From e60c0b8f66ea97bb59e53bd3aca8fd741a430a11 Mon Sep 17 00:00:00 2001 From: Keir Fraser Date: Mon, 20 Jul 2009 10:10:15 +0100 Subject: [PATCH] x86: make show_page_walk() more robust Also add in a missing line in x86-64's do_page_walk(). Signed-off-by: Jan Beulich --- xen/arch/x86/x86_32/traps.c | 6 ++++-- xen/arch/x86/x86_64/mm.c | 1 + xen/arch/x86/x86_64/traps.c | 9 ++++++--- 3 files changed, 11 insertions(+), 5 deletions(-) diff --git a/xen/arch/x86/x86_32/traps.c b/xen/arch/x86/x86_32/traps.c index c58e5e2918..68682d2545 100644 --- a/xen/arch/x86/x86_32/traps.c +++ b/xen/arch/x86/x86_32/traps.c @@ -164,7 +164,8 @@ void show_page_walk(unsigned long addr) printk(" L3[0x%03lx] = %"PRIpte" %08lx\n", l3_table_offset(addr), l3e_get_intpte(l3e), pfn); unmap_domain_page(l3t); - if ( !(l3e_get_flags(l3e) & _PAGE_PRESENT) ) + if ( !(l3e_get_flags(l3e) & _PAGE_PRESENT) || + !mfn_valid(mfn) ) return; l2t = map_domain_page(mfn); @@ -176,7 +177,8 @@ void show_page_walk(unsigned long addr) (l2e_get_flags(l2e) & _PAGE_PSE) ? "(PSE)" : ""); unmap_domain_page(l2t); if ( !(l2e_get_flags(l2e) & _PAGE_PRESENT) || - (l2e_get_flags(l2e) & _PAGE_PSE) ) + (l2e_get_flags(l2e) & _PAGE_PSE) || + !mfn_valid(mfn) ) return; l1t = map_domain_page(mfn); diff --git a/xen/arch/x86/x86_64/mm.c b/xen/arch/x86/x86_64/mm.c index 87b8957ff5..352fa439c5 100644 --- a/xen/arch/x86/x86_64/mm.c +++ b/xen/arch/x86/x86_64/mm.c @@ -123,6 +123,7 @@ void *do_page_walk(struct vcpu *v, unsigned long addr) l3e = l3t[l3_table_offset(addr)]; mfn = l3e_get_pfn(l3e); if ( !(l3e_get_flags(l3e) & _PAGE_PRESENT) || !mfn_valid(mfn) ) + return NULL; if ( (l3e_get_flags(l3e) & _PAGE_PSE) ) return mfn_to_virt(mfn) + (addr & ((1UL << L3_PAGETABLE_SHIFT) - 1)); diff --git a/xen/arch/x86/x86_64/traps.c b/xen/arch/x86/x86_64/traps.c index f458f491c7..4c74785c74 100644 --- a/xen/arch/x86/x86_64/traps.c +++ b/xen/arch/x86/x86_64/traps.c @@ -179,7 +179,8 @@ void show_page_walk(unsigned long addr) pfn = mfn_valid(mfn) ? get_gpfn_from_mfn(mfn) : INVALID_M2P_ENTRY; printk(" L4[0x%03lx] = %"PRIpte" %016lx\n", l4_table_offset(addr), l4e_get_intpte(l4e), pfn); - if ( !(l4e_get_flags(l4e) & _PAGE_PRESENT) ) + if ( !(l4e_get_flags(l4e) & _PAGE_PRESENT) || + !mfn_valid(mfn) ) return; l3t = mfn_to_virt(mfn); @@ -190,7 +191,8 @@ void show_page_walk(unsigned long addr) l3_table_offset(addr), l3e_get_intpte(l3e), pfn, (l3e_get_flags(l3e) & _PAGE_PSE) ? " (PSE)" : ""); if ( !(l3e_get_flags(l3e) & _PAGE_PRESENT) || - (l3e_get_flags(l3e) & _PAGE_PSE) ) + (l3e_get_flags(l3e) & _PAGE_PSE) || + !mfn_valid(mfn) ) return; l2t = mfn_to_virt(mfn); @@ -201,7 +203,8 @@ void show_page_walk(unsigned long addr) l2_table_offset(addr), l2e_get_intpte(l2e), pfn, (l2e_get_flags(l2e) & _PAGE_PSE) ? "(PSE)" : ""); if ( !(l2e_get_flags(l2e) & _PAGE_PRESENT) || - (l2e_get_flags(l2e) & _PAGE_PSE) ) + (l2e_get_flags(l2e) & _PAGE_PSE) || + !mfn_valid(mfn) ) return; l1t = mfn_to_virt(mfn); -- 2.30.2