Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm fixes from Paolo Bonzini:
 "ARM:

   - Address some fallout of the locking rework, this time affecting the
     way the vgic is configured

   - Fix an issue where the page table walker frees a subtree and then
     proceeds with walking what it has just freed...

   - Check that a given PA donated to the guest is actually memory (only
     affecting pKVM)

   - Correctly handle MTE CMOs by Set/Way

   - Fix the reported address of a watchpoint forwarded to userspace

   - Fix the freeing of the root of stage-2 page tables

   - Stop creating spurious PMU events to perform detection of the
     default PMU and use the existing PMU list instead

  x86:

   - Fix a memslot lookup bug in the NX recovery thread that could
     theoretically let userspace bypass the NX hugepage mitigation

   - Fix a s/BLOCKING/PENDING bug in SVM's vNMI support

   - Account exit stats for fastpath VM-Exits that never leave the super
     tight run-loop

   - Fix an out-of-bounds bug in the optimized APIC map code, and add a
     regression test for the race"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: selftests: Add test for race in kvm_recalculate_apic_map()
  KVM: x86: Bail from kvm_recalculate_phys_map() if x2APIC ID is out-of-bounds
  KVM: x86: Account fastpath-only VM-Exits in vCPU stats
  KVM: SVM: vNMI pending bit is V_NMI_PENDING_MASK not V_NMI_BLOCKING_MASK
  KVM: x86/mmu: Grab memslot for correct address space in NX recovery worker
  KVM: arm64: Document default vPMU behavior on heterogeneous systems
  KVM: arm64: Iterate arm_pmus list to probe for default PMU
  KVM: arm64: Drop last page ref in kvm_pgtable_stage2_free_removed()
  KVM: arm64: Populate fault info for watchpoint
  KVM: arm64: Reload PTE after invoking walker callback on preorder traversal
  KVM: arm64: Handle trap of tagged Set/Way CMOs
  arm64: Add missing Set/Way CMO encodings
  KVM: arm64: Prevent unconditional donation of unmapped regions from the host
  KVM: arm64: vgic: Fix a comment
  KVM: arm64: vgic: Fix locking comment
  KVM: arm64: vgic: Wrap vgic_its_create() with config_lock
  KVM: arm64: vgic: Fix a circular locking issue

arch/arm64/include/asm/kvm_pgtable.h

@@ -632,9 +632,9 @@ int kvm_pgtable_stage2_flush(struct kvm_pgtable *pgt, u64 addr, u64 size);
  *
  * The walker will walk the page-table entries corresponding to the input
  * address range specified, visiting entries according to the walker flags.
- * Invalid entries are treated as leaf entries. Leaf entries are reloaded
- * after invoking the walker callback, allowing the walker to descend into
- * a newly installed table.
+ * Invalid entries are treated as leaf entries. The visited page table entry is
+ * reloaded after invoking the walker callback, allowing the walker to descend
+ * into a newly installed table.
  *
  * Returning a negative error code from the walker callback function will
  * terminate the walk immediately with the same error code.

arch/arm64/include/asm/sysreg.h

@@ -115,8 +115,14 @@
 #define SB_BARRIER_INSN			__SYS_BARRIER_INSN(0, 7, 31)
 
 #define SYS_DC_ISW			sys_insn(1, 0, 7, 6, 2)
+#define SYS_DC_IGSW			sys_insn(1, 0, 7, 6, 4)
+#define SYS_DC_IGDSW			sys_insn(1, 0, 7, 6, 6)
 #define SYS_DC_CSW			sys_insn(1, 0, 7, 10, 2)
+#define SYS_DC_CGSW			sys_insn(1, 0, 7, 10, 4)
+#define SYS_DC_CGDSW			sys_insn(1, 0, 7, 10, 6)
 #define SYS_DC_CISW			sys_insn(1, 0, 7, 14, 2)
+#define SYS_DC_CIGSW			sys_insn(1, 0, 7, 14, 4)
+#define SYS_DC_CIGDSW			sys_insn(1, 0, 7, 14, 6)
 
 /*
  * Automatically generated definitions for system registers, the

arch/arm64/kvm/hyp/include/hyp/switch.h

@@ -412,17 +412,21 @@ static bool kvm_hyp_handle_cp15_32(struct kvm_vcpu *vcpu, u64 *exit_code)
 	return false;
 }
 
