[PATCH 21/23] KVM: x86 emulator: move interruptibility state tracking out of emulator

[Gleb Natapov <gleb@redhat.com>]

Emulator shouldn't access vcpu directly.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
---
 arch/x86/kvm/emulate.c |   19 ++-----------------
 arch/x86/kvm/x86.c     |   20 +++++++++++++++++---
 2 files changed, 19 insertions(+), 20 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 74b0d94..b3557c6 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -1861,20 +1861,6 @@ static inline int writeback(struct x86_emulate_ctxt *ctxt,
 	return X86EMUL_CONTINUE;
 }
 
-static void toggle_interruptibility(struct x86_emulate_ctxt *ctxt, u32 mask)
-{
-	u32 int_shadow = kvm_x86_ops->get_interrupt_shadow(ctxt->vcpu, mask);
-	/*
-	 * an sti; sti; sequence only disable interrupts for the first
-	 * instruction. So, if the last instruction, be it emulated or
-	 * not, left the system with the INT_STI flag enabled, it
-	 * means that the last instruction is an sti. We should not
-	 * leave the flag on in this case. The same goes for mov ss
-	 */
-	if (!(int_shadow & mask))
-		ctxt->interruptibility = mask;
-}
-
 static inline void
 setup_syscalls_segments(struct x86_emulate_ctxt *ctxt,
 			struct x86_emulate_ops *ops, struct desc_struct *cs,
@@ -2545,7 +2531,6 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 	int rc = X86EMUL_CONTINUE;
 	int saved_dst_type = c->dst.type;
 
-	ctxt->interruptibility = 0;
 	ctxt->decode.mem_read.pos = 0;
 
 	if (ctxt->mode == X86EMUL_MODE_PROT64 && (c->d & No64)) {
@@ -2818,7 +2803,7 @@ special_insn:
 		}
 
 		if (c->modrm_reg == VCPU_SREG_SS)
-			toggle_interruptibility(ctxt, KVM_X86_SHADOW_INT_MOV_SS);
+			ctxt->interruptibility = KVM_X86_SHADOW_INT_MOV_SS;
 
 		rc = load_segment_descriptor(ctxt, ops, sel, c->modrm_reg);
 
@@ -2987,7 +2972,7 @@ special_insn:
 		if (emulator_bad_iopl(ctxt, ops))
 			kvm_inject_gp(ctxt->vcpu, 0);
 		else {
-			toggle_interruptibility(ctxt, KVM_X86_SHADOW_INT_STI);
+			ctxt->interruptibility = KVM_X86_SHADOW_INT_STI;
 			ctxt->eflags |= X86_EFLAGS_IF;
 			c->dst.type = OP_NONE;	/* Disable writeback. */
 		}
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5757b9d..ed15b20 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3769,12 +3769,26 @@ static void cache_all_regs(struct kvm_vcpu *vcpu)
 	vcpu->arch.regs_dirty = ~0;
 }
 
+static void toggle_interruptibility(struct kvm_vcpu *vcpu, u32 mask)
+{
+	u32 int_shadow = kvm_x86_ops->get_interrupt_shadow(vcpu, mask);
+	/*
+	 * an sti; sti; sequence only disable interrupts for the first
+	 * instruction. So, if the last instruction, be it emulated or
+	 * not, left the system with the INT_STI flag enabled, it
+	 * means that the last instruction is an sti. We should not
+	 * leave the flag on in this case. The same goes for mov ss
+	 */
+	if (!(int_shadow & mask))
+		kvm_x86_ops->set_interrupt_shadow(vcpu, mask);
+}
+
 int emulate_instruction(struct kvm_vcpu *vcpu,
 			unsigned long cr2,
 			u16 error_code,
 			int emulation_type)
 {
-	int r, shadow_mask;
+	int r;
 	struct decode_cache *c = &vcpu->arch.emulate_ctxt.decode;
 
 	kvm_clear_exception_queue(vcpu);
@@ -3804,6 +3818,7 @@ int emulate_instruction(struct kvm_vcpu *vcpu,
 			? X86EMUL_MODE_PROT32 : X86EMUL_MODE_PROT16;
 		memset(c, 0, sizeof(struct decode_cache));
 		memcpy(c->regs, vcpu->arch.regs, sizeof c->regs);
+		vcpu->arch.emulate_ctxt.interruptibility = 0;
 
 		r = x86_decode_insn(&vcpu->arch.emulate_ctxt, &emulate_ops);
 		trace_kvm_emulate_insn_start(vcpu);
@@ -3871,8 +3886,7 @@ restart:
 		return EMULATE_FAIL;
 	}
 
-	shadow_mask = vcpu->arch.emulate_ctxt.interruptibility;
-	kvm_x86_ops->set_interrupt_shadow(vcpu, shadow_mask);
+	toggle_interruptibility(vcpu, vcpu->arch.emulate_ctxt.interruptibility);
 	kvm_x86_ops->set_rflags(vcpu, vcpu->arch.emulate_ctxt.eflags);
 	memcpy(vcpu->arch.regs, c->regs, sizeof c->regs);
 	kvm_rip_write(vcpu, vcpu->arch.emulate_ctxt.eip);
-- 
1.6.5