On Mon, Sep 30, 2024 at 6:45 PM Daniel Verkamp <dverk...@chromium.org> wrote: > On Wed, Sep 25, 2024 at 4:42 PM Max Gurtovoy <mgurto...@nvidia.com> wrote: [...] > > I'm curious if you've encountered any actual implementations where > > drivers send non-block-size-aligned requests to block devices. I never > > saw such implementation. > > I don't know of any real-world implementations like this, but the > point of the spec is to allow interoperability without having to know > about every implementation.
I did find at least one existing real-world driver implementation that ignores blk_size and VIRTIO_BLK_F_BLK_SIZE - the u-boot virtio-blk driver: https://github.com/u-boot/u-boot/blob/master/drivers/virtio/virtio_blk.c So this is not just spec language lawyering; this driver depends on the ability to read/write at arbitrary 512-byte sector addresses and data sizes, and it seems like it should be allowed to do that based on my reading of the spec. (Perhaps u-boot's driver does not work with the QEMU's virtio-blk device with certain storage configurations, per Stefan's note, but that is again just one device implementation.) -- Daniel
