[PATCH v6 07/24] KVM: arm64: vgic-its: Implement vgic_its_has_attr_regs and attr_regs_access

Eric Auger
2017-05-04T11:44:27Z

This patch implements vgic_its_has_attr_regs and vgic_its_attr_regs_access
upon the MMIO framework. VGIC ITS KVM device KVM_DEV_ARM_VGIC_GRP_ITS_REGS
group becomes functional.

At least GITS_CREADR and GITS_IIDR require to differentiate a guest write
action from a user access. As such let's introduce a new uaccess_its_write
vgic_register_region callback.

Signed-off-by: Eric Auger <eric.auger@redhat.com>

---
v6 -> v6:
- fix GITS_PIDR/CIDR accesses
- remove vgic_data_mmio_bus_to_host/vgic_data_host_to_mmio_bus
- 64b full reg access comment rewording
- vgic_its_attr_regs_access declaration block rework including
removal of iodev

v4 -> v5:
- use GITS_TYPER instead of offset 0x8
- uaccess_its_write now can return an error

v3 -> v4:
- remove changes to the REGISTER_ITS_DESC macro. This will be handled in
subsequent patch with the introduction of a new REGISTER_ITS_DESC_UACCESS
macro
- fix IIDR access and add a comment wrt full length access
- handle endianness
- add kvm lock and vcpus lock
---
virt/kvm/arm/vgic/vgic-its.c | 70 +++++++++++++++++++++++++++++++++++++++++--
virt/kvm/arm/vgic/vgic-mmio.h | 9 ++++--
2 files changed, 75 insertions(+), 4 deletions(-)

diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index f687e91..222fad5 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -1469,14 +1469,80 @@ static void vgic_its_destroy(struct kvm_device *kvm_dev)
int vgic_its_has_attr_regs(struct kvm_device *dev,
struct kvm_device_attr *attr)
{
- return -ENXIO;
+ const struct vgic_register_region *region;
+ gpa_t offset = attr->attr;
+
+ region = vgic_find_mmio_region(its_registers,
+ ARRAY_SIZE(its_registers),
+ offset);
+ if (!region)
+ return -ENXIO;
+
+ return 0;
}

int vgic_its_attr_regs_access(struct kvm_device *dev,
struct kvm_device_attr *attr,
u64 *reg, bool is_write)
{
- return -ENXIO;
+ const struct vgic_register_region *region;
+ struct vgic_its *its;
+ gpa_t addr, offset;
+ unsigned int len;
+ int align, ret = 0;
+
+ its = dev->private;
+ offset = attr->attr;
+
+ /*
+ * Although the spec supports upper/lower 32-bit accesses to
+ * 64-bit ITS registers, the userspace ABI requires 64-bit
+ * accesses to all 64-bit wide registers. We therefore only
+ * support 32-bit accesses to GITS_CTLR, GITS_IIDR and GITS ID
+ * registers
+ */
+ align = (offset < GITS_TYPER) || (offset >= GITS_PIDR4) ? 0x3 : 0x7;
+
+ if (offset & align)
+ return -EINVAL;
+
+ mutex_lock(&dev->kvm->lock);
+
+ if (IS_VGIC_ADDR_UNDEF(its->vgic_its_base)) {
+ ret = -ENXIO;
+ goto out;
+ }
+
+ region = vgic_find_mmio_region(its_registers,
+ ARRAY_SIZE(its_registers),
+ offset);
+ if (!region) {
+ ret = -ENXIO;
+ goto out;
+ }
+
+ if (!lock_all_vcpus(dev->kvm)) {
+ ret = -EBUSY;
+ goto out;
+ }
+
+ addr = its->vgic_its_base + offset;
+
+ len = region->access_flags & VGIC_ACCESS_64bit ? 8 : 4;
+
+ if (is_write) {
+ if (region->uaccess_its_write)
+ ret = region->uaccess_its_write(dev->kvm, its, addr,
+ len, *reg);
+ else
+ region->its_write(dev->kvm, its, addr, len, *reg);
+ } else {
+ *reg = region->its_read(dev->kvm, its, addr, len);
+ }
+ unlock_all_vcpus(dev->kvm);
+out:
+ mutex_unlock(&dev->kvm->lock);
+ return ret;
}

static int vgic_its_has_attr(struct kvm_device *dev,
diff --git a/virt/kvm/arm/vgic/vgic-mmio.h b/virt/kvm/arm/vgic/vgic-mmio.h
index 6eec91b..ea4171a 100644
--- a/virt/kvm/arm/vgic/vgic-mmio.h
+++ b/virt/kvm/arm/vgic/vgic-mmio.h
@@ -36,8 +36,13 @@ struct vgic_register_region {
};
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);
+ union {
+ void (*uaccess_write)(struct kvm_vcpu *vcpu, gpa_t addr,
+ unsigned int len, unsigned long val);
+ int (*uaccess_its_write)(struct kvm *kvm, struct vgic_its *its,
+ gpa_t addr, unsigned int len,
+ unsigned long val);
+ };
};

extern struct kvm_io_device_ops kvm_io_gic_ops;
--
2.5.5