Date: Sat, 12 Oct 2019 11:59:00 +0200 From: Roger Pau =?iso-8859-1?Q?Monn=E9?= <roger.pau@citrix.com> To: Brian Buhrow <buhrow@nfbcal.org> Cc: <freebsd-xen@freebsd.org> Subject: Re: i/o is very slow on FreeBSD dom0 with Xen-4.12 and Freebsd-12 Message-ID: <20191012095900.GA14005@Air-de-Roger> In-Reply-To: <201910112322.x9BNMWlp020596@lothlorien.nfbcal.org> References: <201910112153.x9BLrQSI028763@lothlorien.nfbcal.org> <201910112322.x9BNMWlp020596@lothlorien.nfbcal.org>
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On Fri, Oct 11, 2019 at 04:22:32PM -0700, Brian Buhrow wrote: > hello. Following up on this issue yet again, I'm pretty sure I have > the hardware discussed in the link below. I tried disabling interrupt > remapping as the article suggests, but that just makes matters worse. As I > understand it, when FreeBSD is running as a dom0, it must have iommu > interrupt remapping enabled in order to function. PVH dom0 requires iommu DMA remapping. Interrupt remapping is not mandated for PVH dom0. Can you also post the log when booting with iommu=verbose,debug,no-intremap? Can you also try booting without the no-intremap option, and then switch to the hypervisor console (Ctrl-A on the serial line) and paste the output of the i the M and the z debug keys at the point where FreeBSD freezes? (together with the full serial log) > Should I conclude that > this hardware just cannot run FreeBSD as a dom0 or is there another work > around that I might use? I need to look deeper, I'm quite sure the issue is with Xen. There are also some bugfixes for the iommu in Xen unstable, which I can try to backport to the FreeBSD 4.12.1 Xen packages, albeit there have been a lot of changes in the iommu code, so backporting might not be feasible for some of them. I'm leaving home today and will be on PTO until Tuesday, and I don't expect to be able to look into this until then, sorry. Thanks, Roger.
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