Re: [Xen-devel] [v5][PATCH 2/5] xen, gfx passthrough: create pseudo intel isa bridge

["Michael S. Tsirkin" <mst@xxxxxxxxxx>]

On Wed, Jun 25, 2014 at 05:14:30PM +0800, Chen, Tiejun wrote:
> On 2014/6/25 17:04, Michael S. Tsirkin wrote:
> >On Wed, Jun 25, 2014 at 04:48:02PM +0800, Chen, Tiejun wrote:
> >>On 2014/6/25 16:43, Michael S. Tsirkin wrote:
> >>>On Wed, Jun 25, 2014 at 04:39:07PM +0800, Chen, Tiejun wrote:
> >>>>>In fact it's exactly what passthrough does.
> >>>>>I wonder if more bits from ./hw/i386/kvm/pci-assign.c
> >>>>>can be reused. How do you poke at the host device? sysfs?
> >>>>
> >>>>Yes, sysfs.
> >>>>
> >>>>Thanks
> >>>>Tiejun
> >>>
> >>>Then you should be able to re-use large chunks of
> >>>./hw/i386/kvm/pci-assign.c: basically everything
> >>>that deals with emulation.
> >>
> >>Do you mean those hooks to get info from the real device? Xen have its own
> >>wrapper, xen_host_pci_get_block(), so we always go there in xen scenario.
> >>
> >>Thanks
> >>Tiejun
> >
> >Yes and that's not good.  We have two pieces of code doing mostly
> >identical things slightly differently.
> >hw/i386/kvm/pci-assign.c is a bit younger so it's cleaner,
> >but these really need to be unified.
> >
> 
> Sorry, take a look at this again,
> 
> xen_host_pci_get_block(XenHostPCIDevice *d, int pos, uint8_t *buf, int len)
>       |
>       + xen_host_pci_config_read(d, pos, buf, len)
>               |
>               + pread(d->config_fd, buf, len, pos)
> 
> I thinks this should be same as kvm.
> 
> Thanks
> Tiejun

get_block is trivial.

I really mean the whole PT infrastructure for
- discovering host devices through sysfs
- virtualizing devices

rom, bars, msi ...
the list goes on.

logic is mostly the same.



-- 
MST

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