From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andres Lagar-Cavilla Subject: [PATCH] x86/mm: Make asserts on types and counts of shared pages more accurate Date: Thu, 09 Feb 2012 01:01:37 -0500 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: xen-devel@lists.xensource.com Cc: andres@gridcentric.ca, tim@xen.org, adin@gridcentric.ca List-Id: xen-devel@lists.xenproject.org xen/arch/x86/mm/mem_sharing.c | 4 +++- xen/arch/x86/mm/p2m.c | 6 ++++-- 2 files changed, 7 insertions(+), 3 deletions(-) Signed-off-by: Andres Lagar-Cavilla diff -r 667191f054c3 -r f2efbfaa8d26 xen/arch/x86/mm/mem_sharing.c --- a/xen/arch/x86/mm/mem_sharing.c +++ b/xen/arch/x86/mm/mem_sharing.c @@ -200,7 +200,9 @@ static struct page_info* mem_sharing_loo /* Count has to be at least two, because we're called * with the mfn locked (1) and this is supposed to be * a shared page (1). */ - ASSERT((page->u.inuse.type_info & PGT_count_mask) >= 2); + ASSERT((page->u.inuse.type_info & + (PGT_shared_page | PGT_count_mask)) >= + (PGT_shared_page | 2)); ASSERT(get_gpfn_from_mfn(mfn) == SHARED_M2P_ENTRY); return page; } diff -r 667191f054c3 -r f2efbfaa8d26 xen/arch/x86/mm/p2m.c --- a/xen/arch/x86/mm/p2m.c +++ b/xen/arch/x86/mm/p2m.c @@ -745,8 +745,10 @@ set_shared_p2m_entry(struct domain *d, u * sharable first */ ASSERT(p2m_is_shared(ot)); ASSERT(mfn_valid(omfn)); - if ( ((mfn_to_page(omfn)->u.inuse.type_info & PGT_type_mask) - != PGT_shared_page) ) + /* Set the m2p entry to invalid only if there are no further type + * refs to this page as shared */ + if ( (mfn_to_page(omfn)->u.inuse.type_info & + (PGT_shared_page | PGT_count_mask)) <= PGT_shared_page ) set_gpfn_from_mfn(mfn_x(omfn), INVALID_M2P_ENTRY); P2M_DEBUG("set shared %lx %lx\n", gfn, mfn_x(mfn));