpuid bit for the SVM vNMI feature support for the x86\AMD
platforms. The feature support is indicated by the CPUID
Fn8000_000A_EDX[25] = 1.
Add defines for the three SVM's Virtual NMI (vNMI) managements bits in the
VMCB structure's vintr_t:
vintr_t(11) - Virtual NMI is pending.
vintr_t(12) - Virtual NMI is masked.
vintr_t(26) - Enable NMI virtualization.
Signed-off-by: Abdelkareem Abdelsaamad <abdelkareem.abdelsaamad@citrix.com>
Reviewed-by: Teddy Astie <teddy.astie@vates.tech>
Acked-by: Jan Beulich <jbeulich@suse.com>
master commit: 0294292b4c
master date: 2026-02-23 08:41:32 +0100
libxl_nocpuid.c needs the same treatment as libxl_cpuid.c
Fixes: f6c6f2679d ("libxl: Convert libxl__object_to_json() to json-c")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>
(cherry picked from commit ca7906501e)
These do not add any value to the analysis other than duplicating some reports
in whole-program analysis, as the intermediate linking steps are only used to
build the symbol table.
Suggested-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Nicola Vetrini <nicola.vetrini@bugseng.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: 79e060ea03
master date: 2026-05-14 13:38:04 +0100
If there are any local symbols in an object file, GNU ld will create an
STT_FILE symbol derived from the object file name if there is none in the
incoming symbol table. The object file name, however, varies between
linking passes. As a result, symbol name compression can yield different
results if any of those local symbols need retaining (Arm [and RISC-V]
mapping symbols are omitted, for example). If that difference in
compression would yield a difference in the sizes of symbol_names[] or
symbols_token_table[], the compare-symbol-tables sanity check will fail.
Fixes: d37d63d4b5 ("symbols: prefix static symbols with their source file names")
Reported-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Tested-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
master commit: c5d554edff
master date: 2026-05-13 10:00:52 +0200
Overlapping requests may need processing backwards, or else the intended
effect wouldn't be achieved (and instead some pages would be moved more
than once).
With some adjustment there this also covers XEN_DMOP_relocate_memory,
where the potential issue was first noticed.
Fixes: a04811a315 ("mm: New XENMEM space, XENMAPSPACE_gmfn_range")
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Tested-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: 7acc7dd36b
master date: 2026-05-13 09:59:19 +0200
As a comment next to one of the invocations states, get_wallclock_time()
can take over a second. The order of evaluation of function arguments is
in principle unspecified; in practice at least gcc looks to be evaluating
them from last to first. Hence with NOW() invoked first, the respective
value passed to do_settime() can be off by over a second (which is in
contrast to __get_cmos_time() attempting to get the time exactly after an
update, i.e. [pretty] precisely at a seconds boundary).
This also addresses a Misra C:2012 rule 13.2 ("The value of an expression
and its persistent side-effects shall be the same under all permitted
evaluation orders") violation each. The violations aren't flagged because
the entire file is (bogusly) excluded from scanning.
Fixes: f64134cdb8 ("x86: Fix time_resume() to notify all domains of wallclock change")
Fixes: 0bfcf984b7 ("x86: Reintroduce clocksource=tsc")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
master commit: 54ca0aadc8
master date: 2026-05-07 16:10:52 +0200
When booting Xen with CONFIG_USBAN=y and CONFIG_XSM_FLASK=y,
UBSAN reports undefined behaviour in avc_dump_av() due to a left
shift on a signed int:
(XEN) [ 1.104348] ================================================================================
(XEN) [ 1.105096] UBSAN: Undefined behaviour in xsm/flask/avc.c:184:14
(XEN) [ 1.106052] left shift of 1073741824 by 1 places cannot be represented in type 'int'
(XEN) [ 1.107546] Xen WARN at common/ubsan/ubsan.c:176
(XEN) [ 1.108295] ----[ Xen-4.21.1 arm64 debug=y ubsan=y Not tainted ]----
(XEN) [ 1.108848] CPU: 0
(XEN) [ 1.109147] PC: 00000a00002f64fc ubsan.c#ubsan_epilogue+0x10/0xd4
[...]
