Treat code #DBs as inhibited in MOV/POP-SS shadows for vCPU models that
are Intel compatible, not just strictly vCPUs with vendor==Intel. The
behavior is explicitly called out in the SDM, and thus architectural, i.e.
applies to all CPUs that implement Intel's architecture, and isn't a quirk
that is unique to CPUs manufactured by Intel:
However, if an instruction breakpoint is placed on an instruction located
immediately after a POP SS/MOV SS instruction, the breakpoint will be
suppressed as if EFLAGS.RF were 1.
Applying the behavior strictly to Intel wasn't intentional, KVM simply
didn't have a concept of "Intel compatible" as of commit baf67ca8e545
("KVM: x86: Suppress code #DBs on Intel if MOV/POP SS blocking is active").
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/x86.c | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index d9719141502a..8ea6f4fc910f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8984,19 +8984,17 @@ EXPORT_SYMBOL_GPL(kvm_skip_emulated_instruction);
static bool kvm_is_code_breakpoint_inhibited(struct kvm_vcpu *vcpu)
{
- u32 shadow;
-
if (kvm_get_rflags(vcpu) & X86_EFLAGS_RF)
return true;
/*
- * Intel CPUs inhibit code #DBs when MOV/POP SS blocking is active,
- * but AMD CPUs do not. MOV/POP SS blocking is rare, check that first
- * to avoid the relatively expensive CPUID lookup.
+ * Intel compatible CPUs inhibit code #DBs when MOV/POP SS blocking is
+ * active, but AMD compatible CPUs do not.
*/
- shadow = static_call(kvm_x86_get_interrupt_shadow)(vcpu);
- return (shadow & KVM_X86_SHADOW_INT_MOV_SS) &&
- guest_cpuid_is_intel(vcpu);
+ if (!guest_cpuid_is_intel_compatible(vcpu))
+ return false;
+
+ return static_call(kvm_x86_get_interrupt_shadow)(vcpu) & KVM_X86_SHADOW_INT_MOV_SS;
}
static bool kvm_vcpu_check_code_breakpoint(struct kvm_vcpu *vcpu,
--
2.44.0.478.gd926399ef9-goog
