[RFC PATCH v3 1/5] arm/arm64: vgic-new: Implement support for userspace access

[vijay.kilari@gmail.com (vijay.kilari at gmail.com)]

From: Vijaya Kumar K <Vijaya.Kumar@cavium.com>

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-its.txt
for handling of ISPENDR, ICPENDR registers handling.

Add infrastructure to support guest and userspace read
and write for the required registers

Signed-off-by: Vijaya Kumar K <Vijaya.Kumar@cavium.com>
---
 virt/kvm/arm/vgic/vgic-mmio-v2.c |  5 ++-
 virt/kvm/arm/vgic/vgic-mmio-v3.c | 40 ++++++++++++++----
 virt/kvm/arm/vgic/vgic-mmio.c    | 87 ++++++++++++++++++++++++++++++++++++----
 virt/kvm/arm/vgic/vgic-mmio.h    | 25 ++++++++++++
 4 files changed, 139 insertions(+), 18 deletions(-)

diff --git a/virt/kvm/arm/vgic/vgic-mmio-v2.c b/virt/kvm/arm/vgic/vgic-mmio-v2.c
index b44b359..cd37159 100644
--- a/virt/kvm/arm/vgic/vgic-mmio-v2.c
+++ b/virt/kvm/arm/vgic/vgic-mmio-v2.c
@@ -421,9 +421,10 @@ static int vgic_uaccess(struct kvm_vcpu *vcpu, struct vgic_io_device *dev,
 
 	if (is_write) {
 		vgic_data_host_to_mmio_bus(buf, len, *val);
-		ret = kvm_io_gic_ops.write(vcpu, &dev->dev, offset, len, buf);
+		ret = vgic_mmio_uaccess_write(vcpu, &dev->dev, offset,
+					      len, buf);
 	} else {
-		ret = kvm_io_gic_ops.read(vcpu, &dev->dev, offset, len, buf);
+		ret = vgic_mmio_uaccess_read(vcpu, &dev->dev, offset, len, buf);
 		if (!ret)
 			*val = vgic_data_mmio_bus_to_host(buf, len);
 	}
diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c
index ff668e0..dd0d602 100644
--- a/virt/kvm/arm/vgic/vgic-mmio-v3.c
+++ b/virt/kvm/arm/vgic/vgic-mmio-v3.c
@@ -367,6 +367,26 @@ static void vgic_mmio_write_pendbase(struct kvm_vcpu *vcpu,
 		.write = wr,						\
 	}
 
+#define REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED_UACCESS(off, rd, wr, ur, \
+							uw, bpi, acc)	\
+	{								\
+		.reg_offset = off,					\
+		.bits_per_irq = bpi,					\
+		.len = (bpi * VGIC_NR_PRIVATE_IRQS) / 8,		\
+		.access_flags = acc,					\
+		.read = vgic_mmio_read_raz,				\
+		.write = vgic_mmio_write_wi,				\
+	}, {								\
+		.reg_offset = off + (bpi * VGIC_NR_PRIVATE_IRQS) / 8,	\
+		.bits_per_irq = bpi,					\
+		.len = (bpi * (1024 - VGIC_NR_PRIVATE_IRQS)) / 8,	\
+		.access_flags = acc,					\
+		.read = rd,						\
+		.write = wr,						\
+		.uaccess_read = ur,					\
+		.uaccess_write = uw,					\
+	}
+
 static const struct vgic_register_region vgic_v3_dist_registers[] = {
 	REGISTER_DESC_WITH_LENGTH(GICD_CTLR,
 		vgic_mmio_read_v3_misc, vgic_mmio_write_v3_misc, 16,
@@ -380,11 +400,13 @@ static const struct vgic_register_region vgic_v3_dist_registers[] = {
 	REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ICENABLER,
 		vgic_mmio_read_enable, vgic_mmio_write_cenable, 1,
 		VGIC_ACCESS_32bit),
-	REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ISPENDR,
-		vgic_mmio_read_pending, vgic_mmio_write_spending, 1,
+	REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED_UACCESS(GICD_ISPENDR,
+		vgic_mmio_read_pending, vgic_mmio_write_spending,
+		vgic_mmio_read_soft_pending, vgic_mmio_write_spending, 1,
 		VGIC_ACCESS_32bit),
-	REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ICPENDR,
-		vgic_mmio_read_pending, vgic_mmio_write_cpending, 1,
+	REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED_UACCESS(GICD_ICPENDR,
+		vgic_mmio_read_pending, vgic_mmio_write_cpending,
+		vgic_mmio_read_soft_pending, vgic_mmio_write_cpending, 1,
 		VGIC_ACCESS_32bit),
 	REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ISACTIVER,
 		vgic_mmio_read_active, vgic_mmio_write_sactive, 1,
@@ -443,11 +465,13 @@ 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_mmio_read_soft_pending, vgic_mmio_write_spending, 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_soft_pending, vgic_mmio_write_cpending, 4,
 		VGIC_ACCESS_32bit),
 	REGISTER_DESC_WITH_LENGTH(GICR_ISACTIVER0,
 		vgic_mmio_read_active, vgic_mmio_write_sactive, 4,
diff --git a/virt/kvm/arm/vgic/vgic-mmio.c b/virt/kvm/arm/vgic/vgic-mmio.c
index 3bad3c5..dcf5d25 100644
--- a/virt/kvm/arm/vgic/vgic-mmio.c
+++ b/virt/kvm/arm/vgic/vgic-mmio.c
@@ -100,6 +100,26 @@ void vgic_mmio_write_cenable(struct kvm_vcpu *vcpu,
 	}
 }
 
