Pull x86 fixes from Ingo Molnar:
- Add more AMD Zen6 models (Pratik Vishwakarma)
- Avoid confusing bootup message by the Intel resctl enumeration
code when running on certain AMD systems (Tony Luck)
* tag 'x86-urgent-2026-06-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/resctrl: Only check Intel systems for SNC
x86/CPU/AMD: Add more Zen6 models
Pull Rust fixes from Miguel Ojeda:
"Toolchain and infrastructure:
- Fix 'rustc-option' (the Makefile one) when cross-compiling that
leads to build or boot failures in certain configs
- Work around a Rust compiler bug (already fixed for Rust 1.98.0)
thats lead to boot failures in certain configs due to missing
'uwtable' LLVM module flags
- Support a Rust compiler change (starting with Rust 1.98.0) in the
unstable target specification JSON files
- Forbid Rust + arm + KASAN configs, which do not build
'kernel' crate:
- Fix NOMMU build by adding a missing helper"
* tag 'rust-fixes-7.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux:
rust: x86: support Rust >= 1.98.0 target spec
rust: arm64: set uwtable llvm module flag for CONFIG_UNWIND_TABLES
rust: helpers: add is_vmalloc_addr wrapper for NOMMU builds
rust: kasan/kbuild: fix rustc-option when cross-compiling
ARM: Do not select HAVE_RUST when KASAN is enabled
Pull kvm fixes from Paolo Bonzini:
"arm64:
- Correctly drop the ITS translation cache reference when it actually
gets invalidated
- Take the SRCU lock for SW page table walks
- Restore POR_EL0 access to host EL0, avoiding POR_EL0 becoming
inaccessible from EL0 after running a guest
- Reassign nested_mmus array behind mmu_lock, ensuring that vcpu init
and MMU notifiers are mutually exclusive
- Correctly handle FEAT_XNX at stage-2
s390:
- More fixes for the new page table management and nested
virtualization
x86:
- More fixes for GHCB issues:
- Read start/end indices of page size change requests exactly once
per vmexit
- Unmap and unpin the GHCB as needed on vCPU free"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (23 commits)
KVM: arm64: Correctly identify executable PTEs at stage-2
KVM: arm64: nv: Fix handling of XN[0] when !FEAT_XNX
KVM: arm64: Reassign nested_mmus array behind mmu_lock
KVM: arm64: Restore POR_EL0 access to host EL0
KVM: arm64: Take the SRCU lock for page table walks in fault injection and AT emulation
KVM: arm64: vgic-its: Drop the translation cache reference only for the erased entry
KVM: SEV: Unmap and unpin the GHCB as needed on vCPU free
KVM: SEV: Decouple the need to sync the GHCB SA from the need to free the SA
KVM: SEV: Move sev_free_vcpu() down below sev_es_unmap_ghcb()
KVM: Don't WARN if memory is dirtied without a vCPU when the VM is dying
KVM: SEV: Read start/end indices of PSC requests exactly once per #VMGEXIT
KVM: SEV: Add an anonymous "psc" struct to track current PSC metadata
KVM: SEV: Make it more obvious when KVM is writing back the current PSC index
KVM: s390: Remove ptep_zap_softleaf_entry()
KVM: s390: Fix possible reference leak in fault-in code
KVM: s390: Prevent memslots outside the ASCE range
KVM: s390: Lock pte when making page secure
KVM: s390: Fix fault-in code
KVM: s390: vsie: Fix rmap handling in _do_shadow_crste()
KVM: s390: Fix guest / virtual address confusion in _essa_clear_cbrl()
...
KVM/arm64 fixes for 7.1, take #5
- Correctly drop the ITS translation cache reference when it actually
gets invalidated
- Take the SRCU lock for SW page table walks
- Restore POR_EL0 access to host EL0, avoiding POR_EL0 becoming
inaccessible from EL0 after running a guest
- Reassign nested_mmus array behind mmu_lock, ensuring that vcpu init
and MMU notifiers are mutually exclusive
- Correctly handle FEAT_XNX at stage-2
KVM invalidates the I-cache before installing an executable PTE on
implementations without DIC. Unfortunately, support for FEAT_XNX
broke this check as KVM_PTE_LEAF_ATTR_HI_S2_XN was expanded to a
bitfield.
