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.auger@redhat.com>

Reviewed-by: Philippe Mathieu-Daudé <philmd@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;