-static bool kvm_hyp_handle_iabt_low(struct kvm_vcpu *vcpu, u64 *exit_code)
+static bool kvm_hyp_handle_memory_fault(struct kvm_vcpu *vcpu, u64 *exit_code)
 {
 	if (!__populate_fault_info(vcpu))
 		return true;
 
 	return false;
 }
+static bool kvm_hyp_handle_iabt_low(struct kvm_vcpu *vcpu, u64 *exit_code)
+	__alias(kvm_hyp_handle_memory_fault);
+static bool kvm_hyp_handle_watchpt_low(struct kvm_vcpu *vcpu, u64 *exit_code)
+	__alias(kvm_hyp_handle_memory_fault);
 
 static bool kvm_hyp_handle_dabt_low(struct kvm_vcpu *vcpu, u64 *exit_code)
 {
-	if (!__populate_fault_info(vcpu))
+	if (kvm_hyp_handle_memory_fault(vcpu, exit_code))
 		return true;
 
 	if (static_branch_unlikely(&vgic_v2_cpuif_trap)) {

arch/arm64/kvm/hyp/nvhe/mem_protect.c

@@ -575,7 +575,7 @@ struct pkvm_mem_donation {
 
 struct check_walk_data {
 	enum pkvm_page_state	desired;
-	enum pkvm_page_state	(*get_page_state)(kvm_pte_t pte);
+	enum pkvm_page_state	(*get_page_state)(kvm_pte_t pte, u64 addr);
 };
 
 static int __check_page_state_visitor(const struct kvm_pgtable_visit_ctx *ctx,
@@ -583,10 +583,7 @@ static int __check_page_state_visitor(const struct kvm_pgtable_visit_ctx *ctx,
 {
 	struct check_walk_data *d = ctx->arg;
 
-	if (kvm_pte_valid(ctx->old) && !addr_is_allowed_memory(kvm_pte_to_phys(ctx->old)))
-		return -EINVAL;
-
-	return d->get_page_state(ctx->old) == d->desired ? 0 : -EPERM;
+	return d->get_page_state(ctx->old, ctx->addr) == d->desired ? 0 : -EPERM;
 }
 
 static int check_page_state_range(struct kvm_pgtable *pgt, u64 addr, u64 size,
@@ -601,8 +598,11 @@ static int check_page_state_range(struct kvm_pgtable *pgt, u64 addr, u64 size,
 	return kvm_pgtable_walk(pgt, addr, size, &walker);
 }
 
-static enum pkvm_page_state host_get_page_state(kvm_pte_t pte)
+static enum pkvm_page_state host_get_page_state(kvm_pte_t pte, u64 addr)
 {
+	if (!addr_is_allowed_memory(addr))
+		return PKVM_NOPAGE;
+
 	if (!kvm_pte_valid(pte) && pte)
 		return PKVM_NOPAGE;
 
@@ -709,7 +709,7 @@ static int host_complete_donation(u64 addr, const struct pkvm_mem_transition *tx
 	return host_stage2_set_owner_locked(addr, size, host_id);
 }
 
-static enum pkvm_page_state hyp_get_page_state(kvm_pte_t pte)
+static enum pkvm_page_state hyp_get_page_state(kvm_pte_t pte, u64 addr)
 {
 	if (!kvm_pte_valid(pte))
 		return PKVM_NOPAGE;

arch/arm64/kvm/hyp/nvhe/switch.c

@@ -186,6 +186,7 @@ static const exit_handler_fn hyp_exit_handlers[] = {
 	[ESR_ELx_EC_FP_ASIMD]		= kvm_hyp_handle_fpsimd,
 	[ESR_ELx_EC_IABT_LOW]		= kvm_hyp_handle_iabt_low,
 	[ESR_ELx_EC_DABT_LOW]		= kvm_hyp_handle_dabt_low,
+	[ESR_ELx_EC_WATCHPT_LOW]	= kvm_hyp_handle_watchpt_low,
 	[ESR_ELx_EC_PAC]		= kvm_hyp_handle_ptrauth,
 };
 
@@ -196,6 +197,7 @@ static const exit_handler_fn pvm_exit_handlers[] = {
 	[ESR_ELx_EC_FP_ASIMD]		= kvm_hyp_handle_fpsimd,
 	[ESR_ELx_EC_IABT_LOW]		= kvm_hyp_handle_iabt_low,
 	[ESR_ELx_EC_DABT_LOW]		= kvm_hyp_handle_dabt_low,
+	[ESR_ELx_EC_WATCHPT_LOW]	= kvm_hyp_handle_watchpt_low,
 	[ESR_ELx_EC_PAC]		= kvm_hyp_handle_ptrauth,
 };
 

arch/arm64/kvm/hyp/pgtable.c

@@ -209,14 +209,26 @@ static inline int __kvm_pgtable_visit(struct kvm_pgtable_walk_data *data,
 		.flags	= flags,
 	};
 	int ret = 0;
+	bool reload = false;
 	kvm_pteref_t childp;
 	bool table = kvm_pte_table(ctx.old, level);
 
