KVM: arm/arm64: vgic: Implement support for userspace access

Read and write of some registers like ISPENDR and ICPENDR
from userspace requires special handling when compared to
guest access for these registers.

Refer to Documentation/virtual/kvm/devices/arm-vgic-v3.txt
for handling of ISPENDR, ICPENDR registers handling.

Add infrastructure to support guest and userspace read
and write for the required registers
Also moved vgic_uaccess from vgic-mmio-v2.c to vgic-mmio.c

Signed-off-by: Vijaya Kumar K <Vijaya.Kumar@cavium.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

1 files changed, 78 insertions, 18 deletions

diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c
index 2aca52a6c9eb..3548bb207a1b 100644
--- a/virt/kvm/arm/vgic/vgic-mmio-v3.c
+++ b/virt/kvm/arm/vgic/vgic-mmio-v3.c
@@ -207,6 +207,60 @@ static unsigned long vgic_mmio_read_v3_idregs(struct kvm_vcpu *vcpu,
 	return 0;
 }
 
+static unsigned long vgic_v3_uaccess_read_pending(struct kvm_vcpu *vcpu,
+						  gpa_t addr, unsigned int len)
+{
+	u32 intid = VGIC_ADDR_TO_INTID(addr, 1);
+	u32 value = 0;
+	int i;
+
+	/*
+	 * pending state of interrupt is latched in pending_latch variable.
+	 * Userspace will save and restore pending state and line_level
+	 * separately.
+	 * Refer to Documentation/virtual/kvm/devices/arm-vgic-v3.txt
+	 * for handling of ISPENDR and ICPENDR.
+	 */
+	for (i = 0; i < len * 8; i++) {
+		struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
+
+		if (irq->pending_latch)
+			value |= (1U << i);
+
+		vgic_put_irq(vcpu->kvm, irq);
+	}
+
+	return value;
+}
+
+static void vgic_v3_uaccess_write_pending(struct kvm_vcpu *vcpu,
+					  gpa_t addr, unsigned int len,
+					  unsigned long val)
+{
+	u32 intid = VGIC_ADDR_TO_INTID(addr, 1);
+	int i;
+
+	for (i = 0; i < len * 8; i++) {
+		struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
+
+		spin_lock(&irq->irq_lock);
+		if (test_bit(i, &val)) {
+			/*
+			 * pending_latch is set irrespective of irq type
+			 * (level or edge) to avoid dependency that VM should
+			 * restore irq config before pending info.
+			 */
+			irq->pending_latch = true;
+			vgic_queue_irq_unlock(vcpu->kvm, irq);
+		} else {
+			irq->pending_latch = false;
+			spin_unlock(&irq->irq_lock);
+		}
+
+		vgic_put_irq(vcpu->kvm, irq);
+	}
+}
+
 /* We want to avoid outer shareable. */
 u64 vgic_sanitise_shareability(u64 field)
 {
@@ -356,7 +410,7 @@ static void vgic_mmio_write_pendbase(struct kvm_vcpu *vcpu,
  * We take some special care here to fix the calculation of the register
  * offset.
  */
-#define REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(off, rd, wr, bpi, acc)	\
+#define REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(off, rd, wr, ur, uw, bpi, acc) \
 	{								\
 		.reg_offset = off,					\
 		.bits_per_irq = bpi,					\
@@ -371,6 +425,8 @@ static void vgic_mmio_write_pendbase(struct kvm_vcpu *vcpu,
 		.access_flags = acc,					\
 		.read = rd,						\
 		.write = wr,						\
+		.uaccess_read = ur,					\
+		.uaccess_write = uw,					\
 	}
 