+unsigned long vgic_mmio_read_soft_pending(struct kvm_vcpu *vcpu,
+					  gpa_t addr, unsigned int len)
+{
+	u32 intid = VGIC_ADDR_TO_INTID(addr, 1);
+	u32 value = 0;
+	int i;
+
+	/* Loop over all IRQs affected by this read */
+	for (i = 0; i < len * 8; i++) {
+		struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
+
+		if (irq->config == VGIC_CONFIG_LEVEL && irq->soft_pending)
+			value |= (1U << i);
+		if (irq->config != VGIC_CONFIG_LEVEL && irq->pending)
+			value |= (1U << i);
+	}
+
+	return value;
+}
+
 unsigned long vgic_mmio_read_pending(struct kvm_vcpu *vcpu,
 				     gpa_t addr, unsigned int len)
 {
@@ -468,6 +488,62 @@ static bool check_region(const struct vgic_register_region *region,
 	return false;
 }
 
+static const struct vgic_register_region *
+	vgic_get_mmio_region(struct vgic_io_device *iodev, gpa_t addr, int len)
+{
+	const struct vgic_register_region *region;
+
+	region = vgic_find_mmio_region(iodev->regions, iodev->nr_regions,
+				       addr - iodev->base_addr);
+	if (!region || !check_region(region, addr, len))
+		return NULL;
+
+	return region;
+}
+
+int vgic_mmio_uaccess_read(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
+			   gpa_t addr, int len, void *val)
+{
+	struct vgic_io_device *iodev = kvm_to_vgic_iodev(dev);
+	const struct vgic_register_region *region;
+	struct kvm_vcpu *r_vcpu;
+	unsigned long data;
+
+	region = vgic_get_mmio_region(iodev, addr, len);
+	if (!region) {
+		memset(val, 0, len);
+		return 0;
+	}
+
+	r_vcpu = iodev->redist_vcpu ? iodev->redist_vcpu : vcpu;
+	if (region->uaccess_read != NULL)
+		data = region->uaccess_read(r_vcpu, addr, len);
+	else
+		data = region->read(r_vcpu, addr, len);
+	vgic_data_host_to_mmio_bus(val, len, data);
+	return 0;
+}
+
+int vgic_mmio_uaccess_write(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
+			    gpa_t addr, int len, const void *val)
+{
+	struct vgic_io_device *iodev = kvm_to_vgic_iodev(dev);
+	const struct vgic_register_region *region;
+	struct kvm_vcpu *r_vcpu;
+	unsigned long data = vgic_data_mmio_bus_to_host(val, len);
+
+	region = vgic_get_mmio_region(iodev, addr, len);
+	if (!region)
+		return 0;
+
+	r_vcpu = iodev->redist_vcpu ? iodev->redist_vcpu : vcpu;
+	if (region->uaccess_write != NULL)
+		region->uaccess_write(r_vcpu, addr, len, data);
+	else
+		region->write(r_vcpu, addr, len, data);
+	return 0;
+}
+
 static int dispatch_mmio_read(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
 			      gpa_t addr, int len, void *val)
 {
@@ -475,9 +551,8 @@ static int dispatch_mmio_read(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
 	const struct vgic_register_region *region;
 	unsigned long data = 0;
 