-	if (table && (ctx.flags & KVM_PGTABLE_WALK_TABLE_PRE))
+	if (table && (ctx.flags & KVM_PGTABLE_WALK_TABLE_PRE)) {
 		ret = kvm_pgtable_visitor_cb(data, &ctx, KVM_PGTABLE_WALK_TABLE_PRE);
+		reload = true;
+	}
 
 	if (!table && (ctx.flags & KVM_PGTABLE_WALK_LEAF)) {
 		ret = kvm_pgtable_visitor_cb(data, &ctx, KVM_PGTABLE_WALK_LEAF);
+		reload = true;
+	}
+
+	/*
+	 * Reload the page table after invoking the walker callback for leaf
+	 * entries or after pre-order traversal, to allow the walker to descend
+	 * into a newly installed or replaced table.
+	 */
+	if (reload) {
 		ctx.old = READ_ONCE(*ptep);
 		table = kvm_pte_table(ctx.old, level);
 	}
@@ -1320,4 +1332,7 @@ void kvm_pgtable_stage2_free_removed(struct kvm_pgtable_mm_ops *mm_ops, void *pg
 	};
 
 	WARN_ON(__kvm_pgtable_walk(&data, mm_ops, ptep, level + 1));
+
+	WARN_ON(mm_ops->page_count(pgtable) != 1);
+	mm_ops->put_page(pgtable);
 }

arch/arm64/kvm/hyp/vhe/switch.c

@@ -110,6 +110,7 @@ static const exit_handler_fn hyp_exit_handlers[] = {
 	[ESR_ELx_EC_FP_ASIMD]		= kvm_hyp_handle_fpsimd,
 	[ESR_ELx_EC_IABT_LOW]		= kvm_hyp_handle_iabt_low,
 	[ESR_ELx_EC_DABT_LOW]		= kvm_hyp_handle_dabt_low,
+	[ESR_ELx_EC_WATCHPT_LOW]	= kvm_hyp_handle_watchpt_low,
 	[ESR_ELx_EC_PAC]		= kvm_hyp_handle_ptrauth,
 };
 

arch/arm64/kvm/pmu-emul.c

@@ -694,45 +694,23 @@ void kvm_host_pmu_init(struct arm_pmu *pmu)
 
 static struct arm_pmu *kvm_pmu_probe_armpmu(void)
 {
-	struct perf_event_attr attr = { };
-	struct perf_event *event;
-	struct arm_pmu *pmu = NULL;
-
-	/*
-	 * Create a dummy event that only counts user cycles. As we'll never
-	 * leave this function with the event being live, it will never
-	 * count anything. But it allows us to probe some of the PMU
-	 * details. Yes, this is terrible.
-	 */
-	attr.type = PERF_TYPE_RAW;
-	attr.size = sizeof(attr);
-	attr.pinned = 1;
-	attr.disabled = 0;
-	attr.exclude_user = 0;
-	attr.exclude_kernel = 1;
-	attr.exclude_hv = 1;
-	attr.exclude_host = 1;
-	attr.config = ARMV8_PMUV3_PERFCTR_CPU_CYCLES;
-	attr.sample_period = GENMASK(63, 0);
+	struct arm_pmu *tmp, *pmu = NULL;
+	struct arm_pmu_entry *entry;
+	int cpu;
 
-	event = perf_event_create_kernel_counter(&attr, -1, current,
-						 kvm_pmu_perf_overflow, &attr);
+	mutex_lock(&arm_pmus_lock);
 
-	if (IS_ERR(event)) {
-		pr_err_once("kvm: pmu event creation failed %ld\n",
-			    PTR_ERR(event));
-		return NULL;
-	}
+	cpu = smp_processor_id();
+	list_for_each_entry(entry, &arm_pmus, entry) {
+		tmp = entry->arm_pmu;
 
-	if (event->pmu) {
-		pmu = to_arm_pmu(event->pmu);
-		if (pmu->pmuver == ID_AA64DFR0_EL1_PMUVer_NI ||
-		    pmu->pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF)
-			pmu = NULL;
+		if (cpumask_test_cpu(cpu, &tmp->supported_cpus)) {
+			pmu = tmp;
+			break;
+		}
 	}
 
