Commit c3199f28 authored by Christoffer Dall's avatar Christoffer Dall
Browse files

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



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: default avatarChristoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: default avatarAndre Przywara <andre.przywara@arm.com>
parent f94591e2

virt/kvm/arm/vgic/vgic-mmio-v2.c

+36 −0
Original line number Diff line number Diff line
@@ -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);

}

virt/kvm/arm/vgic/vgic.h

+2 −0
Original line number Diff line number Diff line
@@ -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);

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