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[79.24.227.66]) by smtp.gmail.com with ESMTPSA id z140sm2839639wmc.30.2020.12.09.03.07.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 09 Dec 2020 03:07:47 -0800 (PST) Date: Wed, 9 Dec 2020 12:07:45 +0100 From: Stefano Garzarella To: Jason Wang , "Michael S. Tsirkin" Cc: virtualization@lists.linux-foundation.org, Stefan Hajnoczi , Oren Duer , Laurent Vivier , linux-kernel@vger.kernel.org, Max Gurtovoy , Shahaf Shuler , Eli Cohen Subject: Re: [PATCH v3 13/19] vdpa_sim: add get_config callback in vdpasim_dev_attr Message-ID: <20201209110745.p4ybybanzip2lav3@steredhat> References: <20201203170511.216407-1-sgarzare@redhat.com> <20201203170511.216407-14-sgarzare@redhat.com> <829a5026-a68c-6d02-49ef-f237dcae2460@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <829a5026-a68c-6d02-49ef-f237dcae2460@redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 07, 2020 at 01:29:17PM +0800, Jason Wang wrote: > >On 2020/12/4 上午1:05, Stefano Garzarella wrote: >>The get_config callback can be used by the device to fill the >>config structure. >>The callback will be invoked in vdpasim_get_config() before copying >>bytes into caller buffer. >> >>Move vDPA-net config updates from vdpasim_set_features() in the >>new vdpasim_net_get_config() callback. >> >>Signed-off-by: Stefano Garzarella >>--- >>v3: >>- checked if get_config callback is set before call it >>--- >> drivers/vdpa/vdpa_sim/vdpa_sim.c | 35 +++++++++++++++++++------------- >> 1 file changed, 21 insertions(+), 14 deletions(-) >> >>diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c >>index fe71ed7890e1..f935ade0806b 100644 >>--- a/drivers/vdpa/vdpa_sim/vdpa_sim.c >>+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c >>@@ -60,6 +60,8 @@ struct vdpasim_virtqueue { >> #define VDPASIM_NET_FEATURES (VDPASIM_FEATURES | \ >> (1ULL << VIRTIO_NET_F_MAC)) >>+struct vdpasim; >>+ >> struct vdpasim_dev_attr { >> u64 supported_features; >> size_t config_size; >>@@ -67,6 +69,7 @@ struct vdpasim_dev_attr { >> u32 id; >> work_func_t work_fn; >>+ void (*get_config)(struct vdpasim *vdpasim, void *config); >> }; >> /* State of each vdpasim device */ >>@@ -522,8 +525,6 @@ static u64 vdpasim_get_features(struct vdpa_device *vdpa) >> static int vdpasim_set_features(struct vdpa_device *vdpa, u64 features) >> { >> struct vdpasim *vdpasim = vdpa_to_sim(vdpa); >>- struct virtio_net_config *config = >>- (struct virtio_net_config *)vdpasim->config; >> /* DMA mapping must be done by driver */ >> if (!(features & (1ULL << VIRTIO_F_ACCESS_PLATFORM))) >>@@ -531,16 +532,6 @@ static int vdpasim_set_features(struct vdpa_device *vdpa, u64 features) >> vdpasim->features = features & vdpasim->dev_attr.supported_features; >>- /* We generally only know whether guest is using the legacy interface >>- * here, so generally that's the earliest we can set config fields. >>- * Note: We actually require VIRTIO_F_ACCESS_PLATFORM above which >>- * implies VIRTIO_F_VERSION_1, but let's not try to be clever here. >>- */ >>- >>- config->mtu = cpu_to_vdpasim16(vdpasim, 1500); >>- config->status = cpu_to_vdpasim16(vdpasim, VIRTIO_NET_S_LINK_UP); >>- memcpy(config->mac, macaddr_buf, ETH_ALEN); > > >Patch looks good to me. > >But we need Michael to confirm whether doing moving like this is safe. >I guess what has been done were trying to make sure get_config() fail >before set_features(), but it's not clear to me whether it's useful. IIUC, also looking the QEMU code, the set_features() should be called every time before get_config(), but to be sure, in get_config(), I can check for example if 'vdpasim->features' is not zero (we require VIRTIO_F_ACCESS_PLATFORM set). @Michael any suggestion? Thanks, Stefano > >Thanks > > >>- >> return 0; >> } >>@@ -595,8 +586,13 @@ static void vdpasim_get_config(struct vdpa_device *vdpa, unsigned int offset, >> { >> struct vdpasim *vdpasim = vdpa_to_sim(vdpa); >>- if (offset + len < vdpasim->dev_attr.config_size) >>- memcpy(buf, vdpasim->config + offset, len); >>+ if (offset + len > vdpasim->dev_attr.config_size) >>+ return; >>+ >>+ if (vdpasim->dev_attr.get_config) >>+ vdpasim->dev_attr.get_config(vdpasim, vdpasim->config); >>+ >>+ memcpy(buf, vdpasim->config + offset, len); >> } >> static void vdpasim_set_config(struct vdpa_device *vdpa, unsigned int offset, >>@@ -739,6 +735,16 @@ static const struct vdpa_config_ops vdpasim_batch_config_ops = { >> .free = vdpasim_free, >> }; >>+static void vdpasim_net_get_config(struct vdpasim *vdpasim, void *config) >>+{ >>+ struct virtio_net_config *net_config = >>+ (struct virtio_net_config *)config; >>+ >>+ net_config->mtu = cpu_to_vdpasim16(vdpasim, 1500); >>+ net_config->status = cpu_to_vdpasim16(vdpasim, VIRTIO_NET_S_LINK_UP); >>+ memcpy(net_config->mac, macaddr_buf, ETH_ALEN); >>+} >>+ >> static int __init vdpasim_dev_init(void) >> { >> struct vdpasim_dev_attr dev_attr = {}; >>@@ -747,6 +753,7 @@ static int __init vdpasim_dev_init(void) >> dev_attr.supported_features = VDPASIM_NET_FEATURES; >> dev_attr.nvqs = VDPASIM_VQ_NUM; >> dev_attr.config_size = sizeof(struct virtio_net_config); >>+ dev_attr.get_config = vdpasim_net_get_config; >> dev_attr.work_fn = vdpasim_net_work; >> vdpasim_dev = vdpasim_create(&dev_attr); >