Forward these two calls to the IOVA manager.

Signed-off-by: Fam Zheng <famz@redhat.com>
---
 block/nvme.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/block/nvme.c b/block/nvme.c
index eb999a1..7913017 100644
--- a/block/nvme.c
+++ b/block/nvme.c
@@ -1056,6 +1056,20 @@ static void nvme_aio_unplug(BlockDriverState *bs)
     }
 }
 
+static void nvme_dma_map(BlockDriverState *bs, void *host, size_t size)
+{
+    BDRVNVMeState *s = bs->opaque;
+
+    nvme_vfio_dma_map(s->vfio, host, size, false, NULL);
+}
+
+static void nvme_dma_unmap(BlockDriverState *bs, void *host)
+{
+    BDRVNVMeState *s = bs->opaque;
+
+    nvme_vfio_dma_unmap(s->vfio, host);
+}
+
 static BlockDriver bdrv_nvme = {
     .format_name              = "nvme",
     .protocol_name            = "nvme",
@@ -1081,6 +1095,9 @@ static BlockDriver bdrv_nvme = {
 
     .bdrv_io_plug             = nvme_aio_plug,
     .bdrv_io_unplug           = nvme_aio_unplug,
+
+    .bdrv_dma_map             = nvme_dma_map,
+    .bdrv_dma_unmap           = nvme_dma_unmap,
 };
 
 static void bdrv_nvme_init(void)
-- 
2.9.4

On Wed, Jul 05, 2017 at 09:36:33PM +0800, Fam Zheng wrote:
> +static void nvme_dma_map(BlockDriverState *bs, void *host, size_t size)
> +{
> +    BDRVNVMeState *s = bs->opaque;
> +
> +    nvme_vfio_dma_map(s->vfio, host, size, false, NULL);

Since temporary=false repeated calls to map/unmap will run out of space
and stop working after some time?

On 10/07/2017 16:59, Stefan Hajnoczi wrote:
>> +static void nvme_dma_map(BlockDriverState *bs, void *host, size_t size)
>> +{
>> +    BDRVNVMeState *s = bs->opaque;
>> +
>> +    nvme_vfio_dma_map(s->vfio, host, size, false, NULL);
> Since temporary=false repeated calls to map/unmap will run out of space
> and stop working after some time?

Yes, the point of bdrv_dma_map/unmap is to add a permanent mapping.
Temporary mappings are only valid inside nvme.c, because the
corresponding iova is not recorded anywhere.  Instead,
bdrv_dma_map/unmap cache the iova just like we do for RAMBlock areas
during system emulation.

The solution is simply not to do that, just like img_bench only calls
map/unmap once.  If it happens, things just become slower as the driver
falls back to temporary mappings.

Paolo

On Mon, Jul 10, 2017 at 05:09:25PM +0200, Paolo Bonzini wrote:
> On 10/07/2017 16:59, Stefan Hajnoczi wrote:
> >> +static void nvme_dma_map(BlockDriverState *bs, void *host, size_t size)
> >> +{
> >> +    BDRVNVMeState *s = bs->opaque;
> >> +
> >> +    nvme_vfio_dma_map(s->vfio, host, size, false, NULL);
> > Since temporary=false repeated calls to map/unmap will run out of space
> > and stop working after some time?
> 
> Yes, the point of bdrv_dma_map/unmap is to add a permanent mapping.
> Temporary mappings are only valid inside nvme.c, because the
> corresponding iova is not recorded anywhere.  Instead,
> bdrv_dma_map/unmap cache the iova just like we do for RAMBlock areas
> during system emulation.
> 
> The solution is simply not to do that, just like img_bench only calls
> map/unmap once.  If it happens, things just become slower as the driver
> falls back to temporary mappings.

The constraints need to be documented.  Someone might try to use
blk_dma_map() and waste time debugging poor performance in the future.

Stefan