Fix it by reusing kvm_pgtable_stage2_pte_prot() and testing the abstract
permission bits instead.
Fixes: 2608563b46 ("KVM: arm64: Add support for FEAT_XNX stage-2 permissions")
Reported-by: Sashiko (gemini/gemini-3.1-pro-preview)
Signed-off-by: Oliver Upton <oupton@kernel.org>
Reviewed-by: Wei-Lin Chang <weilin.chang@arm.com>
Link: https://patch.msgid.link/20260602165901.52800-3-oupton@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
kvm->arch.nested_mmus[] is walked under kvm->mmu_lock, including from the
MMU notifier path (kvm_unmap_gfn_range() -> kvm_nested_s2_unmap()), which
can run at any time. kvm_vcpu_init_nested() reallocates the array and frees
the old buffer while holding only kvm->arch.config_lock, so such a walker
can reference the freed array.
Allocate the new array outside of mmu_lock, as the allocation can sleep.
Under the lock, copy the existing entries, fix up the back pointers and
reassign the array. Free the old buffer after dropping the lock, as
kvfree() can sleep as well.
Fixes: 4f128f8e1a ("KVM: arm64: nv: Support multiple nested Stage-2 mmu structures")
Signed-off-by: Hyunwoo Kim <imv4bel@gmail.com>
Reviewed-by: Oliver Upton <oupton@kernel.org>
Link: https://patch.msgid.link/aiKIVVeIr1aAB1yp@v4bel
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger,kernel.org
walk_s1() and kvm_walk_nested_s2() expect to be called while holding
kvm->srcu to guard against memslot changes. While this is generally
the case, __kvm_at_s12() and __kvm_find_s1_desc_level() call into the
respective walkers without taking kvm->srcu.
Fix by acquiring kvm->srcu prior to the table walk in both instances.
Cc: stable@vger.kernel.org
Fixes: 50f77dc87f ("KVM: arm64: Populate level on S1PTW SEA injection")
Fixes: be04cebf3e ("KVM: arm64: nv: Add emulation of AT S12E{0,1}{R,W}")
Suggested-by: Oliver Upton <oupton@kernel.org>
Signed-off-by: Hyunwoo Kim <imv4bel@gmail.com>
Reviewed-by: Oliver Upton <oupton@kernel.org>
Link: https://patch.msgid.link/aiAZfdeyanIvP8SD@v4bel
Signed-off-by: Marc Zyngier <maz@kernel.org>
vgic_its_invalidate_cache() walks the per-ITS translation cache with
xa_for_each() and drops the cache's reference on each entry with
vgic_put_irq(). It puts the iterated pointer, though, rather than the
value returned by xa_erase().
The function is called from contexts that do not exclude one another: the
ITS command handlers hold its_lock, the GITS_CTLR write path holds
cmd_lock, and the path that clears EnableLPIs in a redistributor's
GICR_CTLR holds neither. Two or more of them can drain the same cache
concurrently, and if each one observes the same entry, erases it and then
puts it, the single reference the cache holds on that entry is dropped
more than once. The entry can then be freed while an ITE still maps it.
xa_erase() is atomic and returns the previous entry, so put only the entry
that this context actually removed. The cache reference is then dropped
exactly once per entry even when the invalidations run concurrently, and
the behavior is unchanged when only one context runs.
