Michael S. Tsirkin
2023-Oct-30 15:57 UTC
[PATCH V2 vfio 5/9] virtio-pci: Initialize the supported admin commands
On Mon, Oct 30, 2023 at 05:27:50PM +0200, Yishai Hadas wrote:> On 29/10/2023 22:17, Michael S. Tsirkin wrote: > > On Sun, Oct 29, 2023 at 05:59:48PM +0200, Yishai Hadas wrote: > > > Initialize the supported admin commands upon activating the admin queue. > > > > > > The supported commands are saved as part of the admin queue context, it > > > will be used by the next patches from this series. > > > > > > Note: > > > As we don't want to let upper layers to execute admin commands before > > > that this initialization step was completed, we set ref count to 1 only > > > post of that flow and use a non ref counted version command for this > > > internal flow. > > > > > > Signed-off-by: Yishai Hadas <yishaih at nvidia.com> > > > --- > > > drivers/virtio/virtio_pci_common.h | 1 + > > > drivers/virtio/virtio_pci_modern.c | 77 +++++++++++++++++++++++++++++- > > > 2 files changed, 77 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/virtio/virtio_pci_common.h b/drivers/virtio/virtio_pci_common.h > > > index a21b9ba01a60..9e07e556a51a 100644 > > > --- a/drivers/virtio/virtio_pci_common.h > > > +++ b/drivers/virtio/virtio_pci_common.h > > > @@ -46,6 +46,7 @@ struct virtio_pci_admin_vq { > > > struct virtio_pci_vq_info info; > > > struct completion flush_done; > > > refcount_t refcount; > > > + u64 supported_cmds; > > > /* Name of the admin queue: avq.$index. */ > > > char name[10]; > > > u16 vq_index; > > > diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c > > > index ccd7a4d9f57f..25e27aa79cab 100644 > > > --- a/drivers/virtio/virtio_pci_modern.c > > > +++ b/drivers/virtio/virtio_pci_modern.c > > > @@ -19,6 +19,9 @@ > > > #define VIRTIO_RING_NO_LEGACY > > > #include "virtio_pci_common.h" > > > +static int vp_modern_admin_cmd_exec(struct virtio_device *vdev, > > > + struct virtio_admin_cmd *cmd); > > > + > > I don't much like forward declarations. Just order functions sensibly > > and they will not be needed. > > OK, will be part of V3. > > > > > > static u64 vp_get_features(struct virtio_device *vdev) > > > { > > > struct virtio_pci_device *vp_dev = to_vp_device(vdev); > > > @@ -59,6 +62,42 @@ vp_modern_avq_set_abort(struct virtio_pci_admin_vq *admin_vq, bool abort) > > > WRITE_ONCE(admin_vq->abort, abort); > > > } > > > +static void virtio_pci_admin_init_cmd_list(struct virtio_device *virtio_dev) > > > +{ > > > + struct virtio_pci_device *vp_dev = to_vp_device(virtio_dev); > > > + struct virtio_admin_cmd cmd = {}; > > > + struct scatterlist result_sg; > > > + struct scatterlist data_sg; > > > + __le64 *data; > > > + int ret; > > > + > > > + data = kzalloc(sizeof(*data), GFP_KERNEL); > > > + if (!data) > > > + return; > > > + > > > + sg_init_one(&result_sg, data, sizeof(*data)); > > > + cmd.opcode = cpu_to_le16(VIRTIO_ADMIN_CMD_LIST_QUERY); > > > + cmd.group_type = cpu_to_le16(VIRTIO_ADMIN_GROUP_TYPE_SRIOV); > > > + cmd.result_sg = &result_sg; > > > + > > > + ret = vp_modern_admin_cmd_exec(virtio_dev, &cmd); > > > + if (ret) > > > + goto end; > > > + > > > + sg_init_one(&data_sg, data, sizeof(*data)); > > > + cmd.opcode = cpu_to_le16(VIRTIO_ADMIN_CMD_LIST_USE); > > > + cmd.data_sg = &data_sg; > > > + cmd.result_sg = NULL; > > > + > > > + ret = vp_modern_admin_cmd_exec(virtio_dev, &cmd); > > > + if (ret) > > > + goto end; > > > + > > > + vp_dev->admin_vq.supported_cmds = le64_to_cpu(*data); > > > +end: > > > + kfree(data); > > > +} > > > + > > > static void vp_modern_avq_activate(struct virtio_device *vdev) > > > { > > > struct virtio_pci_device *vp_dev = to_vp_device(vdev); > > > @@ -67,6 +106,7 @@ static void vp_modern_avq_activate(struct virtio_device *vdev) > > > if (!virtio_has_feature(vdev, VIRTIO_F_ADMIN_VQ)) > > > return; > > > + virtio_pci_admin_init_cmd_list(vdev); > > > init_completion(&admin_vq->flush_done); > > > refcount_set(&admin_vq->refcount, 1); > > > vp_modern_avq_set_abort(admin_vq, false); > > > @@ -562,6 +602,35 @@ static bool vp_get_shm_region(struct virtio_device *vdev, > > > return true; > > > } > > > +static int __virtqueue_exec_admin_cmd(struct virtio_pci_admin_vq *admin_vq, > > > + struct scatterlist **sgs, > > > + unsigned int out_num, > > > + unsigned int in_num, > > > + void *data, > > > + gfp_t gfp) > > > +{ > > > + struct virtqueue *vq; > > > + int ret, len; > > > + > > > + vq = admin_vq->info.vq; > > > + > > > + ret = virtqueue_add_sgs(vq, sgs, out_num, in_num, data, gfp); > > > + if (ret < 0) > > > + return ret; > > > + > > > + if (unlikely(!virtqueue_kick(vq))) > > > + return -EIO; > > > + > > > + while (!virtqueue_get_buf(vq, &len) && > > > + !virtqueue_is_broken(vq)) > > > + cpu_relax(); > > > + > > > + if (virtqueue_is_broken(vq)) > > > + return -EIO; > > > + > > > + return 0; > > > +} > > > + > > > > This is tolerable I guess but it might pin the CPU for a long time. > > The difficulty is handling suprize removal well which we currently > > don't do with interrupts. I would say it's ok as is but add > > a TODO comments along the lines of /* TODO: use interrupts once these virtqueue_is_broken */ > > I assume that you asked for adding the below comment before the while loop: > /* TODO use interrupts to reduce cpu cycles in the future */ > > Right ? > > YishaiWell I wrote what I meant. in the future is redundant - everyone knows we can't change the past.> > > > > static int virtqueue_exec_admin_cmd(struct virtio_pci_admin_vq *admin_vq, > > > struct scatterlist **sgs, > > > unsigned int out_num, > > > @@ -653,7 +722,13 @@ static int vp_modern_admin_cmd_exec(struct virtio_device *vdev, > > > in_num++; > > > } > > > - ret = virtqueue_exec_admin_cmd(&vp_dev->admin_vq, sgs, > > > + if (cmd->opcode == VIRTIO_ADMIN_CMD_LIST_QUERY || > > > + cmd->opcode == VIRTIO_ADMIN_CMD_LIST_USE) > > > + ret = __virtqueue_exec_admin_cmd(&vp_dev->admin_vq, sgs, > > > + out_num, in_num, > > > + sgs, GFP_KERNEL); > > > + else > > > + ret = virtqueue_exec_admin_cmd(&vp_dev->admin_vq, sgs, > > > out_num, in_num, > > > sgs, GFP_KERNEL); > > > if (ret) { > > > -- > > > 2.27.0 >
Yishai Hadas
2023-Oct-30 16:06 UTC
