Merge branch kvm-arm64/vcpu-first-run into kvmarm-master/next

* kvm-arm64/vcpu-first-run:
  : Rework the "vcpu first run" sequence to be driven by KVM's
  : "PID change" callback, removing the need for extra state.
  KVM: arm64: Drop vcpu->arch.has_run_once for vcpu->pid
  KVM: arm64: Merge kvm_arch_vcpu_run_pid_change() and kvm_vcpu_first_run_init()
  KVM: arm64: Restructure the point where has_run_once is advertised
  KVM: arm64: Move kvm_arch_vcpu_run_pid_change() out of line
  KVM: arm64: Move SVE state mapping at HYP to finalize-time

Signed-off-by: Marc Zyngier <[email protected]>

Author: Marc Zyngier

arch/arm64/include/asm/kvm_host.h

@@ -367,9 +367,6 @@ struct kvm_vcpu_arch {
 	int target;
 	DECLARE_BITMAP(features, KVM_VCPU_MAX_FEATURES);
 
-	/* Detect first run of a vcpu */
-	bool has_run_once;
-
 	/* Virtual SError ESR to restore when HCR_EL2.VSE is set */
 	u64 vsesr_el2;
 
@@ -606,6 +603,8 @@ int __kvm_arm_vcpu_set_events(struct kvm_vcpu *vcpu,
 void kvm_arm_halt_guest(struct kvm *kvm);
 void kvm_arm_resume_guest(struct kvm *kvm);
 
+#define vcpu_has_run_once(vcpu)	!!rcu_access_pointer((vcpu)->pid)
+
 #ifndef __KVM_NVHE_HYPERVISOR__
 #define kvm_call_hyp_nvhe(f, ...)						\
 	({								\
@@ -749,12 +748,7 @@ static inline bool kvm_pmu_counter_deferred(struct perf_event_attr *attr)
 void kvm_arch_vcpu_load_debug_state_flags(struct kvm_vcpu *vcpu);
 void kvm_arch_vcpu_put_debug_state_flags(struct kvm_vcpu *vcpu);
 
-#ifdef CONFIG_KVM /* Avoid conflicts with core headers if CONFIG_KVM=n */
-static inline int kvm_arch_vcpu_run_pid_change(struct kvm_vcpu *vcpu)
-{
-	return kvm_arch_vcpu_run_map_fp(vcpu);
-}
-
+#ifdef CONFIG_KVM
 void kvm_set_pmu_events(u32 set, struct perf_event_attr *attr);
 void kvm_clr_pmu_events(u32 clr);
 

arch/arm64/kvm/arm.c

@@ -351,7 +351,7 @@ void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
 
 void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
 {
-	if (vcpu->arch.has_run_once && unlikely(!irqchip_in_kernel(vcpu->kvm)))
+	if (vcpu_has_run_once(vcpu) && unlikely(!irqchip_in_kernel(vcpu->kvm)))
 		static_branch_dec(&userspace_irqchip_in_use);
 
 	kvm_mmu_free_memory_cache(&vcpu->arch.mmu_page_cache);
@@ -584,18 +584,33 @@ static void update_vmid(struct kvm_vmid *vmid)
 	spin_unlock(&kvm_vmid_lock);
 }
 
-static int kvm_vcpu_first_run_init(struct kvm_vcpu *vcpu)
+static int kvm_vcpu_initialized(struct kvm_vcpu *vcpu)
+{
+	return vcpu->arch.target >= 0;
+}
+
+/*
+ * Handle both the initialisation that is being done when the vcpu is
+ * run for the first time, as well as the updates that must be
+ * performed each time we get a new thread dealing with this vcpu.
+ */
+int kvm_arch_vcpu_run_pid_change(struct kvm_vcpu *vcpu)
 {
 	struct kvm *kvm = vcpu->kvm;
-	int ret = 0;
+	int ret;
 
-	if (likely(vcpu->arch.has_run_once))
-		return 0;
+	if (!kvm_vcpu_initialized(vcpu))
+		return -ENOEXEC;
 
 	if (!kvm_arm_vcpu_is_finalized(vcpu))
 		return -EPERM;
 
-	vcpu->arch.has_run_once = true;
+	ret = kvm_arch_vcpu_run_map_fp(vcpu);
+	if (ret)
+		return ret;
+
+	if (likely(vcpu_has_run_once(vcpu)))
+		return 0;
 
 	kvm_arm_vcpu_init_debug(vcpu);
 