Fixes: 8201d1028c ("KVM: arm64: vgic-its: Maintain a translation cache per ITS")
Signed-off-by: Hyunwoo Kim <imv4bel@gmail.com>
Reviewed-by: Oliver Upton <oupton@kernel.org>
Link: https://patch.msgid.link/ah2c5lu4JbUg7dj-@v4bel
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
Pull s390 fixes from Alexander Gordeev:
- Enable IOMMUFD and VFIO cdev such that PCI pass-through to
QEMU/KVM can optionally utilize native IOMMUFD
- With HAVE_ARCH_BUG_FORMAT enabled the BUG infrastructure might
misinterpret flags or fault. Fix this by moving the "format"
field emission into __BUG_ENTRY()
- The generic version of _THIS_IP_ is known to be brittle and may
break with current and future GCC and Clang optimizations. Fix
it by overriding _THIS_IP_
* tag 's390-7.1-4' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
s390: Implement _THIS_IP_ using inline asm
s390/bug: Always emit format word in __BUG_ENTRY
s390/configs: Enable IOMMUFD and VFIO cdev in defconfigs
Add a "psc" struct to vcpu_sev_es_state to avoid having to prefix all of
the fields with "psc_".
Take advantage of the code churn to opportunistically rename local
variables to "guest_psc" to make it more obvious that the buffer is guest
data, and more importantly, guest accessible!
Opportunistically rename inflight => batch_size as well, because there can
really only be one operation in-flight (per-vCPU), i.e. "inflight" _looks_
like a boolean, but in actuality is an integer tracking how many pages are
being handled by the current operation.
No functional change intended.
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20260501202250.2115252-13-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20260529183549.1104619-13-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Pull SoC fixes from Arnd Bergmann:
"Following the previous set of fixes, this addresses another
significant number of small issues found in firmware drivers (tee,
optee, qcomtee, qcom ice, exynos acpm) drivers through various tools.
This is about error handling, resource leaks, concurrency and a
use-after-free bug.
The fixes for the Qualcomm ICE driver also introduce interface changes
in the UFS and MMC drivers using it.
Outside of firmware drivers, there are a few fixes across the tree:
- Minor driver code mistakes in the Atmel EBI memory controller, the
i.MX soc ID driver and socfpga boot logic
- A defconfig change to avoid a boot time regression on multiple
qualcomm boards
- Device tree fixes for qualcomm, at91 and gemini, addressing mostly
minor configuration mistakes"
* tag 'soc-fixes-7.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (28 commits)
firmware: samsung: acpm: Fix infinite loop on sequence number exhaustion
firmware: samsung: acpm: Fix missing LKMM barriers in sequence allocator
firmware: samsung: acpm: Fix false timeouts and Use-After-Free in polling
ARM: dts: gemini: Fix partition offsets
ARM: socfpga: Fix OF node refcount leak in SMP setup
soc: qcom: ice: Fix the error code when 'qcom,ice' property is not found
arm64: dts: qcom: eliza: Add power-domain and iface clk for ice node
arm64: dts: qcom: milos: Add power-domain and iface clk for ice node
tee: qcomtee: add missing va_end in early return qcomtee_object_user_init()
tee: fix params_from_user() error path in tee_ioctl_supp_recv
tee: shm: fix shm leak in register_shm_helper()
tee: fix tee_ioctl_object_invoke_arg padding
arm64: defconfig: Enable PCI M.2 power sequencing driver
scsi: ufs: ufs-qcom: Remove NULL check from devm_of_qcom_ice_get()
mmc: sdhci-msm: Remove NULL check from devm_of_qcom_ice_get()
soc: qcom: ice: Return proper error codes from devm_of_qcom_ice_get() instead of NULL
soc: qcom: ice: Return -ENODEV if the ICE platform device is not found
soc: qcom: ice: Fix race between qcom_ice_probe() and of_qcom_ice_get()
ARM: dts: microchip: sam9x7: fix GMAC clock configuration
firmware: samsung: acpm: Fix mailbox channel leak on probe error
...
Migration entries do not need to be removed.
The swap subsystem has been (and still is being) heavily reworked. The
current implementation of ptep_zap_softleaf_entry() has been slowly
modified and is now wrong, since it unconditionally calls
swap_put_entries_direct() for both swap and migration entries.
Remove ptep_zap_softleaf_entry() altogether, merge the path for proper
swap entries directly in the only caller, and ignore migration entries.
Fixes: 200197908d ("KVM: s390: Refactor and split some gmap helpers")
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Message-ID: <20260602142356.169458-11-imbrenda@linux.ibm.com>
If kvm_s390_new_mmu_cache() fails, kvm_s390_faultin_gfn() returns
without releasing the faulted page.
