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@xxxxxxxxxx> --- 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
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
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