[PATCH v3 15/20] KVM: x86: Reject EVEX-prefixed instructions

Chang S. Bae
2026-04-28T05:26:36Z

Explicitly mark EVEX-prefixed opcodes (0x62) as unsupported.

Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
---
arch/x86/kvm/emulate.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index efe8adca1317..31118ae3b6a1 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -5052,6 +5052,11 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len, int
if (ctxt->d & NoRex2 && ctxt->rex_prefix == REX2_PREFIX)
opcode.flags = Undefined;

+ /* EVEX-prefixed instructions are not implemented */
+ if (ctxt->opcode_len == 1 && ctxt->b == 0x62 &&
+ (mode == X86EMUL_MODE_PROT64 || (ctxt->modrm & 0xc0) == 0xc0))
+ opcode.flags = NotImpl;
+
if (opcode.flags & ModRM)
ctxt->modrm = insn_fetch(u8, ctxt);

--
2.51.0