Fix this by moving the allocation of the memory cache outside of the
loop. There is no reason to check at every iteration.
Opportunistically fix a comment.
Fixes: e907ae5301 ("KVM: s390: Add helper functions for fault handling")
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Message-ID: <20260602142356.169458-10-imbrenda@linux.ibm.com>
With KVM_S390_VM_MEM_LIMIT_SIZE, userspace can set the highest address
allowed for the VM. Creating a memslot that lies over the maximum
address does not make sense and is only a potential source of bugs.
Prevent creation of memslots over the maximum address, and prevent the
maximum address from being reduced below the end of existing memslots.
Fixes: e38c884df9 ("KVM: s390: Switch to new gmap")
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Message-ID: <20260602142356.169458-9-imbrenda@linux.ibm.com>
Make sure _kvm_s390_pv_make_secure() takes the pte lock for the given
address when attempting to make the page secure.
One of the steps in making the page secure is freezing the folio using
folio_ref_freeze(), which temporarily sets the reference count to 0.
Any attempt to get such a folio while frozen will fail and cause a
warning to be printed.
Other users of folio_ref_freeze() make sure that the page is not mapped
while it's being frozen, thus preventing gup functions from being able
to access it. For _kvm_s390_pv_make_secure(), this is not possible,
because the page needs to be mapped in order for the import to succeed.
By taking the pte lock, gup functions will be blocked until the import
operation is done, thus avoiding the race.
In theory this does not completely solve the issue: if a page is mapped
through multiple mappings, locking one pte does not protect from
calling gup on it through the other mapping. In practice this does not
happen and it is a decent stopgap solution until a more correct
solution is available.
Fixes: e38c884df9 ("KVM: s390: Switch to new gmap")
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Message-ID: <20260602142356.169458-8-imbrenda@linux.ibm.com>
Fix the fault-in code so that it does not return success if a
concurrent unmap event invalidated the fault-in process between the
best-effort lockless check and the proper check with lock.
The new behaviour is to retry, like the best-effort lockless check
already did.
This prevents the fault-in handler from returning success without
having actually faulted in the requested page.
Fixes: e907ae5301 ("KVM: s390: Add helper functions for fault handling")
Reviewed-by: Steffen Eiden <seiden@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Message-ID: <20260602142356.169458-7-imbrenda@linux.ibm.com>
Fix _do_shadow_crste() to also apply a mask on the reverse address, to
prevent spurious entries from being created, like already done in
gmap_protect_rmap().
Fixes: e38c884df9 ("KVM: s390: Switch to new gmap")
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Message-ID: <20260602142356.169458-6-imbrenda@linux.ibm.com>
Until now, gmap_helper_zap_one_page() was being called with the guest
absolute address, but it expects a userspace virtual address.
This meant that in the best case the requested pages were not being
discarded, and in the worst case that the wrong pages were being
discarded.
Fix this by converting the guest absolute address to host virtual
before passing it to gmap_helper_zap_one_page().
Fixes: e38c884df9 ("KVM: s390: Switch to new gmap")
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Message-ID: <20260602142356.169458-5-imbrenda@linux.ibm.com>
Factor out try_get_locked_pte(), which behaves similarly to
get_locked_pte(), but does not attempt to allocate missing tables and
performs a spin_trylock() instead of blocking.
The new function is also exported, since it will be used in other
patches.
If intermediate entries are missing, there can be no pte swap entry to
free, so it's safe to ignore them.
This avoids potentially sleeping while atomic.
Fixes: e38c884df9 ("KVM: s390: Switch to new gmap")
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Message-ID: <20260602142356.169458-4-imbrenda@linux.ibm.com>
The previous incorrect behaviour cleared the vsie_notif bit without
returning false, which allowed shadow crstes to be installed without
the vsie_notif bit.
Return false and do not perform the operation if an unshadow event has
been triggered, but still attempt to clear the vsie_notif bit from the
existing crste.
