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KVM: arm/arm64: vgic-new: Export register access interface

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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@linaro.org>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
This commit is contained in:
Christoffer Dall 2016-04-25 01:11:37 +02:00
parent f94591e2e6
commit c3199f28e0
2 changed files with 38 additions and 0 deletions
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36
virt/kvm/arm/vgic/vgic-mmio-v2.c
View file

@ -296,3 +296,39 @@ 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);
}

2
virt/kvm/arm/vgic/vgic.h
View file

@ -38,6 +38,8 @@ 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);