Prior to this change both functions returned 0 for success, -1 for failure
and +1 to indicate that an exception was injected into the guest.
The numerical value of ERESTART also happens to be -1 so when these functions
returned -1 it had to be translated to a positive errno value to prevent the
VM_RUN ioctl from being inadvertently restarted. This made it easy to introduce
bugs when writing emulation code.
Fix this by adding an 'int *guest_fault' parameter and setting it to '1' if
an exception was delivered to the guest. The return value is 0 or EFAULT so
no additional translation is needed.
Reviewed by: tychon
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D2428
It is not required to use CLO to recover from task file error, it should
be enough to do only stop/start, that does not clear the PxTFD.STS.ERR.
MFC after: 13 days
Using status updates in r282364, block queue on BSY, DRQ or ERR bits set.
This can be a performance penalization for non-NCQ commands, but it is
required for proper error recovery and standard compliance.
MFC after: 2 weeks
GEOM does not support scatter/gather lists in its I/Os. Such requests
are cut in pieces by physio(), that may be problematic, if those pieces
are not multiple of provider's sector size. If such case is detected,
move the data through temporary sequential buffer.
MFC after: 2 weeks
There are a number of assumptions about legacy interrupts always
being available in virtio so don't allow back-ends to make the
decision to support them.
This fixes the issue seen with virtio-rnd on OpenBSD. MSI-x vectors
were not being used, and the virtio-rnd backend wasn't allocating a
legacy interrupt resulting in a bhyve assert and guest exit.
Reported by: Julian Hsiao, madoka at nyanisore dot net
Reviewed by: neel
MFC after: 1 week
I've missed that network driver sometimes returns taken request back to
available queue without processing. Add new helper function for that case.
Reported by: flo
MFC after: 2 weeks
I/O interface.
Asynchronous operation, based on r280026 change, allows to not block virtual
CPU during I/O processing, that on slow/busy storage can take seconds.
Use of recently improved block I/O interface allows to process multiple
requests same time, that improves random I/O performance on wide storages.
Benchmarks of virtual disk, backed by ZVOL on RAID10 pool of 4 HDDs, show
~3.5 times random read performance improvements, while no degradation on
linear I/O. Guest CPU usage during test dropped from 100% to almost zero.
MFC after: 2 weeks
Original virtqueue design allows queued and out-of-order processing, but
helpers added in r253440 suppose only direct blocking in-order one.
It could be fine for network, etc., but it is a huge limitation for storage
devices.
On parallel random I/O this allows better utilize wide storage pools.
To not confuse prefetcher on linear I/O, consecutive requests are executed
sequentially, following the same logic as was earlier implemented in CTL.
Benchmarks of virtual AHCI disk, backed by ZVOL on RAID10 pool of 4 HDDs,
show ~3.5 times random read performance improvements, while no degradation
on linear I/O.
MFC after: 2 weeks
It works only for virtual disks backed by ZVOLs and raw devices supporting
BIO_DELETE. Virtual disks backed by files won't report this capability.
MFC after: 2 weeks
Relnotes: yes