This will prevent the installation of shadow crstes without vsie_notif
bit and will also prevent the caller from looping forever if it was
not checking for the sg->invalidated flag.
Fixes: b827ef02f4 ("KVM: s390: Remove non-atomic dat_crstep_xchg()")
Fixes: a2c17f9270 ("KVM: s390: New gmap code")
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Message-ID: <20260602142356.169458-3-imbrenda@linux.ibm.com>
In _gmap_unmap_crste(), the crste to be unmapped is zapped calling
gmap_crstep_xchg_atomic() exactly once, and expecting it to succeed.
This is a reasonable sanity check, since kvm->mmu_lock is being held in
write mode, and thus no races should be possible.
An upcoming patch will change the behaviour of gmap_crstep_xchg_atomic()
to return false and clear the vsie_notif bit if the operation triggers
an unshadow operation. With the new behaviour, an unmap operation that
triggers an unshadow would cause the VM to be killed.
Prepare for the change by checking if the vsie_notif bit was set in
the old crste if gmap_crstep_xchg_atomic() fails the first time, and
try a second time. The second time no failures are allowed.
Fixes: b827ef02f4 ("KVM: s390: Remove non-atomic dat_crstep_xchg()")
Fixes: a2c17f9270 ("KVM: s390: New gmap code")
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Message-ID: <20260602142356.169458-2-imbrenda@linux.ibm.com>
SoCFPGA dts fix for v7.1
- Fix OF node refcount leak
* tag 'socfpga_fix_for_v7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/dinguyen/linux:
ARM: socfpga: Fix OF node refcount leak in SMP setup
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Microchip AT91 fixes for v7.1
This update includes:
- a fix for the GMAC DT node on SAM9X7 SoC to properly describe the
available clocks
* tag 'at91-fixes-7.1' of https://git.kernel.org/pub/scm/linux/kernel/git/at91/linux:
ARM: dts: microchip: sam9x7: fix GMAC clock configuration
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Pull x86 fixes from Ingo Molnar:
- Make the clearcpuid= boot parameter less prominent
and warn about its dangers & caveats (Borislav Petkov)
- Do not access the (new) PLATFORM_ID MSR when running
as a guest (Borislav Petkov)
- x86 ftrace: Relocate %rip-relative percpu refs in dynamic
trampolines, to fix crash when using such trampolines
(Alexis Lothoré)
- Fix x86-64 CFI build error (Peter Zijlstra)
- Revert FPU signal return magic number check optimization,
because it broke CRIU and gVisor in certain FPU configurations
(Andrei Vagin)
* tag 'x86-urgent-2026-05-31' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
Revert "x86/fpu: Refine and simplify the magic number check during signal return"
x86/kvm/vmx: Fix x86_64 CFI build
x86/ftrace: Relocate %rip-relative percpu refs in dynamic trampolines
x86/microcode: Do not access MSR_IA32_PLATFORM_ID when running as a guest
Documentation/arch/x86: Hide clearcpuid=
Pull tty/serial driver fixes from Greg KH:
"Here are some small serial driver fixes for 7.1-rc6. Included in here
are:
- mips serial driver fixes to resolve some long-standing issues with
how they interacted with the console. That's the "majority" of the
changes in this merge request
- sh-sci driver regression fix
- 8250 driver regression fixes
- other small serial driver fixes for reported problems.
All of these have been in linux-next for over a week with no reported
issues"
* tag 'tty-7.1-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
serial: dz: Enable modular build
serial: zs: Convert to use a platform device
serial: dz: Convert to use a platform device
serial: zs: Switch to using channel reset
serial: zs: Fix bootconsole handover lockup
serial: dz: Fix bootconsole handover lockup
serial: dz: Fix bootconsole message clobbering at chip reset
serial: 8250_dw: dispatch SysRq character in dw8250_handle_irq()
serial: 8250: dispatch SysRq character in serial8250_handle_irq()
serial: core: introduce guard(uart_port_lock_check_sysrq_irqsave)
tty: serial: samsung: Remove redundant port lock acquisition in rx helpers
serial: altera_jtaguart: handle uart_add_one_port() failures
serial: qcom_geni: fix kfifo underflow when flush precedes DMA completion IRQ
serial: fsl_lpuart: fix rx buffer and DMA map leaks in start_rx_dma
tty: add missing tty_driver include to tty_port.h
serial: qcom-geni: fix UART_RX_PAR_EN bit position
serial: sh-sci: fix memory region release in error path
tty: serial: pch_uart: add check for dma_alloc_coherent()
serial: zs: Fix swapped RI/DSR modem line transition counting
Both GCC [1] and Clang [2] consider the generic version of _THIS_IP_ to
be broken:
#define _THIS_IP_ ({ __label__ __here; __here: (unsigned long)&&__here; })
In particular, the address of a label is only expected to be used with a
computed goto.
