KVM: Provide current eip as part of emulator context.

Eliminate the need to call back into KVM to get it from emulator.
Signed-off-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

arch/x86/include/asm/kvm_emulate.h

@@ -141,7 +141,7 @@ struct decode_cache {
 	u8 seg_override;
 	unsigned int d;
 	unsigned long regs[NR_VCPU_REGS];
-	unsigned long eip, eip_orig;
+	unsigned long eip;
 	/* modrm */
 	u8 modrm;
 	u8 modrm_mod;
@@ -160,6 +160,7 @@ struct x86_emulate_ctxt {
 	struct kvm_vcpu *vcpu;
 
 	unsigned long eflags;
+	unsigned long eip; /* eip before instruction emulation */
 	/* Emulated execution mode, represented by an X86EMUL_MODE value. */
 	int mode;
 	u32 cs_base;

arch/x86/kvm/emulate.c

@@ -667,7 +667,7 @@ static int do_insn_fetch(struct x86_emulate_ctxt *ctxt,
 	int rc;
 
 	/* x86 instructions are limited to 15 bytes. */
-	if (eip + size - ctxt->decode.eip_orig > 15)
+	if (eip + size - ctxt->eip > 15)
 		return X86EMUL_UNHANDLEABLE;
 	eip += ctxt->cs_base;
 	while (size--) {
@@ -927,7 +927,7 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 	/* Shadow copy of register state. Committed on successful emulation. */
 
 	memset(c, 0, sizeof(struct decode_cache));
-	c->eip = c->eip_orig = kvm_rip_read(ctxt->vcpu);
+	c->eip = ctxt->eip;
 	ctxt->cs_base = seg_base(ctxt, VCPU_SREG_CS);
 	memcpy(c->regs, ctxt->vcpu->arch.regs, sizeof c->regs);
 
@@ -1878,7 +1878,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 			}
 		}
 		register_address_increment(c, &c->regs[VCPU_REGS_RCX], -1);
-		c->eip = kvm_rip_read(ctxt->vcpu);
+		c->eip = ctxt->eip;
 	}
 
 	if (c->src.type == OP_MEM) {
@@ -2447,7 +2447,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 				goto done;
 
 			/* Let the processor re-execute the fixed hypercall */
-			c->eip = kvm_rip_read(ctxt->vcpu);
+			c->eip = ctxt->eip;
 			/* Disable writeback. */
 			c->dst.type = OP_NONE;
 			break;
@@ -2551,7 +2551,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 			| ((u64)c->regs[VCPU_REGS_RDX] << 32);
 		if (kvm_set_msr(ctxt->vcpu, c->regs[VCPU_REGS_RCX], msr_data)) {
 			kvm_inject_gp(ctxt->vcpu, 0);
-			c->eip = kvm_rip_read(ctxt->vcpu);
+			c->eip = ctxt->eip;
 		}
 		rc = X86EMUL_CONTINUE;
 		c->dst.type = OP_NONE;
@@ -2560,7 +2560,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 		/* rdmsr */
 		if (kvm_get_msr(ctxt->vcpu, c->regs[VCPU_REGS_RCX], &msr_data)) {
 			kvm_inject_gp(ctxt->vcpu, 0);
-			c->eip = kvm_rip_read(ctxt->vcpu);
+			c->eip = ctxt->eip;
 		} else {
 			c->regs[VCPU_REGS_RAX] = (u32)msr_data;
 			c->regs[VCPU_REGS_RDX] = msr_data >> 32;

arch/x86/kvm/x86.c

@@ -3531,6 +3531,7 @@ int emulate_instruction(struct kvm_vcpu *vcpu,
 
 		vcpu->arch.emulate_ctxt.vcpu = vcpu;
 		vcpu->arch.emulate_ctxt.eflags = kvm_x86_ops->get_rflags(vcpu);
+		vcpu->arch.emulate_ctxt.eip = kvm_rip_read(vcpu);
 		vcpu->arch.emulate_ctxt.mode =
 			(!is_protmode(vcpu)) ? X86EMUL_MODE_REAL :
 			(vcpu->arch.emulate_ctxt.eflags & X86_EFLAGS_VM)