(XEN) [ 1.146320] Xen call trace:
(XEN) [ 1.146663] [<00000a00002f64fc>] ubsan.c#ubsan_epilogue+0x10/0xd4 (PC)
(XEN) [ 1.147227] [<00000a00002f7bc4>] __ubsan_handle_shift_out_of_bounds+0x1a0/0x290 (LR)
(XEN) [ 1.147868]
(XEN) [ 1.148177] ================================================================================
This can be solved by making 'perm' an unsigned 32-bit type (u32).
Signed-off-by: Dmytro Prokopchuk <dmytro_prokopchuk1@epam.com>
Acked-by: Daniel P. Smith <dpsmith@apertussolutions.com>
master commit: 4f9457ece1
master date: 2026-05-06 15:11:18 +0200
The boot services FreePages() needs passing the size. Since we allocated
one more byte to put a trailing nul there, we also need to bump the size
passed there. Make a small helper function to centralize this.
Note that there's no permanent memory leak because of the oversight: The
allocation is done using EfiLoaderData, and all memory of that type is
later reclaimed anyway.
Fixes: df75f77092 ("EFI: avoid OOB config file reads")
Reported-by: Bernhard Kaindl <bernhard.kaindl@citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Bernhard Kaindl <bernhard.kaindl@citrix.com>
Acked-by: Daniel P. Smith <dpsmith@apertussolutions.com>
master commit: 4ff927133e
master date: 2026-05-06 15:11:11 +0200
What c4f427ec87 ("xen: Swap order of actions in the FREE*() macros") did
should have been done right away when XVFREE() was introduced.
Fixes: 9102fcd957 ("mm: introduce xvmalloc() et al and use for grant table allocations")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
master commit: 96ffccef5a
master date: 2026-05-06 15:11:11 +0200
Under SVM, there are two copies of guest CR2. One is v->arch.hvm.guest_cr[2]
and one is in the VMCB.
Xen doesn't intercept CR2 accesses, so this mostly goes unnoticed; hardware
loads and saves the guest CR2 in the VMCB across VMRUN/VMExit.
For HAP guests (where #PF is not intercepted, and therefore we don't typically
inject #PF either), this causes the guest CR2 value to be lost on migrate. As
migration is cooperative and not done from the #PF handler, this also goes
unnoticed by guests.
It also means that an emulated MOV-from-CR2 reads a stale value.
Reported-by: Stefano Stabellini <sstabellini@kernel.org>
Fixes: d1bd157fbc ("Big merge the HVM full-virtualisation abstractions.")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Tested-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Teddy Astie <teddy.astie@vates.tech>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 3e6bca616b
master date: 2026-05-05 11:45:00 +0100
Gitlab CI reported a crash on boot on Alder Lake hardware. The bug is years
old, making it an incredibly rare occurance:
(XEN) *** DOUBLE FAULT ***
(XEN) ----[ Xen-4.22-unstable x86_64 debug=y ubsan=y Not tainted ]----
(XEN) CPU: 0
(XEN) RIP: e008:[<ffff82d04077bbc4>] arch/x86/setup.c#reinit_bsp_stack+0xfa/0x160
(XEN) RFLAGS: 0000000000010202 CONTEXT: hypervisor
(XEN) rax: 0000000000000007 rbx: ffff83049a4b0000 rcx: 00000000000006a2
(XEN) rdx: 0000000000000000 rsi: 0000000000000000 rdi: 0000000000000000
(XEN) rbp: ffff83049a4b7f00 rsp: ffff83049a4b7ef8 r8: ffff830497e47000
(XEN) r9: 00000000ffffffff r10: 00000000900c2121 r11: 000000009a392956
(XEN) r12: ffff830497e47000 r13: ffff830497e49f40 r14: 0000000000000000
(XEN) r15: ffff82d0407dad10 cr0: 0000000080050033 cr4: 0000000000f526e0
(XEN) cr3: 0000000043c16000 cr2: fffffffffffffffc
(XEN) fsb: 0000000000000000 gsb: 0000000000000000 gss: 0000000000000000
(XEN) ds: 0000 es: 0000 fs: 0000 gs: 0000 ss: 0000 cs: e008
(XEN) Xen code around <ffff82d04077bbc4> (arch/x86/setup.c#reinit_bsp_stack+0xfa/0x160):
(XEN) 00 b9 a2 06 00 00 0f 30 <80> 3d 71 26 f1 ff 00 74 3e 48 8d 93 f8 5f 00 00
(XEN) Valid stack range: ffff83049a4b6000-ffff83049a4b8000, sp=ffff83049a4b7ef8, tss.rsp0=ffff83049a4b7fb0
(XEN) No stack overflow detected. Skipping stack trace.