While the generic version more or less works today, it is known to be
brittle and may break with current and future optimizations. For
example, Clang -O2 always returns 1 when this function is inlined:
static inline unsigned long get_ip(void)
{ return ({ __label__ __here; __here: (unsigned long)&&__here; }); }
Fix it by overriding _THIS_IP_ in <asm/linkage.h> (which is included by
<linux/instruction_pointer.h>) using an architecture-specific inline asm
version. Additionally, avoiding taking the address of a label prevents
compilers from emitting spurious indirect branch targets (e.g. ENDBR or
BTI) under control-flow integrity schemes.
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120071 [1]
Link: https://github.com/llvm/llvm-project/issues/138272 [2]
Signed-off-by: Marco Elver <elver@google.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Due to a rustc bug [1] the -Cforce-unwind-tables=y flag only emits the
uwtable annotation for functions, but not for the module. This means
that compiler-generated functions such as 'asan.module_ctor' do not
receive the uwtable annotation.
When CONFIG_UNWIND_PATCH_PAC_INTO_SCS is enabled, this leads to boot
failures because the dwarf information emitted for the kasan
constructors is wrong, which causes the SCS boot patching code to
patch the constructor in an illegal manner. Specifically, the paciasp
instruction is patched, but the autiasp instruction is not. This
mismatch leads to a crash when the constructor is called during boot.
==================================================================
BUG: KASAN: global-out-of-bounds in do_basic_setup+0x4c/0x90
Read of size 8 at addr ffffffe3cc7eb488 by task swapper/0/1
Specifically the faulting instruction is the (*fn)() to invoke the
constructor in do_ctors() of the init/main.c file.
Once the fix lands in rustc, this flag can be made conditional on the
rustc version. Note that passing the flag on a rustc with the fix
present has no effect.
[ The fix [1] has landed for Rust 1.98.0 (expected release on
2026-08-20).
Thus add a version check as discussed.
- Miguel ]
Fixes: d077242d68 ("rust: support for shadow call stack sanitizer")
Cc: stable@kernel.org
Link: https://github.com/rust-lang/rust/pull/156973 [1]
Reported-by: Bo Ye <bo.ye@mediatek.com>
Debugged-by: Isaac Manjarres <isaacmanjarres@google.com>
Debugged-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Isaac Manjarres <isaacmanjarres@google.com>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Link: https://patch.msgid.link/20260527-uwtable-module-flag-v1-1-caa41342be4b@google.com
[ Adjusted link and comment. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Pull clang build fix from Nathan Chancellor:
"A small fix to disable -Wattribute-alias for clang in the few places
it is already disabled for GCC, now that tip of tree clang has
implemented -Wattribute-alias as GCC has"
* tag 'clang-fixes-7.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/nathan/linux:
Disable -Wattribute-alias for clang-23 and newer
This reverts
dc8aa31a7a ("x86/fpu: Refine and simplify the magic number check during signal return").
The aforementioned commit broke applications that construct signal frames in
userspace (such as CRIU and gVisor) if the frame's xstate size is smaller than
the kernel's fpstate->user_size.
Furthermore, this introduces a critical issue for checkpoint/restore tools
like CRIU. If a process is checkpointed while inside a signal handler, its
stack contains a signal frame formatted according to the source host's xstate
capabilities.
