On Tue, Aug 27, 2019 at 05:23:33PM +0200, Jan Beulich wrote: > On 23.08.2019 07:58, Tian, Kevin wrote: > > > From: Roger Pau Monne [mailto:roger....@citrix.com] > > > Sent: Tuesday, August 20, 2019 11:38 PM > > > > > > The level passed to ept_invalidate_emt corresponds to the EPT entry > > > passed as the mfn parameter, which is a pointer to an EPT page table, > > > hence the entries in that page table will have one level less than the > > > parent. > > > > > > Fix the call to atomic_write_ept_entry to pass the correct level, ie: > > > one level less than the parent. > > > > > > Fixes: 50fe6e73705 ('pvh dom0: add and remove foreign pages') > > > Signed-off-by: Roger Pau Monné <roger....@citrix.com> > > > --- > > > Cc: Jun Nakajima <jun.nakaj...@intel.com> > > > Cc: Kevin Tian <kevin.t...@intel.com> > > > Cc: George Dunlap <george.dun...@eu.citrix.com> > > > Cc: Jan Beulich <jbeul...@suse.com> > > > Cc: Andrew Cooper <andrew.coop...@citrix.com> > > > Cc: Wei Liu <w...@xen.org> > > > Cc: Sergey Dyasli <sergey.dya...@citrix.com> > > > Cc: Paul Durrant <paul.durr...@citrix.com> > > > --- > > > xen/arch/x86/mm/p2m-ept.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/xen/arch/x86/mm/p2m-ept.c b/xen/arch/x86/mm/p2m-ept.c > > > index 6b8468c793..23ae6e9da3 100644 > > > --- a/xen/arch/x86/mm/p2m-ept.c > > > +++ b/xen/arch/x86/mm/p2m-ept.c > > > @@ -367,7 +367,7 @@ static bool_t ept_invalidate_emt(struct p2m_domain > > > *p2m, mfn_t mfn, > > > e.emt = MTRR_NUM_TYPES; > > > if ( recalc ) > > > e.recalc = 1; > > > - rc = atomic_write_ept_entry(p2m, &epte[i], e, level); > > > + rc = atomic_write_ept_entry(p2m, &epte[i], e, level - 1); > > > ASSERT(rc == 0); > > > changed = 1; > > > } > > > > Reviewed-by: Kevin Tian <kevin.t...@intel.com>. > > > > One small comment about readability. What about renaming 'level' > > to 'parent_level' in this function? > > And also taking the opportunity and making it unsigned int?
I've been thinking about this, and I'm not sure renaming level to parent_level is correct, level actually matches the level of the mfn also passed as a parameter, and hence it's correct. It's the function itself that actually iterates over the page table entries, and hence descends one level into the page tables. ie: I could add something like ASSERT(level) to make sure no level 0 entries are passed to the function, but renaming doesn't seem correct to me. Thanks, Roger. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
