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Re: [Qemu-devel] [Bug 1580459] Re: Windows (10?) guest freezes entire ho
From: |
Alex Williamson |
Subject: |
Re: [Qemu-devel] [Bug 1580459] Re: Windows (10?) guest freezes entire host on shutdown if using PCI passthrough |
Date: |
Thu, 7 Jul 2016 15:03:16 -0600 |
On Thu, 07 Jul 2016 20:34:15 -0000
Clif Houck <address@hidden> wrote:
> I was also experiencing the host hard locking when shutting down a
> Windows 10 guest with a Nvidia GPU passed-through, but the issue appears
> to be completely solved after switching the card to MSI mode in the
> Windows guest.
>
> However, I would be interested in understanding *why* using the card in
> line-interrupt mode in the guest causes the host to lockup when the
> guest relinquishes control of the device. Is it a bug in qemu or vfio,
> or even the Linux kernel?
>
> I don't know if its relevant, but I've noticed when the card is not
> being used by the guest it is listed as MSI: Enable- by lspci,
> suggesting that vfio is keeping the card in line-interrupt mode when not
> in use.
>
Interrupts are disabled when the card is not in use. Can you test
whether the following commit fixes the problem:
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=956b56a984ddf10aa69b25318dc04430101beed6
This was added in v4.7-rc2, so it will also be included in anything
newer. Thanks,
Alex