Merge tag 'kvm-4.15-2' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM updates from Radim Krčmář:
 "Trimmed second batch of KVM changes for Linux 4.15:

   - GICv4 Support for KVM/ARM

   - re-introduce support for CPUs without virtual NMI (cc stable) and
     allow testing of KVM without virtual NMI on available CPUs

   - fix long-standing performance issues with assigned devices on AMD
     (cc stable)"

* tag 'kvm-4.15-2' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (30 commits)
  kvm: vmx: Allow disabling virtual NMI support
  kvm: vmx: Reinstate support for CPUs without virtual NMI
  KVM: SVM: obey guest PAT
  KVM: arm/arm64: Don't queue VLPIs on INV/INVALL
  KVM: arm/arm64: Fix GICv4 ITS initialization issues
  KVM: arm/arm64: GICv4: Theory of operations
  KVM: arm/arm64: GICv4: Enable VLPI support
  KVM: arm/arm64: GICv4: Prevent userspace from changing doorbell affinity
  KVM: arm/arm64: GICv4: Prevent a VM using GICv4 from being saved
  KVM: arm/arm64: GICv4: Enable virtual cpuif if VLPIs can be delivered
  KVM: arm/arm64: GICv4: Hook vPE scheduling into vgic flush/sync
  KVM: arm/arm64: GICv4: Use the doorbell interrupt as an unblocking source
  KVM: arm/arm64: GICv4: Add doorbell interrupt handling
  KVM: arm/arm64: GICv4: Use pending_last as a scheduling hint
  KVM: arm/arm64: GICv4: Handle INVALL applied to a vPE
  KVM: arm/arm64: GICv4: Propagate property updates to VLPIs
  KVM: arm/arm64: GICv4: Handle MOVALL applied to a vPE
  KVM: arm/arm64: GICv4: Handle CLEAR applied to a VLPI
  KVM: arm/arm64: GICv4: Propagate affinity changes to the physical ITS
  KVM: arm/arm64: GICv4: Unmap VLPI when freeing an LPI
  ...

Documentation/admin-guide/kernel-parameters.txt

@@ -1890,6 +1890,10 @@
 			[KVM,ARM] Trap guest accesses to GICv3 common
 			system registers
 
+	kvm-arm.vgic_v4_enable=
+			[KVM,ARM] Allow use of GICv4 for direct injection of
+			LPIs.
+
 	kvm-intel.ept=	[KVM,Intel] Disable extended page tables
 			(virtualized MMU) support on capable Intel chips.
 			Default is 1 (enabled)

Documentation/virtual/kvm/devices/arm-vgic-its.txt

@@ -64,6 +64,8 @@ Groups:
     -EINVAL: Inconsistent restored data
     -EFAULT: Invalid guest ram access
     -EBUSY:  One or more VCPUS are running
+    -EACCES: The virtual ITS is backed by a physical GICv4 ITS, and the
+	     state is not available
 
   KVM_DEV_ARM_VGIC_GRP_ITS_REGS
   Attributes:

arch/arm/kvm/Kconfig

@@ -4,6 +4,7 @@
 #
 
 source "virt/kvm/Kconfig"
+source "virt/lib/Kconfig"
 
 menuconfig VIRTUALIZATION
 	bool "Virtualization"
@@ -23,6 +24,8 @@ config KVM
 	select PREEMPT_NOTIFIERS
 	select ANON_INODES
 	select ARM_GIC
+	select ARM_GIC_V3
+	select ARM_GIC_V3_ITS
 	select HAVE_KVM_CPU_RELAX_INTERCEPT
 	select HAVE_KVM_ARCH_TLB_FLUSH_ALL
 	select KVM_MMIO
@@ -36,6 +39,8 @@ config KVM
 	select HAVE_KVM_IRQCHIP
 	select HAVE_KVM_IRQ_ROUTING
 	select HAVE_KVM_MSI
+	select IRQ_BYPASS_MANAGER
+	select HAVE_KVM_IRQ_BYPASS
 	depends on ARM_VIRT_EXT && ARM_LPAE && ARM_ARCH_TIMER
 	---help---
 	  Support hosting virtualized guest machines.

arch/arm/kvm/Makefile

@@ -32,6 +32,7 @@ obj-y += $(KVM)/arm/vgic/vgic-init.o
 obj-y += $(KVM)/arm/vgic/vgic-irqfd.o
 obj-y += $(KVM)/arm/vgic/vgic-v2.o
 obj-y += $(KVM)/arm/vgic/vgic-v3.o
+obj-y += $(KVM)/arm/vgic/vgic-v4.o
 obj-y += $(KVM)/arm/vgic/vgic-mmio.o
 obj-y += $(KVM)/arm/vgic/vgic-mmio-v2.o
 obj-y += $(KVM)/arm/vgic/vgic-mmio-v3.o

arch/arm64/kvm/Kconfig

@@ -4,6 +4,7 @@
 #
 
 source "virt/kvm/Kconfig"
+source "virt/lib/Kconfig"
 
 menuconfig VIRTUALIZATION
 	bool "Virtualization"
@@ -36,6 +37,8 @@ config KVM
 	select HAVE_KVM_MSI
 	select HAVE_KVM_IRQCHIP
 	select HAVE_KVM_IRQ_ROUTING
+	select IRQ_BYPASS_MANAGER
+	select HAVE_KVM_IRQ_BYPASS
 	---help---
 	  Support hosting virtualized guest machines.
 	  We don't support KVM with 16K page tables yet, due to the multiple

arch/arm64/kvm/Makefile

@@ -27,6 +27,7 @@ kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic/vgic-init.o
 kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic/vgic-irqfd.o
 kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic/vgic-v2.o
 kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic/vgic-v3.o
+kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic/vgic-v4.o
 kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic/vgic-mmio.o
 kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic/vgic-mmio-v2.o
 kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic/vgic-mmio-v3.o

arch/x86/kvm/svm.c

@@ -3671,6 +3671,13 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr)
 	u32 ecx = msr->index;
 	u64 data = msr->data;
 	switch (ecx) {
+	case MSR_IA32_CR_PAT:
+		if (!kvm_mtrr_valid(vcpu, MSR_IA32_CR_PAT, data))
+			return 1;
+		vcpu->arch.pat = data;
+		svm->vmcb->save.g_pat = data;
+		mark_dirty(svm->vmcb, VMCB_NPT);
+		break;
 	case MSR_IA32_TSC:
 		kvm_write_tsc(vcpu, msr);
 		break;

arch/x86/kvm/vmx.c

@@ -70,6 +70,9 @@ MODULE_DEVICE_TABLE(x86cpu, vmx_cpu_id);
 static bool __read_mostly enable_vpid = 1;
 module_param_named(vpid, enable_vpid, bool, 0444);
 
+static bool __read_mostly enable_vnmi = 1;
+module_param_named(vnmi, enable_vnmi, bool, S_IRUGO);
+
 static bool __read_mostly flexpriority_enabled = 1;
 module_param_named(flexpriority, flexpriority_enabled, bool, S_IRUGO);
 
@@ -202,6 +205,10 @@ struct loaded_vmcs {
 	bool nmi_known_unmasked;
 	unsigned long vmcs_host_cr3;	/* May not match real cr3 */
 	unsigned long vmcs_host_cr4;	/* May not match real cr4 */
+	/* Support for vnmi-less CPUs */
+	int soft_vnmi_blocked;
+	ktime_t entry_time;
+	s64 vnmi_blocked_time;
 	struct list_head loaded_vmcss_on_cpu_link;
 };
 
@@ -1291,6 +1298,11 @@ static inline bool cpu_has_vmx_invpcid(void)
 		SECONDARY_EXEC_ENABLE_INVPCID;
 }
 
+static inline bool cpu_has_virtual_nmis(void)
+{
+	return vmcs_config.pin_based_exec_ctrl & PIN_BASED_VIRTUAL_NMIS;
+}
+
 static inline bool cpu_has_vmx_wbinvd_exit(void)
 {
 	return vmcs_config.cpu_based_2nd_exec_ctrl &
@@ -1348,11 +1360,6 @@ static inline bool nested_cpu_has2(struct vmcs12 *vmcs12, u32 bit)
 		(vmcs12->secondary_vm_exec_control & bit);
 }
 
