arm/arm64: KVM: add virtual GICv3 distributor emulation

With everything separated and prepared, we implement a model of a
GICv3 distributor and redistributors by using the existing framework
to provide handler functions for each register group.

Currently we limit the emulation to a model enforcing a single
security state, with SRE==1 (forcing system register access) and
ARE==1 (allowing more than 8 VCPUs).

We share some of the functions provided for GICv2 emulation, but take
the different ways of addressing (v)CPUs into account.
Save and restore is currently not implemented.

Similar to the split-off of the GICv2 specific code, the new emulation
code goes into a new file (vgic-v3-emul.c).
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

arch/arm64/kvm/Makefile

@@ -24,5 +24,6 @@ kvm-$(CONFIG_KVM_ARM_VGIC) += $(KVM)/arm/vgic-v2.o
 kvm-$(CONFIG_KVM_ARM_VGIC) += $(KVM)/arm/vgic-v2-emul.o
 kvm-$(CONFIG_KVM_ARM_VGIC) += vgic-v2-switch.o
 kvm-$(CONFIG_KVM_ARM_VGIC) += $(KVM)/arm/vgic-v3.o
+kvm-$(CONFIG_KVM_ARM_VGIC) += $(KVM)/arm/vgic-v3-emul.o
 kvm-$(CONFIG_KVM_ARM_VGIC) += vgic-v3-switch.o
 kvm-$(CONFIG_KVM_ARM_TIMER) += $(KVM)/arm/arch_timer.o

include/kvm/arm_vgic.h

@@ -162,7 +162,11 @@ struct vgic_dist {
 
 	/* Distributor and vcpu interface mapping in the guest */
 	phys_addr_t		vgic_dist_base;
-	phys_addr_t		vgic_cpu_base;
+	/* GICv2 and GICv3 use different mapped register blocks */
+	union {
+		phys_addr_t		vgic_cpu_base;
+		phys_addr_t		vgic_redist_base;
+	};
 
 	/* Distributor enabled */
 	u32			enabled;
@@ -224,6 +228,9 @@ struct vgic_dist {
 	 */
 	struct vgic_bitmap	*irq_spi_target;
 
+	/* Target MPIDR for each IRQ (needed for GICv3 IROUTERn) only */
+	u32			*irq_spi_mpidr;
+
 	/* Bitmap indicating which CPU has something pending */
 	unsigned long		*irq_pending_on_cpu;
 

include/linux/irqchip/arm-gic-v3.h

@@ -33,6 +33,7 @@
 #define GICD_SETSPI_SR			0x0050
 #define GICD_CLRSPI_SR			0x0058
 #define GICD_SEIR			0x0068
+#define GICD_IGROUPR			0x0080
 #define GICD_ISENABLER			0x0100
 #define GICD_ICENABLER			0x0180
 #define GICD_ISPENDR			0x0200
@@ -41,14 +42,37 @@
 #define GICD_ICACTIVER			0x0380
 #define GICD_IPRIORITYR			0x0400
 #define GICD_ICFGR			0x0C00
+#define GICD_IGRPMODR			0x0D00
+#define GICD_NSACR			0x0E00
 #define GICD_IROUTER			0x6000
+#define GICD_IDREGS			0xFFD0
 #define GICD_PIDR2			0xFFE8
 
+/*
+ * Those registers are actually from GICv2, but the spec demands that they
+ * are implemented as RES0 if ARE is 1 (which we do in KVM's emulated GICv3).
+ */
+#define GICD_ITARGETSR			0x0800
+#define GICD_SGIR			0x0F00
+#define GICD_CPENDSGIR			0x0F10
+#define GICD_SPENDSGIR			0x0F20
+
 #define GICD_CTLR_RWP			(1U << 31)
+#define GICD_CTLR_DS			(1U << 6)
 #define GICD_CTLR_ARE_NS		(1U << 4)
 #define GICD_CTLR_ENABLE_G1A		(1U << 1)
 #define GICD_CTLR_ENABLE_G1		(1U << 0)
 
+/*
+ * In systems with a single security state (what we emulate in KVM)
+ * the meaning of the interrupt group enable bits is slightly different
+ */
+#define GICD_CTLR_ENABLE_SS_G1		(1U << 1)
+#define GICD_CTLR_ENABLE_SS_G0		(1U << 0)
+
+#define GICD_TYPER_LPIS			(1U << 17)
+#define GICD_TYPER_MBIS			(1U << 16)
+
 #define GICD_TYPER_ID_BITS(typer)	((((typer) >> 19) & 0x1f) + 1)
 #define GICD_TYPER_IRQS(typer)		((((typer) & 0x1f) + 1) * 32)
 #define GICD_TYPER_LPIS			(1U << 17)
@@ -60,6 +84,8 @@
 #define GIC_PIDR2_ARCH_GICv3		0x30
 #define GIC_PIDR2_ARCH_GICv4		0x40
 
+#define GIC_V3_DIST_SIZE		0x10000
+
 /*
  * Re-Distributor registers, offsets from RD_base
  */
@@ -78,6 +104,7 @@
 #define GICR_SYNCR			0x00C0
 #define GICR_MOVLPIR			0x0100
 #define GICR_MOVALLR			0x0110
+#define GICR_IDREGS			GICD_IDREGS
 #define GICR_PIDR2			GICD_PIDR2
 
