On Tue, Sep 29, 2015 at 04:47:00AM -0600, Jan Beulich wrote: > >>> On 23.09.15 at 16:00, <wei.l...@citrix.com> wrote: > > On Tue, Sep 22, 2015 at 08:15:39AM -0600, Jan Beulich wrote: > >> >>> On 21.09.15 at 16:02, <jbeul...@suse.com> wrote: > >> > In the EPT case permission changes should also result in updates or > >> > TLB flushes. > >> > > >> > In the NPT case the old MFN does not depend on the new entry being > >> > valid (but solely on the old one), and the need to update or TLB-flush > >> > again also depends on permission changes. > >> > > >> > In the shadow mode case, iommu_hap_pt_share should be ignored. > >> > > >> > Furthermore in the NPT/shadow case old intermediate page tables must > >> > be freed only after IOMMU side updates/flushes have got carried out. > >> > > >> > Signed-off-by: Jan Beulich <jbeul...@suse.com> > >> > >> Wei, > >> > >> I'm sorry, I forgot to Cc you on the patch and state that I think this > >> should be considered for 4.6. > > > > While I think having this issue fixed for 4.6 would be nice, I would > > like to ... > > > >> > --- > >> > In addition to the fixes here it looks to me as if both EPT and > >> > NPT/shadow code lack invalidation of IOMMU side paging structure > >> > caches, i.e. further changes may be needed. Am I overlooking something? > > > > have this question answered. Having a "fix" that doesn't actually fix > > the issue is not very useful... > > So I suppose you saw my reasoning of there not actually being any > further flushing necessary right now. Following the discussion with
Yes, I saw it. I'm convinced. > George I split off and applied the EPT side of this, which I'd like to > see go into 4.6 too. The NPT/shadow side will need a little more work EPT side: Release-acked-by: Wei Liu <wei.l...@citrix.com> > (including further splitting the original patch), partly depending on > a decision on whether to keep the dead page table sharing code in > p2m-pt.c. > > I did already split out the intermediate page table freeing patch. > The only other bug is the incomplete checking of iommu_hap_pt_share > in shadow mode, everything else would be cleanup only no matter > what route we go. The only thing is that this broken check would > go away altogether if we decided to drop the pt-share logic, but I > suppose for backporting purposes it would be worthwhile to have > that fix separated regardless of further direction. > I will reply separately to your other two patches. Wei. > Jan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