[PATCH V2 vfio 5/9] virtio-pci: Initialize the supported admin commands
On 30/10/2023 17:57, Michael S. Tsirkin wrote:> On Mon, Oct 30, 2023 at 05:27:50PM +0200, Yishai Hadas wrote: >> On 29/10/2023 22:17, Michael S. Tsirkin wrote: >>> On Sun, Oct 29, 2023 at 05:59:48PM +0200, Yishai Hadas wrote: >>>> Initialize the supported admin commands upon activating the admin queue. >>>> >>>> The supported commands are saved as part of the admin queue context, it >>>> will be used by the next patches from this series. >>>> >>>> Note: >>>> As we don't want to let upper layers to execute admin commands before >>>> that this initialization step was completed, we set ref count to 1 only >>>> post of that flow and use a non ref counted version command for this >>>> internal flow. >>>> >>>> Signed-off-by: Yishai Hadas <yishaih at nvidia.com> >>>> --- >>>> drivers/virtio/virtio_pci_common.h | 1 + >>>> drivers/virtio/virtio_pci_modern.c | 77 +++++++++++++++++++++++++++++- >>>> 2 files changed, 77 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/drivers/virtio/virtio_pci_common.h b/drivers/virtio/virtio_pci_common.h >>>> index a21b9ba01a60..9e07e556a51a 100644 >>>> --- a/drivers/virtio/virtio_pci_common.h >>>> +++ b/drivers/virtio/virtio_pci_common.h >>>> @@ -46,6 +46,7 @@ struct virtio_pci_admin_vq { >>>> struct virtio_pci_vq_info info; >>>> struct completion flush_done; >>>> refcount_t refcount; >>>> + u64 supported_cmds; >>>> /* Name of the admin queue: avq.$index. */ >>>> char name[10]; >>>> u16 vq_index; >>>> diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c >>>> index ccd7a4d9f57f..25e27aa79cab 100644 >>>> --- a/drivers/virtio/virtio_pci_modern.c >>>> +++ b/drivers/virtio/virtio_pci_modern.c >>>> @@ -19,6 +19,9 @@ >>>> #define VIRTIO_RING_NO_LEGACY >>>> #include "virtio_pci_common.h" >>>> +static int vp_modern_admin_cmd_exec(struct virtio_device *vdev, >>>> + struct virtio_admin_cmd *cmd); >>>> + >>> I don't much like forward declarations. Just order functions sensibly >>> and they will not be needed. >> OK, will be part of V3. >> >>>> static u64 vp_get_features(struct virtio_device *vdev) >>>> { >>>> struct virtio_pci_device *vp_dev = to_vp_device(vdev); >>>> @@ -59,6 +62,42 @@ vp_modern_avq_set_abort(struct virtio_pci_admin_vq *admin_vq, bool abort) >>>> WRITE_ONCE(admin_vq->abort, abort); >>>> } >>>> +static void virtio_pci_admin_init_cmd_list(struct virtio_device *virtio_dev) >>>> +{ >>>> + struct virtio_pci_device *vp_dev = to_vp_device(virtio_dev); >>>> + struct virtio_admin_cmd cmd = {}; >>>> + struct scatterlist result_sg; >>>> + struct scatterlist data_sg; >>>> + __le64 *data; >>>> + int ret; >>>> + >>>> + data = kzalloc(sizeof(*data), GFP_KERNEL); >>>> + if (!data) >>>> + return; >>>> + >>>> + sg_init_one(&result_sg, data, sizeof(*data)); >>>> + cmd.opcode = cpu_to_le16(VIRTIO_ADMIN_CMD_LIST_QUERY); >>>> + cmd.group_type = cpu_to_le16(VIRTIO_ADMIN_GROUP_TYPE_SRIOV); >>>> + cmd.result_sg = &result_sg; >>>> + >>>> + ret = vp_modern_admin_cmd_exec(virtio_dev, &cmd); >>>> + if (ret) >>>> + goto