 #define GICR_CTLR_ENABLE_LPIS		(1UL << 0)
@@ -104,6 +131,7 @@
 /*
  * Re-Distributor registers, offsets from SGI_base
  */
+#define GICR_IGROUPR0			GICD_IGROUPR
 #define GICR_ISENABLER0			GICD_ISENABLER
 #define GICR_ICENABLER0			GICD_ICENABLER
 #define GICR_ISPENDR0			GICD_ISPENDR
@@ -112,11 +140,15 @@
 #define GICR_ICACTIVER0			GICD_ICACTIVER
 #define GICR_IPRIORITYR0		GICD_IPRIORITYR
 #define GICR_ICFGR0			GICD_ICFGR
+#define GICR_IGRPMODR0			GICD_IGRPMODR
+#define GICR_NSACR			GICD_NSACR
 
 #define GICR_TYPER_PLPIS		(1U << 0)
 #define GICR_TYPER_VLPIS		(1U << 1)
 #define GICR_TYPER_LAST			(1U << 4)
 
+#define GIC_V3_REDIST_SIZE		0x20000
+
 #define LPI_PROP_GROUP1			(1 << 1)
 #define LPI_PROP_ENABLED		(1 << 0)
 

include/linux/kvm_host.h

@@ -1052,6 +1052,7 @@ void kvm_unregister_device_ops(u32 type);
 extern struct kvm_device_ops kvm_mpic_ops;
 extern struct kvm_device_ops kvm_xics_ops;
 extern struct kvm_device_ops kvm_arm_vgic_v2_ops;
+extern struct kvm_device_ops kvm_arm_vgic_v3_ops;
 
 #ifdef CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT
 

include/uapi/linux/kvm.h

@@ -952,6 +952,8 @@ enum kvm_device_type {
 #define KVM_DEV_TYPE_ARM_VGIC_V2	KVM_DEV_TYPE_ARM_VGIC_V2
 	KVM_DEV_TYPE_FLIC,
 #define KVM_DEV_TYPE_FLIC		KVM_DEV_TYPE_FLIC
+	KVM_DEV_TYPE_ARM_VGIC_V3,
+#define KVM_DEV_TYPE_ARM_VGIC_V3	KVM_DEV_TYPE_ARM_VGIC_V3
 	KVM_DEV_TYPE_MAX,
 };
 

virt/kvm/arm/vgic.c

@@ -1249,7 +1249,7 @@ static int vgic_update_irq_pending(struct kvm *kvm, int cpuid,
 	struct kvm_vcpu *vcpu;
 	int edge_triggered, level_triggered;
 	int enabled;
-	bool ret = true;
+	bool ret = true, can_inject = true;
 
 	spin_lock(&dist->lock);
 
@@ -1264,6 +1264,11 @@ static int vgic_update_irq_pending(struct kvm *kvm, int cpuid,
 
 	if (irq_num >= VGIC_NR_PRIVATE_IRQS) {
 		cpuid = dist->irq_spi_cpu[irq_num - VGIC_NR_PRIVATE_IRQS];
+		if (cpuid == VCPU_NOT_ALLOCATED) {
+			/* Pretend we use CPU0, and prevent injection */
+			cpuid = 0;
+			can_inject = false;
+		}
 		vcpu = kvm_get_vcpu(kvm, cpuid);
 	}
 
@@ -1286,7 +1291,7 @@ static int vgic_update_irq_pending(struct kvm *kvm, int cpuid,
 
 	enabled = vgic_irq_is_enabled(vcpu, irq_num);
 
-	if (!enabled) {
+	if (!enabled || !can_inject) {
 		ret = false;
 		goto out;
 	}
@@ -1439,6 +1444,7 @@ void kvm_vgic_destroy(struct kvm *kvm)
 	}
 	kfree(dist->irq_sgi_sources);
 	kfree(dist->irq_spi_cpu);
+	kfree(dist->irq_spi_mpidr);
 	kfree(dist->irq_spi_target);
 	kfree(dist->irq_pending_on_cpu);
 	dist->irq_sgi_sources = NULL;
@@ -1594,6 +1600,7 @@ int kvm_vgic_create(struct kvm *kvm, u32 type)
 	kvm->arch.vgic.vctrl_base = vgic->vctrl_base;
 	kvm->arch.vgic.vgic_dist_base = VGIC_ADDR_UNDEF;
 	kvm->arch.vgic.vgic_cpu_base = VGIC_ADDR_UNDEF;
+	kvm->arch.vgic.vgic_redist_base = VGIC_ADDR_UNDEF;
 
 out_unlock:
 	for (; vcpu_lock_idx >= 0; vcpu_lock_idx--) {

virt/kvm/arm/vgic.h

@@ -35,6 +35,8 @@
 #define ACCESS_WRITE_VALUE	(3 << 1)
 #define ACCESS_WRITE_MASK(x)	((x) & (3 << 1))
 
+#define VCPU_NOT_ALLOCATED	((u8)-1)
+
 unsigned long *vgic_bitmap_get_shared_map(struct vgic_bitmap *x);
 
 void vgic_update_state(struct kvm *kvm);
@@ -116,5 +118,6 @@ int vgic_get_common_attr(struct kvm_device *dev, struct kvm_device_attr *attr);
 
 int vgic_init(struct kvm *kvm);
 void vgic_v2_init_emulation(struct kvm *kvm);
+void vgic_v3_init_emulation(struct kvm *kvm);
 
 #endif