+CC Dario who is also watching this patch set. On February 25, 2016 4:59pm, <jbeul...@suse.com> wrote: > >>> On 25.02.16 at 07:56, <quan...@intel.com> wrote: > >> On February 17, 2016 10:23pm, <jbeul...@suse.com> wrote: > >> >>> On 05.02.16 at 11:18, <quan...@intel.com> wrote: > >> > to pass down a flag indicating whether the lock is being held, and > >> > check the way up the call trees. > >> > >> Same comments as on the previous patch; most of the changes outside > >> of xen/drivers/passthrough/ seem to be avoidable here. > >> > > > > (VT-d RMRR / P2M EPT) > > > > Jan, > > When I fix the VT-d RMRR related code > > 1. $... iommu_map_page()/iommu_unmap_page() > > --p2m->set_entry()--p2m_set_entry()--set_identity_p2m_entry() / > > clear_identity_p2m_entry()-- rmrr_identity_mapping()--... , > > 2. $... iommu_pte_flush() > > --p2m->set_entry()--p2m_set_entry()--set_identity_p2m_entry() / > > clear_identity_p2m_entry()-- rmrr_identity_mapping()--... , > > > > I found that the pcidevs_lock is being held for p2m_set_entry(). It > > is a corner case which is _not_ fix in previous patch set. As similar, > > I think I need to add p2m_set_entry_locked() to pass down a flag > > indicating whether the pcidevs_lock is being held. Right? > > Well, to me this would seem rather gross a hack - George, how about you?
George, I look forward to your comments and suggestions. :) > I'd > really suggest investigating alternatives. One that comes to mind would be to > move acquiring/releasing pcidevs_lock into a helper function, and setting a > per-CPU flag indicating ownership. To me, this might be fine. Does Per-CPU flag refer to this_cpu(iommu_dont_flush_iotlb) or variant? > However, the same effect could be achieved > by making the lock a recursive one, which would then seem to more > conventional approach (but requiring as much code to be touched). > Both approached would eliminate the need to pass down "locked" > flags. > > > BTW, just a quick question, what's the difference between p2m-ept.c > > and p2m-pt.c ? Thanks. > > The former, as its name says, is used for EPT, while the latter is the P2M > implementation for both NPT and shadow mode. > Thanks!. Got it. Quan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
