kernel/linux.git/arch/x86, branch v6.12.91

KVM: x86: Fix Xen hypercall tracepoint argument assignment

2026-05-23T11:04:59+00:00

commit 2b72f1674e427c56e3772c5ccf785fdda2138820 upstream. TRACE_EVENT(kvm_xen_hypercall) stores a5 in __entry->a4 instead of __entry->a5. That overwrites the recorded a4 argument and leaves a5 unset in the trace entry. Fix the typo so both arguments are captured correctly. Signed-off-by: Qiang Ma Link: https://patch.msgid.link/20260512015313.1685784-1-maqianga@uniontech.com/ Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

Revert "ACPI: CPPC: Adjust debug messages in amd_set_max_freq_ratio() to warn"

2026-05-23T11:04:58+00:00

commit db5dadb562cabb6da49959b473ed0d9645b6f2da upstream. Some older systems don't support CPPC in the firmware and this just makes noise for them when booting. Drop back to debug. This reverts commit 21fb59ab4b9767085f4fe1edbdbe3177fbb9ec97. Fixes: 21fb59ab4b976 ("ACPI: CPPC: Adjust debug messages in amd_set_max_freq_ratio() to warn") Suggested-by: Kim Phillips Signed-off-by: Mario Limonciello Tested-by: Kim Phillips Cc: All applicable Link: https://patch.msgid.link/20260504230141.484743-2-mario.limonciello@amd.com Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman

x86/um: fix vDSO installation

2026-05-23T11:04:46+00:00

[ Upstream commit d1895c15fc7d90a615bc8c455feb02acaf08ef1e ] The generic vDSO installation logic used by 'make vdso_install' requires that $(vdso-install-y) is defined by the top-level architecture Makefile and that it contains a path relative to the root of the tree. For UML neither of these is satisfied. Move the definition of $(vdso-install-y) to a place which is included by the arch/um/Makefile and use the full relative path. Fixes: f1c2bb8b9964 ("um: implement a x86_64 vDSO") Signed-off-by: Thomas Weißschuh Link: https://patch.msgid.link/20260318-um-vdso-install-v1-1-26a4ca5c4210@weissschuh.net Signed-off-by: Johannes Berg Signed-off-by: Sasha Levin

x86/um/vdso: Drop VDSO64-y from Makefile

2026-05-23T11:04:46+00:00

[ Upstream commit 3c9b904f9033fb250db72d258bbdec791dc89405 ] This symbol is unnecessary, remove it. Signed-off-by: Thomas Weißschuh Link: https://patch.msgid.link/20251013-uml-vdso-cleanup-v1-4-a079c7adcc69@weissschuh.net Signed-off-by: Johannes Berg Stable-dep-of: d1895c15fc7d ("x86/um: fix vDSO installation") Signed-off-by: Sasha Levin

fdget(), trivial conversions

2026-05-23T11:04:35+00:00

[ Upstream commit 6348be02eead77bdd1562154ed6b3296ad3b3750 ] fdget() is the first thing done in scope, all matching fdput() are immediately followed by leaving the scope. Reviewed-by: Christian Brauner Signed-off-by: Al Viro Stable-dep-of: 66052a768d47 ("fanotify: call fanotify_events_supported() before path_permission() and security_path_notify()") Signed-off-by: Sasha Levin

x86/CPU/AMD: Prevent improper isolation of shared resources in Zen2's op cache

2026-05-14T13:29:29+00:00

commit c21b90f77687075115d989e53a8ec5e2bb427ab1 upstream. Make sure resources are not improperly shared in the op cache and cause instruction corruption this way. Signed-off-by: Prathyushi Nangia Co-developed-by: Borislav Petkov (AMD) Signed-off-by: Borislav Petkov (AMD) Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

KVM: x86: check for nEPT/nNPT in slow flush hypercalls

2026-05-14T13:29:25+00:00

commit 464af6fc2b1dcc74005b7f58ee3812b17777efee upstream. Checking is_guest_mode(vcpu) is incorrect, because translate_nested_gpa() is only valid if an L2 guest is running *with nested EPT/NPT enabled*. Instead use the same condition as translate_nested_gpa() itself. Cc: stable@vger.kernel.org Reviewed-by: Sean Christopherson Fixes: aee738236dca ("KVM: x86: Prepare kvm_hv_flush_tlb() to handle L2's GPAs", 2022-11-18) Link: https://patch.msgid.link/20260503200905.106077-1-pbonzini@redhat.com/ Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

