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virtio fix cfg endian-ness for BE targets

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address_space_rw assumes data is in target format
and byte-swaps it if target is BE and device is LE.
Use fixed-endian LE APIs instead.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Michael S. Tsirkin 2015-07-05 15:08:09 +02:00
parent ada434cd0b
commit 1e40356ce5
1 changed files with 83 additions and 8 deletions
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91
hw/virtio/virtio-pci.c
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@ -443,6 +443,83 @@ static const MemoryRegionOps virtio_pci_config_ops = {
.endianness = DEVICE_LITTLE_ENDIAN,
};
/* Below are generic functions to do memcpy from/to an address space,
* without byteswaps, with input validation.
*
* As regular address_space_* APIs all do some kind of byteswap at least for
* some host/target combinations, we are forced to explicitly convert to a
* known-endianness integer value.
* It doesn't really matter which endian format to go through, so the code
* below selects the endian that causes the least amount of work on the given
* host.
*
* Note: host pointer must be aligned.
*/
static
void virtio_address_space_write(AddressSpace *as, hwaddr addr,
const uint8_t *buf, int len)
{
uint32_t val;
/* address_space_* APIs assume an aligned address.
* As address is under guest control, handle illegal values.
*/
addr &= ~(len - 1);
/* Make sure caller aligned buf properly */
assert(!(((uintptr_t)buf) & (len - 1)));
switch (len) {
case 1:
val = pci_get_byte(buf);
address_space_stb(as, addr, val, MEMTXATTRS_UNSPECIFIED, NULL);
break;
case 2:
val = pci_get_word(buf);
address_space_stw_le(as, addr, val, MEMTXATTRS_UNSPECIFIED, NULL);
break;
case 4:
val = pci_get_long(buf);
address_space_stl_le(as, addr, val, MEMTXATTRS_UNSPECIFIED, NULL);
break;
default:
/* As length is under guest control, handle illegal values. */
break;
}
}
static void
virtio_address_space_read(AddressSpace *as, hwaddr addr, uint8_t *buf, int len)
{
uint32_t val;
/* address_space_* APIs assume an aligned address.
* As address is under guest control, handle illegal values.
*/
addr &= ~(len - 1);
/* Make sure caller aligned buf properly */
assert(!(((uintptr_t)buf) & (len - 1)));
switch (len) {
case 1:
val = address_space_ldub(as, addr, MEMTXATTRS_UNSPECIFIED, NULL);
pci_set_byte(buf, val);
break;
case 2:
val = address_space_lduw_le(as, addr, MEMTXATTRS_UNSPECIFIED, NULL);
pci_set_word(buf, val);
break;
case 4:
val = address_space_ldl_le(as, addr, MEMTXATTRS_UNSPECIFIED, NULL);
pci_set_long(buf, val);
break;
default:
/* As length is under guest control, handle illegal values. */
break;
}
}
static void virtio_write_config(PCIDevice *pci_dev, uint32_t address,
uint32_t val, int len)
{
@ -469,10 +546,9 @@ static void virtio_write_config(PCIDevice *pci_dev, uint32_t address,
off = le32_to_cpu(cfg->cap.offset);
len = le32_to_cpu(cfg->cap.length);
if ((len == 1 || len == 2 || len == 4)) {
address_space_write(&proxy->modern_as, off,
MEMTXATTRS_UNSPECIFIED,
cfg->pci_cfg_data, len);
if (len <= sizeof cfg->pci_cfg_data) {
virtio_address_space_write(&proxy->modern_as, off,
cfg->pci_cfg_data, len);
}
}
}
@ -494,10 +570,9 @@ static uint32_t virtio_read_config(PCIDevice *pci_dev,
off = le32_to_cpu(cfg->cap.offset);
len = le32_to_cpu(cfg->cap.length);
if ((len == 1 || len == 2 || len == 4)) {
address_space_read(&proxy->modern_as, off,
MEMTXATTRS_UNSPECIFIED,
cfg->pci_cfg_data, len);
if (len <= sizeof cfg->pci_cfg_data) {
virtio_address_space_read(&proxy->modern_as, off,
cfg->pci_cfg_data, len);
}
}