From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:32808) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dSdjN-0004hn-Nu for qemu-devel@nongnu.org; Wed, 05 Jul 2017 02:24:11 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dSdjI-0004kx-RI for qemu-devel@nongnu.org; Wed, 05 Jul 2017 02:24:09 -0400 Date: Wed, 5 Jul 2017 14:23:59 +0800 From: Fam Zheng Message-ID: <20170705062359.GC29382@lemon.lan> References: <1499170866-9068-1-git-send-email-jasowang@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1499170866-9068-1-git-send-email-jasowang@redhat.com> Subject: Re: [Qemu-devel] [PATCH] virtio-scsi: finalize IOMMU support List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: mst@redhat.com, pbonzini@redhat.com, Jason Wang Cc: qemu-devel@nongnu.org, qemu-stable@nongnu.org On Tue, 07/04 20:21, Jason Wang wrote: > After converting to use DMA api for virtio devices, we should use > dma_as instead of address_space_memory. Otherwise it won't work if > IOMMU is enabled. > > Fixes: commit 8607f5c3072c ("virtio: convert to use DMA api") > Cc: qemu-stable@nongnu.org > Signed-off-by: Jason Wang > --- > hw/scsi/virtio-scsi.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c > index f46f06d..d076fe7 100644 > --- a/hw/scsi/virtio-scsi.c > +++ b/hw/scsi/virtio-scsi.c > @@ -43,12 +43,13 @@ static inline SCSIDevice *virtio_scsi_device_find(VirtIOSCSI *s, uint8_t *lun) > > void virtio_scsi_init_req(VirtIOSCSI *s, VirtQueue *vq, VirtIOSCSIReq *req) > { > + VirtIODevice *vdev = VIRTIO_DEVICE(s); > const size_t zero_skip = > offsetof(VirtIOSCSIReq, resp_iov) + sizeof(req->resp_iov); > > req->vq = vq; > req->dev = s; > - qemu_sglist_init(&req->qsgl, DEVICE(s), 8, &address_space_memory); > + qemu_sglist_init(&req->qsgl, DEVICE(s), 8, vdev->dma_as); Not related to this patch, but is our vIOMMU iotlb implementation safe for data plane (both virtio-blk and virtio-scsi)? There we don't have BQL to synchronize between IOVA lookup and update, which means threads can race when accessing the iotlb GHashTable. Did I overlook a synchronization mechanism? Or is it missing? Paolo, MST? Fam > qemu_iovec_init(&req->resp_iov, 1); > memset((uint8_t *)req + zero_skip, 0, sizeof(*req) - zero_skip); > } > -- > 2.7.4 > >