If that process is later restored on a destination host with larger xstate
capabilities (e.g., a newer CPU with more features enabled, resulting in
a larger fpstate->user_size), the kernel will look for FP_XSTATE_MAGIC2 at the
destination host's larger user_size offset instead of the offset encoded in
the frame's fx_sw->xstate_size.
This causes the magic2 check to fail, forcing sigreturn to silently fall back
to "FX-only" mode. Upon return from the signal handler, the process's extended
state is reset to initial values instead of being restored, leading to silent
data corruption.
The aforementioned commit cited
d877550eaf ("x86/fpu: Stop relying on userspace for info to fault in xsave buffer")
as justification to stop relying on userspace for the magic number check.
However, these two changes are fundamentally different. The last one only
changed how much memory the kernel ensures is paged-in before running XRSTOR
to prevent an infinite loop. It did not change the signal frame format or how
the layout is validated.
Reverting this change restores the use of fx_sw->xstate_size for
locating magic2 and restores the necessary sanity checks, ensuring that
the signal frame remains self-describing and portable.
[ bp: Massage commit message. ]
Fixes: dc8aa31a7a ("x86/fpu: Refine and simplify the magic number check during signal return")
Signed-off-by: Andrei Vagin <avagin@google.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Chang S. Bae <chang.seok.bae@intel.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20260429000623.3356606-1-avagin@google.com
Use READ_ONCE() when reading entries/indices from the guest-accessible
Page State Change buffer to defend against TOCTOU bugs.
Don't bother with READ_ONCE()/WRITE_ONCE() for cases where KVM is writing
(and not consuming the result!), as the guest isn't supposed to touch the
buffer while it's being processed. I.e. using READ_ONCE() is all about
protecting against misbehaving guests.
Fixes: 9b54e248d2 ("KVM: SEV: Add support to handle Page State Change VMGEXIT")
Cc: stable@vger.kernel.org
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20260501202250.2115252-11-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When processing Page State Change (PSC) requests, validate the PSC buffer
against the effective size of the scratch area, which could be less than
the maximum size if the guest provided a pointer that isn't exactly at the
start of the GHCB shared buffer.
Fixes: 9b54e248d2 ("KVM: SEV: Add support to handle Page State Change VMGEXIT")
Cc: stable@vger.kernel.org
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20260501202250.2115252-10-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When setting the length of the GHCB scratch area, and the area is in the
GHCB shared buffer, set the effective length of the scratch area to the max
possible size given the start of the guest-provided pointer, and the end of
the shared buffer.
The code was "fine" when first introduced, as KVM doesn't consult the
length of the buffer when emulating MMIO, because the passed in @len always
specifies the *max* size required. But for PSC requests, the incoming @len
is just the minimum length (to process the header), and KVM needs to know
the full size of the scratch area to avoid buffer overflows (spoiler alert).
Opportunistically rename @len => @min_len to better reflect its role.
Fixes: 9b54e248d2 ("KVM: SEV: Add support to handle Page State Change VMGEXIT")
Cc: stable@vger.kernel.org
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20260501202250.2115252-7-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When handling a Page State Change (PSC) #VMGEXIT use the size of the PSC
header as the minimum size for the scratch area. Per the GHCB spec, PSC
requests do NOT provide the length, i.e. using control->exit_info_2 for the
length is completely made up behavior. The existing code "works", e.g.
even though Linux-as-a-guest always passes '0', because KVM doesn't do
anything with the length when the request is in the GHCB's shared buffer.
Use the header as the min length. Once the header is retrieved, KVM can
use the specified indices to compute the full size of the request.
Fixes: 9b54e248d2 ("KVM: SEV: Add support to handle Page State Change VMGEXIT")
Cc: stable@vger.kernel.org
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20260501202250.2115252-6-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Explicitly ignore Port I/O requests of length '0' (or count '0'), so that
setting up the software scratch area (and other code) doesn't have to
worry about underflowing the length, and to allow for WARNing on trying
to configure the scratch area with len==0.
Fixes: 291bd20d5d ("KVM: SVM: Add initial support for a VMGEXIT VMEXIT")
Cc: stable@vger.kernel.org
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20260501202250.2115252-5-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When using GHCB v2+, reject MMIO requests that are larger than 8 bytes.
