On December 5, 2015 at 20:38:17, Hristo Iliev (hri...@hiliev.eu) wrote:
Hi Okky,
Just to add another data point. My system is also Haswell-E (i7-5820K on an
X99 motherboard) and my Win10 VM does not make it past the OVMF spash screen
with the symptomatic 100% CPU usage when the host is running linux-lts, but
boots flawlessly on linux-vfio-lts.
Hi Hristo,
Actually the 100% CPU usage issue reside on the changes on the kernel linux
starting 4.2.x and the implementation of OVMF. Since the latest linux-vfio is
based on linux 4.2.x, the issue also reside on that kernel. There’s a patch [1]
for linux 4.3-mainline if you want to upgrade your kernel, I’ve tried it out
myself on Z87 platform, but I haven’t found a patch for linux 4.2.x. If you
want stableness, linux-lts-4.1.13 seems the latest stable right now.
I just upgraded my rig to a Haswell-E platform (Intel Core i7-5820K also, plus
ASUS X99-A) last weekend, and I found no issues running pure linux-lts-4.1.13
(even the config is from lts). Though, I recompiled the kernel again with ABS
and native CFLAGS hoping to have even better performance. Are you sure you
meant linux-lts not linux-vfio (4.2.x)?
Oddly enough, sometimes the VM seems to be able to boot on linux-lts too,
but only once it was successfully booted on the vfio-patched kernel. Could
have something to do with some sort of initialisation of the GPU I'm passing
through (GTX 970), which is able to survive host reboots. I'm using OVMF
from the RPMs linked on the Arch Wiki and updating it regularly.
Hmm, that’s weird. Haswell-E platform should not need any PCIe ACS workaround
patch. Its IOMMU groups are separated nicely for each device. Can you try using
linux-vfio-lts’ config and recompile linux-lts using the config with ABS and
try booting the guest again?
I would really prefer to use linux-lts instead of waiting for the newest
linux-vfio-lts to finish compiling each time it gets updated, but that
doesn't seem currently possible.
Recompiling on your machine probably just took around 10 minutes actually. :D
Hristo
[1] http://www.spinics.net/lists/kvm/msg123325.html
--
Okky Hendriansyah
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