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Tsirkin" To: Jason Wang Cc: virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, netdev@vger.kernel.org, xieyongji@bytedance.com, stefanha@redhat.com Subject: Re: [PATCH 2/2] vdpa: vp_vdpa: don't use hard-coded maximum virtqueue size Message-ID: <20210705065534-mutt-send-email-mst@kernel.org> References: <20210705071910.31965-1-jasowang@redhat.com> <20210705071910.31965-2-jasowang@redhat.com> <20210705032602-mutt-send-email-mst@kernel.org> <02139c5f-92c5-eda6-8d2d-8e1b6ac70f3e@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <02139c5f-92c5-eda6-8d2d-8e1b6ac70f3e@redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 05, 2021 at 03:29:47PM +0800, Jason Wang wrote: > > 在 2021/7/5 下午3:26, Michael S. Tsirkin 写道: > > On Mon, Jul 05, 2021 at 03:19:10PM +0800, Jason Wang wrote: > > > This patch switch to read virtqueue size from the capability instead > > > of depending on the hardcoded value. This allows the per virtqueue > > > size could be advertised. > > > > > > Signed-off-by: Jason Wang > > So let's add an ioctl for this? It's really a bug we don't.. > > > As explained in patch 1. Qemu doesn't use VHOST_VDPA_GET_VRING_NUM actually. > Instead it checks the result VHOST_VDPA_SET_VRING_NUM. > > So I change VHOST_VDPA_GET_VRING_NUM to return the minimal size of all the > virtqueues. > > If you wish we can add a VHOST_VDPA_GET_VRING_NUM2, but I'm not sure it will > have a user or not. > > Thanks Question is how do we know returning the minimal and not e.g. the max size is the right thing to do? > > > > > > --- > > > drivers/vdpa/virtio_pci/vp_vdpa.c | 6 ++++-- > > > 1 file changed, 4 insertions(+), 2 deletions(-) > > > > > > diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c b/drivers/vdpa/virtio_pci/vp_vdpa.c > > > index 2926641fb586..198f7076e4d9 100644 > > > --- a/drivers/vdpa/virtio_pci/vp_vdpa.c > > > +++ b/drivers/vdpa/virtio_pci/vp_vdpa.c > > > @@ -18,7 +18,6 @@ > > > #include > > > #include > > > -#define VP_VDPA_QUEUE_MAX 256 > > > #define VP_VDPA_DRIVER_NAME "vp_vdpa" > > > #define VP_VDPA_NAME_SIZE 256 > > > @@ -197,7 +196,10 @@ static void vp_vdpa_set_status(struct vdpa_device *vdpa, u8 status) > > > static u16 vp_vdpa_get_vq_num_max(struct vdpa_device *vdpa, u16 qid) > > > { > > > - return VP_VDPA_QUEUE_MAX; > > > + struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa); > > > + struct virtio_pci_modern_device *mdev = &vp_vdpa->mdev; > > > + > > > + return vp_modern_get_queue_size(mdev, qid); > > > } > > > static int vp_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 qid, > > > -- > > > 2.25.1