Stefano Garzarella
2023-Jan-13 10:11 UTC
[PATCH v6 2/4] vhost-vdpa: Introduce RESUME backend feature bit
On Tue, Jan 03, 2023 at 11:51:06AM +0100, sebastien.boeuf at intel.com wrote:>From: Sebastien Boeuf <sebastien.boeuf at intel.com> > >Userspace knows if the device can be resumed or not by checking this >feature bit. > >It's only exposed if the vdpa driver backend implements the resume() >operation callback. Userspace trying to negotiate this feature when it >hasn't been exposed will result in an error. > >Acked-by: Jason Wang <jasowang at redhat.com> >Signed-off-by: Sebastien Boeuf <sebastien.boeuf at intel.com> >--- > drivers/vhost/vdpa.c | 16 +++++++++++++++- > include/uapi/linux/vhost_types.h | 2 ++ > 2 files changed, 17 insertions(+), 1 deletion(-) > >diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c >index 166044642fd5..833617d00ef6 100644 >--- a/drivers/vhost/vdpa.c >+++ b/drivers/vhost/vdpa.c >@@ -355,6 +355,14 @@ static bool vhost_vdpa_can_suspend(const struct vhost_vdpa *v) > return ops->suspend; > } > >+static bool vhost_vdpa_can_resume(const struct vhost_vdpa *v) >+{ >+ struct vdpa_device *vdpa = v->vdpa; >+ const struct vdpa_config_ops *ops = vdpa->config; >+ >+ return ops->resume; >+} >+ > static long vhost_vdpa_get_features(struct vhost_vdpa *v, u64 __user *featurep) > { > struct vdpa_device *vdpa = v->vdpa; >@@ -602,11 +610,15 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep, > if (copy_from_user(&features, featurep, sizeof(features))) > return -EFAULT; > if (features & ~(VHOST_VDPA_BACKEND_FEATURES | >- BIT_ULL(VHOST_BACKEND_F_SUSPEND))) >+ BIT_ULL(VHOST_BACKEND_F_SUSPEND) | >+ BIT_ULL(VHOST_BACKEND_F_RESUME))) > return -EOPNOTSUPP; > if ((features & BIT_ULL(VHOST_BACKEND_F_SUSPEND)) && > !vhost_vdpa_can_suspend(v)) > return -EOPNOTSUPP; >+ if ((features & BIT_ULL(VHOST_BACKEND_F_RESUME)) && >+ !vhost_vdpa_can_resume(v)) >+ return -EOPNOTSUPP;Not for this patch, but I'd like to refactor this code a bit to fill a `backend_features` field in vhost_vdpa during the vhost_vdpa_probe(), so we don't need to change this code or the VHOST_GET_BACKEND_FEATURES for every new backend feature. I'll send a patch. This LGTM: Reviewed-by: Stefano Garzarella <sgarzare at redhat.com>> vhost_set_backend_features(&v->vdev, features); > return 0; > } >@@ -658,6 +670,8 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep, > features = VHOST_VDPA_BACKEND_FEATURES; > if (vhost_vdpa_can_suspend(v)) > features |= BIT_ULL(VHOST_BACKEND_F_SUSPEND); >+ if (vhost_vdpa_can_resume(v)) >+ features |= BIT_ULL(VHOST_BACKEND_F_RESUME); > if (copy_to_user(featurep, &features, sizeof(features))) > r = -EFAULT; > break; >diff --git a/include/uapi/linux/vhost_types.h b/include/uapi/linux/vhost_types.h >index 53601ce2c20a..c5690a8992d8 100644 >--- a/include/uapi/linux/vhost_types.h >+++ b/include/uapi/linux/vhost_types.h >@@ -163,5 +163,7 @@ struct vhost_vdpa_iova_range { > #define VHOST_BACKEND_F_IOTLB_ASID 0x3 > /* Device can be suspended */ > #define VHOST_BACKEND_F_SUSPEND 0x4 >+/* Device can be resumed */ >+#define VHOST_BACKEND_F_RESUME 0x5 > > #endif >-- >2.37.2 > >--------------------------------------------------------------------- >Intel Corporation SAS (French simplified joint stock company) >Registered headquarters: "Les Montalets"- 2, rue de Paris, >92196 Meudon Cedex, France >Registration Number: 302 456 199 R.C.S. NANTERRE >Capital: 5 208 026.16 Euros > >This e-mail and any attachments may contain confidential material for >the sole use of the intended recipient(s). Any review or distribution >by others is strictly prohibited. If you are not the intended >recipient, please contact the sender and delete all copies. >