KVM: x86 emulator: handle undecoded rex.b with r/m = 5 in certain cases

x86_64 does not decode rex.b in certain cases, where the r/m field = 5.

Signed-off-by: Avi Kivity <avi@qumranet.com>

diff --git a/arch/x86/kvm/x86_emulate.c b/arch/x86/kvm/x86_emulate.c
index 2808291..3721cfd 100644 (file)
--- a/arch/x86/kvm/x86_emulate.c
+++ b/arch/x86/kvm/x86_emulate.c
@@ -750,6 +750,7 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt,
 
                        switch (base_reg) {
                        case 5:
+                       case 13:
                                if (c->modrm_mod != 0)
                                        c->modrm_ea += c->regs[base_reg];
                                else
@@ -767,6 +768,7 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt,
                        }
                        break;
                case 5:
+               case 13:
                        if (c->modrm_mod != 0)
                                c->modrm_ea += c->regs[c->modrm_rm];
                        else if (ctxt->mode == X86EMUL_MODE_PROT64)