KVM: x86 emulator: Add pusha and popa instructions

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>

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index db0820d..d226dff 100644 (file)
--- 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;