From 92bc18632011c85a58247ce305ffa4ca583f52cd Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Fri, 30 Oct 2020 14:27:23 +0100 Subject: [PATCH] x86/shadow: correct GFN use by sh_unshadow_for_p2m_change() Luckily sh_remove_all_mappings()'s use of the parameter is limited to generation of log messages. Nevertheless we'd better pass correct GFNs around: - the incoming GFN, when replacing a large page, may not be large page aligned, - incrementing by page-size-scaled values can't be right. Signed-off-by: Jan Beulich Reviewed-by: Tim Deegan --- xen/arch/x86/mm/shadow/common.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/xen/arch/x86/mm/shadow/common.c b/xen/arch/x86/mm/shadow/common.c index 0d59dea6ad..9c3d9a7cfd 100644 --- a/xen/arch/x86/mm/shadow/common.c +++ b/xen/arch/x86/mm/shadow/common.c @@ -3121,6 +3121,8 @@ static void sh_unshadow_for_p2m_change(struct domain *d, unsigned long gfn, && mfn_valid(nmfn) ) npte = map_domain_page(nmfn); + gfn &= ~(L1_PAGETABLE_ENTRIES - 1); + for ( i = 0; i < L1_PAGETABLE_ENTRIES; i++ ) { if ( !npte @@ -3129,8 +3131,7 @@ static void sh_unshadow_for_p2m_change(struct domain *d, unsigned long gfn, { /* This GFN->MFN mapping has gone away */ sh_remove_all_shadows_and_parents(d, omfn); - if ( sh_remove_all_mappings(d, omfn, - _gfn(gfn + (i << PAGE_SHIFT))) ) + if ( sh_remove_all_mappings(d, omfn, _gfn(gfn + i)) ) cpumask_or(&flushmask, &flushmask, d->dirty_cpumask); } omfn = mfn_add(omfn, 1); -- 2.30.2