-static inline bool nested_cpu_has_virtual_nmis(struct vmcs12 *vmcs12)
-{
-	return vmcs12->pin_based_vm_exec_control & PIN_BASED_VIRTUAL_NMIS;
-}
-
 static inline bool nested_cpu_has_preemption_timer(struct vmcs12 *vmcs12)
 {
 	return vmcs12->pin_based_vm_exec_control &
@@ -3712,9 +3719,9 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf)
 				&_vmexit_control) < 0)
 		return -EIO;
 
-	min = PIN_BASED_EXT_INTR_MASK | PIN_BASED_NMI_EXITING |
-		PIN_BASED_VIRTUAL_NMIS;
-	opt = PIN_BASED_POSTED_INTR | PIN_BASED_VMX_PREEMPTION_TIMER;
+	min = PIN_BASED_EXT_INTR_MASK | PIN_BASED_NMI_EXITING;
+	opt = PIN_BASED_VIRTUAL_NMIS | PIN_BASED_POSTED_INTR |
+		 PIN_BASED_VMX_PREEMPTION_TIMER;
 	if (adjust_vmx_controls(min, opt, MSR_IA32_VMX_PINBASED_CTLS,
 				&_pin_based_exec_control) < 0)
 		return -EIO;
@@ -5232,6 +5239,10 @@ static u32 vmx_pin_based_exec_ctrl(struct vcpu_vmx *vmx)
 
 	if (!kvm_vcpu_apicv_active(&vmx->vcpu))
 		pin_based_exec_ctrl &= ~PIN_BASED_POSTED_INTR;
+
+	if (!enable_vnmi)
+		pin_based_exec_ctrl &= ~PIN_BASED_VIRTUAL_NMIS;
+
 	/* Enable the preemption timer dynamically */
 	pin_based_exec_ctrl &= ~PIN_BASED_VMX_PREEMPTION_TIMER;
 	return pin_based_exec_ctrl;
@@ -5666,7 +5677,8 @@ static void enable_irq_window(struct kvm_vcpu *vcpu)
 
 static void enable_nmi_window(struct kvm_vcpu *vcpu)
 {
-	if (vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & GUEST_INTR_STATE_STI) {
+	if (!enable_vnmi ||
+	    vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & GUEST_INTR_STATE_STI) {
 		enable_irq_window(vcpu);
 		return;
 	}
@@ -5706,6 +5718,19 @@ static void vmx_inject_nmi(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 
+	if (!enable_vnmi) {
+		/*
+		 * Tracking the NMI-blocked state in software is built upon
+		 * finding the next open IRQ window. This, in turn, depends on
+		 * well-behaving guests: They have to keep IRQs disabled at
+		 * least as long as the NMI handler runs. Otherwise we may
+		 * cause NMI nesting, maybe breaking the guest. But as this is
+		 * highly unlikely, we can live with the residual risk.
+		 */
+		vmx->loaded_vmcs->soft_vnmi_blocked = 1;
+		vmx->loaded_vmcs->vnmi_blocked_time = 0;
+	}
+
 	++vcpu->stat.nmi_injections;
 	vmx->loaded_vmcs->nmi_known_unmasked = false;
 
@@ -5724,6 +5749,8 @@ static bool vmx_get_nmi_mask(struct kvm_vcpu *vcpu)
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 	bool masked;
 
+	if (!enable_vnmi)
+		return vmx->loaded_vmcs->soft_vnmi_blocked;
 	if (vmx->loaded_vmcs->nmi_known_unmasked)
 		return false;
 	masked = vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & GUEST_INTR_STATE_NMI;
@@ -5735,6 +5762,12 @@ static void vmx_set_nmi_mask(struct kvm_vcpu *vcpu, bool masked)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 
+	if (!enable_vnmi) {
+		if (vmx->loaded_vmcs->soft_vnmi_blocked != masked) {
+			vmx->loaded_vmcs->soft_vnmi_blocked = masked;
+			vmx->loaded_vmcs->vnmi_blocked_time = 0;
+		}
+	} else {
 		vmx->loaded_vmcs->nmi_known_unmasked = !masked;
 		if (masked)
 			vmcs_set_bits(GUEST_INTERRUPTIBILITY_INFO,
@@ -5742,6 +5775,7 @@ static void vmx_set_nmi_mask(struct kvm_vcpu *vcpu, bool masked)
 		else
 			vmcs_clear_bits(GUEST_INTERRUPTIBILITY_INFO,
 					GUEST_INTR_STATE_NMI);
+	}
 }
 
 static int vmx_nmi_allowed(struct kvm_vcpu *vcpu)
@@ -5749,6 +5783,10 @@ static int vmx_nmi_allowed(struct kvm_vcpu *vcpu)
 	if (to_vmx(vcpu)->nested.nested_run_pending)
 		return 0;
 
+	if (!enable_vnmi &&
+	    to_vmx(vcpu)->loaded_vmcs->soft_vnmi_blocked)
+		return 0;
+
 	return	!(vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) &
 		  (GUEST_INTR_STATE_MOV_SS | GUEST_INTR_STATE_STI
 		   | GUEST_INTR_STATE_NMI));
@@ -6476,6 +6514,7 @@ static int handle_ept_violation(struct kvm_vcpu *vcpu)
 	 * AAK134, BY25.
 	 */
 	if (!(to_vmx(vcpu)->idt_vectoring_info & VECTORING_INFO_VALID_MASK) &&
+			enable_vnmi &&
 			(exit_qualification & INTR_INFO_UNBLOCK_NMI))
 		vmcs_set_bits(GUEST_INTERRUPTIBILITY_INFO, GUEST_INTR_STATE_NMI);
 
@@ -6535,6 +6574,7 @@ static int handle_ept_misconfig(struct kvm_vcpu *vcpu)
 
 static int handle_nmi_window(struct kvm_vcpu *vcpu)
 {
+	WARN_ON_ONCE(!enable_vnmi);
 	vmcs_clear_bits(CPU_BASED_VM_EXEC_CONTROL,
 			CPU_BASED_VIRTUAL_NMI_PENDING);
 	++vcpu->stat.nmi_window_exits;
@@ -6758,6 +6798,9 @@ static __init int hardware_setup(void)
 	if (!cpu_has_vmx_flexpriority())
 		flexpriority_enabled = 0;
 
+	if (!cpu_has_virtual_nmis())
+		enable_vnmi = 0;
+
 	/*
 	 * set_apic_access_page_addr() is used to reload apic access
 	 * page upon invalidation.  No need to do anything if not
@@ -6962,7 +7005,7 @@ static struct loaded_vmcs *nested_get_current_vmcs02(struct vcpu_vmx *vmx)
 	}
 
 	/* Create a new VMCS */
-	item = kmalloc(sizeof(struct vmcs02_list), GFP_KERNEL);
+	item = kzalloc(sizeof(struct vmcs02_list), GFP_KERNEL);
 	if (!item)
 		return NULL;
 	item->vmcs02.vmcs = alloc_vmcs();
@@ -7979,6 +8022,7 @@ static int handle_pml_full(struct kvm_vcpu *vcpu)
 	 * "blocked by NMI" bit has to be set before next VM entry.
 	 */
 	if (!(to_vmx(vcpu)->idt_vectoring_info & VECTORING_INFO_VALID_MASK) &&
+			enable_vnmi &&
 			(exit_qualification & INTR_INFO_UNBLOCK_NMI))
 		vmcs_set_bits(GUEST_INTERRUPTIBILITY_INFO,
 				GUEST_INTR_STATE_NMI);
@@ -8823,6 +8867,25 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu)
 		return 0;
 	}
 