@@ -607,19 +622,23 @@ static int kvm_vcpu_first_run_init(struct kvm_vcpu *vcpu)
 		ret = kvm_vgic_map_resources(kvm);
 		if (ret)
 			return ret;
-	} else {
-		/*
-		 * Tell the rest of the code that there are userspace irqchip
-		 * VMs in the wild.
-		 */
-		static_branch_inc(&userspace_irqchip_in_use);
 	}
 
 	ret = kvm_timer_enable(vcpu);
 	if (ret)
 		return ret;
 
 	ret = kvm_arm_pmu_v3_enable(vcpu);
+	if (ret)
+		return ret;
+
+	if (!irqchip_in_kernel(kvm)) {
+		/*
+		 * Tell the rest of the code that there are userspace irqchip
+		 * VMs in the wild.
+		 */
+		static_branch_inc(&userspace_irqchip_in_use);
+	}
 
 	/*
 	 * Initialize traps for protected VMs.
@@ -679,11 +698,6 @@ static void vcpu_req_sleep(struct kvm_vcpu *vcpu)
 	smp_rmb();
 }
 
-static int kvm_vcpu_initialized(struct kvm_vcpu *vcpu)
-{
-	return vcpu->arch.target >= 0;
-}
-
 static void check_vcpu_requests(struct kvm_vcpu *vcpu)
 {
 	if (kvm_request_pending(vcpu)) {
@@ -779,13 +793,6 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
 	struct kvm_run *run = vcpu->run;
 	int ret;
 
-	if (unlikely(!kvm_vcpu_initialized(vcpu)))
-		return -ENOEXEC;
-
-	ret = kvm_vcpu_first_run_init(vcpu);
-	if (ret)
-		return ret;
-
 	if (run->exit_reason == KVM_EXIT_MMIO) {
 		ret = kvm_handle_mmio_return(vcpu);
 		if (ret)
@@ -1123,7 +1130,7 @@ static int kvm_arch_vcpu_ioctl_vcpu_init(struct kvm_vcpu *vcpu,
 	 * need to invalidate the I-cache though, as FWB does *not*
 	 * imply CTR_EL0.DIC.
 	 */
-	if (vcpu->arch.has_run_once) {
+	if (vcpu_has_run_once(vcpu)) {
 		if (!cpus_have_final_cap(ARM64_HAS_STAGE2_FWB))
 			stage2_unmap_vm(vcpu->kvm);
 		else

arch/arm64/kvm/fpsimd.c

@@ -43,17 +43,6 @@ int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu)
 	if (ret)
 		goto error;
 
-	if (vcpu->arch.sve_state) {
-		void *sve_end;
-
-		sve_end = vcpu->arch.sve_state + vcpu_sve_state_size(vcpu);
-
-		ret = create_hyp_mappings(vcpu->arch.sve_state, sve_end,
-					  PAGE_HYP);
-		if (ret)
-			goto error;
-	}
-
 	vcpu->arch.host_thread_info = kern_hyp_va(ti);
 	vcpu->arch.host_fpsimd_state = kern_hyp_va(fpsimd);
 error:

arch/arm64/kvm/reset.c

@@ -94,6 +94,8 @@ static int kvm_vcpu_finalize_sve(struct kvm_vcpu *vcpu)
 {
 	void *buf;
 	unsigned int vl;
+	size_t reg_sz;
+	int ret;
 
 	vl = vcpu->arch.sve_max_vl;
 
@@ -106,10 +108,17 @@ static int kvm_vcpu_finalize_sve(struct kvm_vcpu *vcpu)
 		    vl > SVE_VL_ARCH_MAX))
 		return -EIO;
 
-	buf = kzalloc(SVE_SIG_REGS_SIZE(sve_vq_from_vl(vl)), GFP_KERNEL_ACCOUNT);
+	reg_sz = vcpu_sve_state_size(vcpu);
+	buf = kzalloc(reg_sz, GFP_KERNEL_ACCOUNT);
 	if (!buf)
 		return -ENOMEM;
 
+	ret = create_hyp_mappings(buf, buf + reg_sz, PAGE_HYP);
+	if (ret) {
+		kfree(buf);
+		return ret;
+	}
+	
 	vcpu->arch.sve_state = buf;
 	vcpu->arch.flags |= KVM_ARM64_VCPU_SVE_FINALIZED;
 	return 0;

arch/arm64/kvm/vgic/vgic-init.c

@@ -91,7 +91,7 @@ int kvm_vgic_create(struct kvm *kvm, u32 type)
 		return ret;
 
 	kvm_for_each_vcpu(i, vcpu, kvm) {
-		if (vcpu->arch.has_run_once)
+		if (vcpu_has_run_once(vcpu))
 			goto out_unlock;
 	}
 	ret = 0;