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References: <20231219180858.120898-1-dtatulea@nvidia.com> <20231219180858.120898-3-dtatulea@nvidia.com>
In-Reply-To: <20231219180858.120898-3-dtatulea@nvidia.com>
From: Eugenio Perez Martin <eperezma@redhat.com>
Date: Wed, 20 Dec 2023 17:09:24 +0100
Message-ID: <CAJaqyWeOJSne+qfj1pq_bgzML2Hc49MBCQm735fqrRThkeJAyQ@mail.gmail.com>
Subject: Re: [PATCH vhost v4 02/15] vdpa: Add VHOST_BACKEND_F_CHANGEABLE_VQ_ADDR_IN_SUSPEND
 flag
To: Dragos Tatulea <dtatulea@nvidia.com>
Cc: "Michael S . Tsirkin" <mst@redhat.com>, Jason Wang <jasowang@redhat.com>, 
	Si-Wei Liu <si-wei.liu@oracle.com>, Saeed Mahameed <saeedm@nvidia.com>, 
	Leon Romanovsky <leon@kernel.org>, virtualization@lists.linux-foundation.org, 
	Gal Pressman <gal@nvidia.com>, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, 
	Parav Pandit <parav@nvidia.com>, Xuan Zhuo <xuanzhuo@linux.alibaba.com>
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On Tue, Dec 19, 2023 at 7:09=E2=80=AFPM Dragos Tatulea <dtatulea@nvidia.com=
> wrote:
>
> The virtio spec doesn't allow changing virtqueue addresses after
> DRIVER_OK. Some devices do support this operation when the device is
> suspended. The VHOST_BACKEND_F_CHANGEABLE_VQ_ADDR_IN_SUSPEND flag
> advertises this support as a backend features.
>
> Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
> Suggested-by: Eugenio P=C3=A9rez <eperezma@redhat.com>
> ---
>  include/uapi/linux/vhost_types.h | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/include/uapi/linux/vhost_types.h b/include/uapi/linux/vhost_=
types.h
> index d7656908f730..aacd067afc89 100644
> --- a/include/uapi/linux/vhost_types.h
> +++ b/include/uapi/linux/vhost_types.h
> @@ -192,5 +192,9 @@ struct vhost_vdpa_iova_range {
>  #define VHOST_BACKEND_F_DESC_ASID    0x7
>  /* IOTLB don't flush memory mapping across device reset */
>  #define VHOST_BACKEND_F_IOTLB_PERSIST  0x8
> +/* Device supports changing virtqueue addresses when device is suspended
> + * and is in state DRIVER_OK.
> + */
> +#define VHOST_BACKEND_F_CHANGEABLE_VQ_ADDR_IN_SUSPEND  0x9
>

If we go by feature flag,

Acked-by: Eugenio P=C3=A9rez <eperezma@redhat.com>

>  #endif
> --
> 2.43.0
>