+	if (unlikely(!enable_vnmi &&
+		     vmx->loaded_vmcs->soft_vnmi_blocked)) {
+		if (vmx_interrupt_allowed(vcpu)) {
+			vmx->loaded_vmcs->soft_vnmi_blocked = 0;
+		} else if (vmx->loaded_vmcs->vnmi_blocked_time > 1000000000LL &&
+			   vcpu->arch.nmi_pending) {
+			/*
+			 * This CPU don't support us in finding the end of an
+			 * NMI-blocked window if the guest runs with IRQs
+			 * disabled. So we pull the trigger after 1 s of
+			 * futile waiting, but inform the user about this.
+			 */
+			printk(KERN_WARNING "%s: Breaking out of NMI-blocked "
+			       "state on VCPU %d after 1 s timeout\n",
+			       __func__, vcpu->vcpu_id);
+			vmx->loaded_vmcs->soft_vnmi_blocked = 0;
+		}
+	}
+
 	if (exit_reason < kvm_vmx_max_exit_handlers
 	    && kvm_vmx_exit_handlers[exit_reason])
 		return kvm_vmx_exit_handlers[exit_reason](vcpu);
@@ -9105,6 +9168,7 @@ static void vmx_recover_nmi_blocking(struct vcpu_vmx *vmx)
 
 	idtv_info_valid = vmx->idt_vectoring_info & VECTORING_INFO_VALID_MASK;
 
+	if (enable_vnmi) {
 		if (vmx->loaded_vmcs->nmi_known_unmasked)
 			return;
 		/*
@@ -9132,6 +9196,10 @@ static void vmx_recover_nmi_blocking(struct vcpu_vmx *vmx)
 			vmx->loaded_vmcs->nmi_known_unmasked =
 				!(vmcs_read32(GUEST_INTERRUPTIBILITY_INFO)
 				  & GUEST_INTR_STATE_NMI);
+	} else if (unlikely(vmx->loaded_vmcs->soft_vnmi_blocked))
+		vmx->loaded_vmcs->vnmi_blocked_time +=
+			ktime_to_ns(ktime_sub(ktime_get(),
+					      vmx->loaded_vmcs->entry_time));
 }
 
 static void __vmx_complete_interrupts(struct kvm_vcpu *vcpu,
@@ -9248,6 +9316,11 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 	unsigned long debugctlmsr, cr3, cr4;
 
+	/* Record the guest's net vcpu time for enforced NMI injections. */
+	if (unlikely(!enable_vnmi &&
+		     vmx->loaded_vmcs->soft_vnmi_blocked))
+		vmx->loaded_vmcs->entry_time = ktime_get();
+
 	/* Don't enter VMX if guest state is invalid, let the exit handler
 	   start emulation until we arrive back to a valid state */
 	if (vmx->emulation_required)

include/kvm/arm_vgic.h

@@ -26,6 +26,8 @@
 #include <linux/list.h>
 #include <linux/jump_label.h>
 
+#include <linux/irqchip/arm-gic-v4.h>
+
 #define VGIC_V3_MAX_CPUS	255
 #define VGIC_V2_MAX_CPUS	8
 #define VGIC_NR_IRQS_LEGACY     256
@@ -73,6 +75,9 @@ struct vgic_global {
 	/* Only needed for the legacy KVM_CREATE_IRQCHIP */
 	bool			can_emulate_gicv2;
 
+	/* Hardware has GICv4? */
+	bool			has_gicv4;
+
 	/* GIC system register CPU interface */
 	struct static_key_false gicv3_cpuif;
 
@@ -116,6 +121,7 @@ struct vgic_irq {
 	bool hw;			/* Tied to HW IRQ */
 	struct kref refcount;		/* Used for LPIs */
 	u32 hwintid;			/* HW INTID number */
+	unsigned int host_irq;		/* linux irq corresponding to hwintid */
 	union {
 		u8 targets;			/* GICv2 target VCPUs mask */
 		u32 mpidr;			/* GICv3 target VCPU */
@@ -232,6 +238,15 @@ struct vgic_dist {
 
 	/* used by vgic-debug */
 	struct vgic_state_iter *iter;
+
+	/*
+	 * GICv4 ITS per-VM data, containing the IRQ domain, the VPE
+	 * array, the property table pointer as well as allocation
+	 * data. This essentially ties the Linux IRQ core and ITS
+	 * together, and avoids leaking KVM's data structures anywhere
+	 * else.
+	 */
+	struct its_vm		its_vm;
 };
 
 struct vgic_v2_cpu_if {
@@ -250,6 +265,14 @@ struct vgic_v3_cpu_if {
 	u32		vgic_ap0r[4];
 	u32		vgic_ap1r[4];
 	u64		vgic_lr[VGIC_V3_MAX_LRS];
+
+	/*
+	 * GICv4 ITS per-VPE data, containing the doorbell IRQ, the
+	 * pending table pointer, the its_vm pointer and a few other
+	 * HW specific things. As for the its_vm structure, this is
+	 * linking the Linux IRQ subsystem and the ITS together.
+	 */
+	struct its_vpe	its_vpe;
 };
 
 struct vgic_cpu {
@@ -307,9 +330,10 @@ void kvm_vgic_init_cpu_hardware(void);
 
 int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid,
 			bool level, void *owner);
-int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, u32 virt_irq, u32 phys_irq);
-int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int virt_irq);
-bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, unsigned int virt_irq);
+int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, unsigned int host_irq,
+			  u32 vintid);
+int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int vintid);
+bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, unsigned int vintid);
 
 int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu);
 
@@ -349,4 +373,15 @@ int kvm_vgic_setup_default_irq_routing(struct kvm *kvm);
 
 int kvm_vgic_set_owner(struct kvm_vcpu *vcpu, unsigned int intid, void *owner);
 
+struct kvm_kernel_irq_routing_entry;
+
+int kvm_vgic_v4_set_forwarding(struct kvm *kvm, int irq,
+			       struct kvm_kernel_irq_routing_entry *irq_entry);
+
+int kvm_vgic_v4_unset_forwarding(struct kvm *kvm, int irq,
+				 struct kvm_kernel_irq_routing_entry *irq_entry);
+
+void kvm_vgic_v4_enable_doorbell(struct kvm_vcpu *vcpu);
+void kvm_vgic_v4_disable_doorbell(struct kvm_vcpu *vcpu);
+
 #endif /* __KVM_ARM_VGIC_H */

virt/kvm/arm/arch_timer.c

@@ -817,9 +817,6 @@ int kvm_timer_enable(struct kvm_vcpu *vcpu)
 {
 	struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
 	struct arch_timer_context *vtimer = vcpu_vtimer(vcpu);
-	struct irq_desc *desc;
-	struct irq_data *data;
-	int phys_irq;
 	int ret;
 
 	if (timer->enabled)
@@ -837,26 +834,7 @@ int kvm_timer_enable(struct kvm_vcpu *vcpu)
 		return -EINVAL;
 	}
 
-	/*
-	 * Find the physical IRQ number corresponding to the host_vtimer_irq
-	 */
-	desc = irq_to_desc(host_vtimer_irq);
-	if (!desc) {
-		kvm_err("%s: no interrupt descriptor\n", __func__);
-		return -EINVAL;
-	}
-
-	data = irq_desc_get_irq_data(desc);
-	while (data->parent_data)
-		data = data->parent_data;
-
-	phys_irq = data->hwirq;
-
-	/*
-	 * Tell the VGIC that the virtual interrupt is tied to a
-	 * physical interrupt. We do that once per VCPU.
-	 */
-	ret = kvm_vgic_map_phys_irq(vcpu, vtimer->irq.irq, phys_irq);
+	ret = kvm_vgic_map_phys_irq(vcpu, host_vtimer_irq, vtimer->irq.irq);
 	if (ret)
 		return ret;
 

virt/kvm/arm/arm.c

@@ -27,6 +27,8 @@
 #include <linux/mman.h>
 #include <linux/sched.h>
 #include <linux/kvm.h>
+#include <linux/kvm_irqfd.h>
+#include <linux/irqbypass.h>
 #include <trace/events/kvm.h>
 #include <kvm/arm_pmu.h>
 
@@ -175,6 +177,8 @@ void kvm_arch_destroy_vm(struct kvm *kvm)
 {
 	int i;
 
