KVM/ARM Changes for v4.8 - Take 2

Includes GSI routing support to go along with the new VGIC and a small fix that
 has been cooking in -next for a while.
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Merge tag 'kvm-arm-for-4.8-take2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/ARM Changes for v4.8 - Take 2

Includes GSI routing support to go along with the new VGIC and a small fix that
has been cooking in -next for a while.

Documentation/virtual/kvm/api.txt

@@ -1433,13 +1433,16 @@ KVM_ASSIGN_DEV_IRQ. Partial deassignment of host or guest IRQ is allowed.
 4.52 KVM_SET_GSI_ROUTING
 
 Capability: KVM_CAP_IRQ_ROUTING
-Architectures: x86 s390
+Architectures: x86 s390 arm arm64
 Type: vm ioctl
 Parameters: struct kvm_irq_routing (in)
 Returns: 0 on success, -1 on error
 
 Sets the GSI routing table entries, overwriting any previously set entries.
 
+On arm/arm64, GSI routing has the following limitation:
+- GSI routing does not apply to KVM_IRQ_LINE but only to KVM_IRQFD.
+
 struct kvm_irq_routing {
 	__u32 nr;
 	__u32 flags;
@@ -1468,7 +1471,13 @@ struct kvm_irq_routing_entry {
 #define KVM_IRQ_ROUTING_S390_ADAPTER 3
 #define KVM_IRQ_ROUTING_HV_SINT 4
 
-No flags are specified so far, the corresponding field must be set to zero.
+flags:
+- KVM_MSI_VALID_DEVID: used along with KVM_IRQ_ROUTING_MSI routing entry
+  type, specifies that the devid field contains a valid value.  The per-VM
+  KVM_CAP_MSI_DEVID capability advertises the requirement to provide
+  the device ID.  If this capability is not available, userspace should
+  never set the KVM_MSI_VALID_DEVID flag as the ioctl might fail.
+- zero otherwise
 
 struct kvm_irq_routing_irqchip {
 	__u32 irqchip;
@@ -1479,9 +1488,16 @@ struct kvm_irq_routing_msi {
 	__u32 address_lo;
 	__u32 address_hi;
 	__u32 data;
-	__u32 pad;
+	union {
+		__u32 pad;
+		__u32 devid;
+	};
 };
 
+If KVM_MSI_VALID_DEVID is set, devid contains a unique device identifier
+for the device that wrote the MSI message.  For PCI, this is usually a
+BFD identifier in the lower 16 bits.
+
 On x86, address_hi is ignored unless the KVM_X2APIC_API_USE_32BIT_IDS
 feature of KVM_CAP_X2APIC_API capability is enabled.  If it is enabled,
 address_hi bits 31-8 provide bits 31-8 of the destination id.  Bits 7-0 of
@@ -2199,14 +2215,14 @@ struct kvm_msi {
 	__u8  pad[12];
 };
 
-flags: KVM_MSI_VALID_DEVID: devid contains a valid value
-devid: If KVM_MSI_VALID_DEVID is set, contains a unique device identifier
-       for the device that wrote the MSI message.
-       For PCI, this is usually a BFD identifier in the lower 16 bits.
+flags: KVM_MSI_VALID_DEVID: devid contains a valid value.  The per-VM
+  KVM_CAP_MSI_DEVID capability advertises the requirement to provide
+  the device ID.  If this capability is not available, userspace
+  should never set the KVM_MSI_VALID_DEVID flag as the ioctl might fail.
 
-The per-VM KVM_CAP_MSI_DEVID capability advertises the need to provide
-the device ID. If this capability is not set, userland cannot rely on
-the kernel to allow the KVM_MSI_VALID_DEVID flag being set.
+If KVM_MSI_VALID_DEVID is set, devid contains a unique device identifier
+for the device that wrote the MSI message.  For PCI, this is usually a
+BFD identifier in the lower 16 bits.
 
 On x86, address_hi is ignored unless the KVM_CAP_X2APIC_API capability is
 enabled.  If it is enabled, address_hi bits 31-8 provide bits 31-8 of the
@@ -2383,9 +2399,13 @@ Note that closing the resamplefd is not sufficient to disable the
 irqfd.  The KVM_IRQFD_FLAG_RESAMPLE is only necessary on assignment
 and need not be specified with KVM_IRQFD_FLAG_DEASSIGN.
 
