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References: <20231219180858.120898-1-dtatulea@nvidia.com> <20231219180858.120898-15-dtatulea@nvidia.com>
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From: Jason Wang <jasowang@redhat.com>
Date: Wed, 20 Dec 2023 11:47:08 +0800
Message-ID: <CACGkMEtMkjORddUC4x+O9JsDevQBpo0KiJu1XCcvxgKgqfXuGQ@mail.gmail.com>
Subject: Re: [PATCH vhost v4 14/15] vdpa/mlx5: Introduce reference counting to mrs
To: Dragos Tatulea <dtatulea@nvidia.com>
Cc: "Michael S . Tsirkin" <mst@redhat.com>, Eugenio Perez Martin <eperezma@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 Wed, Dec 20, 2023 at 2:10=E2=80=AFAM Dragos Tatulea <dtatulea@nvidia.com=
> wrote:
>
> Deleting the old mr during mr update (.set_map) and then modifying the
> vqs with the new mr is not a good flow for firmware. The firmware
> expects that mkeys are deleted after there are no more vqs referencing
> them.
>
> Introduce reference counting for mrs to fix this. It is the only way to
> make sure that mkeys are not in use by vqs.
>
> An mr reference is taken when the mr is associated to the mr asid table
> and when the mr is linked to the vq on create/modify. The reference is
> released when the mkey is unlinked from the vq (trough modify/destroy)
> and from the mr asid table.
>
> To make things consistent, get rid of mlx5_vdpa_destroy_mr and use
> get/put semantics everywhere.
>
> Reviewed-by: Gal Pressman <gal@nvidia.com>
> Acked-by: Eugenio P=C3=A9rez <eperezma@redhat.com>
> Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
> ---

Acked-by: Jason Wang <jasowang@redhat.com>

Thanks