Cornelia Huck 68a6199cf3 virtio/s390: implement virtio-ccw revision 2 correctly ... commit 182f709c5cff683e6732d04c78e328de0532284f upstream. CCW_CMD_READ_STATUS was introduced with revision 2 of virtio-ccw, and drivers should only rely on it being implemented when they negotiated at least that revision with the device. However, virtio_ccw_get_status() issued READ_STATUS for any device operating at least at revision 1. If the device accepts READ_STATUS regardless of the negotiated revision (which some implementations like QEMU do, even though the spec currently does not allow it), everything works as intended. While a device rejecting the command should also be handled gracefully, we will not be able to see any changes the device makes to the status, such as setting NEEDS_RESET or setting the status to zero after a completed reset. We negotiated the revision to at most 1, as we never bumped the maximum revision; let's do that now and properly send READ_STATUS only if we are operating at least at revision 2. Cc: stable@vger.kernel.org Fixes: 7d3ce5ab94 ("virtio/s390: support READ_STATUS command for virtio-ccw") Reviewed-by: Halil Pasic <pasic@linux.ibm.com> Signed-off-by: Cornelia Huck <cohuck@redhat.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Link: https://lore.kernel.org/r/20210216110645.1087321-1-cohuck@redhat.com Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2021-03-04 11:38:42 +01:00
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Makefile
virtio_ccw.c