-On ARM/ARM64, the gsi field in the kvm_irqfd struct specifies the Shared
-Peripheral Interrupt (SPI) index, such that the GIC interrupt ID is
-given by gsi + 32.
+On arm/arm64, gsi routing being supported, the following can happen:
+- in case no routing entry is associated to this gsi, injection fails
+- in case the gsi is associated to an irqchip routing entry,
+  irqchip.pin + 32 corresponds to the injected SPI ID.
+- in case the gsi is associated to an MSI routing entry, the MSI
+  message and device ID are translated into an LPI (support restricted
+  to GICv3 ITS in-kernel emulation).
 
 4.76 KVM_PPC_ALLOCATE_HTAB
 

arch/arm/kvm/Kconfig

@@ -32,6 +32,8 @@ config KVM
 	select KVM_VFIO
 	select HAVE_KVM_EVENTFD
 	select HAVE_KVM_IRQFD
+	select HAVE_KVM_IRQCHIP
+	select HAVE_KVM_IRQ_ROUTING
 	depends on ARM_VIRT_EXT && ARM_LPAE && ARM_ARCH_TIMER
 	---help---
 	  Support hosting virtualized guest machines.

arch/arm/kvm/Makefile

@@ -29,4 +29,5 @@ obj-y += $(KVM)/arm/vgic/vgic-v2.o
 obj-y += $(KVM)/arm/vgic/vgic-mmio.o
 obj-y += $(KVM)/arm/vgic/vgic-mmio-v2.o
 obj-y += $(KVM)/arm/vgic/vgic-kvm-device.o
+obj-y += $(KVM)/irqchip.o
 obj-y += $(KVM)/arm/arch_timer.o

arch/arm/kvm/irq.h

@@ -0,0 +1,19 @@
+/*
+ * irq.h: in kernel interrupt controller related definitions
+ * Copyright (c) 2016 Red Hat, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This header is included by irqchip.c. However, on ARM, interrupt
+ * controller declarations are located in include/kvm/arm_vgic.h since
+ * they are mostly shared between arm and arm64.
+ */
+
+#ifndef __IRQ_H
+#define __IRQ_H
+
+#include <kvm/arm_vgic.h>
+
+#endif

arch/arm64/kvm/Kconfig

@@ -37,6 +37,8 @@ config KVM
 	select KVM_ARM_VGIC_V3
 	select KVM_ARM_PMU if HW_PERF_EVENTS
 	select HAVE_KVM_MSI
+	select HAVE_KVM_IRQCHIP
+	select HAVE_KVM_IRQ_ROUTING
 	---help---
 	  Support hosting virtualized guest machines.
 	  We don't support KVM with 16K page tables yet, due to the multiple

arch/arm64/kvm/Makefile

@@ -30,5 +30,6 @@ kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic/vgic-mmio-v2.o
 kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic/vgic-mmio-v3.o
 kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic/vgic-kvm-device.o
 kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic/vgic-its.o
+kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/irqchip.o
 kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/arch_timer.o
 kvm-$(CONFIG_KVM_ARM_PMU) += $(KVM)/arm/pmu.o

arch/arm64/kvm/inject_fault.c

@@ -132,16 +132,14 @@ static u64 get_except_vector(struct kvm_vcpu *vcpu, enum exception_type type)
 static void inject_abt64(struct kvm_vcpu *vcpu, bool is_iabt, unsigned long addr)
 {
 	unsigned long cpsr = *vcpu_cpsr(vcpu);
-	bool is_aarch32;
+	bool is_aarch32 = vcpu_mode_is_32bit(vcpu);
 	u32 esr = 0;
 
-	is_aarch32 = vcpu_mode_is_32bit(vcpu);
-
-	*vcpu_spsr(vcpu) = cpsr;
 	*vcpu_elr_el1(vcpu) = *vcpu_pc(vcpu);
-
 	*vcpu_pc(vcpu) = get_except_vector(vcpu, except_type_sync);
+
 	*vcpu_cpsr(vcpu) = PSTATE_FAULT_BITS_64;
+	*vcpu_spsr(vcpu) = cpsr;
 
 	vcpu_sys_reg(vcpu, FAR_EL1) = addr;
 
