Virtualization - Nov 2015 - [RFC] kvmtool: add support for modern virtio-pci

On 11/18/2015 12:52 PM, Gerd Hoffmann wrote:
>   Hi,
> 
>> Thanks for testing! I didn't even thing about seabios as a testing
target.
> 
> Not surprising, support isn't upstream, ran into a bunch of
issues[1][2]
> last time I tried to combine the two, ran into some issues and nobody
> seemed to care, so the seabios patches where just sitting in a branch in
> my repo ...
> 
>> $ cat .config | grep 'KVMTOOL\|DEBUG'
>> CONFIG_KVMTOOL=y
>> CONFIG_DEBUG_LEVEL=9
> 
> Hmm, 'CONFIG_KVMTOOL=y > .config; make olddefconfig' should give
you a
> working configuration.
> 
> Setting 'CONFIG_DEBUG_LEVEL=9' is useful for trouble-shooting as it
> makes the virtio drivers more verbose, but not mandatory to have.
> 
> Serial line support is needed to get output:
> 
> CONFIG_DEBUG_SERIAL=y
> CONFIG_DEBUG_SERIAL_PORT=0x3f8
> 
> Also I think rom size must be 128k b/c kvmtool expects it to be that
> way:
> 
> CONFIG_ROM_SIZE=128
> 
> But those are the defaults, and after "make olddefconfig" you
should
> already have them ...
It was the ROM_SIZE one as it seems, it was set to 0 here.

Anyways, I debugged it for a bit a found that seabios attempts to write to
the notification BAR, I look further tomorrow to narrow it down and fix it.


Thanks,
Sasha

On 11/18/2015 11:00 PM, Sasha Levin wrote:
> Anyways, I debugged it for a bit a found that seabios attempts to write to
> the notification BAR, I look further tomorrow to narrow it down and fix it.
Err, *read*, obviously.

I've never implemented that because the kernel doesn't try to do that
(it doesn't
make much sense, I think...).


Thanks,
Sasha

On Mi, 2015-11-18 at 23:01 -0500, Sasha Levin wrote:
> On 11/18/2015 11:00 PM, Sasha Levin wrote:
> > Anyways, I debugged it for a bit a found that seabios attempts to
write to
> > the notification BAR, I look further tomorrow to narrow it down and
fix it.
> 
> Err, *read*, obviously.
> 
> I've never implemented that because the kernel doesn't try to do
that (it doesn't
> make much sense, I think...).
It doesn't make sense indeed (kvmtool still shouldn't segfault though),
and on a quick look I can't spot a place in seabios doing that ...

It's reading ISR, as part of device reset, to make sure any pending
interrupts are cleared.

cheers,
  Gerd