From 46785b54f8cda84811f02bdeee8d9bd780fa29dc Mon Sep 17 00:00:00 2001 From: Keir Fraser Date: Thu, 14 Jan 2010 14:11:25 +0000 Subject: [PATCH] Make sure the minimum shadow allocation is never zero. Signed-off-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 434d567536..5e37bb01d4 100644 --- a/xen/arch/x86/mm/shadow/common.c +++ b/xen/arch/x86/mm/shadow/common.c @@ -1244,10 +1244,11 @@ int shadow_cmpxchg_guest_entry(struct vcpu *v, intpte_t *p, * instruction, we must be able to map a large number (about thirty) VAs * at the same time, which means that to guarantee progress, we must * allow for more than ninety allocated pages per vcpu. We round that - * up to 128 pages, or half a megabyte per vcpu. */ + * up to 128 pages, or half a megabyte per vcpu, and add 1 more vcpu's + * worth to make sure we never return zero. */ static unsigned int shadow_min_acceptable_pages(struct domain *d) { - u32 vcpu_count = 0; + u32 vcpu_count = 1; struct vcpu *v; for_each_vcpu(d, v) -- 2.30.2