diff options
Diffstat (limited to 'virt/kvm/arm/vgic/vgic-mmio.c')
| -rw-r--r-- | virt/kvm/arm/vgic/vgic-mmio.c | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/virt/kvm/arm/vgic/vgic-mmio.c b/virt/kvm/arm/vgic/vgic-mmio.c new file mode 100644 index 000000000000..012b82bec918 --- /dev/null +++ b/virt/kvm/arm/vgic/vgic-mmio.c @@ -0,0 +1,184 @@ +/* + * VGIC MMIO handling functions + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/bitops.h> +#include <linux/bsearch.h> +#include <linux/kvm.h> +#include <linux/kvm_host.h> +#include <kvm/iodev.h> +#include <kvm/arm_vgic.h> + +#include "vgic.h" +#include "vgic-mmio.h" + +unsigned long vgic_mmio_read_raz(struct kvm_vcpu *vcpu, + gpa_t addr, unsigned int len) +{ + return 0; +} + +unsigned long vgic_mmio_read_rao(struct kvm_vcpu *vcpu, + gpa_t addr, unsigned int len) +{ + return -1UL; +} + +void vgic_mmio_write_wi(struct kvm_vcpu *vcpu, gpa_t addr, + unsigned int len, unsigned long val) +{ + /* Ignore */ +} + +static int match_region(const void *key, const void *elt) +{ + const unsigned int offset = (unsigned long)key; + const struct vgic_register_region *region = elt; + + if (offset < region->reg_offset) + return -1; + + if (offset >= region->reg_offset + region->len) + return 1; + + return 0; +} + +/* Find the proper register handler entry given a certain address offset. */ +static const struct vgic_register_region * +vgic_find_mmio_region(const struct vgic_register_region *region, int nr_regions, + unsigned int offset) +{ + return bsearch((void *)(uintptr_t)offset, region, nr_regions, + sizeof(region[0]), match_region); +} + +/* + * kvm_mmio_read_buf() returns a value in a format where it can be converted + * to a byte array and be directly observed as the guest wanted it to appear + * in memory if it had done the store itself, which is LE for the GIC, as the + * guest knows the GIC is always LE. + * + * We convert this value to the CPUs native format to deal with it as a data + * value. + */ +unsigned long vgic_data_mmio_bus_to_host(const void *val, unsigned int len) +{ + unsigned long data = kvm_mmio_read_buf(val, len); + + switch (len) { + case 1: + return data; + case 2: + return le16_to_cpu(data); + case 4: + return le32_to_cpu(data); + default: + return le64_to_cpu(data); + } +} + +/* + * kvm_mmio_write_buf() expects a value in a format such that if converted to + * a byte array it is observed as the guest would see it if it could perform + * the load directly. Since the GIC is LE, and the guest knows this, the + * guest expects a value in little endian format. + * + * We convert the data value from the CPUs native format to LE so that the + * value is returned in the proper format. + */ +void vgic_data_host_to_mmio_bus(void *buf, unsigned int len, + unsigned long data) +{ + switch (len) { + case 1: + break; + case 2: + data = cpu_to_le16(data); + break; + case 4: + data = cpu_to_le32(data); + break; + default: + data = cpu_to_le64(data); + } + + kvm_mmio_write_buf(buf, len, data); +} + +static +struct vgic_io_device *kvm_to_vgic_iodev(const struct kvm_io_device *dev) +{ + return container_of(dev, struct vgic_io_device, dev); +} + +static bool check_region(const struct vgic_register_region *region, + gpa_t addr, int len) +{ + if ((region->access_flags & VGIC_ACCESS_8bit) && len == 1) + return true; + if ((region->access_flags & VGIC_ACCESS_32bit) && + len == sizeof(u32) && !(addr & 3)) + return true; + if ((region->access_flags & VGIC_ACCESS_64bit) && + len == sizeof(u64) && !(addr & 7)) + return true; + + return false; +} + +static int dispatch_mmio_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_find_mmio_region(iodev->regions, iodev->nr_regions, + addr - iodev->base_addr); + if (!region || !check_region(region, addr, len)) { + memset(val, 0, len); + return 0; + } + + r_vcpu = iodev->redist_vcpu ? iodev->redist_vcpu : vcpu; + data = region->read(r_vcpu, addr, len); + vgic_data_host_to_mmio_bus(val, len, data); + return 0; +} + +static int dispatch_mmio_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_find_mmio_region(iodev->regions, iodev->nr_regions, + addr - iodev->base_addr); + if (!region) + return 0; + + if (!check_region(region, addr, len)) + return 0; + + r_vcpu = iodev->redist_vcpu ? iodev->redist_vcpu : vcpu; + region->write(r_vcpu, addr, len, data); + return 0; +} + +struct kvm_io_device_ops kvm_io_gic_ops = { + .read = dispatch_mmio_read, + .write = dispatch_mmio_write, +}; |