From b733f8a8b8db83f2d438cab3adb38b387cecfce0 Mon Sep 17 00:00:00 2001 From: Wei Liu Date: Sat, 11 Jan 2020 21:57:42 +0000 Subject: [PATCH] x86/mm: Refactor modify_xen_mappings to have one exit path We will soon need to perform clean-ups before returning. No functional change. This is part of XSA-345. Reported-by: Hongyan Xia Signed-off-by: Wei Liu Signed-off-by: Hongyan Xia Signed-off-by: George Dunlap Acked-by: Jan Beulich --- xen/arch/x86/mm.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c index 0495b6891a..1b8202852e 100644 --- a/xen/arch/x86/mm.c +++ b/xen/arch/x86/mm.c @@ -5468,6 +5468,7 @@ int modify_xen_mappings(unsigned long s, unsigned long e, unsigned int nf) l1_pgentry_t *pl1e; unsigned int i; unsigned long v = s; + int rc = -ENOMEM; /* Set of valid PTE bits which may be altered. */ #define FLAGS_MASK (_PAGE_NX|_PAGE_DIRTY|_PAGE_ACCESSED|_PAGE_RW|_PAGE_PRESENT) @@ -5511,7 +5512,8 @@ int modify_xen_mappings(unsigned long s, unsigned long e, unsigned int nf) /* PAGE1GB: shatter the superpage and fall through. */ l2t = alloc_xen_pagetable(); if ( !l2t ) - return -ENOMEM; + goto out; + for ( i = 0; i < L2_PAGETABLE_ENTRIES; i++ ) l2e_write(l2t + i, l2e_from_pfn(l3e_get_pfn(*pl3e) + @@ -5568,7 +5570,8 @@ int modify_xen_mappings(unsigned long s, unsigned long e, unsigned int nf) /* PSE: shatter the superpage and try again. */ l1t = alloc_xen_pagetable(); if ( !l1t ) - return -ENOMEM; + goto out; + for ( i = 0; i < L1_PAGETABLE_ENTRIES; i++ ) l1e_write(&l1t[i], l1e_from_pfn(l2e_get_pfn(*pl2e) + i, @@ -5701,7 +5704,10 @@ int modify_xen_mappings(unsigned long s, unsigned long e, unsigned int nf) flush_area(NULL, FLUSH_TLB_GLOBAL); #undef FLAGS_MASK - return 0; + rc = 0; + + out: + return rc; } #undef flush_area -- 2.30.2