-	perf_event_disable(event);
-	perf_event_release_kernel(event);
+	mutex_unlock(&arm_pmus_lock);
 
 	return pmu;
 }
@@ -912,7 +890,17 @@ int kvm_arm_pmu_v3_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
 		return -EBUSY;
 
 	if (!kvm->arch.arm_pmu) {
-		/* No PMU set, get the default one */
+		/*
+		 * No PMU set, get the default one.
+		 *
+		 * The observant among you will notice that the supported_cpus
+		 * mask does not get updated for the default PMU even though it
+		 * is quite possible the selected instance supports only a
+		 * subset of cores in the system. This is intentional, and
+		 * upholds the preexisting behavior on heterogeneous systems
+		 * where vCPUs can be scheduled on any core but the guest
+		 * counters could stop working.
+		 */
 		kvm->arch.arm_pmu = kvm_pmu_probe_armpmu();
 		if (!kvm->arch.arm_pmu)
 			return -ENODEV;

arch/arm64/kvm/sys_regs.c

@@ -211,6 +211,19 @@ static bool access_dcsw(struct kvm_vcpu *vcpu,
 	return true;
 }
 
+static bool access_dcgsw(struct kvm_vcpu *vcpu,
+			 struct sys_reg_params *p,
+			 const struct sys_reg_desc *r)
+{
+	if (!kvm_has_mte(vcpu->kvm)) {
+		kvm_inject_undefined(vcpu);
+		return false;
+	}
+
+	/* Treat MTE S/W ops as we treat the classic ones: with contempt */
+	return access_dcsw(vcpu, p, r);
+}
+
 static void get_access_mask(const struct sys_reg_desc *r, u64 *mask, u64 *shift)
 {
 	switch (r->aarch32_map) {
@@ -1756,8 +1769,14 @@ static bool access_spsr(struct kvm_vcpu *vcpu,
  */
 static const struct sys_reg_desc sys_reg_descs[] = {
 	{ SYS_DESC(SYS_DC_ISW), access_dcsw },
+	{ SYS_DESC(SYS_DC_IGSW), access_dcgsw },
+	{ SYS_DESC(SYS_DC_IGDSW), access_dcgsw },
 	{ SYS_DESC(SYS_DC_CSW), access_dcsw },
+	{ SYS_DESC(SYS_DC_CGSW), access_dcgsw },
+	{ SYS_DESC(SYS_DC_CGDSW), access_dcgsw },
 	{ SYS_DESC(SYS_DC_CISW), access_dcsw },
+	{ SYS_DESC(SYS_DC_CIGSW), access_dcgsw },
+	{ SYS_DESC(SYS_DC_CIGDSW), access_dcgsw },
 
 	DBG_BCR_BVR_WCR_WVR_EL1(0),
 	DBG_BCR_BVR_WCR_WVR_EL1(1),

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

@@ -235,9 +235,9 @@ int kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu)
 	 * KVM io device for the redistributor that belongs to this VCPU.
 	 */
 	if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3) {
-		mutex_lock(&vcpu->kvm->arch.config_lock);
+		mutex_lock(&vcpu->kvm->slots_lock);
 		ret = vgic_register_redist_iodev(vcpu);
-		mutex_unlock(&vcpu->kvm->arch.config_lock);
+		mutex_unlock(&vcpu->kvm->slots_lock);
 	}
 	return ret;
 }
@@ -406,7 +406,7 @@ void kvm_vgic_destroy(struct kvm *kvm)
 
 /**
  * vgic_lazy_init: Lazy init is only allowed if the GIC exposed to the guest
- * is a GICv2. A GICv3 must be explicitly initialized by the guest using the
+ * is a GICv2. A GICv3 must be explicitly initialized by userspace using the
  * KVM_DEV_ARM_VGIC_GRP_CTRL KVM_DEVICE group.
  * @kvm: kvm struct pointer
  */
@@ -446,11 +446,13 @@ int vgic_lazy_init(struct kvm *kvm)
 int kvm_vgic_map_resources(struct kvm *kvm)
 {
 	struct vgic_dist *dist = &kvm->arch.vgic;
+	gpa_t dist_base;
 	int ret = 0;
 
 	if (likely(vgic_ready(kvm)))
 		return 0;
 
+	mutex_lock(&kvm->slots_lock);
 	mutex_lock(&kvm->arch.config_lock);
 	if (vgic_ready(kvm))
 		goto out;
@@ -463,13 +465,26 @@ int kvm_vgic_map_resources(struct kvm *kvm)
 	else
 		ret = vgic_v3_map_resources(kvm);
 