@@ -172,11 +170,11 @@ static void inject_undef64(struct kvm_vcpu *vcpu)
 	unsigned long cpsr = *vcpu_cpsr(vcpu);
 	u32 esr = (ESR_ELx_EC_UNKNOWN << ESR_ELx_EC_SHIFT);
 
-	*vcpu_spsr(vcpu) = cpsr;
 	*vcpu_elr_el1(vcpu) = *vcpu_pc(vcpu);
-
 	*vcpu_pc(vcpu) = get_except_vector(vcpu, except_type_sync);
+
 	*vcpu_cpsr(vcpu) = PSTATE_FAULT_BITS_64;
+	*vcpu_spsr(vcpu) = cpsr;
 
 	/*
 	 * Build an unknown exception, depending on the instruction

arch/arm64/kvm/irq.h

@@ -0,0 +1,19 @@
+/*
+ * irq.h: in kernel interrupt controller related definitions
+ * Copyright (c) 2016 Red Hat, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This header is included by irqchip.c. However, on ARM, interrupt
+ * controller declarations are located in include/kvm/arm_vgic.h since
+ * they are mostly shared between arm and arm64.
+ */
+
+#ifndef __IRQ_H
+#define __IRQ_H
+
+#include <kvm/arm_vgic.h>
+
+#endif

arch/x86/kvm/irq.h

@@ -120,4 +120,7 @@ void __kvm_migrate_timers(struct kvm_vcpu *vcpu);
 
 int apic_has_pending_timer(struct kvm_vcpu *vcpu);
 
+int kvm_setup_default_irq_routing(struct kvm *kvm);
+int kvm_setup_empty_irq_routing(struct kvm *kvm);
+
 #endif

include/kvm/arm_vgic.h

@@ -34,6 +34,7 @@
 #define VGIC_MAX_SPI		1019
 #define VGIC_MAX_RESERVED	1023
 #define VGIC_MIN_LPI		8192
+#define KVM_IRQCHIP_NUM_PINS	(1020 - 32)
 
 enum vgic_type {
 	VGIC_V2,		/* Good ol' GICv2 */
@@ -314,4 +315,10 @@ static inline int kvm_vgic_get_max_vcpus(void)
 
 int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi);
 
+/**
+ * kvm_vgic_setup_default_irq_routing:
+ * Setup a default flat gsi routing table mapping all SPIs
+ */
+int kvm_vgic_setup_default_irq_routing(struct kvm *kvm);
+
 #endif /* __KVM_ARM_VGIC_H */

include/linux/kvm_host.h

@@ -317,7 +317,13 @@ struct kvm_kernel_irq_routing_entry {
 			unsigned irqchip;
 			unsigned pin;
 		} irqchip;
-		struct msi_msg msi;
+		struct {
+			u32 address_lo;
+			u32 address_hi;
+			u32 data;
+			u32 flags;
+			u32 devid;
+		} msi;
 		struct kvm_s390_adapter_int adapter;
 		struct kvm_hv_sint hv_sint;
 	};
@@ -1003,12 +1009,12 @@ static inline int mmu_notifier_retry(struct kvm *kvm, unsigned long mmu_seq)
 
 #ifdef CONFIG_S390
 #define KVM_MAX_IRQ_ROUTES 4096 //FIXME: we can have more than that...
+#elif defined(CONFIG_ARM64)
+#define KVM_MAX_IRQ_ROUTES 4096
 #else
 #define KVM_MAX_IRQ_ROUTES 1024
 #endif
 
-int kvm_setup_default_irq_routing(struct kvm *kvm);
-int kvm_setup_empty_irq_routing(struct kvm *kvm);
 int kvm_set_irq_routing(struct kvm *kvm,
 			const struct kvm_irq_routing_entry *entries,
 			unsigned nr,

include/uapi/linux/kvm.h

@@ -882,7 +882,10 @@ struct kvm_irq_routing_msi {
 	__u32 address_lo;
 	__u32 address_hi;
 	__u32 data;
-	__u32 pad;
+	union {
+		__u32 pad;
+		__u32 devid;
+	};
 };
 
 struct kvm_irq_routing_s390_adapter {

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

@@ -264,6 +264,10 @@ int vgic_init(struct kvm *kvm)
 	kvm_for_each_vcpu(i, vcpu, kvm)
 		kvm_vgic_vcpu_init(vcpu);
 
