6.5-stable review patch. If anyone has any objections, please let me know.
------------------
From: Sean Christopherson <seanjc@xxxxxxxxxx>
commit 50011c2a245792993f2756e5b5b571512bfa409e upstream.
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@xxxxxxxxx>
Fixes: 11df586d774f ("KVM: VMX: Handle NMI VM-Exits in noinstr region")
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/20230825014532.2846714-1-seanjc@xxxxxxxxxx
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/vmx/vmx.c | 21 +++++++++++----------
1 file changed, 11 insertions(+), 10 deletions(-)
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7243,13 +7243,20 @@ static noinstr void vmx_vcpu_enter_exit(
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))) {
@@ -7258,6 +7265,7 @@ static noinstr void vmx_vcpu_enter_exit(
kvm_after_interrupt(vcpu);
}
+out:
guest_state_exit_irqoff();
}
@@ -7379,8 +7387,6 @@ static fastpath_t vmx_vcpu_run(struct kv
loadsegment(es, __USER_DS);
#endif
- vcpu->arch.regs_avail &= ~VMX_REGS_LAZY_LOAD_SET;
-
pt_guest_exit(vmx);
kvm_load_host_xsave_state(vcpu);
@@ -7397,17 +7403,12 @@ static fastpath_t vmx_vcpu_run(struct kv
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))
