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authorMichael S. Tsirkin <mst@redhat.com>2015-07-05 15:08:09 +0200
committerMichael S. Tsirkin <mst@redhat.com>2015-07-07 15:38:35 +0300
commita61a2a68f2ba58079b0cd325059a9db92f3d7316 (patch)
tree8d8f77df3a80f24ee9add149056535fd94539f0f
parenta62fd590ca8ab6013e80b57f43950e206566a74a (diff)
downloadqemu-arm-a61a2a68f2ba58079b0cd325059a9db92f3d7316.tar.gz
virtio fix cfg endian-ness for BE targets
address_space_rw assumes data is in target format and byte-swaps it if target is BE and device is LE. Use a fixed-endian APIs instead. Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
-rw-r--r--hw/virtio/virtio-pci.c111
1 files changed, 103 insertions, 8 deletions
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 7890b00fd7..f754ef3728 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -443,6 +443,103 @@ 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 = *buf;
+ address_space_stb(as, addr, val, MEMTXATTRS_UNSPECIFIED, NULL);
+ break;
+ case 2:
+#if defined(HOST_WORDS_BIGENDIAN)
+ val = lduw_be_p(buf);
+ address_space_stw_be(as, addr, val, MEMTXATTRS_UNSPECIFIED, NULL);
+#else
+ val = lduw_le_p(buf);
+ address_space_stw_le(as, addr, val, MEMTXATTRS_UNSPECIFIED, NULL);
+#endif
+ break;
+ case 4:
+#if defined(HOST_WORDS_BIGENDIAN)
+ val = ldl_be_p(buf);
+ address_space_stl_be(as, addr, val, MEMTXATTRS_UNSPECIFIED, NULL);
+#else
+ val = ldl_le_p(buf);
+ address_space_stl_le(as, addr, val, MEMTXATTRS_UNSPECIFIED, NULL);
+#endif
+ 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);
+ *buf = val;
+ break;
+ case 2:
+#if defined(HOST_WORDS_BIGENDIAN)
+ val = address_space_lduw_be(as, addr, MEMTXATTRS_UNSPECIFIED, NULL);
+ stw_be_p(buf, val);
+#else
+ val = address_space_lduw_le(as, addr, MEMTXATTRS_UNSPECIFIED, NULL);
+ stw_le_p(buf, val);
+#endif
+ break;
+ case 4:
+#if defined(HOST_WORDS_BIGENDIAN)
+ val = address_space_ldl_be(as, addr, MEMTXATTRS_UNSPECIFIED, NULL);
+ stl_be_p(buf, val);
+#else
+ val = address_space_ldl_le(as, addr, MEMTXATTRS_UNSPECIFIED, NULL);
+ stl_le_p(buf, val);
+#endif
+ 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 +566,9 @@ 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 +590,9 @@ 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);
}
}