Per the GHCB spec:
SW_EXITINFO2 must be less than or equal to 0x7fffffff for version 1 and
less than or equal to 0x8 for all other versions.
Fixes: 4af663c2f6 ("KVM: SEV: Allow per-guest configuration of GHCB protocol version")
Cc: stable@vger.kernel.org
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20260501202250.2115252-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
As per the GHCB spec, when using GHCB v2+ require the software scratch area
to reside in the GHCB's shared buffer. Note, things like Page State Change
(PSC) requests _rely_ on this behavior, as the guest can't provide a length
when making the request, i.e. the size of the guest payload is bounded by
the size of the shared buffer.
Failure to force usage of the GHCB, and a slew of other flaws, lets a
malicious SNP guest corrupt host kernel heap memory, and leak host heap
layout information.
setup_vmgexit_scratch() allocates a buffer via kvzalloc(exit_info_2),
where exit_info_2 is guest-controlled. With exit_info_2=24, this yields
a 24-byte allocation in kmalloc-cg-32 (32-byte slab objects). The buffer
holds an 8-byte psc_hdr followed by 8-byte psc_entry structs, so only
entries[0] and entries[1] are in-bounds.
snp_begin_psc() validates end_entry against VMGEXIT_PSC_MAX_COUNT (253)
but NOT against the actual buffer size:
idx_end = hdr->end_entry;
if (idx_end >= VMGEXIT_PSC_MAX_COUNT) { // checks 253, not buffer
snp_complete_psc(svm, ...);
return 1;
}
for (idx = idx_start; idx <= idx_end; idx++) {
entry_start = entries[idx]; // OOB when idx >= 2
The guest sets end_entry=10+, causing the host to iterate entries[2+]
which are OOB into adjacent slab objects. For each OOB entry:
- The host reads 8 bytes (OOB READ / info leak oracle)
- If the data passes PSC validation, __snp_complete_one_psc() writes
cur_page = 1 or 512 into the entry (OOB WRITE, sev.c:3806)
- If validation fails, the error response reveals whether adjacent
memory is zero vs non-zero (information disclosure to guest)
The guest controls allocation size (exit_info_2), entry range
(cur_entry/end_entry), and can fire unlimited VMGEXITs to repeatedly
hit different slab positions.
By exploiting the variety of bugs, a malicious SEV-SNP guest can:
- OOB read adjacent kmalloc-cg-32 objects (heap layout disclosure)
- OOB write cur_page bits into adjacent objects (heap corruption)
- Trigger use-after-free conditions across VMGEXITs
E.g. with KASAN enabled, a single insmod of the PoC guest module
produces 73 KASAN reports:
BUG: KASAN: slab-out-of-bounds in snp_begin_psc+0x126/0x890
Read of size 8 at addr ffff888219ffb5e0 by task qemu-system-x86/2199
BUG: KASAN: slab-out-of-bounds in snp_begin_psc+0x468/0x890
Write of size 8 at addr ffff888351566648 by task qemu-system-x86/2199
The buggy address belongs to the object at ffff888XXXXXXXXX
which belongs to the cache kmalloc-cg-32 of size 32
The buggy address is located N bytes to the right of
allocated 32-byte region [ffff888XXXXXXXXX, ffff888XXXXXXXXX)
Breakdown:
62 slab-out-of-bounds (reads + writes past allocation)
7 slab-use-after-free
4 use-after-free
All credit to Stan for the wonderful description and reproducer!
Reported-by: Stan Shaw <shawstan96@gmail.com>
Cc: Michael Roth <michael.roth@amd.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Peter Gonda <pgonda@google.com>
Cc: Jacky Li <jackyli@google.com>
Fixes: 4af663c2f6 ("KVM: SEV: Allow per-guest configuration of GHCB protocol version")
Cc: stable@vger.kernel.org
Signed-off-by: Michael Roth <michael.roth@amd.com>
[sean: write changelog]
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20260501202250.2115252-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
