Messages in this thread | | | Date | Thu, 29 Aug 2013 17:50:38 +0800 | From | Zhenzhong Duan <> | Subject | Re: [Xen-devel] [PATCH 2/3 v3] Refactor MSI restore call-chain to drop unnecessary argument |
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On 2013-08-29 15:23, Jan Beulich wrote: >>>> On 29.08.13 at 04:52, Zhenzhong Duan <zhenzhong.duan@oracle.com> wrote: >> But in initial domain (aka priviliged guest), it's different. >> Driver init call graph under initial domain: >> driver_init-> >> msix_capability_init-> >> msix_program_entries-> >> msix_mask_irq-> >> entry->masked = 1 >> request_irq-> >> __setup_irq-> >> irq_startup-> >> __startup_pirq-> >> EVTCHNOP_bind_pirq hypercall (trap into Xen) >> [Xen:] >> pirq_guest_bind-> >> startup_msi_irq-> >> unmask_msi_irq-> >> msi_set_mask_bit-> >> entry->msi_attrib.masked = 0 >> >> So entry->msi_attrib.masked in xen side always has newest value. entry->masked >> in initial domain is untouched and is 1 after msix_capability_init. > And as said several times before - Linux shouldn't be touching > the MSI-X table at all during initial setup or resume (it should in > particular not rely on such accesses to not fault, as being a > privilege violation); all it needs to do is update its software state. My patch just remove access to msix mask register in dom0. Anything wrong with that? > > Hence fiddling with default_restore_msi_irqs() seems the wrong > approach towards solving the problem. dom0 uses xen_initdom_restore_msi_irqs, default_restore_msi_irqs is for baremetal.
zduan
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