/*
* 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,
};