+	kvm_vgic_destroy(kvm);
+
 	free_percpu(kvm->arch.last_vcpu_ran);
 	kvm->arch.last_vcpu_ran = NULL;
 
@@ -184,8 +188,6 @@ void kvm_arch_destroy_vm(struct kvm *kvm)
 			kvm->vcpus[i] = NULL;
 		}
 	}
-
-	kvm_vgic_destroy(kvm);
 }
 
 int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
@@ -313,11 +315,13 @@ int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
 void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu)
 {
 	kvm_timer_schedule(vcpu);
+	kvm_vgic_v4_enable_doorbell(vcpu);
 }
 
 void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu)
 {
 	kvm_timer_unschedule(vcpu);
+	kvm_vgic_v4_disable_doorbell(vcpu);
 }
 
 int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
@@ -1450,6 +1454,46 @@ struct kvm_vcpu *kvm_mpidr_to_vcpu(struct kvm *kvm, unsigned long mpidr)
 	return NULL;
 }
 
+bool kvm_arch_has_irq_bypass(void)
+{
+	return true;
+}
+
+int kvm_arch_irq_bypass_add_producer(struct irq_bypass_consumer *cons,
+				      struct irq_bypass_producer *prod)
+{
+	struct kvm_kernel_irqfd *irqfd =
+		container_of(cons, struct kvm_kernel_irqfd, consumer);
+
+	return kvm_vgic_v4_set_forwarding(irqfd->kvm, prod->irq,
+					  &irqfd->irq_entry);
+}
+void kvm_arch_irq_bypass_del_producer(struct irq_bypass_consumer *cons,
+				      struct irq_bypass_producer *prod)
+{
+	struct kvm_kernel_irqfd *irqfd =
+		container_of(cons, struct kvm_kernel_irqfd, consumer);
+
+	kvm_vgic_v4_unset_forwarding(irqfd->kvm, prod->irq,
+				     &irqfd->irq_entry);
+}
+
+void kvm_arch_irq_bypass_stop(struct irq_bypass_consumer *cons)
+{
+	struct kvm_kernel_irqfd *irqfd =
+		container_of(cons, struct kvm_kernel_irqfd, consumer);
+
+	kvm_arm_halt_guest(irqfd->kvm);
+}
+
+void kvm_arch_irq_bypass_start(struct irq_bypass_consumer *cons)
+{
+	struct kvm_kernel_irqfd *irqfd =
+		container_of(cons, struct kvm_kernel_irqfd, consumer);
+
+	kvm_arm_resume_guest(irqfd->kvm);
+}
+
 /**
  * Initialize Hyp-mode and memory mappings on all CPUs.
  */

virt/kvm/arm/hyp/vgic-v3-sr.c

@@ -258,7 +258,8 @@ void __hyp_text __vgic_v3_save_state(struct kvm_vcpu *vcpu)
 			cpu_if->vgic_ap1r[0] = __vgic_v3_read_ap1rn(0);
 		}
 	} else {
-		if (static_branch_unlikely(&vgic_v3_cpuif_trap))
+		if (static_branch_unlikely(&vgic_v3_cpuif_trap) ||
+		    cpu_if->its_vpe.its_vm)
 			write_gicreg(0, ICH_HCR_EL2);
 
 		cpu_if->vgic_elrsr = 0xffff;
@@ -337,9 +338,11 @@ void __hyp_text __vgic_v3_restore_state(struct kvm_vcpu *vcpu)
 		/*
 		 * If we need to trap system registers, we must write
 		 * ICH_HCR_EL2 anyway, even if no interrupts are being
-		 * injected,
+		 * injected. Same thing if GICv4 is used, as VLPI
+		 * delivery is gated by ICH_HCR_EL2.En.
 		 */
-		if (static_branch_unlikely(&vgic_v3_cpuif_trap))
+		if (static_branch_unlikely(&vgic_v3_cpuif_trap) ||
+		    cpu_if->its_vpe.its_vm)
 			write_gicreg(cpu_if->vgic_hcr, ICH_HCR_EL2);
 	}
 

virt/kvm/arm/vgic/vgic-init.c

@@ -285,6 +285,10 @@ int vgic_init(struct kvm *kvm)
 	if (ret)
 		goto out;
 
+	ret = vgic_v4_init(kvm);
+	if (ret)
+		goto out;
+
 	kvm_for_each_vcpu(i, vcpu, kvm)
 		kvm_vgic_vcpu_enable(vcpu);
 
@@ -320,6 +324,9 @@ static void kvm_vgic_dist_destroy(struct kvm *kvm)
 
 	kfree(dist->spis);
 	dist->nr_spis = 0;
+
+	if (vgic_supports_direct_msis(kvm))
+		vgic_v4_teardown(kvm);
 }
 
 void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu)

virt/kvm/arm/vgic/vgic-its.c

@@ -38,7 +38,7 @@ static int vgic_its_save_tables_v0(struct vgic_its *its);
 static int vgic_its_restore_tables_v0(struct vgic_its *its);
 static int vgic_its_commit_v0(struct vgic_its *its);
 static int update_lpi_config(struct kvm *kvm, struct vgic_irq *irq,
-			     struct kvm_vcpu *filter_vcpu);
+			     struct kvm_vcpu *filter_vcpu, bool needs_inv);
 
 /*
  * Creates a new (reference to a) struct vgic_irq for a given LPI.
@@ -106,7 +106,7 @@ static struct vgic_irq *vgic_add_lpi(struct kvm *kvm, u32 intid,
 	 * However we only have those structs for mapped IRQs, so we read in
 	 * the respective config data from memory here upon mapping the LPI.
 	 */
-	ret = update_lpi_config(kvm, irq, NULL);
+	ret = update_lpi_config(kvm, irq, NULL, false);
 	if (ret)
 		return ERR_PTR(ret);
 
@@ -273,7 +273,7 @@ static struct its_collection *find_collection(struct vgic_its *its, int coll_id)
  * VCPU. Unconditionally applies if filter_vcpu is NULL.
  */
 static int update_lpi_config(struct kvm *kvm, struct vgic_irq *irq,
-			     struct kvm_vcpu *filter_vcpu)
+			     struct kvm_vcpu *filter_vcpu, bool needs_inv)
 {
 	u64 propbase = GICR_PROPBASER_ADDRESS(kvm->arch.vgic.propbaser);
 	u8 prop;
@@ -292,11 +292,17 @@ static int update_lpi_config(struct kvm *kvm, struct vgic_irq *irq,
 		irq->priority = LPI_PROP_PRIORITY(prop);
 		irq->enabled = LPI_PROP_ENABLE_BIT(prop);
 
+		if (!irq->hw) {
 			vgic_queue_irq_unlock(kvm, irq, flags);
-	} else {
-		spin_unlock_irqrestore(&irq->irq_lock, flags);
+			return 0;
+		}
 	}
 
+	spin_unlock_irqrestore(&irq->irq_lock, flags);
+
+	if (irq->hw)
+		return its_prop_update_vlpi(irq->host_irq, prop, needs_inv);
+
 	return 0;
 }
 
@@ -336,6 +342,29 @@ static int vgic_copy_lpi_list(struct kvm_vcpu *vcpu, u32 **intid_ptr)
 	return i;
 }
 
+static int update_affinity(struct vgic_irq *irq, struct kvm_vcpu *vcpu)
+{
+	int ret = 0;
+
+	spin_lock(&irq->irq_lock);
+	irq->target_vcpu = vcpu;
+	spin_unlock(&irq->irq_lock);
+
+	if (irq->hw) {
+		struct its_vlpi_map map;
+
+		ret = its_get_vlpi(irq->host_irq, &map);
+		if (ret)
+			return ret;
+
+		map.vpe = &vcpu->arch.vgic_cpu.vgic_v3.its_vpe;
+
+		ret = its_map_vlpi(irq->host_irq, &map);
+	}
+
+	return ret;
+}
+
 /*
  * Promotes the ITS view of affinity of an ITTE (which redistributor this LPI
  * is targeting) to the VGIC's view, which deals with target VCPUs.
@@ -350,10 +379,7 @@ static void update_affinity_ite(struct kvm *kvm, struct its_ite *ite)
 		return;
 
 	vcpu = kvm_get_vcpu(kvm, ite->collection->target_addr);
-
-	spin_lock(&ite->irq->irq_lock);
-	ite->irq->target_vcpu = vcpu;
-	spin_unlock(&ite->irq->irq_lock);
+	update_affinity(ite->irq, vcpu);
 }
 