-	if (ret)
+	if (ret) {
 		__kvm_vgic_destroy(kvm);
-	else
-		dist->ready = true;
+		goto out;
+	}
+	dist->ready = true;
+	dist_base = dist->vgic_dist_base;
+	mutex_unlock(&kvm->arch.config_lock);
+
+	ret = vgic_register_dist_iodev(kvm, dist_base,
+				       kvm_vgic_global_state.type);
+	if (ret) {
+		kvm_err("Unable to register VGIC dist MMIO regions\n");
+		kvm_vgic_destroy(kvm);
+	}
+	mutex_unlock(&kvm->slots_lock);
+	return ret;
 
 out:
 	mutex_unlock(&kvm->arch.config_lock);
+	mutex_unlock(&kvm->slots_lock);
 	return ret;
 }
 

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

@@ -1936,6 +1936,7 @@ void vgic_lpi_translation_cache_destroy(struct kvm *kvm)
 
 static int vgic_its_create(struct kvm_device *dev, u32 type)
 {
+	int ret;
 	struct vgic_its *its;
 
 	if (type != KVM_DEV_TYPE_ARM_VGIC_ITS)
@@ -1945,9 +1946,12 @@ static int vgic_its_create(struct kvm_device *dev, u32 type)
 	if (!its)
 		return -ENOMEM;
 
+	mutex_lock(&dev->kvm->arch.config_lock);
+
 	if (vgic_initialized(dev->kvm)) {
-		int ret = vgic_v4_init(dev->kvm);
+		ret = vgic_v4_init(dev->kvm);
 		if (ret < 0) {
+			mutex_unlock(&dev->kvm->arch.config_lock);
 			kfree(its);
 			return ret;
 		}
@@ -1960,12 +1964,10 @@ static int vgic_its_create(struct kvm_device *dev, u32 type)
 
 	/* Yep, even more trickery for lock ordering... */
 #ifdef CONFIG_LOCKDEP
-	mutex_lock(&dev->kvm->arch.config_lock);
 	mutex_lock(&its->cmd_lock);
 	mutex_lock(&its->its_lock);
 	mutex_unlock(&its->its_lock);
 	mutex_unlock(&its->cmd_lock);
-	mutex_unlock(&dev->kvm->arch.config_lock);
 #endif
 
 	its->vgic_its_base = VGIC_ADDR_UNDEF;
@@ -1986,7 +1988,11 @@ static int vgic_its_create(struct kvm_device *dev, u32 type)
 
 	dev->private = its;
 
-	return vgic_its_set_abi(its, NR_ITS_ABIS - 1);
+	ret = vgic_its_set_abi(its, NR_ITS_ABIS - 1);
+
+	mutex_unlock(&dev->kvm->arch.config_lock);
+
+	return ret;
 }
 
 static void vgic_its_destroy(struct kvm_device *kvm_dev)

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

@@ -102,7 +102,11 @@ static int kvm_vgic_addr(struct kvm *kvm, struct kvm_device_attr *attr, bool wri
 		if (get_user(addr, uaddr))
 			return -EFAULT;
 
-	mutex_lock(&kvm->arch.config_lock);
+	/*
+	 * Since we can't hold config_lock while registering the redistributor
+	 * iodevs, take the slots_lock immediately.
+	 */
+	mutex_lock(&kvm->slots_lock);
 	switch (attr->attr) {
 	case KVM_VGIC_V2_ADDR_TYPE_DIST:
 		r = vgic_check_type(kvm, KVM_DEV_TYPE_ARM_VGIC_V2);
@@ -182,6 +186,7 @@ static int kvm_vgic_addr(struct kvm *kvm, struct kvm_device_attr *attr, bool wri
 	if (r)
 		goto out;
 
+	mutex_lock(&kvm->arch.config_lock);
 	if (write) {
 		r = vgic_check_iorange(kvm, *addr_ptr, addr, alignment, size);
 		if (!r)
@@ -189,9 +194,10 @@ static int kvm_vgic_addr(struct kvm *kvm, struct kvm_device_attr *attr, bool wri
 	} else {
 		addr = *addr_ptr;
 	}
+	mutex_unlock(&kvm->arch.config_lock);
 
 out:
-	mutex_unlock(&kvm->arch.config_lock);
+	mutex_unlock(&kvm->slots_lock);
 
 	if (!r && !write)
 		r =  put_user(addr, uaddr);

arch/arm64/kvm/vgic/vgic-mmio-v3.c

@@ -769,10 +769,13 @@ int vgic_register_redist_iodev(struct kvm_vcpu *vcpu)
 	struct vgic_io_device *rd_dev = &vcpu->arch.vgic_cpu.rd_iodev;
 	struct vgic_redist_region *rdreg;
 	gpa_t rd_base;
-	int ret;
+	int ret = 0;
+
+	lockdep_assert_held(&kvm->slots_lock);
+	mutex_lock(&kvm->arch.config_lock);
 
 	if (!IS_VGIC_ADDR_UNDEF(vgic_cpu->rd_iodev.base_addr))
-		return 0;
+		goto out_unlock;
 