-	region = vgic_find_mmio_region(iodev->regions, iodev->nr_regions,
-				       addr - iodev->base_addr);
-	if (!region || !check_region(region, addr, len)) {
+	region = vgic_get_mmio_region(iodev, addr, len);
+	if (!region) {
 		memset(val, 0, len);
 		return 0;
 	}
@@ -508,14 +583,10 @@ static int dispatch_mmio_write(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
 	const struct vgic_register_region *region;
 	unsigned long data = vgic_data_mmio_bus_to_host(val, len);
 
-	region = vgic_find_mmio_region(iodev->regions, iodev->nr_regions,
-				       addr - iodev->base_addr);
+	region = vgic_get_mmio_region(iodev, addr, len);
 	if (!region)
 		return 0;
 
-	if (!check_region(region, addr, len))
-		return 0;
-
 	switch (iodev->iodev_type) {
 	case IODEV_CPUIF:
 		region->write(vcpu, addr, len, data);
diff --git a/virt/kvm/arm/vgic/vgic-mmio.h b/virt/kvm/arm/vgic/vgic-mmio.h
index 0b3ecf9..b97a97b 100644
--- a/virt/kvm/arm/vgic/vgic-mmio.h
+++ b/virt/kvm/arm/vgic/vgic-mmio.h
@@ -34,6 +34,10 @@ struct vgic_register_region {
 				  gpa_t addr, unsigned int len,
 				  unsigned long val);
 	};
+	unsigned long (*uaccess_read)(struct kvm_vcpu *vcpu, gpa_t addr,
+				      unsigned int len);
+	void (*uaccess_write)(struct kvm_vcpu *vcpu, gpa_t addr,
+			      unsigned int len, unsigned long val);
 };
 
 extern struct kvm_io_device_ops kvm_io_gic_ops;
@@ -86,6 +90,18 @@ extern struct kvm_io_device_ops kvm_io_gic_ops;
 		.write = wr,						\
 	}
 
+#define REGISTER_DESC_WITH_LENGTH_UACCESS(off, rd, wr, urd, uwr, length, acc) \
+	{								\
+		.reg_offset = off,					\
+		.bits_per_irq = 0,					\
+		.len = length,						\
+		.access_flags = acc,					\
+		.read = rd,						\
+		.write = wr,						\
+		.uaccess_read = urd,					\
+		.uaccess_write = uwr,					\
+	}
+
 int kvm_vgic_register_mmio_region(struct kvm *kvm, struct kvm_vcpu *vcpu,
 				  struct vgic_register_region *reg_desc,
 				  struct vgic_io_device *region,
@@ -122,6 +138,9 @@ void vgic_mmio_write_cenable(struct kvm_vcpu *vcpu,
 			     gpa_t addr, unsigned int len,
 			     unsigned long val);
 
+unsigned long vgic_mmio_read_soft_pending(struct kvm_vcpu *vcpu,
+					  gpa_t addr, unsigned int len);
+
 unsigned long vgic_mmio_read_pending(struct kvm_vcpu *vcpu,
 				     gpa_t addr, unsigned int len);
 
@@ -158,6 +177,12 @@ void vgic_mmio_write_config(struct kvm_vcpu *vcpu,
 			    gpa_t addr, unsigned int len,
 			    unsigned long val);
 
+int vgic_mmio_uaccess_read(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
+			   gpa_t addr, int len, void *val);
+
+int vgic_mmio_uaccess_write(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
+			    gpa_t addr, int len, const void *val);
+
 unsigned int vgic_v2_init_dist_iodev(struct vgic_io_device *dev);
 
 unsigned int vgic_v3_init_dist_iodev(struct vgic_io_device *dev);
-- 
1.9.1