On Wed, Sep 16, 2026 at 11:10:50PM +0200, Francesco Valla wrote: > There is currently no way to report the VIRTIO_F_VERSION_1 using the > resource table alone, as the per-vdev feature array is limited to 32 > bits. > > Considering that the VirtIO 1.0 specification is now ~10 years old, > always report the VIRTIO_F_VERSION_1 feature, as some drivers depend on > it. > > Signed-off-by: Francesco Valla <[email protected]> > --- > drivers/remoteproc/remoteproc_virtio.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/drivers/remoteproc/remoteproc_virtio.c > b/drivers/remoteproc/remoteproc_virtio.c > index 74e0da970f1d..cfd66d9d1c9e 100644 > --- a/drivers/remoteproc/remoteproc_virtio.c > +++ b/drivers/remoteproc/remoteproc_virtio.c > @@ -249,7 +249,7 @@ static u64 rproc_virtio_get_features(struct virtio_device > *vdev) > > rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset; > > - return rsc->dfeatures; > + return rsc->dfeatures | (1ULL << VIRTIO_F_VERSION_1);
I understand this. > } > > static void rproc_transport_features(struct virtio_device *vdev) > @@ -275,14 +275,16 @@ static int rproc_virtio_finalize_features(struct > virtio_device *vdev) > /* Give virtio_rproc a chance to accept features. */ > rproc_transport_features(vdev); > > - /* Make sure we don't have any features > 32 bits! */ > - BUG_ON((u32)vdev->features != vdev->features); > + /* Make sure we don't have any features > 32 bits except > VIRTIO_F_VERSION_1 */ > + if (WARN_ON_ONCE((u32)vdev->features != > + (vdev->features & ~(1ULL << VIRTIO_F_VERSION_1)))) > + return -1; And this. > > /* > * Remember the finalized features of our vdev, and provide it > * to the remote processor once it is powered on. > */ > - rsc->gfeatures = vdev->features; > + rsc->gfeatures = vdev->features & ~(1ULL << VIRTIO_F_VERSION_1); > But I'm having trouble with this one. First bit 32 of vdev->features gets cleared and then bit 0 to 31 are assigned to rsc->gfeatures. Why bother with clearing bit 32? > return 0; > } > > -- > 2.55.0 >
