I previously submitted a patch to have the guest virtio-blk driver get the value for the maximum I/O size from the host bdrv, rather than assume that there is no limit. Avi requested that I first patch the virtio spec (http://ozlabs.org/~rusty/virtio-spec/). Below is that patch. Please CC me on replies, as I am not subscribed. Thank you, Avishay Signed-off-by: Avishay Traeger <avishay@xxxxxxxxxx> --- virtio-spec-0.8.2.lyx 2009-11-30 16:34:16.000000000 +0200 +++ virtio-spec-0.8.2-mod.lyx 2009-12-01 16:04:36.000000000 +0200 @@ -3999,6 +3999,20 @@ \end_inset . +\change_inserted 0 1259672174 + +\end_layout + +\begin_layout Description + +\change_inserted 0 1259672252 +VIRTIO_BLK_F_SECTOR_MAX +\begin_inset space ~ +\end_inset + +(10) Maximum sectors in an I/O. +\change_unchanged + \end_layout \end_deeper @@ -4068,6 +4082,17 @@ \begin_layout Plain Layout u32 blk_size; +\change_inserted 0 1259672274 + +\end_layout + +\begin_layout Plain Layout + +\change_inserted 0 1259672305 + + u32 sectors_max; +\change_unchanged + \end_layout \begin_layout Plain Layout @@ -4107,6 +4132,18 @@ \begin_layout Enumerate If the VIRTIO_BLK_F_RO feature is set by the device, any write requests will fail. +\change_inserted 0 1259672345 + +\end_layout + +\begin_layout Enumerate + +\change_inserted 0 1259672454 +If the VIRTIO_BLK_F_SECTOR_MAX feature is negotiated, the sectors_max field + should be read to determine the maximum I/O size for the driver to use. + No requests should be submitted which go beyond this limit. +\change_unchanged + \end_layout \begin_layout Section* -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
