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intel / XenGT-Preview-xen

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No enough available aperture/gm/fence #16

Open Kealpl opened 9 years ago

Kealpl commented 9 years ago

Hi

I'd like to start 3 windows 8 VMs and when first is up and running second won't pass. I get an error:

vGT info:(create_vgt_instance:120) vm_id=11, low_gm_sz=128MB, high_gm_sz=384MB, fence_sz=4, vgt_primary=1 vGT: create_vgt_instance: no enough available aperture/gm/fence!

CPU is i7-4790K with aperture size set in BIOS at 512MB. Auto won't help either. I tried also on Gigabyte Brix with i7-4770R, Iris Pro graphics, fixed size 64MB aperture and problem is the same.

What does it mean and where is the problem ?

Thanks.

l1viathan commented 9 years ago

This is a limitation by BIOS and Windows driver. The windows gfx driver requires at least 128M aperture, while the host gfx driver must reserve some. So you won't be able to create more than 1 windows guest without updating the BIOS and enlarge the aperture.

l1viathan commented 9 years ago

I have no idea what does "GFX allocation" mean in your UEFI settings, but you may want to have a check:

a) set "GFX allocation" to another value, say 128MB, and boot linux; b) run "lspci -v -s 00:0.0" to check if the size of 2nd BAR(line with "Memory at") changed to 128MB

If it changes, then "GFX allocation" does mean aperture.

PS, no kernel changes needed at all :)