Propagates the GPAs (in_xlat_addr/out_xlat_addr) of a VirtQueueElement
to vhost_svq_translate_addr() to translate to IOVAs via GPA->IOVA tree
when descriptors are backed by guest memory.
For descriptors backed by guest memory, the translation is performed
using GPAs via the GPA->IOVA tree. GPAs are unique in the guest's
address space, so this ensures unambiguous IOVA translations.
For descriptors not backed by guest memory, the existing IOVA->HVA tree
is used.
This avoids the issue where different GPAs map to the same HVA, causing
the HVA->IOVA translation to potentially return an IOVA associated with
the wrong intended GPA.
Signed-off-by: Jonah Palmer <jonah.pal...@oracle.com>
---
hw/virtio/vhost-shadow-virtqueue.c | 49 ++++++++++++++++++++++--------
1 file changed, 37 insertions(+), 12 deletions(-)
diff --git a/hw/virtio/vhost-shadow-virtqueue.c
b/hw/virtio/vhost-shadow-virtqueue.c
index 37aca8b431..be0db94ab7 100644
--- a/hw/virtio/vhost-shadow-virtqueue.c
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -78,24 +78,37 @@ uint16_t vhost_svq_available_slots(const
VhostShadowVirtqueue *svq)
* @vaddr: Translated IOVA addresses
* @iovec: Source qemu's VA addresses
* @num: Length of iovec and minimum length of vaddr
+ * @gpas: Descriptors' GPAs, if backed by guest memory
*/
static bool vhost_svq_translate_addr(const VhostShadowVirtqueue *svq,
hwaddr *addrs, const struct iovec *iovec,
- size_t num)
+ size_t num, const hwaddr *gpas)
{
if (num == 0) {
return true;
}
for (size_t i = 0; i < num; ++i) {
- DMAMap needle = {
- .translated_addr = (hwaddr)(uintptr_t)iovec[i].iov_base,
- .size = iovec[i].iov_len,
- };
+ const DMAMap *map;
+ DMAMap needle;
Int128 needle_last, map_last;
size_t off;
- const DMAMap *map = vhost_iova_tree_find_iova(svq->iova_tree, &needle);
+ if (gpas) {
+ /* Search the GPA->IOVA tree */
+ needle = (DMAMap) {
+ .translated_addr = gpas[i],
+ .size = iovec[i].iov_len,
+ };
+ map = vhost_iova_tree_find_gpa(svq->iova_tree, &needle);
+ } else {
+ /* Searh the IOVA->HVA tree */
+ needle = (DMAMap) {
+ .translated_addr = (hwaddr)(uintptr_t)iovec[i].iov_base,
+ .size = iovec[i].iov_len,
+ };
+ map = vhost_iova_tree_find_iova(svq->iova_tree, &needle);
+ }
/*
* Map cannot be NULL since iova map contains all guest space and
* qemu already has a physical address mapped
@@ -132,12 +145,14 @@ static bool vhost_svq_translate_addr(const
VhostShadowVirtqueue *svq,
* @num: iovec length
* @more_descs: True if more descriptors come in the chain
* @write: True if they are writeable descriptors
+ * @gpas: Descriptors' GPAs, if backed by guest memory
*
* Return true if success, false otherwise and print error.
*/
static bool vhost_svq_vring_write_descs(VhostShadowVirtqueue *svq, hwaddr *sg,
const struct iovec *iovec, size_t num,
- bool more_descs, bool write)
+ bool more_descs, bool write,
+ const hwaddr *gpas)
{
uint16_t i = svq->free_head, last = svq->free_head;
unsigned n;
@@ -149,7 +164,7 @@ static bool
vhost_svq_vring_write_descs(VhostShadowVirtqueue *svq, hwaddr *sg,
return true;
}
- ok = vhost_svq_translate_addr(svq, sg, iovec, num);
+ ok = vhost_svq_translate_addr(svq, sg, iovec, num, gpas);
if (unlikely(!ok)) {
return false;
}
@@ -175,7 +190,8 @@ static bool
vhost_svq_vring_write_descs(VhostShadowVirtqueue *svq, hwaddr *sg,
static bool vhost_svq_add_split(VhostShadowVirtqueue *svq,
const struct iovec *out_sg, size_t out_num,
const struct iovec *in_sg, size_t in_num,
- unsigned *head)
+ unsigned *head, const hwaddr *in_gpas,
+ const hwaddr *out_gpas)
{
unsigned avail_idx;
vring_avail_t *avail = svq->vring.avail;
@@ -192,12 +208,13 @@ static bool vhost_svq_add_split(VhostShadowVirtqueue *svq,
}
ok = vhost_svq_vring_write_descs(svq, sgs, out_sg, out_num, in_num > 0,
- false);
+ false, out_gpas);
if (unlikely(!ok)) {
return false;
}
- ok = vhost_svq_vring_write_descs(svq, sgs, in_sg, in_num, false, true);
+ ok = vhost_svq_vring_write_descs(svq, sgs, in_sg, in_num, false, true,
+ in_gpas);
if (unlikely(!ok)) {
return false;
}
@@ -253,12 +270,20 @@ int vhost_svq_add(VhostShadowVirtqueue *svq, const struct
iovec *out_sg,
unsigned qemu_head;
unsigned ndescs = in_num + out_num;
bool ok;
+ hwaddr *in_gpas = NULL;
+ hwaddr *out_gpas = NULL;
if (unlikely(ndescs > vhost_svq_available_slots(svq))) {
return -ENOSPC;
}
- ok = vhost_svq_add_split(svq, out_sg, out_num, in_sg, in_num, &qemu_head);
+ if (elem) {
+ in_gpas = elem->in_xlat_addr;
+ out_gpas = elem->out_xlat_addr;
+ }
+
+ ok = vhost_svq_add_split(svq, out_sg, out_num, in_sg, in_num, &qemu_head,
+ in_gpas, out_gpas);
if (unlikely(!ok)) {
return -EINVAL;
}
--
2.43.5
