Received-SPF: softfail (google.com: domain of transitioning linux-kernel-owner@vger.kernel.org does not designate 23.128.96.19 as permitted sender) client-ip=23.128.96.19;
Date:   Mon, 23 May 2022 10:27:38 +0200
From:   Stefano Garzarella <sgarzare@redhat.com>
To:     Eugenio =?utf-8?B?UMOpcmV6?= <eperezma@redhat.com>
Cc:     virtualization@lists.linux-foundation.org,
        Jason Wang <jasowang@redhat.com>, kvm@vger.kernel.org,
        "Michael S. Tsirkin" <mst@redhat.com>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, Longpeng <longpeng2@huawei.com>,
        Zhu Lingshan <lingshan.zhu@intel.com>, martinh@xilinx.com,
        hanand@xilinx.com, Si-Wei Liu <si-wei.liu@oracle.com>,
        dinang@xilinx.com, Eli Cohen <elic@nvidia.com>, lvivier@redhat.com,
        pabloc@xilinx.com, gautam.dawar@amd.com,
        Xie Yongji <xieyongji@bytedance.com>, habetsm.xilinx@gmail.com,
        Christophe JAILLET <christophe.jaillet@wanadoo.fr>,
        tanuj.kamde@amd.com, Wu Zongyong <wuzongyong@linux.alibaba.com>,
        martinpo@xilinx.com, lulu@redhat.com, ecree.xilinx@gmail.com,
        Parav Pandit <parav@nvidia.com>,
        Dan Carpenter <dan.carpenter@oracle.com>,
        Zhang Min <zhang.min9@zte.com.cn>
Subject: Re: [PATCH 4/4] vdpa_sim: Implement stop vdpa op
Message-ID: <20220523082738.h7lvwkysnqhynf37@sgarzare-redhat>
References: <20220520172325.980884-1-eperezma@redhat.com>
 <20220520172325.980884-5-eperezma@redhat.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1; format=flowed
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <20220520172325.980884-5-eperezma@redhat.com>
Precedence: bulk

On Fri, May 20, 2022 at 07:23:25PM +0200, Eugenio P?rez wrote:
>Implement stop operation for vdpa_sim devices, so vhost-vdpa will offer
>that backend feature and userspace can effectively stop the device.
>
>This is a must before get virtqueue indexes (base) for live migration,
>since the device could modify them after userland gets them. There are
>individual ways to perform that action for some devices
>(VHOST_NET_SET_BACKEND, VHOST_VSOCK_SET_RUNNING, ...) but there was no
>way to perform it for any vhost device (and, in particular, vhost-vdpa).
>
>Signed-off-by: Eugenio P?rez <eperezma@redhat.com>
>---
> drivers/vdpa/vdpa_sim/vdpa_sim.c     | 21 +++++++++++++++++++++
> drivers/vdpa/vdpa_sim/vdpa_sim.h     |  1 +
> drivers/vdpa/vdpa_sim/vdpa_sim_net.c |  3 +++
> 3 files changed, 25 insertions(+)
>
>diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
>index 50d721072beb..0515cf314bed 100644
>--- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
>+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
>@@ -107,6 +107,7 @@ static void vdpasim_do_reset(struct vdpasim *vdpasim)
> 	for (i = 0; i < vdpasim->dev_attr.nas; i++)
> 		vhost_iotlb_reset(&vdpasim->iommu[i]);
>
>+	vdpasim->running = true;
> 	spin_unlock(&vdpasim->iommu_lock);
>
> 	vdpasim->features = 0;
>@@ -505,6 +506,24 @@ static int vdpasim_reset(struct vdpa_device *vdpa)
> 	return 0;
> }
>
>+static int vdpasim_stop(struct vdpa_device *vdpa, bool stop)
>+{
>+	struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
>+	int i;
>+
>+	spin_lock(&vdpasim->lock);
>+	vdpasim->running = !stop;
>+	if (vdpasim->running) {
>+		/* Check for missed buffers */
>+		for (i = 0; i < vdpasim->dev_attr.nvqs; ++i)
>+			vdpasim_kick_vq(vdpa, i);
>+
>+	}
>+	spin_unlock(&vdpasim->lock);
>+
>+	return 0;
>+}
>+
> static size_t vdpasim_get_config_size(struct vdpa_device *vdpa)
> {
> 	struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
>@@ -694,6 +713,7 @@ static const struct vdpa_config_ops vdpasim_config_ops = {
> 	.get_status             = vdpasim_get_status,
> 	.set_status             = vdpasim_set_status,
> 	.reset			= vdpasim_reset,
>+	.stop			= vdpasim_stop,
> 	.get_config_size        = vdpasim_get_config_size,
> 	.get_config             = vdpasim_get_config,
> 	.set_config             = vdpasim_set_config,
>@@ -726,6 +746,7 @@ static const struct vdpa_config_ops vdpasim_batch_config_ops = {
> 	.get_status             = vdpasim_get_status,
> 	.set_status             = vdpasim_set_status,
> 	.reset			= vdpasim_reset,
>+	.stop			= vdpasim_stop,
> 	.get_config_size        = vdpasim_get_config_size,
> 	.get_config             = vdpasim_get_config,
> 	.set_config             = vdpasim_set_config,
>diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.h b/drivers/vdpa/vdpa_sim/vdpa_sim.h
>index 622782e92239..061986f30911 100644
>--- a/drivers/vdpa/vdpa_sim/vdpa_sim.h
>+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.h
>@@ -66,6 +66,7 @@ struct vdpasim {
> 	u32 generation;
> 	u64 features;
> 	u32 groups;
>+	bool running;
> 	/* spinlock to synchronize iommu table */
> 	spinlock_t iommu_lock;
> };
>diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_net.c b/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
>index 5125976a4df8..886449e88502 100644
>--- a/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
>+++ b/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
>@@ -154,6 +154,9 @@ static void vdpasim_net_work(struct work_struct *work)
>
> 	spin_lock(&vdpasim->lock);
>
>+	if (!vdpasim->running)
>+		goto out;
>+

It would be nice to do the same for vdpa_sim_blk as well.

Thanks,
Stefano