From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tim Deegan Subject: [PATCH 5/5] x86/mem_access: check for errors in p2m->set_entry(). Date: Thu, 7 Mar 2013 14:53:03 +0000 Message-ID: <1362667983-24938-6-git-send-email-tim@xen.org> References: <1362667983-24938-1-git-send-email-tim@xen.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1362667983-24938-1-git-send-email-tim@xen.org> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: xen-devel@lists.xen.org Cc: Aravindh Puthiyaparambil List-Id: xen-devel@lists.xenproject.org These calls ought always to succeed. Assert that they do rather than ignoring the return value. Signed-off-by: Tim Deegan Cc: Aravindh Puthiyaparambil --- xen/arch/x86/mm/p2m.c | 25 ++++++++++++++++++------- 1 file changed, 18 insertions(+), 7 deletions(-) diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c index 4837de3..f5ddd20 100644 --- a/xen/arch/x86/mm/p2m.c +++ b/xen/arch/x86/mm/p2m.c @@ -1262,21 +1262,27 @@ bool_t p2m_mem_access_check(paddr_t gpa, bool_t gla_valid, unsigned long gla, p2m_type_t p2mt; p2m_access_t p2ma; mem_event_request_t *req; + int rc; - /* First, handle rx2rw conversion automatically */ + /* First, handle rx2rw conversion automatically. + * These calls to p2m->set_entry() must succeed: we have the gfn + * locked and just did a successful get_entry(). */ gfn_lock(p2m, gfn, 0); mfn = p2m->get_entry(p2m, gfn, &p2mt, &p2ma, 0, NULL); if ( access_w && p2ma == p2m_access_rx2rw ) { - p2m->set_entry(p2m, gfn, mfn, PAGE_ORDER_4K, p2mt, p2m_access_rw); + rc = p2m->set_entry(p2m, gfn, mfn, PAGE_ORDER_4K, p2mt, p2m_access_rw); + ASSERT(rc); gfn_unlock(p2m, gfn, 0); return 1; } else if ( p2ma == p2m_access_n2rwx ) { ASSERT(access_w || access_r || access_x); - p2m->set_entry(p2m, gfn, mfn, PAGE_ORDER_4K, p2mt, p2m_access_rwx); + rc = p2m->set_entry(p2m, gfn, mfn, PAGE_ORDER_4K, + p2mt, p2m_access_rwx); + ASSERT(rc); } gfn_unlock(p2m, gfn, 0); @@ -1294,13 +1300,18 @@ bool_t p2m_mem_access_check(paddr_t gpa, bool_t gla_valid, unsigned long gla, } else { + gfn_lock(p2m, gfn, 0); + mfn = p2m->get_entry(p2m, gfn, &p2mt, &p2ma, 0, NULL); if ( p2ma != p2m_access_n2rwx ) { - /* A listener is not required, so clear the access restrictions */ - gfn_lock(p2m, gfn, 0); - p2m->set_entry(p2m, gfn, mfn, PAGE_ORDER_4K, p2mt, p2m_access_rwx); - gfn_unlock(p2m, gfn, 0); + /* A listener is not required, so clear the access + * restrictions. This set must succeed: we have the + * gfn locked and just did a successful get_entry(). */ + rc = p2m->set_entry(p2m, gfn, mfn, PAGE_ORDER_4K, + p2mt, p2m_access_rwx); + ASSERT(rc); } + gfn_unlock(p2m, gfn, 0); return 1; } } -- 1.7.10.4