 /*
@@ -505,19 +531,11 @@ static unsigned long vgic_mmio_read_its_idregs(struct kvm *kvm,
 	return 0;
 }
 
-/*
- * Find the target VCPU and the LPI number for a given devid/eventid pair
- * and make this IRQ pending, possibly injecting it.
- * Must be called with the its_lock mutex held.
- * Returns 0 on success, a positive error value for any ITS mapping
- * related errors and negative error values for generic errors.
- */
-static int vgic_its_trigger_msi(struct kvm *kvm, struct vgic_its *its,
-				u32 devid, u32 eventid)
+int vgic_its_resolve_lpi(struct kvm *kvm, struct vgic_its *its,
+			 u32 devid, u32 eventid, struct vgic_irq **irq)
 {
 	struct kvm_vcpu *vcpu;
 	struct its_ite *ite;
-	unsigned long flags;
 
 	if (!its->enabled)
 		return -EBUSY;
@@ -533,26 +551,65 @@ static int vgic_its_trigger_msi(struct kvm *kvm, struct vgic_its *its,
 	if (!vcpu->arch.vgic_cpu.lpis_enabled)
 		return -EBUSY;
 
-	spin_lock_irqsave(&ite->irq->irq_lock, flags);
-	ite->irq->pending_latch = true;
-	vgic_queue_irq_unlock(kvm, ite->irq, flags);
-
+	*irq = ite->irq;
 	return 0;
 }
 
-static struct vgic_io_device *vgic_get_its_iodev(struct kvm_io_device *dev)
+struct vgic_its *vgic_msi_to_its(struct kvm *kvm, struct kvm_msi *msi)
 {
+	u64 address;
+	struct kvm_io_device *kvm_io_dev;
 	struct vgic_io_device *iodev;
 
-	if (dev->ops != &kvm_io_gic_ops)
-		return NULL;
+	if (!vgic_has_its(kvm))
+		return ERR_PTR(-ENODEV);
 
-	iodev = container_of(dev, struct vgic_io_device, dev);
+	if (!(msi->flags & KVM_MSI_VALID_DEVID))
+		return ERR_PTR(-EINVAL);
 
+	address = (u64)msi->address_hi << 32 | msi->address_lo;
+
+	kvm_io_dev = kvm_io_bus_get_dev(kvm, KVM_MMIO_BUS, address);
+	if (!kvm_io_dev)
+		return ERR_PTR(-EINVAL);
+
+	if (kvm_io_dev->ops != &kvm_io_gic_ops)
+		return ERR_PTR(-EINVAL);
+
+	iodev = container_of(kvm_io_dev, struct vgic_io_device, dev);
 	if (iodev->iodev_type != IODEV_ITS)
-		return NULL;
+		return ERR_PTR(-EINVAL);
+
+	return iodev->its;
+}
+
+/*
+ * Find the target VCPU and the LPI number for a given devid/eventid pair
+ * and make this IRQ pending, possibly injecting it.
+ * Must be called with the its_lock mutex held.
+ * Returns 0 on success, a positive error value for any ITS mapping
+ * related errors and negative error values for generic errors.
+ */
+static int vgic_its_trigger_msi(struct kvm *kvm, struct vgic_its *its,
+				u32 devid, u32 eventid)
+{
+	struct vgic_irq *irq = NULL;
+	unsigned long flags;
+	int err;
 
-	return iodev;
+	err = vgic_its_resolve_lpi(kvm, its, devid, eventid, &irq);
+	if (err)
+		return err;
+
+	if (irq->hw)
+		return irq_set_irqchip_state(irq->host_irq,
+					     IRQCHIP_STATE_PENDING, true);
+
+	spin_lock_irqsave(&irq->irq_lock, flags);
+	irq->pending_latch = true;
+	vgic_queue_irq_unlock(kvm, irq, flags);
+
+	return 0;
 }
 
 /*
@@ -563,30 +620,16 @@ static struct vgic_io_device *vgic_get_its_iodev(struct kvm_io_device *dev)
  */
 int vgic_its_inject_msi(struct kvm *kvm, struct kvm_msi *msi)
 {
-	u64 address;
-	struct kvm_io_device *kvm_io_dev;
-	struct vgic_io_device *iodev;
+	struct vgic_its *its;
 	int ret;
 
-	if (!vgic_has_its(kvm))
-		return -ENODEV;
-
-	if (!(msi->flags & KVM_MSI_VALID_DEVID))
-		return -EINVAL;
-
-	address = (u64)msi->address_hi << 32 | msi->address_lo;
-
-	kvm_io_dev = kvm_io_bus_get_dev(kvm, KVM_MMIO_BUS, address);
-	if (!kvm_io_dev)
-		return -EINVAL;
+	its = vgic_msi_to_its(kvm, msi);
+	if (IS_ERR(its))
+		return PTR_ERR(its);
 
-	iodev = vgic_get_its_iodev(kvm_io_dev);
-	if (!iodev)
-		return -EINVAL;
-
-	mutex_lock(&iodev->its->its_lock);
-	ret = vgic_its_trigger_msi(kvm, iodev->its, msi->devid, msi->data);
-	mutex_unlock(&iodev->its->its_lock);
+	mutex_lock(&its->its_lock);
+	ret = vgic_its_trigger_msi(kvm, its, msi->devid, msi->data);
+	mutex_unlock(&its->its_lock);
 
 	if (ret < 0)
 		return ret;
@@ -608,8 +651,12 @@ static void its_free_ite(struct kvm *kvm, struct its_ite *ite)
 	list_del(&ite->ite_list);
 
 	/* This put matches the get in vgic_add_lpi. */
-	if (ite->irq)
+	if (ite->irq) {
+		if (ite->irq->hw)
+			WARN_ON(its_unmap_vlpi(ite->irq->host_irq));
+
 		vgic_put_irq(kvm, ite->irq);
+	}
 
 	kfree(ite);
 }
@@ -683,11 +730,7 @@ static int vgic_its_cmd_handle_movi(struct kvm *kvm, struct vgic_its *its,
 	ite->collection = collection;
 	vcpu = kvm_get_vcpu(kvm, collection->target_addr);
 
-	spin_lock(&ite->irq->irq_lock);
-	ite->irq->target_vcpu = vcpu;
-	spin_unlock(&ite->irq->irq_lock);
-
-	return 0;
+	return update_affinity(ite->irq, vcpu);
 }
 
 /*
@@ -1054,6 +1097,10 @@ static int vgic_its_cmd_handle_clear(struct kvm *kvm, struct vgic_its *its,
 
 	ite->irq->pending_latch = false;
 
+	if (ite->irq->hw)
+		return irq_set_irqchip_state(ite->irq->host_irq,
+					     IRQCHIP_STATE_PENDING, false);
+
 	return 0;
 }
 
@@ -1073,7 +1120,7 @@ static int vgic_its_cmd_handle_inv(struct kvm *kvm, struct vgic_its *its,
 	if (!ite)
 		return E_ITS_INV_UNMAPPED_INTERRUPT;
 
-	return update_lpi_config(kvm, ite->irq, NULL);
+	return update_lpi_config(kvm, ite->irq, NULL, true);
 }
 
 /*
@@ -1108,12 +1155,15 @@ static int vgic_its_cmd_handle_invall(struct kvm *kvm, struct vgic_its *its,
 		irq = vgic_get_irq(kvm, NULL, intids[i]);
 		if (!irq)
 			continue;
-		update_lpi_config(kvm, irq, vcpu);
+		update_lpi_config(kvm, irq, vcpu, false);
 		vgic_put_irq(kvm, irq);
 	}
 
 	kfree(intids);
 
