From 3e64b93244858a140f9ffc6e6a7bbbd714cf0e47 Mon Sep 17 00:00:00 2001 From: Keir Fraser Date: Thu, 26 Nov 2009 11:31:16 +0000 Subject: [PATCH] x86 shadow: don't try to unsshadow for p2m changes after the shadows have been torn down. Signed-off-by: Tim Deegan --- xen/arch/x86/mm/shadow/common.c | 25 +++++++++++++++++++------ 1 file changed, 19 insertions(+), 6 deletions(-) diff --git a/xen/arch/x86/mm/shadow/common.c b/xen/arch/x86/mm/shadow/common.c index 94457a3281..dc288fd364 100644 --- a/xen/arch/x86/mm/shadow/common.c +++ b/xen/arch/x86/mm/shadow/common.c @@ -3440,14 +3440,12 @@ static int shadow_test_disable(struct domain *d) * with new content. It is responsible for update the entry, as well as other * shadow processing jobs. */ -void -shadow_write_p2m_entry(struct vcpu *v, unsigned long gfn, - l1_pgentry_t *p, mfn_t table_mfn, - l1_pgentry_t new, unsigned int level) + +static void sh_unshadow_for_p2m_change(struct vcpu *v, unsigned long gfn, + l1_pgentry_t *p, mfn_t table_mfn, + l1_pgentry_t new, unsigned int level) { struct domain *d = v->domain; - - shadow_lock(d); /* If we're removing an MFN from the p2m, remove it from the shadows too */ if ( level == 1 ) @@ -3503,6 +3501,21 @@ shadow_write_p2m_entry(struct vcpu *v, unsigned long gfn, unmap_domain_page(npte); } } +} + +void +shadow_write_p2m_entry(struct vcpu *v, unsigned long gfn, + l1_pgentry_t *p, mfn_t table_mfn, + l1_pgentry_t new, unsigned int level) +{ + struct domain *d = v->domain; + + shadow_lock(d); + + /* If there are any shadows, update them. But if shadow_teardown() + * has already been called then it's not safe to try. */ + if ( likely(d->arch.paging.shadow.total_pages != 0) ) + sh_unshadow_for_p2m_change(v, gfn, p, table_mfn, new, level); /* Update the entry with new content */ safe_write_pte(p, new); -- 2.30.2