+	ret = kvm_vgic_setup_default_irq_routing(kvm);
+	if (ret)
+		goto out;
+
 	dist->initialized = true;
 out:
 	return ret;

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

@@ -17,36 +17,116 @@
 #include <linux/kvm.h>
 #include <linux/kvm_host.h>
 #include <trace/events/kvm.h>
+#include <kvm/arm_vgic.h>
+#include "vgic.h"
 
-int kvm_irq_map_gsi(struct kvm *kvm,
-		    struct kvm_kernel_irq_routing_entry *entries,
-		    int gsi)
+/**
+ * vgic_irqfd_set_irq: inject the IRQ corresponding to the
+ * irqchip routing entry
+ *
+ * This is the entry point for irqfd IRQ injection
+ */
+static int vgic_irqfd_set_irq(struct kvm_kernel_irq_routing_entry *e,
+			struct kvm *kvm, int irq_source_id,
+			int level, bool line_status)
 {
-	return 0;
+	unsigned int spi_id = e->irqchip.pin + VGIC_NR_PRIVATE_IRQS;
+
+	if (!vgic_valid_spi(kvm, spi_id))
+		return -EINVAL;
+	return kvm_vgic_inject_irq(kvm, 0, spi_id, level);
 }
 
-int kvm_irq_map_chip_pin(struct kvm *kvm, unsigned int irqchip,
-			 unsigned int pin)
+/**
+ * kvm_set_routing_entry: populate a kvm routing entry
+ * from a user routing entry
+ *
+ * @kvm: the VM this entry is applied to
+ * @e: kvm kernel routing entry handle
+ * @ue: user api routing entry handle
+ * return 0 on success, -EINVAL on errors.
+ */
+#ifdef KVM_CAP_X2APIC_API
+int kvm_set_routing_entry(struct kvm *kvm,
+			  struct kvm_kernel_irq_routing_entry *e,
+			  const struct kvm_irq_routing_entry *ue)
+#else
+/* Remove this version and the ifdefery once merged into 4.8 */
+int kvm_set_routing_entry(struct kvm_kernel_irq_routing_entry *e,
+			  const struct kvm_irq_routing_entry *ue)
+#endif
 {
-	return pin;
+	int r = -EINVAL;
+
+	switch (ue->type) {
+	case KVM_IRQ_ROUTING_IRQCHIP:
+		e->set = vgic_irqfd_set_irq;
+		e->irqchip.irqchip = ue->u.irqchip.irqchip;
+		e->irqchip.pin = ue->u.irqchip.pin;
+		if ((e->irqchip.pin >= KVM_IRQCHIP_NUM_PINS) ||
+		    (e->irqchip.irqchip >= KVM_NR_IRQCHIPS))
+			goto out;
+		break;
+	case KVM_IRQ_ROUTING_MSI:
+		e->set = kvm_set_msi;
+		e->msi.address_lo = ue->u.msi.address_lo;
+		e->msi.address_hi = ue->u.msi.address_hi;
+		e->msi.data = ue->u.msi.data;
+		e->msi.flags = ue->flags;
+		e->msi.devid = ue->u.msi.devid;
+		break;
+	default:
+		goto out;
+	}
+	r = 0;
+out:
+	return r;
 }
 
-int kvm_set_irq(struct kvm *kvm, int irq_source_id,
-		u32 irq, int level, bool line_status)
+/**
+ * kvm_set_msi: inject the MSI corresponding to the
+ * MSI routing entry
+ *
+ * This is the entry point for irqfd MSI injection
+ * and userspace MSI injection.
+ */
+int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
+		struct kvm *kvm, int irq_source_id,
+		int level, bool line_status)
 {
-	unsigned int spi = irq + VGIC_NR_PRIVATE_IRQS;
+	struct kvm_msi msi;
 