(XEN)
(XEN) ****************************************
(XEN) Panic on CPU 0:
(XEN) DOUBLE FAULT -- system shutdown
(XEN) ****************************************
This is on the instruction boundary after enabling CET (writing MSR_S_CET) and
prior to establishing SSP. Despite identifying this as a critical window
where any fault was deadly (the CPU tries to push a shadow stack frame at 0,
hence the CR2 value wrapping around to the top of the address space), I
clearly forgot that this meant interrupts too, which are enabled.
Disable interrupts during the critical period.
Fixes: b60ab42db2 ("x86/shstk: Activate Supervisor Shadow Stacks")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Teddy Astie <teddy.astie@vates.tech>
master commit: acfd2631b9
master date: 2026-05-05 11:45:00 +0100
The admin can control the upper bound wanted not only via command line
option, but also via XEN_SYSCTL_pm_op_set_max_cstate. While decisions how
to set up the system are okay this way as long as we deem the command line
option a strict upper bound, what to do during S3 resume should not be
based on that potentially varying value. Decisions there need to use
solely the strict upper bound we may have enforced ourselves (or which was
forced onto us via command line option).
Rather than altering pit_broadcast_is_available(), drop the function
altogether. It's pretty odd for acpi/cpu_idle.c to call into time.c, just
for that to call into acpi/cpu_idle.c again.
Fixes: 8d24303023 ("x86: don't write_tsc() non-zero values on CPUs updating only the lower 32 bits")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
master commit: 93acfeb78b
master date: 2026-05-05 08:27:29 +0200
Uninitialized cpu_data[] entries have the apicid field set to BAD_APICID,
not boot_cpu_data.apicid. Fix the check in cpu_smpboot_free() to use the
correct condition.
Fixes: 7126b7f806 ("x86/CPU: re-work populating of cpu_data[]")
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Teddy Astie <teddy.astie@vates.tech>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: cd0413bfac
master date: 2026-05-01 10:51:19 +0100
If a domain tries to map status frames in parallel to switching grant
table version from 2 to 1, the mapping operation may put in place P2M
entries referencing MFNs which gnttab_unpopulate_status_frames() is in the
process of freeing.
Ideally we would refcount pages when entered into P2M tables, but that's a
significant change. Extend the grant-table-locked region instead in
xenmem_add_to_physmap_one() (being the sole caller of gnttab_map_frame()),
such that a race with gnttab_unpopulate_status_frames() is no longer
possible.
This is XSA-486 / CVE-2026-23558.
Fixes: 5ce8fafa94 ("Dynamic grant-table sizing")
Fixes: a98dc13703 ("Introduce a grant_entry_v2 structure")
Reported-by: Rafal Wojtczuk <rafal.wojtczuk@7bulls.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
(cherry picked from commit 02708d3b51)
conn_delete_all_transactions() should be callable in any context,
resetting ALL transaction related data.
This includes number of active transactions and the transaction
pointer in struct connection.
So reset conn->trans to NULL in conn_delete_all_transactions() and
do the cleanup for each transaction in destroy_transaction().
This avoids triggering the assert() in conn_delete_all_transactions()
in case e.g. ignore_connection() was called while an operation inside
a transaction was performed, or XS_RESET_WATCHES was called in a
transaction.
This is XSA-484 / CVE-2026-23557.
