kernel/linux.git/arch/x86, branch v5.15.209

KVM: x86: Acquire SRCU in KVM_GET_MP_STATE to protect guest memory accesses

2026-06-01T15:35:46+00:00

commit ef01cac401f18647d62720cf773d7bb0541827da upstream. Acquire a lock on kvm->srcu when userspace is getting MP state to handle a rather extreme edge case where "accepting" APIC events, i.e. processing pending INIT or SIPI, can trigger accesses to guest memory. If the vCPU is in L2 with INIT *and* a TRIPLE_FAULT request pending, then getting MP state will trigger a nested VM-Exit by way of ->check_nested_events(), and emuating the nested VM-Exit can access guest memory. The splat was originally hit by syzkaller on a Google-internal kernel, and reproduced on an upstream kernel by hacking the triple_fault_event_test selftest to stuff a pending INIT, store an MSR on VM-Exit (to generate a memory access on VMX), and do vcpu_mp_state_get() to trigger the scenario. ============================= WARNING: suspicious RCU usage 6.14.0-rc3-b112d356288b-vmx/pi_lockdep_false_pos-lock #3 Not tainted ----------------------------- include/linux/kvm_host.h:1058 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 1 lock held by triple_fault_ev/1256: #0: ffff88810df5a330 (&vcpu->mutex){+.+.}-{4:4}, at: kvm_vcpu_ioctl+0x8b/0x9a0 [kvm] stack backtrace: CPU: 11 UID: 1000 PID: 1256 Comm: triple_fault_ev Not tainted 6.14.0-rc3-b112d356288b-vmx #3 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 Call Trace: dump_stack_lvl+0x7f/0x90 lockdep_rcu_suspicious+0x144/0x190 kvm_vcpu_gfn_to_memslot+0x156/0x180 [kvm] kvm_vcpu_read_guest+0x3e/0x90 [kvm] read_and_check_msr_entry+0x2e/0x180 [kvm_intel] __nested_vmx_vmexit+0x550/0xde0 [kvm_intel] kvm_check_nested_events+0x1b/0x30 [kvm] kvm_apic_accept_events+0x33/0x100 [kvm] kvm_arch_vcpu_ioctl_get_mpstate+0x30/0x1d0 [kvm] kvm_vcpu_ioctl+0x33e/0x9a0 [kvm] __x64_sys_ioctl+0x8b/0xb0 do_syscall_64+0x6c/0x170 entry_SYSCALL_64_after_hwframe+0x4b/0x53 Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson Message-ID: <20250401150504.829812-1-seanjc@google.com> Signed-off-by: Paolo Bonzini [ Based on kernel 5.15 available functions, using srcu_read_lock/srcu_read_unlock instead of kvm_vcpu_srcu_read_lock/kvm_vcpu_srcu_read_unlock ] Signed-off-by: Rajani Kantha <681739313@139.com> Signed-off-by: Sasha Levin

Revert "x86/vdso: Fix output operand size of RDPID"

2026-06-01T15:35:45+00:00

This reverts commit 64f14b1ab6f39a704b62bf9b3fa28803cf2b3ebe. Signed-off-by: Sasha Levin

KVM: x86: Fix Xen hypercall tracepoint argument assignment

2026-06-01T15:35:44+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

KVM: nSVM: Add missing consistency check for nCR3 validity

2026-06-01T15:35:16+00:00

commit b71138fcc362c67ebe66747bb22cb4e6b4d6a651 upstream. From the APM Volume #2, 15.25.4 (24593—Rev. 3.42—March 2024): When VMRUN is executed with nested paging enabled (NP_ENABLE = 1), the following conditions are considered illegal state combinations, in addition to those mentioned in “Canonicalization and Consistency Checks”: • Any MBZ bit of nCR3 is set. • Any G_PAT.PA field has an unsupported type encoding or any reserved field in G_PAT has a nonzero value. Add the consistency check for nCR3 being a legal GPA with no MBZ bits set. Note, the G_PAT.PA check is being handled separately[*]. Link: https://lore.kernel.org/kvm/20260205214326.1029278-3-jmattson@google.com [*] Fixes: 4b16184c1cca ("KVM: SVM: Initialize Nested Nested MMU context on VMRUN") Cc: stable@vger.kernel.org Signed-off-by: Yosry Ahmed Link: https://patch.msgid.link/20260303003421.2185681-16-yosry@kernel.org [sean: capture everything in CC(), massage changelog formatting] Signed-off-by: Sean Christopherson Signed-off-by: Greg Kroah-Hartman

KVM: nSVM: Clear GIF on nested #VMEXIT(INVALID)

2026-06-01T15:35:16+00:00

commit f85a6ce06e4a0d49652f57967a649ab09e06287c upstream. According to the APM, GIF is set to 0 on any #VMEXIT, including an #VMEXIT(INVALID) due to failed consistency checks. Clear GIF on consistency check failures. Fixes: 3d6368ef580a ("KVM: SVM: Add VMRUN handler") Cc: stable@vger.kernel.org Signed-off-by: Yosry Ahmed Link: https://patch.msgid.link/20260303003421.2185681-11-yosry@kernel.org Signed-off-by: Sean Christopherson Signed-off-by: Greg Kroah-Hartman

