KVM: ARM: vgic: add the GICv3 backend

Introduce the support code for emulating a GICv2 on top of GICv3
hardware.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

arch/arm64/include/asm/kvm_asm.h

@@ -106,6 +106,8 @@ extern void __kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa);
 
 extern int __kvm_vcpu_run(struct kvm_vcpu *vcpu);
 
+extern u64 __vgic_v3_get_ich_vtr_el2(void);
+
 extern char __save_vgic_v2_state[];
 extern char __restore_vgic_v2_state[];
 

arch/arm64/kvm/vgic-v3-switch.S

+/*
+ * Copyright (C) 2012,2013 - 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/linkage.h>
+#include <linux/irqchip/arm-gic-v3.h>
+
+	.text
+	.pushsection	.hyp.text, "ax"
+
+ENTRY(__vgic_v3_get_ich_vtr_el2)
+	mrs	x0, ICH_VTR_EL2
+	ret
+ENDPROC(__vgic_v3_get_ich_vtr_el2)
+
+	.popsection

include/kvm/arm_vgic.h

@@ -33,6 +33,7 @@
 #define VGIC_MAX_CPUS		KVM_MAX_VCPUS
 
 #define VGIC_V2_MAX_LRS		(1 << 6)
+#define VGIC_V3_MAX_LRS		16
 
 /* Sanity checks... */
 #if (VGIC_MAX_CPUS > 8)
@@ -72,6 +73,7 @@ struct kvm_vcpu;
 
 enum vgic_type {
 	VGIC_V2,		/* Good ol' GICv2 */
+	VGIC_V3,		/* New fancy GICv3 */
 };
 
 #define LR_STATE_PENDING	(1 << 0)
@@ -172,6 +174,19 @@ struct vgic_v2_cpu_if {
 	u32		vgic_lr[VGIC_V2_MAX_LRS];
 };
 
+struct vgic_v3_cpu_if {
+#ifdef CONFIG_ARM_GIC_V3
+	u32		vgic_hcr;
+	u32		vgic_vmcr;
+	u32		vgic_misr;	/* Saved only */
+	u32		vgic_eisr;	/* Saved only */
+	u32		vgic_elrsr;	/* Saved only */
+	u32		vgic_ap0r[4];
+	u32		vgic_ap1r[4];
+	u64		vgic_lr[VGIC_V3_MAX_LRS];
+#endif
+};
+
 struct vgic_cpu {
 #ifdef CONFIG_KVM_ARM_VGIC
 	/* per IRQ to LR mapping */
@@ -190,6 +205,7 @@ struct vgic_cpu {
 	/* CPU vif control registers for world switch */
 	union {
 		struct vgic_v2_cpu_if	vgic_v2;
+		struct vgic_v3_cpu_if	vgic_v3;
 	};
 #endif
 };
@@ -224,6 +240,18 @@ bool vgic_handle_mmio(struct kvm_vcpu *vcpu, struct kvm_run *run,
 int vgic_v2_probe(struct device_node *vgic_node,
 		  const struct vgic_ops **ops,
 		  const struct vgic_params **params);
+#ifdef CONFIG_ARM_GIC_V3
+int vgic_v3_probe(struct device_node *vgic_node,
+		  const struct vgic_ops **ops,
+		  const struct vgic_params **params);
+#else
+static inline int vgic_v3_probe(struct device_node *vgic_node,
+				const struct vgic_ops **ops,
+				const struct vgic_params **params)
+{
+	return -ENODEV;
+}
+#endif
 
 #else
 static inline int kvm_vgic_hyp_init(void)