end; >>>> + >>>> + sg_init_one(&data_sg, data, sizeof(*data)); >>>> + cmd.opcode = cpu_to_le16(VIRTIO_ADMIN_CMD_LIST_USE); >>>> + cmd.data_sg = &data_sg; >>>> + cmd.result_sg = NULL; >>>> + >>>> + ret = vp_modern_admin_cmd_exec(virtio_dev, &cmd); >>>> + if (ret) >>>> + goto end; >>>> + >>>> + vp_dev->admin_vq.supported_cmds = le64_to_cpu(*data); >>>> +end: >>>> + kfree(data); >>>> +} >>>> + >>>> static void vp_modern_avq_activate(struct virtio_device *vdev) >>>> { >>>> struct virtio_pci_device *vp_dev = to_vp_device(vdev); >>>> @@ -67,6 +106,7 @@ static void vp_modern_avq_activate(struct virtio_device *vdev) >>>> if (!virtio_has_feature(vdev, VIRTIO_F_ADMIN_VQ)) >>>> return; >>>> + virtio_pci_admin_init_cmd_list(vdev); >>>> init_completion(&admin_vq->flush_done); >>>> refcount_set(&admin_vq->refcount, 1); >>>> vp_modern_avq_set_abort(admin_vq, false); >>>> @@ -562,6 +602,35 @@ static bool vp_get_shm_region(struct virtio_device *vdev, >>>> return true; >>>> } >>>> +static int __virtqueue_exec_admin_cmd(struct virtio_pci_admin_vq *admin_vq, >>>> + struct scatterlist **sgs, >>>> + unsigned int out_num, >>>> + unsigned int in_num, >>>> + void *data, >>>> + gfp_t gfp) >>>> +{ >>>> + struct virtqueue *vq; >>>> + int ret, len; >>>> + >>>> + vq = admin_vq->info.vq; >>>> + >>>> + ret = virtqueue_add_sgs(vq, sgs, out_num, in_num, data, gfp); >>>> + if (ret < 0) >>>> + return ret; >>>> + >>>> + if (unlikely(!virtqueue_kick(vq))) >>>> + return -EIO; >>>> + >>>> + while (!virtqueue_get_buf(vq, &len) && >>>> + !virtqueue_is_broken(vq)) >>>> + cpu_relax(); >>>> + >>>> + if (virtqueue_is_broken(vq)) >>>> + return -EIO; >>>> + >>>> + return 0; >>>> +} >>>> + >>> This is tolerable I guess but it might pin the CPU for a long time. >>> The difficulty is handling suprize removal well which we currently >>> don't do with interrupts. I would say it's ok as is but add >>> a TODO comments along the lines of /* TODO: use interrupts once these virtqueue_is_broken */ >> I assume that you asked for adding the below comment before the while loop: >> /* TODO use interrupts to reduce cpu cycles in the future */ >> >> Right ? >> >> Yishai > Well I wrote what I meant. in the future is redundant - everyone knows > we can't change the past.I agree, no need for 'in the future'. However, in your suggestion you mentioned? "once these virtqueue_is_broken". What does that mean in current polling mode ? Yishai> >>>> static int virtqueue_exec_admin_cmd(struct virtio_pci_admin_vq *admin_vq, >>>> struct scatterlist **sgs, >>>> unsigned int out_num, >>>> @@ -653,7 +722,13 @@ static int vp_modern_admin_cmd_exec(struct virtio_device *vdev, >>>> in_num++; >>>> } >>>> - ret = virtqueue_exec_admin_cmd(&vp_dev->admin_vq, sgs, >>>> + if (cmd->opcode == VIRTIO_ADMIN_CMD_LIST_QUERY || >>>> + cmd->opcode == VIRTIO_ADMIN_CMD_LIST_USE) >>>> + ret = __virtqueue_exec_admin_cmd(&vp_dev->admin_vq, sgs, >>>> + out_num, in_num, >>>> + sgs, GFP_KERNEL); >>>> + else >>>> + ret = virtqueue_exec_admin_cmd(&vp_dev->admin_vq, sgs, >>>> out_num, in_num, >>>> sgs, GFP_KERNEL); >>>> if (ret) { >>>> -- >>>> 2.27.0