 	/*
 	 * We may be creating VCPUs before having set the base address for the
@@ -782,10 +785,12 @@ int vgic_register_redist_iodev(struct kvm_vcpu *vcpu)
 	 */
 	rdreg = vgic_v3_rdist_free_slot(&vgic->rd_regions);
 	if (!rdreg)
-		return 0;
+		goto out_unlock;
 
-	if (!vgic_v3_check_base(kvm))
-		return -EINVAL;
+	if (!vgic_v3_check_base(kvm)) {
+		ret = -EINVAL;
+		goto out_unlock;
+	}
 
 	vgic_cpu->rdreg = rdreg;
 	vgic_cpu->rdreg_index = rdreg->free_index;
@@ -799,16 +804,20 @@ int vgic_register_redist_iodev(struct kvm_vcpu *vcpu)
 	rd_dev->nr_regions = ARRAY_SIZE(vgic_v3_rd_registers);
 	rd_dev->redist_vcpu = vcpu;
 
-	mutex_lock(&kvm->slots_lock);
+	mutex_unlock(&kvm->arch.config_lock);
+
 	ret = kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS, rd_base,
 				      2 * SZ_64K, &rd_dev->dev);
-	mutex_unlock(&kvm->slots_lock);
-
 	if (ret)
 		return ret;
 
+	/* Protected by slots_lock */
 	rdreg->free_index++;
 	return 0;
+
+out_unlock:
+	mutex_unlock(&kvm->arch.config_lock);
+	return ret;
 }
 
 static void vgic_unregister_redist_iodev(struct kvm_vcpu *vcpu)
@@ -834,12 +843,10 @@ static int vgic_register_all_redist_iodevs(struct kvm *kvm)
 		/* The current c failed, so iterate over the previous ones. */
 		int i;
 
-		mutex_lock(&kvm->slots_lock);
 		for (i = 0; i < c; i++) {
 			vcpu = kvm_get_vcpu(kvm, i);
 			vgic_unregister_redist_iodev(vcpu);
 		}
-		mutex_unlock(&kvm->slots_lock);
 	}
 
 	return ret;
@@ -938,7 +945,9 @@ int vgic_v3_set_redist_base(struct kvm *kvm, u32 index, u64 addr, u32 count)
 {
 	int ret;
 
+	mutex_lock(&kvm->arch.config_lock);
 	ret = vgic_v3_alloc_redist_region(kvm, index, addr, count);
+	mutex_unlock(&kvm->arch.config_lock);
 	if (ret)
 		return ret;
 
@@ -950,8 +959,10 @@ int vgic_v3_set_redist_base(struct kvm *kvm, u32 index, u64 addr, u32 count)
 	if (ret) {
 		struct vgic_redist_region *rdreg;
 
+		mutex_lock(&kvm->arch.config_lock);
 		rdreg = vgic_v3_rdist_region_from_index(kvm, index);
 		vgic_v3_free_redist_region(rdreg);
+		mutex_unlock(&kvm->arch.config_lock);
 		return ret;
 	}
 

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

@@ -1096,7 +1096,6 @@ int vgic_register_dist_iodev(struct kvm *kvm, gpa_t dist_base_address,
 			     enum vgic_type type)
 {
 	struct vgic_io_device *io_device = &kvm->arch.vgic.dist_iodev;
-	int ret = 0;
 	unsigned int len;
 
 	switch (type) {
@@ -1114,10 +1113,6 @@ int vgic_register_dist_iodev(struct kvm *kvm, gpa_t dist_base_address,
 	io_device->iodev_type = IODEV_DIST;
 	io_device->redist_vcpu = NULL;
 
-	mutex_lock(&kvm->slots_lock);
-	ret = kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS, dist_base_address,
-				      len, &io_device->dev);
-	mutex_unlock(&kvm->slots_lock);
-
-	return ret;
+	return kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS, dist_base_address,
+				       len, &io_device->dev);
 }

arch/arm64/kvm/vgic/vgic-v2.c

@@ -312,12 +312,6 @@ int vgic_v2_map_resources(struct kvm *kvm)
 		return ret;
 	}
 
