[PATCH 20/42] KVM: x86 emulator: Add pusha and popa instructions

Avi Kivity
2009-11-16T12:26:29Z

From: Mohammed Gamal <m.gamal005@gmail.com>

This adds pusha and popa instructions (opcodes 0x60-0x61), this enables booting
MINIX with invalid guest state emulation on.

[marcelo: remove unused variable]

Signed-off-by: Mohammed Gamal <m.gamal005@gmail.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
arch/x86/kvm/emulate.c | 48 +++++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 47 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index db0820d..d226dff 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -139,7 +139,8 @@ static u32 opcode_table[256] = {
DstReg | Stack, DstReg | Stack, DstReg | Stack, DstReg | Stack,
DstReg | Stack, DstReg | Stack, DstReg | Stack, DstReg | Stack,
/* 0x60 - 0x67 */
- 0, 0, 0, DstReg | SrcMem32 | ModRM | Mov /* movsxd (x86/64) */ ,
+ ImplicitOps | Stack | No64, ImplicitOps | Stack | No64,
+ 0, DstReg | SrcMem32 | ModRM | Mov /* movsxd (x86/64) */ ,
0, 0, 0, 0,
/* 0x68 - 0x6F */
SrcImm | Mov | Stack, 0, SrcImmByte | Mov | Stack, 0,
@@ -1225,6 +1226,43 @@ static int emulate_pop_sreg(struct x86_emulate_ctxt *ctxt,
return rc;
}

+static void emulate_pusha(struct x86_emulate_ctxt *ctxt)
+{
+ struct decode_cache *c = &ctxt->decode;
+ unsigned long old_esp = c->regs[VCPU_REGS_RSP];
+ int reg = VCPU_REGS_RAX;
+
+ while (reg <= VCPU_REGS_RDI) {
+ (reg == VCPU_REGS_RSP) ?
+ (c->src.val = old_esp) : (c->src.val = c->regs[reg]);
+
+ emulate_push(ctxt);
+ ++reg;
+ }
+}
+
+static int emulate_popa(struct x86_emulate_ctxt *ctxt,
+ struct x86_emulate_ops *ops)
+{
+ struct decode_cache *c = &ctxt->decode;
+ int rc = 0;
+ int reg = VCPU_REGS_RDI;
+
+ while (reg >= VCPU_REGS_RAX) {
+ if (reg == VCPU_REGS_RSP) {
+ register_address_increment(c, &c->regs[VCPU_REGS_RSP],
+ c->op_bytes);
+ --reg;
+ }
+
+ rc = emulate_pop(ctxt, ops, &c->regs[reg], c->op_bytes);
+ if (rc != 0)
+ break;
+ --reg;
+ }
+ return rc;
+}
+
static inline int emulate_grp1a(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops)
{
@@ -1816,6 +1854,14 @@ special_insn:
if (rc != 0)
goto done;
break;
+ case 0x60: /* pusha */
+ emulate_pusha(ctxt);
+ break;
+ case 0x61: /* popa */
+ rc = emulate_popa(ctxt, ops);
+ if (rc != 0)
+ goto done;
+ break;
case 0x63: /* movsxd */
if (ctxt->mode != X86EMUL_MODE_PROT64)
goto cannot_emulate;
--
1.6.5.2