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Subject[PATCH 27/36] KVM: x86 emulator: add Src2 decode set
Date
From: Guillaume Thouvenin <guillaume.thouvenin@ext.bull.net>

Instruction like shld has three operands, so we need to add a Src2
decode set. We start with Src2None, Src2CL, and Src2ImmByte, Src2One to
support shld/shrd and we will expand it later.

Signed-off-by: Guillaume Thouvenin <guillaume.thouvenin@ext.bull.net>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
arch/x86/include/asm/kvm_x86_emulate.h | 1 +
arch/x86/kvm/x86_emulate.c | 29 +++++++++++++++++++++++++++++
2 files changed, 30 insertions(+), 0 deletions(-)

diff --git a/arch/x86/include/asm/kvm_x86_emulate.h b/arch/x86/include/asm/kvm_x86_emulate.h
index 16a0026..6a15973 100644
--- a/arch/x86/include/asm/kvm_x86_emulate.h
+++ b/arch/x86/include/asm/kvm_x86_emulate.h
@@ -123,6 +123,7 @@ struct decode_cache {
u8 ad_bytes;
u8 rex_prefix;
struct operand src;
+ struct operand src2;
struct operand dst;
bool has_seg_override;
u8 seg_override;
diff --git a/arch/x86/kvm/x86_emulate.c b/arch/x86/kvm/x86_emulate.c
index 7a07ca4..7f5cd62 100644
--- a/arch/x86/kvm/x86_emulate.c
+++ b/arch/x86/kvm/x86_emulate.c
@@ -70,6 +70,12 @@
#define Group (1<<14) /* Bits 3:5 of modrm byte extend opcode */
#define GroupDual (1<<15) /* Alternate decoding of mod == 3 */
#define GroupMask 0xff /* Group number stored in bits 0:7 */
+/* Source 2 operand type */
+#define Src2None (0<<29)
+#define Src2CL (1<<29)
+#define Src2ImmByte (2<<29)
+#define Src2One (3<<29)
+#define Src2Mask (7<<29)

enum {
Group1_80, Group1_81, Group1_82, Group1_83,
@@ -1000,6 +1006,29 @@ done_prefixes:
break;
}

+ /*
+ * Decode and fetch the second source operand: register, memory
+ * or immediate.
+ */
+ switch (c->d & Src2Mask) {
+ case Src2None:
+ break;
+ case Src2CL:
+ c->src2.bytes = 1;
+ c->src2.val = c->regs[VCPU_REGS_RCX] & 0x8;
+ break;
+ case Src2ImmByte:
+ c->src2.type = OP_IMM;
+ c->src2.ptr = (unsigned long *)c->eip;
+ c->src2.bytes = 1;
+ c->src2.val = insn_fetch(u8, 1, c->eip);
+ break;
+ case Src2One:
+ c->src2.bytes = 1;
+ c->src2.val = 1;
+ break;
+ }
+
/* Decode and fetch the destination operand: register or memory. */
switch (c->d & DstMask) {
case ImplicitOps:
--
1.6.0.3


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