+	if (vcpu->arch.vgic_cpu.vgic_v3.its_vpe.its_vm)
+		its_invall_vpe(&vcpu->arch.vgic_cpu.vgic_v3.its_vpe);
+
 	return 0;
 }
 
@@ -1128,11 +1178,12 @@ static int vgic_its_cmd_handle_invall(struct kvm *kvm, struct vgic_its *its,
 static int vgic_its_cmd_handle_movall(struct kvm *kvm, struct vgic_its *its,
 				      u64 *its_cmd)
 {
-	struct vgic_dist *dist = &kvm->arch.vgic;
 	u32 target1_addr = its_cmd_get_target_addr(its_cmd);
 	u32 target2_addr = its_cmd_mask_field(its_cmd, 3, 16, 32);
 	struct kvm_vcpu *vcpu1, *vcpu2;
 	struct vgic_irq *irq;
+	u32 *intids;
+	int irq_count, i;
 
 	if (target1_addr >= atomic_read(&kvm->online_vcpus) ||
 	    target2_addr >= atomic_read(&kvm->online_vcpus))
@@ -1144,19 +1195,19 @@ static int vgic_its_cmd_handle_movall(struct kvm *kvm, struct vgic_its *its,
 	vcpu1 = kvm_get_vcpu(kvm, target1_addr);
 	vcpu2 = kvm_get_vcpu(kvm, target2_addr);
 
-	spin_lock(&dist->lpi_list_lock);
+	irq_count = vgic_copy_lpi_list(vcpu1, &intids);
+	if (irq_count < 0)
+		return irq_count;
 
-	list_for_each_entry(irq, &dist->lpi_list_head, lpi_list) {
-		spin_lock(&irq->irq_lock);
+	for (i = 0; i < irq_count; i++) {
+		irq = vgic_get_irq(kvm, NULL, intids[i]);
 
-		if (irq->target_vcpu == vcpu1)
-			irq->target_vcpu = vcpu2;
+		update_affinity(irq, vcpu2);
 
-		spin_unlock(&irq->irq_lock);
+		vgic_put_irq(kvm, irq);
 	}
 
-	spin_unlock(&dist->lpi_list_lock);
-
+	kfree(intids);
 	return 0;
 }
 
@@ -1634,6 +1685,14 @@ static int vgic_its_create(struct kvm_device *dev, u32 type)
 	if (!its)
 		return -ENOMEM;
 
+	if (vgic_initialized(dev->kvm)) {
+		int ret = vgic_v4_init(dev->kvm);
+		if (ret < 0) {
+			kfree(its);
+			return ret;
+		}
+	}
+
 	mutex_init(&its->its_lock);
 	mutex_init(&its->cmd_lock);
 
@@ -1946,6 +2005,15 @@ static int vgic_its_save_itt(struct vgic_its *its, struct its_device *device)
 	list_for_each_entry(ite, &device->itt_head, ite_list) {
 		gpa_t gpa = base + ite->event_id * ite_esz;
 
+		/*
+		 * If an LPI carries the HW bit, this means that this
+		 * interrupt is controlled by GICv4, and we do not
+		 * have direct access to that state. Let's simply fail
+		 * the save operation...
+		 */
+		if (ite->irq->hw)
+			return -EACCES;
+
 		ret = vgic_its_save_ite(its, device, ite, gpa, ite_esz);
 		if (ret)
 			return ret;

virt/kvm/arm/vgic/vgic-mmio-v3.c

@@ -54,6 +54,11 @@ bool vgic_has_its(struct kvm *kvm)
 	return dist->has_its;
 }
 
+bool vgic_supports_direct_msis(struct kvm *kvm)
+{
+	return kvm_vgic_global_state.has_gicv4 && vgic_has_its(kvm);
+}
+
 static unsigned long vgic_mmio_read_v3_misc(struct kvm_vcpu *vcpu,
 					    gpa_t addr, unsigned int len)
 {

virt/kvm/arm/vgic/vgic-v3.c

@@ -24,6 +24,7 @@
 static bool group0_trap;
 static bool group1_trap;
 static bool common_trap;
+static bool gicv4_enable;
 
 void vgic_v3_set_underflow(struct kvm_vcpu *vcpu)
 {
@@ -461,6 +462,12 @@ static int __init early_common_trap_cfg(char *buf)
 }
 early_param("kvm-arm.vgic_v3_common_trap", early_common_trap_cfg);
 
+static int __init early_gicv4_enable(char *buf)
+{
+	return strtobool(buf, &gicv4_enable);
+}
+early_param("kvm-arm.vgic_v4_enable", early_gicv4_enable);
+
 /**
  * vgic_v3_probe - probe for a GICv3 compatible interrupt controller in DT
  * @node:	pointer to the DT node
@@ -480,6 +487,13 @@ int vgic_v3_probe(const struct gic_kvm_info *info)
 	kvm_vgic_global_state.can_emulate_gicv2 = false;
 	kvm_vgic_global_state.ich_vtr_el2 = ich_vtr_el2;
 
+	/* GICv4 support? */
+	if (info->has_v4) {
+		kvm_vgic_global_state.has_gicv4 = gicv4_enable;
+		kvm_info("GICv4 support %sabled\n",
+			 gicv4_enable ? "en" : "dis");
+	}
+
 	if (!info->vcpu.start) {
 		kvm_info("GICv3: no GICV resource entry\n");
 		kvm_vgic_global_state.vcpu_base = 0;

