[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] MSI causing softpanics in guest
On 23/9/08 08:50, "Shan, Haitao" <haitao.shan@xxxxxxxxx> wrote: > Just some thoughts on Anish's problem. It seems he reveals a bug in current > code, I think. > > Currently, evnchn_map_pirq is hooked on msi_map_vector > (pci_enable_msi->msi_capability_init->msi_map_vector). Here the pirq type is > set to IRQT_PIRQ. Then request_irq should succeed since pirq type is already > set. > > However, this path only works on the assumption that msi_map_vector and > request_irq are executed in the same domain, to be more specific, dom0. > For PV domU guest, there is no msi_map_vector in its pci_enable_msi ( PV domU > actually asks dom0 to do the msi map, instead. This is a decision made by Keir > and Yunhong long ago. I think it is base on security considerations). So its > irq type is not set correctly (What's more, it incorrectly sets the dom0's irq > type). Then request_irq can trigger this bug_on(). > > Anish, if you use the device in dom0 itself, does it also have this bug_on? > > Keir and Jan, > Do you think this explanation is reasonable for issues Anish met? Yes, actually I remember thinking there should be a hook for Jan's patch into pcifront, but then forgot about it. When pcifront gets back a pirq from pciback, it should evtchn_map_pirq(), right? -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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