On Tue, Jan 6, 2015 at 10:39 PM, Zhang, Yang Z <yang.z.zh...@intel.com> wrote:
> Elena Ufimtseva wrote on 2015-01-07: > > > > > > On Mon, Jan 5, 2015 at 7:53 AM, Zhang, Yang Z <yang.z.zh...@intel.com> > > wrote: > > > > > > Jan Beulich wrote on 2015-01-05: > > > > >>>> Elena Ufimtseva <ufimts...@gmail.com> 01/02/15 7:32 PM >>> > >> The > > last successful command is the reading status register of second >> > > IOMMU >> unit: >> >> <snip from > iommu_enable_translation() in >> > > ./xen/drivers/passthrough/vtd/iommu.c> >> >> 746: sts = > > dmar_readl(iommu->reg, DMAR_GSTS_REG); 747: >> dmar_writel(iommu->reg, > > DMAR_GCMD_REG, sts | DMA_GCMD_TE); >> >> </snip> >> >> > After > > dmar_writel for second iommu the machine hangs. > > That's > rather odd > > - you say it doesn't even reach the IOMMU_WAIT_OP() > right after that? > > That would suggest a fault or other abnormal > condition raised by the > > translation enabling (i.e. some problem with > the page tables, albeit > > that should then have been a problem for the first IOMMU already). > > > Yet an eventual fault can't be delivered at that point due to > > > interrupts being disabled. Perhaps the VT-d maintainers (now Cc-ed) > > > have some suggestion as to what's going on or how to diagnose. > > > > > > I am curious why pv dom0 boot fine. Will pvh dom0 share EPT table > > with VT-d? Maybe try with disable sharing to see whether helps. > > > > > > > > Yes, it is interesting. I am working on pvh guest boot under pv dom0. > > Hi Yang Somehow I dropped the list from this conversation. Adding back. > We can start from this point. It is not very hard to find the difference on > IOMMU setup when booting pvh dom0 and pv dom0. Also, have you seen > any difference on IOMMU register on working and non-working case? > > I compared the registers and I did not find any difference in pv or pvh case. I did it for both iommus, before enabling each unit and after. They are the same. If you would like, I can post the dumps. As for the differences between setting up iommu, I will check and get back with this. Thank you for your advice. > > > > I tried booting with non shared EPTs, but with the same result. > > > > > > > > > > > > > > Jan > > > > > > Best regards, > > Yang > > > > > > > > > > > > > > > Best regards, > Yang > > > -- Elena
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