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Commit d14cb5df authored by Nadav Amit's avatar Nadav Amit Committed by Paolo Bonzini
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KVM: x86: Emulator mis-decodes VEX instructions on real-mode 



Commit 7fe864dc (KVM: x86: Mark VEX-prefix instructions emulation as
unimplemented, 2014-06-02) marked VEX instructions as such in protected
mode.  VEX-prefix instructions are not supported relevant on real-mode
and VM86, but should cause #UD instead of being decoded as LES/LDS.

Fix this behaviour to be consistent with real hardware.

Signed-off-by: default avatarNadav Amit <namit@cs.technion.ac.il>
[Check for mod == 3, rather than 2 or 3. - Paolo]
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 2c2ca2d1

arch/x86/kvm/emulate.c

+1 −2
Original line number Diff line number Diff line
@@ -4517,8 +4517,7 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len) 


	/* vex-prefix instructions are not implemented */

	if (ctxt->opcode_len == 1 && (ctxt->b == 0xc5 || ctxt->b == 0xc4) &&

	    (mode == X86EMUL_MODE_PROT64 ||

	    (mode >= X86EMUL_MODE_PROT16 && (ctxt->modrm & 0x80)))) {

	    (mode == X86EMUL_MODE_PROT64 || (ctxt->modrm & 0xc0) == 0xc0)) {

		ctxt->d = NotImpl;

	}