kvm, emulator: Add initial three-byte insns support

Add initial support for handling three-byte instructions in the
emulator.

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 5418015..6c5cfe9 100644 (file)
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -3892,6 +3892,25 @@ static const struct opcode twobyte_table[256] = {
        N, N, N, N, N, N, N, N, N, N, N, N, N, N, N, N
 };
 
+static const struct gprefix three_byte_0f_38_f0 = {
+       N, N, N, N
+};
+
+static const struct gprefix three_byte_0f_38_f1 = {
+       N, N, N, N
+};
+
+/*
+ * Insns below are selected by the prefix which indexed by the third opcode
+ * byte.
+ */
+static const struct opcode opcode_map_0f_38[256] = {
+       /* 0x00 - 0x7f */
+       X16(N), X16(N), X16(N), X16(N), X16(N), X16(N), X16(N), X16(N),
+       /* 0x80 - 0xff */
+       X16(N), X16(N), X16(N), X16(N), X16(N), X16(N), X16(N), X16(N)
+};
+
 #undef D
 #undef N
 #undef G
@@ -4212,6 +4231,13 @@ done_prefixes:
                ctxt->opcode_len = 2;
                ctxt->b = insn_fetch(u8, ctxt);
                opcode = twobyte_table[ctxt->b];
+
+               /* 0F_38 opcode map */
+               if (ctxt->b == 0x38) {
+                       ctxt->opcode_len = 3;
+                       ctxt->b = insn_fetch(u8, ctxt);
+                       opcode = opcode_map_0f_38[ctxt->b];
+               }
        }
        ctxt->d = opcode.flags;
 
@@ -4543,6 +4569,8 @@ special_insn:
 
        if (ctxt->opcode_len == 2)
                goto twobyte_insn;
+       else if (ctxt->opcode_len == 3)
+               goto threebyte_insn;
 
        switch (ctxt->b) {
        case 0x63:              /* movsxd */
@@ -4727,6 +4755,8 @@ twobyte_insn:
                goto cannot_emulate;
        }
 
+threebyte_insn:
+
        if (rc != X86EMUL_CONTINUE)
                goto done;