On Thu, Oct 29, 2026 at 12:23:55AM +0100, Kevin Wolf wrote:
QEMU has allowed the user to specify serials of arbitrary length for virtio-blk devices, even though the virtio-blk protocol can only communicate 20 characters of the serial to the guest. This means that a longer serial number on the command line is silently truncated to 20 characters from the guest perspective.
As a first step to fix this, deprecate the silent truncation and turn it into a warning; we can later make this a hard error. While touching GET_ID, let's make it more spec compliant and clean up the internal state.
Another part is planned that will actually enable users to use longer serials and additional device identifiers. This will need spec changes and would take more time than we have until the QEMU 11.2 freeze anyway, so I'll address this later. For now, the important thing is to get the deprecation period started.
Kevin Wolf (5): virtio-blk: Implement full NUL padding for GET_ID virtio-blk-test: Add a basic GET_ID test case virtio-blk: Deprecate silent truncation of serial virtio-blk: Represent truncated serial in qdev property virtio-blk-test: Test truncated serial
docs/about/deprecated.rst | 13 +++++ hw/block/virtio-blk.c | 24 +++++++-- tests/qtest/virtio-blk-test.c | 92 +++++++++++++++++++++++++++++++++++ 3 files changed, 125 insertions(+), 4 deletions(-)
Aside from the comments I've sent: Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>