On 05/05/2017 11:13 AM, Paolo Bonzini wrote:
On 05/05/2017 17:03, Eric Farman wrote:
We get a value of x3fffff when sending that to a scsi-disk from bios
code. That's fully emulated though, in scsi_disk_emulate_inquiry. And
that's the scenario that already works.
While there is indeed code in hw/scsi/scsi-generic.c to wire that in,
that only happens after the I/O goes to the device itself. The Block
Limits page isn't supported [1] and thus it gets rejected with "invalid
field in cdb". We never get to that fixup code you reference, since the
returned len is zero.
Should I be refactoring this code to always patch in that block limit
regardless of a response from the host/device? (That is, when page xb0
isn't supported by the hw.)
What is thec value you get?
x140000 bytes when using /dev/sg0 (xa00 sectors when using /dev/sda).
Is there a sensible default value
that you can use when page 0xb0 isn't supported by the hardware?
I was setting max_sectors to x800 with good success, which was the
power-of-2 floor that BLKSECTGET gave us. That kept us within the
limits of the host biovec code. But it's a long way from the
virtio-scsi value of xFFFF when max_sectors isn't specified, so don't
know what side effects that may cause.