[PATCH 06/40] vhost: make svq work with gpa without iova translation

[Si-Wei Liu <si-wei.liu@oracle.com>]

Make vhost_svq_vring_write_descs able to work with GPA directly
without going through iova tree for translation. This will be
needed in the next few patches where the SVQ has dedicated
address space to host its virtqueues. Instead of having to
translate qemu's VA to IOVA via the iova tree, with dedicated
or isolated address space for SVQ descriptors, the IOVA is
exactly same as the guest GPA space where translation would
not be needed any more.

Signed-off-by: Si-Wei Liu <si-wei.liu@oracle.com>
---
 hw/virtio/vhost-shadow-virtqueue.c | 35 +++++++++++++++++++++++------------
 1 file changed, 23 insertions(+), 12 deletions(-)

diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
index fc5f408..97ccd45 100644
--- a/hw/virtio/vhost-shadow-virtqueue.c
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -136,8 +136,8 @@ static bool vhost_svq_translate_addr(const VhostShadowVirtqueue *svq,
  * 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)
+                                        const struct iovec *iovec, hwaddr *addr,
+                                        size_t num, bool more_descs, bool write)
 {
     uint16_t i = svq->free_head, last = svq->free_head;
     unsigned n;
@@ -149,8 +149,15 @@ static bool vhost_svq_vring_write_descs(VhostShadowVirtqueue *svq, hwaddr *sg,
         return true;
     }
 
-    ok = vhost_svq_translate_addr(svq, sg, iovec, num);
-    if (unlikely(!ok)) {
+    if (svq->iova_tree) {
+        ok = vhost_svq_translate_addr(svq, sg, iovec, num);
+        if (unlikely(!ok)) {
+            return false;
+        }
+    } else if (!addr) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "No translation found for vaddr 0x%p\n",
+                      iovec[0].iov_base);
         return false;
     }
 
@@ -161,7 +168,7 @@ static bool vhost_svq_vring_write_descs(VhostShadowVirtqueue *svq, hwaddr *sg,
         } else {
             descs[i].flags = flags;
         }
-        descs[i].addr = cpu_to_le64(sg[n]);
+        descs[i].addr = cpu_to_le64(svq->iova_tree ? sg[n] : addr[n]);
         descs[i].len = cpu_to_le32(iovec[n].iov_len);
 
         last = i;
@@ -173,9 +180,10 @@ 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)
+                                const struct iovec *out_sg, hwaddr *out_addr,
+                                size_t out_num,
+                                const struct iovec *in_sg, hwaddr *in_addr,
+                                size_t in_num, unsigned *head)
 {
     unsigned avail_idx;
     vring_avail_t *avail = svq->vring.avail;
@@ -191,13 +199,14 @@ static bool vhost_svq_add_split(VhostShadowVirtqueue *svq,
         return false;
     }
 
-    ok = vhost_svq_vring_write_descs(svq, sgs, out_sg, out_num, in_num > 0,
-                                     false);
+    ok = vhost_svq_vring_write_descs(svq, sgs, out_sg, out_addr, out_num,
+                                     in_num > 0, false);
     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_addr, in_num,
+                                     false, true);
     if (unlikely(!ok)) {
         return false;
     }
@@ -258,7 +267,9 @@ int vhost_svq_add(VhostShadowVirtqueue *svq, const struct iovec *out_sg,
         return -ENOSPC;
     }
 
-    ok = vhost_svq_add_split(svq, out_sg, out_num, in_sg, in_num, &qemu_head);
+    ok = vhost_svq_add_split(svq, out_sg, elem ? elem->out_addr : NULL,
+                             out_num, in_sg, elem ? elem->in_addr : NULL,
+                             in_num, &qemu_head);
     if (unlikely(!ok)) {
         return -EINVAL;
     }
-- 
1.8.3.1