virt/kvm/arm/vgic/vgic-v4.c

+/*
+ * Copyright (C) 2017 ARM Ltd.
+ * Author: Marc Zyngier <marc.zyngier@arm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/kvm_host.h>
+#include <linux/irqchip/arm-gic-v3.h>
+
+#include "vgic.h"
+
+/*
+ * How KVM uses GICv4 (insert rude comments here):
+ *
+ * The vgic-v4 layer acts as a bridge between several entities:
+ * - The GICv4 ITS representation offered by the ITS driver
+ * - VFIO, which is in charge of the PCI endpoint
+ * - The virtual ITS, which is the only thing the guest sees
+ *
+ * The configuration of VLPIs is triggered by a callback from VFIO,
+ * instructing KVM that a PCI device has been configured to deliver
+ * MSIs to a vITS.
+ *
+ * kvm_vgic_v4_set_forwarding() is thus called with the routing entry,
+ * and this is used to find the corresponding vITS data structures
+ * (ITS instance, device, event and irq) using a process that is
+ * extremely similar to the injection of an MSI.
+ *
+ * At this stage, we can link the guest's view of an LPI (uniquely
+ * identified by the routing entry) and the host irq, using the GICv4
+ * driver mapping operation. Should the mapping succeed, we've then
+ * successfully upgraded the guest's LPI to a VLPI. We can then start
+ * with updating GICv4's view of the property table and generating an
+ * INValidation in order to kickstart the delivery of this VLPI to the
+ * guest directly, without software intervention. Well, almost.
+ *
+ * When the PCI endpoint is deconfigured, this operation is reversed
+ * with VFIO calling kvm_vgic_v4_unset_forwarding().
+ *
+ * Once the VLPI has been mapped, it needs to follow any change the
+ * guest performs on its LPI through the vITS. For that, a number of
+ * command handlers have hooks to communicate these changes to the HW:
+ * - Any invalidation triggers a call to its_prop_update_vlpi()
+ * - The INT command results in a irq_set_irqchip_state(), which
+ *   generates an INT on the corresponding VLPI.
+ * - The CLEAR command results in a irq_set_irqchip_state(), which
+ *   generates an CLEAR on the corresponding VLPI.
+ * - DISCARD translates into an unmap, similar to a call to
+ *   kvm_vgic_v4_unset_forwarding().
+ * - MOVI is translated by an update of the existing mapping, changing
+ *   the target vcpu, resulting in a VMOVI being generated.
+ * - MOVALL is translated by a string of mapping updates (similar to
+ *   the handling of MOVI). MOVALL is horrible.
+ *
+ * Note that a DISCARD/MAPTI sequence emitted from the guest without
+ * reprogramming the PCI endpoint after MAPTI does not result in a
+ * VLPI being mapped, as there is no callback from VFIO (the guest
+ * will get the interrupt via the normal SW injection). Fixing this is
+ * not trivial, and requires some horrible messing with the VFIO
+ * internals. Not fun. Don't do that.
+ *
+ * Then there is the scheduling. Each time a vcpu is about to run on a
+ * physical CPU, KVM must tell the corresponding redistributor about
+ * it. And if we've migrated our vcpu from one CPU to another, we must
+ * tell the ITS (so that the messages reach the right redistributor).
+ * This is done in two steps: first issue a irq_set_affinity() on the
+ * irq corresponding to the vcpu, then call its_schedule_vpe(). You
+ * must be in a non-preemptible context. On exit, another call to
+ * its_schedule_vpe() tells the redistributor that we're done with the
+ * vcpu.
+ *
+ * Finally, the doorbell handling: Each vcpu is allocated an interrupt
+ * which will fire each time a VLPI is made pending whilst the vcpu is
+ * not running. Each time the vcpu gets blocked, the doorbell
+ * interrupt gets enabled. When the vcpu is unblocked (for whatever
+ * reason), the doorbell interrupt is disabled.
+ */
+
+#define DB_IRQ_FLAGS	(IRQ_NOAUTOEN | IRQ_DISABLE_UNLAZY | IRQ_NO_BALANCING)
+
+static irqreturn_t vgic_v4_doorbell_handler(int irq, void *info)
+{
+	struct kvm_vcpu *vcpu = info;
+
+	vcpu->arch.vgic_cpu.vgic_v3.its_vpe.pending_last = true;
+	kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu);
+	kvm_vcpu_kick(vcpu);
+
+	return IRQ_HANDLED;
+}
+
+/**
+ * vgic_v4_init - Initialize the GICv4 data structures
+ * @kvm:	Pointer to the VM being initialized
+ *
+ * We may be called each time a vITS is created, or when the
+ * vgic is initialized. This relies on kvm->lock to be
+ * held. In both cases, the number of vcpus should now be
+ * fixed.
+ */
+int vgic_v4_init(struct kvm *kvm)
+{
+	struct vgic_dist *dist = &kvm->arch.vgic;
+	struct kvm_vcpu *vcpu;
+	int i, nr_vcpus, ret;
+
+	if (!vgic_supports_direct_msis(kvm))
+		return 0; /* Nothing to see here... move along. */
+
+	if (dist->its_vm.vpes)
+		return 0;
+
+	nr_vcpus = atomic_read(&kvm->online_vcpus);
+
+	dist->its_vm.vpes = kzalloc(sizeof(*dist->its_vm.vpes) * nr_vcpus,
+				    GFP_KERNEL);
+	if (!dist->its_vm.vpes)
+		return -ENOMEM;
+
+	dist->its_vm.nr_vpes = nr_vcpus;
+
+	kvm_for_each_vcpu(i, vcpu, kvm)
+		dist->its_vm.vpes[i] = &vcpu->arch.vgic_cpu.vgic_v3.its_vpe;
+
+	ret = its_alloc_vcpu_irqs(&dist->its_vm);
+	if (ret < 0) {
+		kvm_err("VPE IRQ allocation failure\n");
+		kfree(dist->its_vm.vpes);
+		dist->its_vm.nr_vpes = 0;
+		dist->its_vm.vpes = NULL;
+		return ret;
+	}
+
+	kvm_for_each_vcpu(i, vcpu, kvm) {
+		int irq = dist->its_vm.vpes[i]->irq;
+
+		/*
+		 * Don't automatically enable the doorbell, as we're
+		 * flipping it back and forth when the vcpu gets
+		 * blocked. Also disable the lazy disabling, as the
+		 * doorbell could kick us out of the guest too
+		 * early...
+		 */
+		irq_set_status_flags(irq, DB_IRQ_FLAGS);
+		ret = request_irq(irq, vgic_v4_doorbell_handler,
+				  0, "vcpu", vcpu);
+		if (ret) {
+			kvm_err("failed to allocate vcpu IRQ%d\n", irq);
+			/*
+			 * Trick: adjust the number of vpes so we know
+			 * how many to nuke on teardown...
+			 */
+			dist->its_vm.nr_vpes = i;
+			break;
+		}
+	}
+
+	if (ret)
+		vgic_v4_teardown(kvm);
+
+	return ret;
+}
+
+/**
+ * vgic_v4_teardown - Free the GICv4 data structures
+ * @kvm:	Pointer to the VM being destroyed
+ *
+ * Relies on kvm->lock to be held.
+ */
+void vgic_v4_teardown(struct kvm *kvm)
+{
+	struct its_vm *its_vm = &kvm->arch.vgic.its_vm;
+	int i;
+
+	if (!its_vm->vpes)
+		return;
+
+	for (i = 0; i < its_vm->nr_vpes; i++) {
+		struct kvm_vcpu *vcpu = kvm_get_vcpu(kvm, i);
+		int irq = its_vm->vpes[i]->irq;
+
+		irq_clear_status_flags(irq, DB_IRQ_FLAGS);
+		free_irq(irq, vcpu);
+	}
+
+	its_free_vcpu_irqs(its_vm);
+	kfree(its_vm->vpes);
+	its_vm->nr_vpes = 0;
+	its_vm->vpes = NULL;
+}
+
+int vgic_v4_sync_hwstate(struct kvm_vcpu *vcpu)
+{
+	if (!vgic_supports_direct_msis(vcpu->kvm))
+		return 0;
+
+	return its_schedule_vpe(&vcpu->arch.vgic_cpu.vgic_v3.its_vpe, false);
+}
+
+int vgic_v4_flush_hwstate(struct kvm_vcpu *vcpu)
+{
+	int irq = vcpu->arch.vgic_cpu.vgic_v3.its_vpe.irq;
+	int err;
+
+	if (!vgic_supports_direct_msis(vcpu->kvm))
+		return 0;
+
+	/*
+	 * Before making the VPE resident, make sure the redistributor
+	 * corresponding to our current CPU expects us here. See the
+	 * doc in drivers/irqchip/irq-gic-v4.c to understand how this
+	 * turns into a VMOVP command at the ITS level.
+	 */
+	err = irq_set_affinity(irq, cpumask_of(smp_processor_id()));
+	if (err)
+		return err;
+
+	err = its_schedule_vpe(&vcpu->arch.vgic_cpu.vgic_v3.its_vpe, true);
+	if (err)
+		return err;
+
+	/*
+	 * Now that the VPE is resident, let's get rid of a potential
+	 * doorbell interrupt that would still be pending.
+	 */
+	err = irq_set_irqchip_state(irq, IRQCHIP_STATE_PENDING, false);
+
+	return err;
+}
+
+static struct vgic_its *vgic_get_its(struct kvm *kvm,
+				     struct kvm_kernel_irq_routing_entry *irq_entry)
+{
+	struct kvm_msi msi  = (struct kvm_msi) {
+		.address_lo	= irq_entry->msi.address_lo,
+		.address_hi	= irq_entry->msi.address_hi,
+		.data		= irq_entry->msi.data,
+		.flags		= irq_entry->msi.flags,
+		.devid		= irq_entry->msi.devid,
+	};
+
+	return vgic_msi_to_its(kvm, &msi);
+}
+
+int kvm_vgic_v4_set_forwarding(struct kvm *kvm, int virq,
+			       struct kvm_kernel_irq_routing_entry *irq_entry)
+{
+	struct vgic_its *its;
+	struct vgic_irq *irq;
+	struct its_vlpi_map map;
+	int ret;
+
+	if (!vgic_supports_direct_msis(kvm))
+		return 0;
+
+	/*
+	 * Get the ITS, and escape early on error (not a valid
+	 * doorbell for any of our vITSs).
+	 */
+	its = vgic_get_its(kvm, irq_entry);
+	if (IS_ERR(its))
+		return 0;
+
+	mutex_lock(&its->its_lock);
+
+	/* Perform then actual DevID/EventID -> LPI translation. */
+	ret = vgic_its_resolve_lpi(kvm, its, irq_entry->msi.devid,
+				   irq_entry->msi.data, &irq);
+	if (ret)
+		goto out;
+
+	/*
+	 * Emit the mapping request. If it fails, the ITS probably
+	 * isn't v4 compatible, so let's silently bail out. Holding
+	 * the ITS lock should ensure that nothing can modify the
+	 * target vcpu.
+	 */
+	map = (struct its_vlpi_map) {
+		.vm		= &kvm->arch.vgic.its_vm,
+		.vpe		= &irq->target_vcpu->arch.vgic_cpu.vgic_v3.its_vpe,
+		.vintid		= irq->intid,
+		.properties	= ((irq->priority & 0xfc) |
+				   (irq->enabled ? LPI_PROP_ENABLED : 0) |
+				   LPI_PROP_GROUP1),
+		.db_enabled	= true,
+	};
+
+	ret = its_map_vlpi(virq, &map);
+	if (ret)
+		goto out;
+
+	irq->hw		= true;
+	irq->host_irq	= virq;
+
+out:
+	mutex_unlock(&its->its_lock);
+	return ret;
+}
+
+int kvm_vgic_v4_unset_forwarding(struct kvm *kvm, int virq,
+				 struct kvm_kernel_irq_routing_entry *irq_entry)
+{
+	struct vgic_its *its;
+	struct vgic_irq *irq;
+	int ret;
+
+	if (!vgic_supports_direct_msis(kvm))
+		return 0;
+
+	/*
+	 * Get the ITS, and escape early on error (not a valid
+	 * doorbell for any of our vITSs).
+	 */
+	its = vgic_get_its(kvm, irq_entry);
+	if (IS_ERR(its))
+		return 0;
+
+	mutex_lock(&its->its_lock);
+
+	ret = vgic_its_resolve_lpi(kvm, its, irq_entry->msi.devid,
+				   irq_entry->msi.data, &irq);
+	if (ret)
+		goto out;
+
+	WARN_ON(!(irq->hw && irq->host_irq == virq));
+	irq->hw = false;
+	ret = its_unmap_vlpi(virq);
+
+out:
+	mutex_unlock(&its->its_lock);
+	return ret;
+}
+
+void kvm_vgic_v4_enable_doorbell(struct kvm_vcpu *vcpu)
+{
+	if (vgic_supports_direct_msis(vcpu->kvm)) {
+		int irq = vcpu->arch.vgic_cpu.vgic_v3.its_vpe.irq;
+		if (irq)
+			enable_irq(irq);
+	}
+}
+
+void kvm_vgic_v4_disable_doorbell(struct kvm_vcpu *vcpu)
+{
+	if (vgic_supports_direct_msis(vcpu->kvm)) {
+		int irq = vcpu->arch.vgic_cpu.vgic_v3.its_vpe.irq;
+		if (irq)
+			disable_irq(irq);
+	}
+}

