From 087c857e0131c2a045b29401b9f99d9265f8bcd5 Mon Sep 17 00:00:00 2001 From: David Edmondson Date: Tue, 3 Nov 2020 12:04:00 +0000 Subject: [PATCH] KVM: x86: clflushopt should be treated as a no-op by emulation 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 Message-Id: <20201103120400.240882-1-david.edmondson@oracle.com> Reviewed-by: Joao Martins Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/emulate.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 484c32b7f79f..39265b55929d 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -4050,6 +4050,12 @@ static int em_clflush(struct x86_emulate_ctxt *ctxt) 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; @@ -4592,7 +4598,7 @@ 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 = { {