From: "Michael S. Tsirkin" <mst@redhat.com>
To: Eugenio Perez Martin <eperezma@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>,
qemu-devel@nongnu.org, Gautam Dawar <gdawar@xilinx.com>,
Parav Pandit <parav@mellanox.com>,
Zhu Lingshan <lingshan.zhu@intel.com>, Cindy Lu <lulu@redhat.com>,
longpeng2@huawei.com, Eli Cohen <eli@mellanox.com>,
alvaro.karsz@solid-run.com, Lei Yang <leiyang@redhat.com>,
Laurent Vivier <lvivier@redhat.com>
Subject: Re: [PATCH] vhost: accept VIRTIO_F_ORDER_PLATFORM as a valid SVQ feature
Date: Thu, 2 Mar 2023 06:43:29 -0500 [thread overview]
Message-ID: <20230302064234-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <CAJaqyWfpbeoLfe1-GcoR=rtJMg1DGezMe8pjSNPQjBG4BzqMrA@mail.gmail.com>
On Thu, Mar 02, 2023 at 12:30:52PM +0100, Eugenio Perez Martin wrote:
> > You need to pass this to guest. My point is that there is no reason to
> > get it from the kernel driver. QEMU can figure out whether the flag is
> > needed itself.
> >
>
> Ok, I can see now how the HW device does not have all the knowledge to
> offer this flag or not. But I'm not sure how qemu can know either.
>
> If qemu opens /dev/vhost-vdpa-N, how can it know it? It has no way to
> tell if the device is sw or hw as far as I know. Am I missing
> something?
>
> Thanks!
This is what I said earlier. You can safely assume vdpa needs this
flag. Only exception is vduse and we don't care about performance there.
--
MST
next prev parent reply other threads:[~2023-03-02 11:43 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-13 19:19 [PATCH] vhost: accept VIRTIO_F_ORDER_PLATFORM as a valid SVQ feature Eugenio Pérez
2023-02-14 6:31 ` Jason Wang
2023-02-14 7:02 ` Eugenio Perez Martin
2023-02-14 7:50 ` Michael S. Tsirkin
2023-02-14 8:36 ` Eugenio Perez Martin
2023-03-01 21:37 ` Michael S. Tsirkin
2023-03-02 11:30 ` Eugenio Perez Martin
2023-03-02 11:43 ` Michael S. Tsirkin [this message]
2023-03-02 14:47 ` Eugenio Perez Martin
2023-03-02 23:31 ` Michael S. Tsirkin
2023-03-03 9:08 ` Eugenio Perez Martin
2023-03-03 9:16 ` Michael S. Tsirkin
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