From: David Edmondson <[email protected]>

commit 51b958e5aeb1e18c00332e0b37c5d4e95a3eff84 upstream.

The instruction emulator ignores clflush instructions, yet fails to
support clflushopt. Treat both similarly.

Fixes: 13e457e0eebf ("KVM: x86: Emulator does not decode clflush well")
Signed-off-by: David Edmondson <[email protected]>
Message-Id: <[email protected]>
Reviewed-by: Joao Martins <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 arch/x86/kvm/emulate.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -3922,6 +3922,12 @@ static int em_clflush(struct x86_emulate
        return X86EMUL_CONTINUE;
 }
 
+static int em_clflushopt(struct x86_emulate_ctxt *ctxt)
+{
+       /* emulating clflushopt regardless of cpuid */
+       return X86EMUL_CONTINUE;
+}
+
 static int em_movsxd(struct x86_emulate_ctxt *ctxt)
 {
        ctxt->dst.val = (s32) ctxt->src.val;
@@ -4411,7 +4417,7 @@ static const struct opcode group11[] = {
 };
 
 static const struct gprefix pfx_0f_ae_7 = {
-       I(SrcMem | ByteOp, em_clflush), N, N, N,
+       I(SrcMem | ByteOp, em_clflush), I(SrcMem | ByteOp, em_clflushopt), N, N,
 };
 
 static const struct group_dual group15 = { {


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