From: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
Userland can access the emulated GIC to save and restore its state
for initialization or migration purposes.
The kvm_io_bus API requires an absolute gpa, which does not fit the
KVM_DEV_ARM_VGIC_GRP_DIST_REGS user API, that only provides relative
offsets. So we provide a wrapper to plug into our MMIO framework and
find the respective register handler.
Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
---
Changelog v1 .. v2:
- adapt to new MMIO framework
- handle endianess explicitly
Changelog v2 .. v3:
- wrap accessor function for easier reusage later
- moved from earlier in the series
virt/kvm/arm/vgic/vgic-mmio-v2.c | 36 ++++++++++++++++++++++++++++++++++++
virt/kvm/arm/vgic/vgic.h | 2 ++
2 files changed, 38 insertions(+)
diff --git a/virt/kvm/arm/vgic/vgic-mmio-v2.c b/virt/kvm/arm/vgic/vgic-mmio-v2.c
index cf8fee9..c453e6f 100644
--- a/virt/kvm/arm/vgic/vgic-mmio-v2.c
+++ b/virt/kvm/arm/vgic/vgic-mmio-v2.c
@@ -280,3 +280,39 @@ int vgic_v2_has_attr_regs(struct kvm_device *dev, struct kvm_device_attr *attr)
return -ENXIO;
}
+
+/*
+ * When userland tries to access the VGIC register handlers, we need to
+ * create a usable struct vgic_io_device to be passed to the handlers and we
+ * have to set up a buffer similar to what would have happened if a guest MMIO
+ * access occurred, including doing endian conversions on BE systems.
+ */
+static int vgic_uaccess(struct kvm_vcpu *vcpu, struct vgic_io_device *dev,
+ bool is_write, int offset, u32 *val)
+{
+ unsigned int len = 4;
+ u8 buf[4];
+ int ret;
+
+ if (is_write) {
+ vgic_data_host_to_mmio_bus(buf, len, *val);
+ ret = kvm_io_gic_ops.write(vcpu, &dev->dev, offset, len, buf);
+ } else {
+ ret = kvm_io_gic_ops.read(vcpu, &dev->dev, offset, len, buf);
+ if (!ret)
+ *val = vgic_data_mmio_bus_to_host(buf, len);
+ }
+
+ return ret;
+}
+
+int vgic_v2_dist_uaccess(struct kvm_vcpu *vcpu, bool is_write,
+ int offset, u32 *val)
+{
+ struct vgic_io_device dev = {
+ .regions = vgic_v2_dist_registers,
+ .nr_regions = ARRAY_SIZE(vgic_v2_dist_registers),
+ };
+
+ return vgic_uaccess(vcpu, &dev, is_write, offset, val);
+}
diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
index a4397f9..bc5750e 100644
--- a/virt/kvm/arm/vgic/vgic.h
+++ b/virt/kvm/arm/vgic/vgic.h
@@ -37,6 +37,8 @@ void vgic_v2_populate_lr(struct kvm_vcpu *vcpu, struct vgic_irq *irq, int lr);
void vgic_v2_clear_lr(struct kvm_vcpu *vcpu, int lr);
void vgic_v2_set_underflow(struct kvm_vcpu *vcpu);
int vgic_v2_has_attr_regs(struct kvm_device *dev, struct kvm_device_attr *attr);
+int vgic_v2_dist_uaccess(struct kvm_vcpu *vcpu, bool is_write,
+ int offset, u32 *val);
int vgic_register_dist_iodev(struct kvm *kvm, gpa_t dist_base_address,
enum vgic_type);
--
2.7.3
--
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