virt/kvm/arm/vgic-v3.c

+/*
+ * Copyright (C) 2013 ARM Limited, All Rights Reserved.
+ * 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/cpu.h>
+#include <linux/kvm.h>
+#include <linux/kvm_host.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+
+#include <linux/irqchip/arm-gic-v3.h>
+
+#include <asm/kvm_emulate.h>
+#include <asm/kvm_arm.h>
+#include <asm/kvm_mmu.h>
+
+/* These are for GICv2 emulation only */
+#define GICH_LR_VIRTUALID		(0x3ffUL << 0)
+#define GICH_LR_PHYSID_CPUID_SHIFT	(10)
+#define GICH_LR_PHYSID_CPUID		(7UL << GICH_LR_PHYSID_CPUID_SHIFT)
+
+/*
+ * LRs are stored in reverse order in memory. make sure we index them
+ * correctly.
+ */
+#define LR_INDEX(lr)			(VGIC_V3_MAX_LRS - 1 - lr)
+
+static u32 ich_vtr_el2;
+
+static struct vgic_lr vgic_v3_get_lr(const struct kvm_vcpu *vcpu, int lr)
+{
+	struct vgic_lr lr_desc;
+	u64 val = vcpu->arch.vgic_cpu.vgic_v3.vgic_lr[LR_INDEX(lr)];
+
+	lr_desc.irq	= val & GICH_LR_VIRTUALID;
+	if (lr_desc.irq <= 15)
+		lr_desc.source	= (val >> GICH_LR_PHYSID_CPUID_SHIFT) & 0x7;
+	else
+		lr_desc.source = 0;
+	lr_desc.state	= 0;
+
+	if (val & ICH_LR_PENDING_BIT)
+		lr_desc.state |= LR_STATE_PENDING;
+	if (val & ICH_LR_ACTIVE_BIT)
+		lr_desc.state |= LR_STATE_ACTIVE;
+	if (val & ICH_LR_EOI)
+		lr_desc.state |= LR_EOI_INT;
+
+	return lr_desc;
+}
+
+static void vgic_v3_set_lr(struct kvm_vcpu *vcpu, int lr,
+			   struct vgic_lr lr_desc)
+{
+	u64 lr_val = (((u32)lr_desc.source << GICH_LR_PHYSID_CPUID_SHIFT) |
+		      lr_desc.irq);
+
+	if (lr_desc.state & LR_STATE_PENDING)
+		lr_val |= ICH_LR_PENDING_BIT;
+	if (lr_desc.state & LR_STATE_ACTIVE)
+		lr_val |= ICH_LR_ACTIVE_BIT;
+	if (lr_desc.state & LR_EOI_INT)
+		lr_val |= ICH_LR_EOI;
+
+	vcpu->arch.vgic_cpu.vgic_v3.vgic_lr[LR_INDEX(lr)] = lr_val;
+}
+
+static void vgic_v3_sync_lr_elrsr(struct kvm_vcpu *vcpu, int lr,
+				  struct vgic_lr lr_desc)
+{
+	if (!(lr_desc.state & LR_STATE_MASK))
+		vcpu->arch.vgic_cpu.vgic_v3.vgic_elrsr |= (1U << lr);
+}
+
+static u64 vgic_v3_get_elrsr(const struct kvm_vcpu *vcpu)
+{
+	return vcpu->arch.vgic_cpu.vgic_v3.vgic_elrsr;
+}
+
+static u64 vgic_v3_get_eisr(const struct kvm_vcpu *vcpu)
+{
+	return vcpu->arch.vgic_cpu.vgic_v3.vgic_eisr;
+}
+
+static u32 vgic_v3_get_interrupt_status(const struct kvm_vcpu *vcpu)
+{
+	u32 misr = vcpu->arch.vgic_cpu.vgic_v3.vgic_misr;
+	u32 ret = 0;
+
+	if (misr & ICH_MISR_EOI)
+		ret |= INT_STATUS_EOI;
+	if (misr & ICH_MISR_U)
+		ret |= INT_STATUS_UNDERFLOW;
+
+	return ret;
+}
+
+static void vgic_v3_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcrp)
+{
+	u32 vmcr = vcpu->arch.vgic_cpu.vgic_v3.vgic_vmcr;
+
+	vmcrp->ctlr = (vmcr & ICH_VMCR_CTLR_MASK) >> ICH_VMCR_CTLR_SHIFT;
+	vmcrp->abpr = (vmcr & ICH_VMCR_BPR1_MASK) >> ICH_VMCR_BPR1_SHIFT;
+	vmcrp->bpr  = (vmcr & ICH_VMCR_BPR0_MASK) >> ICH_VMCR_BPR0_SHIFT;
+	vmcrp->pmr  = (vmcr & ICH_VMCR_PMR_MASK) >> ICH_VMCR_PMR_SHIFT;
+}
+
+static void vgic_v3_enable_underflow(struct kvm_vcpu *vcpu)
+{
+	vcpu->arch.vgic_cpu.vgic_v3.vgic_hcr |= ICH_HCR_UIE;