Reported-by: Andrii Sultanov <andriy.sultanov@vates.tech>
Fixes: 1f9d04fb02 ("xenstored: allow guest to shutdown all its watches/transactions")
Signed-off-by: Juergen Gross <jgross@suse.com>
(cherry picked from commit e88031d1fe)
The quota object contains both limits and the current node usage counts.
When a domain is torn down, the node data itself is cleaned up but the node
usage counts are not. A later domain reusing the same domid can create fewer
nodes before being deemed to be over quota.
Reset the count when the node permissions are cleaned up.
This is XSA-483 / CVE-2026-23556.
Signed-off-by: Andrii Sultanov <andriy.sultanov@vates.tech>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
(cherry picked from commit af9e77f5ff)
Fix the code which tries to pad the load segment to 2 MiB but only pads
it to a 1 MiB boundary.
This manifests as a page fault while scrubbing RAM during boot on certain
systems.
Xen fails to mark itself as reserved in the E820 (due to spanning multiple
regions), but does restrict the permissions in the directmap. The region of
RAM containing Xen is handed to physical memory manager as available for use,
and scrubbing hit the directmap protections.
Fixes: 4fb075201f ("x86/mkelf32: pad load segment to 2Mb boundary")
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: 5416c455f6
master date: 2026-04-17 18:15:54 +0100
All arches truncate the cpu_khz without taking into account the less
significant digits. Instead use DIV_ROUND() when scaling from Hz to kHz
to get as more accurate kHz value.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 986707b461
master date: 2026-04-16 15:28:32 +0200
When running HVM guest in native TSC mode avoid using the recalculated vTSC
scaling factors based on the cpu_khz value. Using the kHz based frequency
leads to the TSC scaling values possibly not being the same as the ones
used by the per CPU cpu_time->tsc_scale field, which introduces skew
between the guest and Xen's calculations of the system time.
On a 2gHz system, where the frequency is possibly detected as 1999999999Hz
(note this is a worse-case scenario), the cpu_khz variable will be set to
1999999kHz, and hence 999Hz cycles will be not accounted for per second.
Over a second (the time synchronization period), this leads to a skew of:
cycles * 1 / (Hz freq) = 999 / 1999999999 = 499,5ns
So far this has gone unnoticed because the time synchronization rendezvous
forces the update of the tsc_timestamp and system_time fields in the vCPU
time info area, and hence the skew only accumulates up to the rendezvous
period. Attempting to remove the rendezvous causes the skew to grow
unbounded.
Fix by using the native TSC scaling values (as used by Xen) when the guest
TSC is not scaled.
Fixes: eab8a90be7 ("x86/time: scale host TSC in pvclock properly")
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 305c6b901a
master date: 2026-04-16 15:28:32 +0200
The per-channel ENABLE bit is to solely be driven by hpet_enable_channel()
and hpet_msi_{,un}mask(). It doesn't need setting immediately. Except for
the (possible) channel put in legacy mode we don't do so during boot
either.
Instead reset ->arch.cpu_mask, to avoid msi_compose_msg() yielding an
all-zero message (when the passed in CPU mask has no online CPUs). Nothing
would later call msi_compose_msg() / hpet_msi_write(), and hence nothing
would later produce a well-formed message template in
hpet_events[].msi.msg.
Fixes: 15aa6c6748 ("amd iommu: use base platform MSI implementation")
Reported-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Tested-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
master commit: c4d5119195
master date: 2026-04-16 10:44:16 +0200
With an expiry value on the order of 10 hours, and with a bus scale value
of 256k (as supplied by qemu), the (signed) multiplication will be UB. As
we've checked that the value is positive, we mean unsigned multiplication
anyway. Yet let's play safe against even larger expiry and bus scale
values, leveraging the compiler builtin that there is for this purpose.
While there also drop the stray cast from the actual TMICT write.
Fixes: 9062553a0d ("added time and accurate timer support")
Fixes: b95beb1858 ("x86: Clean up APIC local timer handling")
Reported-by: Stewart Hildebrand <stewart.hildebrand@amd.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Tested-by: Stewart Hildebrand <stewart.hildebrand@amd.com>
master commit: 4f14d97a62
master date: 2026-04-16 10:29:54 +0200
Jan Beulich