virt/kvm/arm/vgic/vgic.c

@@ -17,6 +17,8 @@
 #include <linux/kvm.h>
 #include <linux/kvm_host.h>
 #include <linux/list_sort.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
 
 #include "vgic.h"
 
@@ -409,25 +411,56 @@ int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid,
 	return 0;
 }
 
-int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, u32 virt_irq, u32 phys_irq)
+/* @irq->irq_lock must be held */
+static int kvm_vgic_map_irq(struct kvm_vcpu *vcpu, struct vgic_irq *irq,
+			    unsigned int host_irq)
 {
-	struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, virt_irq);
+	struct irq_desc *desc;
+	struct irq_data *data;
+
+	/*
+	 * Find the physical IRQ number corresponding to @host_irq
+	 */
+	desc = irq_to_desc(host_irq);
+	if (!desc) {
+		kvm_err("%s: no interrupt descriptor\n", __func__);
+		return -EINVAL;
+	}
+	data = irq_desc_get_irq_data(desc);
+	while (data->parent_data)
+		data = data->parent_data;
+
+	irq->hw = true;
+	irq->host_irq = host_irq;
+	irq->hwintid = data->hwirq;
+	return 0;
+}
+
+/* @irq->irq_lock must be held */
+static inline void kvm_vgic_unmap_irq(struct vgic_irq *irq)
+{
+	irq->hw = false;
+	irq->hwintid = 0;
+}
+
+int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, unsigned int host_irq,
+			  u32 vintid)
+{
+	struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, vintid);
 	unsigned long flags;
+	int ret;
 
 	BUG_ON(!irq);
 
 	spin_lock_irqsave(&irq->irq_lock, flags);
-
-	irq->hw = true;
-	irq->hwintid = phys_irq;
-
+	ret = kvm_vgic_map_irq(vcpu, irq, host_irq);
 	spin_unlock_irqrestore(&irq->irq_lock, flags);
 	vgic_put_irq(vcpu->kvm, irq);
 
-	return 0;
+	return ret;
 }
 
-int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int virt_irq)
+int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int vintid)
 {
 	struct vgic_irq *irq;
 	unsigned long flags;
@@ -435,14 +468,11 @@ int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int virt_irq)
 	if (!vgic_initialized(vcpu->kvm))
 		return -EAGAIN;
 
-	irq = vgic_get_irq(vcpu->kvm, vcpu, virt_irq);
+	irq = vgic_get_irq(vcpu->kvm, vcpu, vintid);
 	BUG_ON(!irq);
 
 	spin_lock_irqsave(&irq->irq_lock, flags);
-
-	irq->hw = false;
-	irq->hwintid = 0;
-
+	kvm_vgic_unmap_irq(irq);
 	spin_unlock_irqrestore(&irq->irq_lock, flags);
 	vgic_put_irq(vcpu->kvm, irq);
 
@@ -688,6 +718,8 @@ void kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu)
 {
 	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 
+	WARN_ON(vgic_v4_sync_hwstate(vcpu));
+
 	/* An empty ap_list_head implies used_lrs == 0 */
 	if (list_empty(&vcpu->arch.vgic_cpu.ap_list_head))
 		return;
@@ -700,6 +732,8 @@ void kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu)
 /* Flush our emulation state into the GIC hardware before entering the guest. */
 void kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu)
 {
+	WARN_ON(vgic_v4_flush_hwstate(vcpu));
+
 	/*
 	 * If there are no virtual interrupts active or pending for this
 	 * VCPU, then there is no work to do and we can bail out without
@@ -751,6 +785,9 @@ int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu)
 	if (!vcpu->kvm->arch.vgic.enabled)
 		return false;
 
+	if (vcpu->arch.vgic_cpu.vgic_v3.its_vpe.pending_last)
+		return true;
+
 	spin_lock_irqsave(&vgic_cpu->ap_list_lock, flags);
 
 	list_for_each_entry(irq, &vgic_cpu->ap_list_head, ap_list) {
@@ -784,9 +821,9 @@ void vgic_kick_vcpus(struct kvm *kvm)
 	}
 }
 
-bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, unsigned int virt_irq)
+bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, unsigned int vintid)
 {
-	struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, virt_irq);
+	struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, vintid);
 	bool map_is_active;
 	unsigned long flags;
 

virt/kvm/arm/vgic/vgic.h

@@ -237,4 +237,14 @@ static inline int vgic_v3_max_apr_idx(struct kvm_vcpu *vcpu)
 	}
 }
 
+int vgic_its_resolve_lpi(struct kvm *kvm, struct vgic_its *its,
+			 u32 devid, u32 eventid, struct vgic_irq **irq);
+struct vgic_its *vgic_msi_to_its(struct kvm *kvm, struct kvm_msi *msi);
+
+bool vgic_supports_direct_msis(struct kvm *kvm);
+int vgic_v4_init(struct kvm *kvm);
+void vgic_v4_teardown(struct kvm *kvm);
+int vgic_v4_sync_hwstate(struct kvm_vcpu *vcpu);
+int vgic_v4_flush_hwstate(struct kvm_vcpu *vcpu);
+
 #endif