[v3,5/7] KVM: SVM: Handle vectoring error in check_emulate_instruction

Commit Message

Ivan Orlov Dec. 17, 2024, 6:14 p.m. UTC

Detect unhandleable vectoring in check_emulate_instruction to prevent
infinite loop on SVM and eliminate the difference in how intercepted #PF
during vectoring is handled on SVM and VMX.

Signed-off-by: Ivan Orlov <[e-mail]>
---
V1 -> V2:
- Detect the unhandleable vectoring error in svm_check_emulate_instruction
instead of handling it in the common MMU code (which is specific for
cached MMIO)
V2 -> V3:
- Use more generic function to check if emulation is allowed when
vectoring

 arch/x86/kvm/svm/svm.c | 6 ++++++
 1 file changed, 6 insertions(+)

Patch

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index dd15cc635655..e89c6fc2c4e6 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -4802,6 +4802,12 @@  static int svm_check_emulate_instruction(struct kvm_vcpu *vcpu, int emul_type,
 	bool smep, smap, is_user;
 	u64 error_code;
 
+	/* Check that emulation is possible during event vectoring */
+	if ((to_svm(vcpu)->vmcb->control.exit_int_info &
+	    SVM_EXITINTINFO_TYPE_MASK) &&
+	    !kvm_can_emulate_event_vectoring(emul_type))
+		return X86EMUL_UNHANDLEABLE_VECTORING;
+
 	/* Emulation is always possible when KVM has access to all guest state. */
 	if (!sev_guest(vcpu->kvm))
 		return X86EMUL_CONTINUE;