KVM: nSVM: Always inject a #GP if mapping VMCB12 fails on nested VMRUN

2026-06-01T15:35:16+00:00

commit 01ddcdc55e097ca38c28ae656711b8e6d1df71f8 upstream. nested_svm_vmrun() currently only injects a #GP if kvm_vcpu_map() fails with -EINVAL. But it could also fail with -EFAULT if creating a host mapping failed. Inject a #GP in all cases, no reason to treat failure modes differently. Fixes: 8c5fbf1a7231 ("KVM/nSVM: Use the new mapping API for mapping guest memory") CC: stable@vger.kernel.org Co-developed-by: Sean Christopherson Signed-off-by: Yosry Ahmed Link: https://patch.msgid.link/20260303003421.2185681-6-yosry@kernel.org Signed-off-by: Sean Christopherson Signed-off-by: Greg Kroah-Hartman

KVM: nSVM: Ensure AVIC is inhibited when restoring a vCPU to guest mode

2026-06-01T15:35:16+00:00

commit 24f7d36b824b65cf1a2db3db478059187b2a37b0 upstream. On nested VMRUN, KVM ensures AVIC is inhibited by requesting KVM_REQ_APICV_UPDATE, triggering a check of inhibit reasons, finding APICV_INHIBIT_REASON_NESTED, and disabling AVIC. However, when KVM_SET_NESTED_STATE is performed on a vCPU not in guest mode with AVIC enabled, KVM_REQ_APICV_UPDATE is not requested, and AVIC is not inhibited. Request KVM_REQ_APICV_UPDATE in the KVM_SET_NESTED_STATE path if AVIC is active, similar to the nested VMRUN path. Fixes: f44509f849fe ("KVM: x86: SVM: allow AVIC to co-exist with a nested guest running") Cc: stable@vger.kernel.org Signed-off-by: Yosry Ahmed Link: https://patch.msgid.link/20260224225017.3303870-1-yosry@kernel.org Signed-off-by: Sean Christopherson Signed-off-by: Greg Kroah-Hartman

KVM: SVM: Explicitly mark vmcb01 dirty after modifying VMCB intercepts

2026-06-01T15:35:16+00:00

commit d5bde6113aed8315a2bfe708730b721be9c2f48b upstream. When reacting to an intercept update, explicitly mark vmcb01's intercepts dirty, as KVM always initially operates on vmcb01, and nested_svm_vmexit() isn't guaranteed to mark VMCB_INTERCEPTS as dirty. I.e. if L2 is active, KVM will modify the intercepts for L1, but might not mark them as dirty before the next VMRUN of L1. Fixes: 116a0a23676e ("KVM: SVM: Add clean-bit for intercetps, tsc-offset and pause filter count") Cc: stable@vger.kernel.org Reviewed-by: Yosry Ahmed Link: https://patch.msgid.link/20260218230958.2877682-2-seanjc@google.com Signed-off-by: Sean Christopherson Signed-off-by: Greg Kroah-Hartman

KVM: SVM: Inject #UD for INVLPGA if EFER.SVME=0

2026-06-01T15:35:16+00:00

commit d99df02ff427f461102230f9c5b90a6c64ee8e23 upstream. INVLPGA should cause a #UD when EFER.SVME is not set. Add a check to properly inject #UD when EFER.SVME=0. Fixes: ff092385e828 ("KVM: SVM: Implement INVLPGA") Cc: stable@vger.kernel.org Signed-off-by: Kevin Cheng Reviewed-by: Yosry Ahmed Link: https://patch.msgid.link/20260228033328.2285047-3-chengkev@google.com [sean: tag for stable@] Signed-off-by: Sean Christopherson Signed-off-by: Greg Kroah-Hartman

KVM: nSVM: Sync interrupt shadow to cached vmcb12 after VMRUN of L2

2026-06-01T15:35:16+00:00

commit 03bee264f8ebfd39e0254c98e112d033a7aa9055 upstream. After VMRUN in guest mode, nested_sync_control_from_vmcb02() syncs fields written by the CPU from vmcb02 to the cached vmcb12. This is because the cached vmcb12 is used as the authoritative copy of some of the controls, and is the payload when saving/restoring nested state. int_state is also written by the CPU, specifically bit 0 (i.e. SVM_INTERRUPT_SHADOW_MASK) for nested VMs, but it is not sync'd to cached vmcb12. This does not cause a problem if KVM_SET_NESTED_STATE preceeds KVM_SET_VCPU_EVENTS in the restore path, as an interrupt shadow would be correctly restored to vmcb02 (KVM_SET_VCPU_EVENTS overwrites what KVM_SET_NESTED_STATE restored in int_state). However, if KVM_SET_VCPU_EVENTS preceeds KVM_SET_NESTED_STATE, an interrupt shadow would be restored into vmcb01 instead of vmcb02. This would mostly be benign for L1 (delays an interrupt), but not for L2. For L2, the vCPU could hang (e.g. if a wakeup interrupt is delivered before a HLT that should have been in an interrupt shadow). Sync int_state to the cached vmcb12 in nested_sync_control_from_vmcb02() to avoid this problem. With that, KVM_SET_NESTED_STATE restores the correct interrupt shadow state, and if KVM_SET_VCPU_EVENTS follows it would overwrite it with the same value. Fixes: cc440cdad5b7 ("KVM: nSVM: implement KVM_GET_NESTED_STATE and KVM_SET_NESTED_STATE") CC: stable@vger.kernel.org Signed-off-by: Yosry Ahmed Link: https://patch.msgid.link/20260225005950.3739782-3-yosry@kernel.org Signed-off-by: Sean Christopherson Signed-off-by: Greg Kroah-Hartman