-	ret = vgic_register_dist_iodev(kvm, dist->vgic_dist_base, VGIC_V2);
-	if (ret) {
-		kvm_err("Unable to register VGIC MMIO regions\n");
-		return ret;
-	}
-
 	if (!static_branch_unlikely(&vgic_v2_cpuif_trap)) {
 		ret = kvm_phys_addr_ioremap(kvm, dist->vgic_cpu_base,
 					    kvm_vgic_global_state.vcpu_base,

arch/arm64/kvm/vgic/vgic-v3.c

@@ -539,7 +539,6 @@ int vgic_v3_map_resources(struct kvm *kvm)
 {
 	struct vgic_dist *dist = &kvm->arch.vgic;
 	struct kvm_vcpu *vcpu;
-	int ret = 0;
 	unsigned long c;
 
 	kvm_for_each_vcpu(c, vcpu, kvm) {
@@ -569,12 +568,6 @@ int vgic_v3_map_resources(struct kvm *kvm)
 		return -EBUSY;
 	}
 
-	ret = vgic_register_dist_iodev(kvm, dist->vgic_dist_base, VGIC_V3);
-	if (ret) {
-		kvm_err("Unable to register VGICv3 dist MMIO regions\n");
-		return ret;
-	}
-
 	if (kvm_vgic_global_state.has_gicv4_1)
 		vgic_v4_configure_vsgis(kvm);
 

arch/arm64/kvm/vgic/vgic-v4.c

@@ -184,13 +184,14 @@ static void vgic_v4_disable_vsgis(struct kvm_vcpu *vcpu)
 	}
 }
 
-/* Must be called with the kvm lock held */
 void vgic_v4_configure_vsgis(struct kvm *kvm)
 {
 	struct vgic_dist *dist = &kvm->arch.vgic;
 	struct kvm_vcpu *vcpu;
 	unsigned long i;
 
+	lockdep_assert_held(&kvm->arch.config_lock);
+
 	kvm_arm_halt_guest(kvm);
 
 	kvm_for_each_vcpu(i, vcpu, kvm) {

arch/x86/kvm/lapic.c

@@ -228,6 +228,23 @@ static int kvm_recalculate_phys_map(struct kvm_apic_map *new,
 	u32 xapic_id = kvm_xapic_id(apic);
 	u32 physical_id;
 
+	/*
+	 * For simplicity, KVM always allocates enough space for all possible
+	 * xAPIC IDs.  Yell, but don't kill the VM, as KVM can continue on
+	 * without the optimized map.
+	 */
+	if (WARN_ON_ONCE(xapic_id > new->max_apic_id))
+		return -EINVAL;
+
+	/*
+	 * Bail if a vCPU was added and/or enabled its APIC between allocating
+	 * the map and doing the actual calculations for the map.  Note, KVM
+	 * hardcodes the x2APIC ID to vcpu_id, i.e. there's no TOCTOU bug if
+	 * the compiler decides to reload x2apic_id after this check.
+	 */
+	if (x2apic_id > new->max_apic_id)
+		return -E2BIG;
+
 	/*
 	 * Deliberately truncate the vCPU ID when detecting a mismatched APIC
 	 * ID to avoid false positives if the vCPU ID, i.e. x2APIC ID, is a
@@ -253,8 +270,7 @@ static int kvm_recalculate_phys_map(struct kvm_apic_map *new,
 	 */
 	if (vcpu->kvm->arch.x2apic_format) {
 		/* See also kvm_apic_match_physical_addr(). */
-		if ((apic_x2apic_mode(apic) || x2apic_id > 0xff) &&
-			x2apic_id <= new->max_apic_id)
+		if (apic_x2apic_mode(apic) || x2apic_id > 0xff)
 			new->phys_map[x2apic_id] = apic;
 
 		if (!apic_x2apic_mode(apic) && !new->phys_map[xapic_id])

arch/x86/kvm/mmu/mmu.c

@@ -7091,7 +7091,10 @@ static void kvm_recover_nx_huge_pages(struct kvm *kvm)
 		 */
 		slot = NULL;
 		if (atomic_read(&kvm->nr_memslots_dirty_logging)) {
-			slot = gfn_to_memslot(kvm, sp->gfn);
+			struct kvm_memslots *slots;
+
+			slots = kvm_memslots_for_spte_role(kvm, sp->role);
+			slot = __gfn_to_memslot(slots, sp->gfn);
 			WARN_ON_ONCE(!slot);
 		}
 

arch/x86/kvm/svm/svm.c

@@ -3510,7 +3510,7 @@ static bool svm_is_vnmi_pending(struct kvm_vcpu *vcpu)
 	if (!is_vnmi_enabled(svm))
 		return false;
 