+}
+
+static void vgic_v3_disable_underflow(struct kvm_vcpu *vcpu)
+{
+	vcpu->arch.vgic_cpu.vgic_v3.vgic_hcr &= ~ICH_HCR_UIE;
+}
+
+static void vgic_v3_set_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcrp)
+{
+	u32 vmcr;
+
+	vmcr  = (vmcrp->ctlr << ICH_VMCR_CTLR_SHIFT) & ICH_VMCR_CTLR_MASK;
+	vmcr |= (vmcrp->abpr << ICH_VMCR_BPR1_SHIFT) & ICH_VMCR_BPR1_MASK;
+	vmcr |= (vmcrp->bpr << ICH_VMCR_BPR0_SHIFT) & ICH_VMCR_BPR0_MASK;
+	vmcr |= (vmcrp->pmr << ICH_VMCR_PMR_SHIFT) & ICH_VMCR_PMR_MASK;
+
+	vcpu->arch.vgic_cpu.vgic_v3.vgic_vmcr = vmcr;
+}
+
+static void vgic_v3_enable(struct kvm_vcpu *vcpu)
+{
+	/*
+	 * By forcing VMCR to zero, the GIC will restore the binary
+	 * points to their reset values. Anything else resets to zero
+	 * anyway.
+	 */
+	vcpu->arch.vgic_cpu.vgic_v3.vgic_vmcr = 0;
+
+	/* Get the show on the road... */
+	vcpu->arch.vgic_cpu.vgic_v3.vgic_hcr = ICH_HCR_EN;
+}
+
+static const struct vgic_ops vgic_v3_ops = {
+	.get_lr			= vgic_v3_get_lr,
+	.set_lr			= vgic_v3_set_lr,
+	.sync_lr_elrsr		= vgic_v3_sync_lr_elrsr,
+	.get_elrsr		= vgic_v3_get_elrsr,
+	.get_eisr		= vgic_v3_get_eisr,
+	.get_interrupt_status	= vgic_v3_get_interrupt_status,
+	.enable_underflow	= vgic_v3_enable_underflow,
+	.disable_underflow	= vgic_v3_disable_underflow,
+	.get_vmcr		= vgic_v3_get_vmcr,
+	.set_vmcr		= vgic_v3_set_vmcr,
+	.enable			= vgic_v3_enable,
+};
+
+static struct vgic_params vgic_v3_params;
+
+/**
+ * vgic_v3_probe - probe for a GICv3 compatible interrupt controller in DT
+ * @node:	pointer to the DT node
+ * @ops: 	address of a pointer to the GICv3 operations
+ * @params:	address of a pointer to HW-specific parameters
+ *
+ * Returns 0 if a GICv3 has been found, with the low level operations
+ * in *ops and the HW parameters in *params. Returns an error code
+ * otherwise.
+ */
+int vgic_v3_probe(struct device_node *vgic_node,
+		  const struct vgic_ops **ops,
+		  const struct vgic_params **params)
+{
+	int ret = 0;
+	u32 gicv_idx;
+	struct resource vcpu_res;
+	struct vgic_params *vgic = &vgic_v3_params;
+
+	vgic->maint_irq = irq_of_parse_and_map(vgic_node, 0);
+	if (!vgic->maint_irq) {
+		kvm_err("error getting vgic maintenance irq from DT\n");
+		ret = -ENXIO;
+		goto out;
+	}
+
+	ich_vtr_el2 = kvm_call_hyp(__vgic_v3_get_ich_vtr_el2);
+
+	/*
+	 * The ListRegs field is 5 bits, but there is a architectural
+	 * maximum of 16 list registers. Just ignore bit 4...
+	 */
+	vgic->nr_lr = (ich_vtr_el2 & 0xf) + 1;
+
+	if (of_property_read_u32(vgic_node, "#redistributor-regions", &gicv_idx))
+		gicv_idx = 1;
+
+	gicv_idx += 3; /* Also skip GICD, GICC, GICH */
+	if (of_address_to_resource(vgic_node, gicv_idx, &vcpu_res)) {
+		kvm_err("Cannot obtain GICV region\n");
+		ret = -ENXIO;
+		goto out;
+	}
+	vgic->vcpu_base = vcpu_res.start;
+	vgic->vctrl_base = NULL;
+	vgic->type = VGIC_V3;
+
+	kvm_info("%s@%llx IRQ%d\n", vgic_node->name,
+		 vcpu_res.start, vgic->maint_irq);
+
+	*ops = &vgic_v3_ops;
+	*params = vgic;
+
+out:
+	of_node_put(vgic_node);
+	return ret;
+}