Move host state save/restore routine to vmx arch code.

This is a perf optimization on Intel.

Author: Taogle2018

arch/x86/include/asm/kvm_host.h

@@ -687,8 +687,6 @@ struct kvm_x86_ops {
 	void (*vcpu_free)(struct kvm_vcpu *vcpu);
 	void (*vcpu_reset)(struct kvm_vcpu *vcpu, bool init_event);
 
-	void (*save_host_state)(struct kvm_vcpu *vcpu);
-	void (*load_host_state)(struct kvm_vcpu *vcpu);
 	void (*vcpu_load)(struct kvm_vcpu *vcpu, int cpu);
 	void (*vcpu_put)(struct kvm_vcpu *vcpu);
 

arch/x86/kvm/svm.c

@@ -1338,13 +1338,10 @@ static void svm_vcpu_put(struct kvm_vcpu *vcpu)
 static void svm_save_host_state(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
-	int cpu = smp_processor_id();
 	int i;
 
-	if (unlikely(cpu != vcpu->cpu)) {
-		svm->asid_generation = 0;
-		mark_all_dirty(svm->vmcb);
-	}
+	svm->asid_generation = 0;
+	mark_all_dirty(svm->vmcb);
 
 #ifdef CONFIG_X86_64
 	rdmsrl(MSR_GS_BASE, to_svm(vcpu)->host.gs_base);
@@ -4249,6 +4246,8 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu)
 	if (unlikely(svm->nested.exit_required))
 		return;
 
+	svm_save_host_state(vcpu);
+
 	pre_svm_run(svm);
 
 	sync_lapic_to_cr8(vcpu);
@@ -4322,6 +4321,8 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu)
 		svm_handle_mce(svm);
 
 	mark_all_clean(svm->vmcb);
+
+	svm_load_host_state(vcpu);
 }
 
 static void svm_set_cr3(struct kvm_vcpu *vcpu, size_t root)
@@ -4676,8 +4677,6 @@ static struct kvm_x86_ops svm_x86_ops = {
 	.vm_init = avic_vm_init,
 	.vm_destroy = avic_vm_destroy,
 
-	.save_host_state = svm_save_host_state,
-	.load_host_state = svm_load_host_state,
 	.vcpu_load = svm_vcpu_load,
 	.vcpu_put = svm_vcpu_put,
 	.vcpu_blocking = svm_vcpu_blocking,

arch/x86/kvm/vmx.c

@@ -7373,6 +7373,8 @@ static void __declspec(noinline) vmx_vcpu_run(struct kvm_vcpu *vcpu)
 
 	vmx_acquire(vcpu);
 
+	vmx_save_host_state(vcpu);
+
 	if (test_bit(VCPU_REGS_RSP, (size_t *)&vcpu->arch.regs_dirty))
 		vmcs_writel(vcpu, GUEST_RSP, vcpu->arch.regs[VCPU_REGS_RSP]);
 	if (test_bit(VCPU_REGS_RIP, (size_t *)&vcpu->arch.regs_dirty))
@@ -7457,6 +7459,8 @@ static void __declspec(noinline) vmx_vcpu_run(struct kvm_vcpu *vcpu)
 
 	vmx->exit_reason = vmcs_read32(vcpu, VM_EXIT_REASON);
 
+	vmx_load_host_state(vcpu);
+
 	vmx_release(vcpu);
 
 	/*
@@ -9186,8 +9190,6 @@ static struct kvm_x86_ops vmx_x86_ops = {
 	.vcpu_free = vmx_free_vcpu,
 	.vcpu_reset = vmx_vcpu_reset,
 
-	.save_host_state = vmx_save_host_state,
-	.load_host_state = vmx_load_host_state,
 	.vcpu_load = vmx_vcpu_load,
 	.vcpu_put = vmx_vcpu_put,
 

arch/x86/kvm/x86.c

@@ -4577,7 +4577,6 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 #ifdef HOST_STAT_DEBUG
 	save_host_stat_full(enter);
 #endif
-	kvm_x86_ops->save_host_state(vcpu);
 	vcpu->mode = IN_GUEST_MODE;
 	vcpu->cpu = smp_processor_id();
 
@@ -4593,7 +4592,6 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 	if (vcpu->mode == EXITING_GUEST_MODE || vcpu->requests) {
 		vcpu->mode = OUTSIDE_GUEST_MODE;
 		smp_wmb();
-		kvm_x86_ops->load_host_state(vcpu);
 		local_irq_enable();
 		vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
 		r = 1;
@@ -4655,7 +4653,6 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 	smp_wmb();
 
 	kvm_put_guest_xcr0(vcpu);
-	kvm_x86_ops->load_host_state(vcpu);
 	kvm_x86_ops->vcpu_put(vcpu);
 
 #ifdef HOST_STAT_DEBUG