| Message ID | 20190703113326.2344-1-roger.pau@citrix.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] x86/ept: pass correct level to p2m_entry_modify | expand |
On 03.07.2019 13:33, Roger Pau Monne wrote: > EPT differs from NPT and shadow when translating page orders to levels > in the physmap page tables. EPT page tables level for order 0 pages is > 0, while NPT and shadow instead use 1, ie: EPT page tables levels > starts at 0 while NPT and shadow starts at 1. > > Fix the p2m_entry_modify call in atomic_write_ept_entry to always add > one to the level, in order to match NPT and shadow usage. > > While there also add a check to ensure p2m_entry_modify is never > called with level == 0. That should allow to catch future errors > related to the level parameter. > > Fixes: c7a4c088ad1c ('x86/mm: split p2m ioreq server pages special handling into helper') > Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
> From: Roger Pau Monne [mailto:roger.pau@citrix.com] > Sent: Wednesday, July 3, 2019 7:33 PM > > EPT differs from NPT and shadow when translating page orders to levels > in the physmap page tables. EPT page tables level for order 0 pages is > 0, while NPT and shadow instead use 1, ie: EPT page tables levels > starts at 0 while NPT and shadow starts at 1. > > Fix the p2m_entry_modify call in atomic_write_ept_entry to always add > one to the level, in order to match NPT and shadow usage. > > While there also add a check to ensure p2m_entry_modify is never > called with level == 0. That should allow to catch future errors > related to the level parameter. > > Fixes: c7a4c088ad1c ('x86/mm: split p2m ioreq server pages special handling > into helper') > Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reviewed-by: Kevin Tian <kevin.tian@intel.com>
diff --git a/xen/arch/x86/mm/p2m-ept.c b/xen/arch/x86/mm/p2m-ept.c index e3044bee2e..6b8468c793 100644 --- a/xen/arch/x86/mm/p2m-ept.c +++ b/xen/arch/x86/mm/p2m-ept.c @@ -51,7 +51,7 @@ static int atomic_write_ept_entry(struct p2m_domain *p2m, int level) { int rc = p2m_entry_modify(p2m, new.sa_p2mt, entryptr->sa_p2mt, - _mfn(new.mfn), _mfn(entryptr->mfn), level); + _mfn(new.mfn), _mfn(entryptr->mfn), level + 1); if ( rc ) return rc; diff --git a/xen/include/asm-x86/p2m.h b/xen/include/asm-x86/p2m.h index 09ef7e02fd..aff34e3adf 100644 --- a/xen/include/asm-x86/p2m.h +++ b/xen/include/asm-x86/p2m.h @@ -946,6 +946,7 @@ static inline int p2m_entry_modify(struct p2m_domain *p2m, p2m_type_t nt, p2m_type_t ot, mfn_t nfn, mfn_t ofn, unsigned int level) { + BUG_ON(!level); BUG_ON(level > 1 && (nt == p2m_ioreq_server || nt == p2m_map_foreign)); if ( level != 1 || (nt == ot && mfn_eq(nfn, ofn)) )
EPT differs from NPT and shadow when translating page orders to levels in the physmap page tables. EPT page tables level for order 0 pages is 0, while NPT and shadow instead use 1, ie: EPT page tables levels starts at 0 while NPT and shadow starts at 1. Fix the p2m_entry_modify call in atomic_write_ept_entry to always add one to the level, in order to match NPT and shadow usage. While there also add a check to ensure p2m_entry_modify is never called with level == 0. That should allow to catch future errors related to the level parameter. Fixes: c7a4c088ad1c ('x86/mm: split p2m ioreq server pages special handling into helper') Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> --- Cc: Jun Nakajima <jun.nakajima@intel.com> Cc: Kevin Tian <kevin.tian@intel.com> Cc: George Dunlap <george.dunlap@eu.citrix.com> Cc: Jan Beulich <jbeulich@suse.com> Cc: Andrew Cooper <andrew.cooper3@citrix.com> Cc: Wei Liu <wl@xen.org> --- Changes since v1: - Check level is != 0 in p2m_entry_modify. - Expand digits of hash id. --- xen/arch/x86/mm/p2m-ept.c | 2 +- xen/include/asm-x86/p2m.h | 1 + 2 files changed, 2 insertions(+), 1 deletion(-)