Re: [Qemu-devel] [PATCH 0/6] AHCI Device Fixes

[Paolo Bonzini]

On 10/29/2014 12:54 AM, John Snow wrote:
> 
> 
> On 10/28/2014 09:51 AM, Stefan Hajnoczi wrote:
>> On Wed, Oct 01, 2014 at 06:55:45PM -0400, John Snow wrote:
>>> Based off of feedback from the RFC of the same name,
>>> this series batches together a group of fixes that
>>> improve the AHCI device to fix a number of bugs.
>>>
>>> A number of fixes included in the RFC that provide more
>>> radical changes are omitted for now in favor of a smaller,
>>> more easily reviewable set for QEMU 2.2.
>>>
>>> In summary:
>>>
>>> Patch #1 and #6 correct the format of FIS packet responses
>>> that are available to the guest operating system upon interrupt.
>>>
>>> Patch #2 corrects an oversight where we do not inform the
>>> guest how many bytes we've transferred. This is relied upon
>>> for non-NCQ modes and in some early bootup and shutdown code.
>>>
>>> Patch #5 corrects cases with malformed scatter-gather lists that
>>> may cause leaks, or cause QEMU to hang in an allocation loop.
>>>
>>> Patch #4 attempts to continue minimizing the divergence of the
>>> multiple pathways through the AHCI device by re-using existing
>>> callbacks.
>>>
>>> Taken together, these patches should allow non-ncq operation
>>> for Windows hosts, as well as enable hibernation for Windows 7.
>>>
>>> Hibernation for Windows 8 and AHCI remains non-functional.
>>>
>>> John Snow (6):
>>>    ahci: Correct PIO/D2H FIS responses
>>>    ahci: Update byte count after DMA completion
>>>    ide: repair PIO transfers for cases where nsector > 1
>>>    ahci: unify sglist preparation
>>>    ide: Correct handling of malformed/short PRDTs
>>>    ahci: Fix SDB FIS Construction
>>>
>>>   dma-helpers.c     |   3 ++
>>>   hw/ide/ahci.c     | 113
>>> ++++++++++++++++++++++++++++++++----------------------
>>>   hw/ide/ahci.h     |   8 ++++
>>>   hw/ide/core.c     |  17 ++++++--
>>>   hw/ide/internal.h |   2 +
>>>   hw/ide/pci.c      |   5 ++-
>>>   6 files changed, 97 insertions(+), 51 deletions(-)
>>
>> Dropped the broken assert that Paolo spotted.
>>
>> Thanks, applied to my block tree:
>> https://github.com/stefanha/qemu/commits/block
>>
>> Stefan
> 
> Drop the PIO patch for now (#3), I ran into a regression with it with
> CDROM drives. I believe the others are still fine.

Yeah, I was wondering if any commands could have <512 bytes response...
 I sort of convinced myself that the answer was no for ATA commands, but
stupidly forgot about packet (SCSI) commands.  Their results are
obviously shorter than 512 bytes.

Paolo