diff options
| author | Sean Christopherson <seanjc@google.com> | 2023-08-24 18:45:32 -0700 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2023-08-28 20:07:43 -0700 |
| commit | 50011c2a245792993f2756e5b5b571512bfa409e (patch) | |
| tree | 6b9540c61376a86201e97e9b32e8103c48b510c1 | |
| parent | 9ca0c1a1265c03d54f1c71005ea0375f9bccabee (diff) | |
KVM: VMX: Refresh available regs and IDT vectoring info before NMI handling
Reset the mask of available "registers" and refresh the IDT vectoring
info snapshot in vmx_vcpu_enter_exit(), before KVM potentially handles a
an NMI VM-Exit. One of the "registers" that KVM VMX lazily loads is the
vmcs.VM_EXIT_INTR_INFO field, which is holds the vector+type on "exception
or NMI" VM-Exits, i.e. is needed to identify NMIs. Clearing the available
registers bitmask after handling NMIs results in KVM querying info from
the last VM-Exit that read vmcs.VM_EXIT_INTR_INFO, and leads to both
missed NMIs and spurious NMIs in the host.
Opportunistically grab vmcs.IDT_VECTORING_INFO_FIELD early in the VM-Exit
path too, e.g. to guard against similar consumption of stale data. The
field is read on every "normal" VM-Exit, and there's no point in delaying
the inevitable.
Reported-by: Like Xu <like.xu.linux@gmail.com>
Fixes: 11df586d774f ("KVM: VMX: Handle NMI VM-Exits in noinstr region")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230825014532.2846714-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
| -rw-r--r-- | arch/x86/kvm/vmx/vmx.c | 21 |
1 files changed, 11 insertions, 10 deletions
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index b0093b8a72d2..7625d74c056a 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -7209,13 +7209,20 @@ static noinstr void vmx_vcpu_enter_exit(struct kvm_vcpu *vcpu, flags); vcpu->arch.cr2 = native_read_cr2(); + vcpu->arch.regs_avail &= ~VMX_REGS_LAZY_LOAD_SET; + + vmx->idt_vectoring_info = 0; vmx_enable_fb_clear(vmx); - if (unlikely(vmx->fail)) + if (unlikely(vmx->fail)) { vmx->exit_reason.full = 0xdead; - else - vmx->exit_reason.full = vmcs_read32(VM_EXIT_REASON); + goto out; + } + + vmx->exit_reason.full = vmcs_read32(VM_EXIT_REASON); + if (likely(!vmx->exit_reason.failed_vmentry)) + vmx->idt_vectoring_info = vmcs_read32(IDT_VECTORING_INFO_FIELD); if ((u16)vmx->exit_reason.basic == EXIT_REASON_EXCEPTION_NMI && is_nmi(vmx_get_intr_info(vcpu))) { @@ -7224,6 +7231,7 @@ static noinstr void vmx_vcpu_enter_exit(struct kvm_vcpu *vcpu, kvm_after_interrupt(vcpu); } +out: guest_state_exit_irqoff(); } @@ -7345,8 +7353,6 @@ static fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu) loadsegment(es, __USER_DS); #endif - vcpu->arch.regs_avail &= ~VMX_REGS_LAZY_LOAD_SET; - pt_guest_exit(vmx); kvm_load_host_xsave_state(vcpu); @@ -7363,17 +7369,12 @@ static fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu) vmx->nested.nested_run_pending = 0; } - vmx->idt_vectoring_info = 0; - if (unlikely(vmx->fail)) return EXIT_FASTPATH_NONE; if (unlikely((u16)vmx->exit_reason.basic == EXIT_REASON_MCE_DURING_VMENTRY)) kvm_machine_check(); - if (likely(!vmx->exit_reason.failed_vmentry)) - vmx->idt_vectoring_info = vmcs_read32(IDT_VECTORING_INFO_FIELD); - trace_kvm_exit(vcpu, KVM_ISA_VMX); if (unlikely(vmx->exit_reason.failed_vmentry)) |