Commit d14cb5df authored Nov 02, 2014 by Nadav Amit Committed by Paolo Bonzini Nov 08, 2014

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: Nadav Amit <namit@cs.technion.ac.il>
[Check for mod == 3, rather than 2 or 3. - Paolo]
Signed-off-by: Paolo 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 @@ done_prefixes:

		/* 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;
		}

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