KVM: SVM: check validity of VMCB controls when returning from SMM

2026-05-14T13:29:18+00:00

commit be5fa8737d42c5ba16d2ea72c23681f8abbb07e8 upstream. The VMCB12 is stored in guest memory and can be mangled while in SMM; it is then reloaded by svm_leave_smm(), but it is not checked again for validity. Move the cached vmcb12 control and save consistency checks out of svm_set_nested_state() and into a helper, and reuse it in svm_leave_smm(). Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

KVM: x86: Fix shadow paging use-after-free due to unexpected GFN

2026-05-14T13:29:17+00:00

commit 0cb2af2ea66ad8ff195c156ea690f11216285bdf upstream. The shadow MMU computes GFNs for direct shadow pages using sp->gfn plus the SPTE index. This assumption breaks for shadow paging if the guest page tables are modified between VM entries (similar to commit aad885e77496, "KVM: x86/mmu: Drop/zap existing present SPTE even when creating an MMIO SPTE", 2026-03-27). The flow is as follows: - a PDE is installed for a 2MB mapping, and a page in that area is accessed. KVM creates a kvm_mmu_page consisting of 512 4KB pages; the kvm_mmu_page is marked by FNAME(fetch) as direct-mapped because the guest's mapping is a huge page (and thus contiguous). - the PDE mapping is changed from outside the guest. - the guest accesses another page in the same 2MB area. KVM installs a new leaf SPTE and rmap entry; the SPTE uses the "correct" GFN (i.e. based on the new mapping, as changed in the previous step) but that GFN is outside of the [sp->gfn, sp->gfn + 511] range; therefore the rmap entry cannot be found and removed when the kvm_mmu_page is zapped. - the memslot that covers the first 2MB mapping is deleted, and the kvm_mmu_page for the now-invalid GPA is zapped. However, rmap_remove() only looks at the [sp->gfn, sp->gfn + 511] range established in step 1, and fails to find the rmap entry that was recorded by step 3. - any operation that causes an rmap walk for the same page accessed by step 3 then walks a stale rmap and dereferences a freed kvm_mmu_page. This includes dirty logging or MMU notifier invalidations (e.g., from MADV_DONTNEED). The underlying issue is that KVM's walking of shadow PTEs assumes that if a SPTE is present when KVM wants to install a non-leaf SPTE, then the existing kvm_mmu_page must be for the correct gfn. Because the only way for the gfn to be wrong is if KVM messed up and failed to zap a SPTE... which shouldn't happen, but *actually* only happens in response to a guest write. That bug dates back literally forever, as even the first version of KVM assumes that the GFN matches and walks into the "wrong" shadow page. However, that was only an imprecision until 2032a93d66fa ("KVM: MMU: Don't allocate gfns page for direct mmu pages") came along. Fix it by checking for a target gfn mismatch and zapping the existing SPTE. That way the old SP and rmap entries are gone, KVM installs the rmap in the right location, and everyone is happy. Fixes: 2032a93d66fa ("KVM: MMU: Don't allocate gfns page for direct mmu pages") Fixes: 6aa8b732ca01 ("kvm: userspace interface") Reported-by: Alexander Bulekov Reported-by: Fred Griffoul Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson Link: https://patch.msgid.link/20260503201029.106481-1-pbonzini@redhat.com/ Signed-off-by: Paolo Bonzini Signed-off-by: Sasha Levin

x86/shstk: Prevent deadlock during shstk sigreturn

2026-05-14T13:29:17+00:00

[ Upstream commit 9874b2917b9fbc30956fee209d3c4aa47201c64e ] During sigreturn the shadow stack signal frame is popped. The kernel does this by reading the shadow stack using normal read accesses. When it can't assume the memory is shadow stack, it takes extra steps to makes sure it is reading actual shadow stack memory and not other normal readable memory. It does this by holding the mmap read lock while doing the access and checking the flags of the VMA. Unfortunately that is not safe. If the read of the shadow stack sigframe hits a page fault, the fault handler will try to recursively grab another mmap read lock. This normally works ok, but if a writer on another CPU is also waiting, the second read lock could fail and cause a deadlock. Fix this by doing the read of the userspace memory via gup. Embed it in the get_shstk_data() helper. Currently there is a check that skips the lookup work when the SSP can be assumed to be on a shadow stack. While reorganizing the function, remove the optimization to make the tricky code flows more common, such that issues like this cannot escape detection for so long. [Due to missing per-vma MM sequence counter, use a simpler GUP based solution for the backport] Cc: # Depends on https://lore.kernel.org/all/20260504205856.536296-1-rick.p.edgecombe@intel.com/ Signed-off-by: Rick Edgecombe Signed-off-by: Sasha Levin