 static const struct vgic_register_region vgic_v3_dist_registers[] = {
@@ -378,40 +434,42 @@ static const struct vgic_register_region vgic_v3_dist_registers[] = {
 		vgic_mmio_read_v3_misc, vgic_mmio_write_v3_misc, 16,
 		VGIC_ACCESS_32bit),
 	REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_IGROUPR,
-		vgic_mmio_read_rao, vgic_mmio_write_wi, 1,
+		vgic_mmio_read_rao, vgic_mmio_write_wi, NULL, NULL, 1,
 		VGIC_ACCESS_32bit),
 	REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ISENABLER,
-		vgic_mmio_read_enable, vgic_mmio_write_senable, 1,
+		vgic_mmio_read_enable, vgic_mmio_write_senable, NULL, NULL, 1,
 		VGIC_ACCESS_32bit),
 	REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ICENABLER,
-		vgic_mmio_read_enable, vgic_mmio_write_cenable, 1,
+		vgic_mmio_read_enable, vgic_mmio_write_cenable, NULL, NULL, 1,
 		VGIC_ACCESS_32bit),
 	REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ISPENDR,
-		vgic_mmio_read_pending, vgic_mmio_write_spending, 1,
+		vgic_mmio_read_pending, vgic_mmio_write_spending,
+		vgic_v3_uaccess_read_pending, vgic_v3_uaccess_write_pending, 1,
 		VGIC_ACCESS_32bit),
 	REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ICPENDR,
-		vgic_mmio_read_pending, vgic_mmio_write_cpending, 1,
+		vgic_mmio_read_pending, vgic_mmio_write_cpending,
+		vgic_mmio_read_raz, vgic_mmio_write_wi, 1,
 		VGIC_ACCESS_32bit),
 	REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ISACTIVER,
-		vgic_mmio_read_active, vgic_mmio_write_sactive, 1,
+		vgic_mmio_read_active, vgic_mmio_write_sactive, NULL, NULL, 1,
 		VGIC_ACCESS_32bit),
 	REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ICACTIVER,
-		vgic_mmio_read_active, vgic_mmio_write_cactive, 1,
+		vgic_mmio_read_active, vgic_mmio_write_cactive, NULL, NULL, 1,
 		VGIC_ACCESS_32bit),
 	REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_IPRIORITYR,
-		vgic_mmio_read_priority, vgic_mmio_write_priority, 8,
-		VGIC_ACCESS_32bit | VGIC_ACCESS_8bit),
+		vgic_mmio_read_priority, vgic_mmio_write_priority, NULL, NULL,
+		8, VGIC_ACCESS_32bit | VGIC_ACCESS_8bit),
 	REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ITARGETSR,
-		vgic_mmio_read_raz, vgic_mmio_write_wi, 8,
+		vgic_mmio_read_raz, vgic_mmio_write_wi, NULL, NULL, 8,
 		VGIC_ACCESS_32bit | VGIC_ACCESS_8bit),
 	REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ICFGR,
-		vgic_mmio_read_config, vgic_mmio_write_config, 2,
+		vgic_mmio_read_config, vgic_mmio_write_config, NULL, NULL, 2,
 		VGIC_ACCESS_32bit),
 	REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_IGRPMODR,
-		vgic_mmio_read_raz, vgic_mmio_write_wi, 1,
+		vgic_mmio_read_raz, vgic_mmio_write_wi, NULL, NULL, 1,
 		VGIC_ACCESS_32bit),
 	REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_IROUTER,
-		vgic_mmio_read_irouter, vgic_mmio_write_irouter, 64,
+		vgic_mmio_read_irouter, vgic_mmio_write_irouter, NULL, NULL, 64,
 		VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
 	REGISTER_DESC_WITH_LENGTH(GICD_IDREGS,
 		vgic_mmio_read_v3_idregs, vgic_mmio_write_wi, 48,
@@ -449,11 +507,13 @@ static const struct vgic_register_region vgic_v3_sgibase_registers[] = {
 	REGISTER_DESC_WITH_LENGTH(GICR_ICENABLER0,
 		vgic_mmio_read_enable, vgic_mmio_write_cenable, 4,
 		VGIC_ACCESS_32bit),
-	REGISTER_DESC_WITH_LENGTH(GICR_ISPENDR0,
-		vgic_mmio_read_pending, vgic_mmio_write_spending, 4,
+	REGISTER_DESC_WITH_LENGTH_UACCESS(GICR_ISPENDR0,
+		vgic_mmio_read_pending, vgic_mmio_write_spending,
+		vgic_v3_uaccess_read_pending, vgic_v3_uaccess_write_pending, 4,
 		VGIC_ACCESS_32bit),
-	REGISTER_DESC_WITH_LENGTH(GICR_ICPENDR0,
-		vgic_mmio_read_pending, vgic_mmio_write_cpending, 4,
+	REGISTER_DESC_WITH_LENGTH_UACCESS(GICR_ICPENDR0,
+		vgic_mmio_read_pending, vgic_mmio_write_cpending,
+		vgic_mmio_read_raz, vgic_mmio_write_wi, 4,
 		VGIC_ACCESS_32bit),
 	REGISTER_DESC_WITH_LENGTH(GICR_ISACTIVER0,
 		vgic_mmio_read_active, vgic_mmio_write_sactive, 4,