-	trace_kvm_set_irq(irq, level, irq_source_id);
+	msi.address_lo = e->msi.address_lo;
+	msi.address_hi = e->msi.address_hi;
+	msi.data = e->msi.data;
+	msi.flags = e->msi.flags;
+	msi.devid = e->msi.devid;
 
-	BUG_ON(!vgic_initialized(kvm));
+	if (!vgic_has_its(kvm))
+		return -ENODEV;
 
-	return kvm_vgic_inject_irq(kvm, 0, spi, level);
+	return vgic_its_inject_msi(kvm, &msi);
 }
 
-/* MSI not implemented yet */
-int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
-		struct kvm *kvm, int irq_source_id,
-		int level, bool line_status)
+int kvm_vgic_setup_default_irq_routing(struct kvm *kvm)
 {
-	return 0;
+	struct kvm_irq_routing_entry *entries;
+	struct vgic_dist *dist = &kvm->arch.vgic;
+	u32 nr = dist->nr_spis;
+	int i, ret;
+
+	entries = kcalloc(nr, sizeof(struct kvm_kernel_irq_routing_entry),
+			  GFP_KERNEL);
+	if (!entries)
+		return -ENOMEM;
+
+	for (i = 0; i < nr; i++) {
+		entries[i].gsi = i;
+		entries[i].type = KVM_IRQ_ROUTING_IRQCHIP;
+		entries[i].u.irqchip.irqchip = 0;
+		entries[i].u.irqchip.pin = i;
+	}
+	ret = kvm_set_irq_routing(kvm, entries, nr, 0);
+	kfree(entries);
+	return ret;
 }

virt/kvm/arm/vgic/vgic.c

@@ -711,10 +711,3 @@ bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, unsigned int virt_irq)
 	return map_is_active;
 }
 
-int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi)
-{
-	if (vgic_has_its(kvm))
-		return vgic_its_inject_msi(kvm, msi);
-	else
-		return -ENODEV;
-}

virt/kvm/irqchip.c

@@ -62,12 +62,14 @@ int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi)
 {
 	struct kvm_kernel_irq_routing_entry route;
 
-	if (!irqchip_in_kernel(kvm) || msi->flags != 0)
+	if (!irqchip_in_kernel(kvm) || (msi->flags & ~KVM_MSI_VALID_DEVID))
 		return -EINVAL;
 
 	route.msi.address_lo = msi->address_lo;
 	route.msi.address_hi = msi->address_hi;
 	route.msi.data = msi->data;
+	route.msi.flags = msi->flags;
+	route.msi.devid = msi->devid;
 
 	return kvm_set_msi(&route, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1, false);
 }
@@ -177,6 +179,7 @@ int kvm_set_irq_routing(struct kvm *kvm,
 			unsigned flags)
 {
 	struct kvm_irq_routing_table *new, *old;
+	struct kvm_kernel_irq_routing_entry *e;
 	u32 i, j, nr_rt_entries = 0;
 	int r;
 
@@ -200,23 +203,25 @@ int kvm_set_irq_routing(struct kvm *kvm,
 			new->chip[i][j] = -1;
 
 	for (i = 0; i < nr; ++i) {
-		struct kvm_kernel_irq_routing_entry *e;
-
 		r = -ENOMEM;
 		e = kzalloc(sizeof(*e), GFP_KERNEL);
 		if (!e)
 			goto out;
 
 		r = -EINVAL;
-		if (ue->flags) {
-			kfree(e);
-			goto out;
+		switch (ue->type) {
+		case KVM_IRQ_ROUTING_MSI:
+			if (ue->flags & ~KVM_MSI_VALID_DEVID)
+				goto free_entry;
+			break;
+		default:
+			if (ue->flags)
+				goto free_entry;
+			break;
 		}
 		r = setup_routing_entry(kvm, new, e, ue);
-		if (r) {
-			kfree(e);
-			goto out;
-		}
+		if (r)
+			goto free_entry;
 		++ue;
 	}
 
@@ -233,7 +238,10 @@ int kvm_set_irq_routing(struct kvm *kvm,
 
 	new = old;
 	r = 0;
+	goto out;
 
+free_entry:
+	kfree(e);
 out:
 	free_irq_routing_table(new);