Re: [Qemu-devel] [PATCH] vfio/pci-quirks: Set non-zero GMS memory size for IGD

[Alex Williamson]

On Fri, 28 Jul 2017 08:22:45 +0300
Dmitry Fleytman <address@hidden> wrote:

> > On 28 Jul 2017, at 07:51 AM, Zhang, Xiong Y <address@hidden> wrote:
> >   
> >>> On 26 Jul 2017, at 08:22 AM, Zhang, Xiong Y <address@hidden>  
> >> wrote:  
> >>> 
> >>> Sorry, we indeed found Intel windows guest graphic driver couldn't be 
> >>> bind  
> >> when GMS memory size is zero. And we have fixed it and the next intel
> >> windows driver release will contain this fix.  
> >>> So currently please use x-igd-gms in legacy mode to work around this.
> >>> 
> >>> BTW, how did you know window driver allocate extra ~4G memory when  
> >> GMS size set to 0 ?
> >> 
> >> We noticed that with new IGD driver memory usage on VMs raised by around
> >> 4G.
> >> 
> >> Then we examined memory allocations with poolmon
> >> (https://docs.microsoft.com/en-us/windows-hardware/drivers/devtest/poolm
> >> on)
> >> and saw that around 4G of memory is allocated with IGD driver pool tag.
> >> Additionally we noticed that on VMs with less than 5G of memory IGD driver
> >> does not load and system does fallback to standard VGA driver.
> >>   
> > [Zhang, Xiong Y]  I tried our internal driver and didn't found the above 
> > two issues, please wait for the next intel graphic driver release.  
> 
> Thanks!

So to close on this, we should just be recommending that users
encountering this problem add the x-igd-gms=1 option to the device
until the next Intel graphics release.  I won't plan to push this
change.  Thanks all,

Alex