Re: [RFC 5/5] block/nvme: Align iov's va and size on host page size

[Philippe Mathieu-Daudé]

On 10/15/20 1:52 PM, Eric Auger wrote:

Make sure iov's va and size are properly aligned on the host page
size.

Signed-off-by: Eric Auger <eric.au...@redhat.com>

Reviewed-by: Philippe Mathieu-Daudé <phi...@redhat.com>

---
  block/nvme.c | 13 +++++++------
  1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/block/nvme.c b/block/nvme.c
index be8ec48bf2..45807ed110 100644
--- a/block/nvme.c
+++ b/block/nvme.c
@@ -978,11 +978,12 @@ static coroutine_fn int 
nvme_cmd_map_qiov(BlockDriverState *bs, NvmeCmd *cmd,
      for (i = 0; i < qiov->niov; ++i) {
          bool retry = true;
          uint64_t iova;
+        size_t len = QEMU_ALIGN_UP(qiov->iov[i].iov_len,
+                                   qemu_real_host_page_size);
  try_map:
          r = qemu_vfio_dma_map(s->vfio,
                                qiov->iov[i].iov_base,
-                              qiov->iov[i].iov_len,
-                              true, &iova);
+                              len, true, &iova);
          if (r == -ENOMEM && retry) {
              retry = false;
              trace_nvme_dma_flush_queue_wait(s);
@@ -1126,8 +1127,8 @@ static inline bool nvme_qiov_aligned(BlockDriverState *bs,
      BDRVNVMeState *s = bs->opaque;

for (i = 0; i < qiov->niov; ++i) {

-        if (!QEMU_PTR_IS_ALIGNED(qiov->iov[i].iov_base, s->page_size) ||
-            !QEMU_IS_ALIGNED(qiov->iov[i].iov_len, s->page_size)) {
+        if (!QEMU_PTR_IS_ALIGNED(qiov->iov[i].iov_base, 
qemu_real_host_page_size) ||
+            !QEMU_IS_ALIGNED(qiov->iov[i].iov_len, qemu_real_host_page_size)) {
              trace_nvme_qiov_unaligned(qiov, i, qiov->iov[i].iov_base,
                                        qiov->iov[i].iov_len, s->page_size);
              return false;
@@ -1143,7 +1144,7 @@ static int nvme_co_prw(BlockDriverState *bs, uint64_t 
offset, uint64_t bytes,
      int r;
      uint8_t *buf = NULL;
      QEMUIOVector local_qiov;
-
+    size_t len = QEMU_ALIGN_UP(bytes, qemu_real_host_page_size);
      assert(QEMU_IS_ALIGNED(offset, s->page_size));
      assert(QEMU_IS_ALIGNED(bytes, s->page_size));
      assert(bytes <= s->max_transfer);
@@ -1151,7 +1152,7 @@ static int nvme_co_prw(BlockDriverState *bs, uint64_t 
offset, uint64_t bytes,
          return nvme_co_prw_aligned(bs, offset, bytes, qiov, is_write, flags);
      }
      trace_nvme_prw_buffered(s, offset, bytes, qiov->niov, is_write);
-    buf = qemu_try_memalign(s->page_size, bytes);
+    buf = qemu_try_memalign(qemu_real_host_page_size, len);

if (!buf) {

          return -ENOMEM;