-	return !!(svm->vmcb->control.int_ctl & V_NMI_BLOCKING_MASK);
+	return !!(svm->vmcb->control.int_ctl & V_NMI_PENDING_MASK);
 }
 
 static bool svm_set_vnmi_pending(struct kvm_vcpu *vcpu)

arch/x86/kvm/x86.c

@@ -10758,6 +10758,9 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 			exit_fastpath = EXIT_FASTPATH_EXIT_HANDLED;
 			break;
 		}
+
+		/* Note, VM-Exits that go down the "slow" path are accounted below. */
+		++vcpu->stat.exits;
 	}
 
 	/*

tools/testing/selftests/kvm/Makefile

@@ -116,6 +116,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/sev_migrate_tests
 TEST_GEN_PROGS_x86_64 += x86_64/amx_test
 TEST_GEN_PROGS_x86_64 += x86_64/max_vcpuid_cap_test
 TEST_GEN_PROGS_x86_64 += x86_64/triple_fault_event_test
+TEST_GEN_PROGS_x86_64 += x86_64/recalc_apic_map_test
 TEST_GEN_PROGS_x86_64 += access_tracking_perf_test
 TEST_GEN_PROGS_x86_64 += demand_paging_test
 TEST_GEN_PROGS_x86_64 += dirty_log_test

tools/testing/selftests/kvm/x86_64/recalc_apic_map_test.c

+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Test edge cases and race conditions in kvm_recalculate_apic_map().
+ */
+
+#include <sys/ioctl.h>
+#include <pthread.h>
+#include <time.h>
+
+#include "processor.h"
+#include "test_util.h"
+#include "kvm_util.h"
+#include "apic.h"
+
+#define TIMEOUT		5	/* seconds */
+
+#define LAPIC_DISABLED	0
+#define LAPIC_X2APIC	(MSR_IA32_APICBASE_ENABLE | X2APIC_ENABLE)
+#define MAX_XAPIC_ID	0xff
+
+static void *race(void *arg)
+{
+	struct kvm_lapic_state lapic = {};
+	struct kvm_vcpu *vcpu = arg;
+
+	while (1) {
+		/* Trigger kvm_recalculate_apic_map(). */
+		vcpu_ioctl(vcpu, KVM_SET_LAPIC, &lapic);
+		pthread_testcancel();
+	}
+
+	return NULL;
+}
+
+int main(void)
+{
+	struct kvm_vcpu *vcpus[KVM_MAX_VCPUS];
+	struct kvm_vcpu *vcpuN;
+	struct kvm_vm *vm;
+	pthread_t thread;
+	time_t t;
+	int i;
+
+	kvm_static_assert(KVM_MAX_VCPUS > MAX_XAPIC_ID);
+
+	/*
+	 * Create the max number of vCPUs supported by selftests so that KVM
+	 * has decent amount of work to do when recalculating the map, i.e. to
+	 * make the problematic window large enough to hit.
+	 */
+	vm = vm_create_with_vcpus(KVM_MAX_VCPUS, NULL, vcpus);
+
+	/*
+	 * Enable x2APIC on all vCPUs so that KVM doesn't bail from the recalc
+	 * due to vCPUs having aliased xAPIC IDs (truncated to 8 bits).
+	 */
+	for (i = 0; i < KVM_MAX_VCPUS; i++)
+		vcpu_set_msr(vcpus[i], MSR_IA32_APICBASE, LAPIC_X2APIC);
+
+	ASSERT_EQ(pthread_create(&thread, NULL, race, vcpus[0]), 0);
+
+	vcpuN = vcpus[KVM_MAX_VCPUS - 1];
+	for (t = time(NULL) + TIMEOUT; time(NULL) < t;) {
+		vcpu_set_msr(vcpuN, MSR_IA32_APICBASE, LAPIC_X2APIC);
+		vcpu_set_msr(vcpuN, MSR_IA32_APICBASE, LAPIC_DISABLED);
+	}
+
+	ASSERT_EQ(pthread_cancel(thread), 0);
+	ASSERT_EQ(pthread_join(thread, NULL), 0);
+
+	kvm_vm_free(vm);
+
+	return 0;
+}