From 15aaa819e20cb183f26392ed8ea16020630ef142 Mon Sep 17 00:00:00 2001 From: Marcelo Tosatti Date: Mon, 17 Mar 2008 10:08:18 -0300 Subject: [PATCH] KVM: MMU: handle page removal with shadow mapping Do not assume that a shadow mapping will always point to the same host frame number. Fixes crash with madvise(MADV_DONTNEED). [avi: move after first printk(), add another printk()] Signed-off-by: Marcelo Tosatti Signed-off-by: Avi Kivity --- arch/x86/kvm/mmu.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index e49c4d433c0..4ba85d95bd2 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -892,14 +892,25 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte, int *ptwrite, gfn_t gfn, struct page *page) { u64 spte; - int was_rmapped = is_rmap_pte(*shadow_pte); + int was_rmapped = 0; int was_writeble = is_writeble_pte(*shadow_pte); + hfn_t host_pfn = (*shadow_pte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT; pgprintk("%s: spte %llx access %x write_fault %d" " user_fault %d gfn %lx\n", __FUNCTION__, *shadow_pte, pt_access, write_fault, user_fault, gfn); + if (is_rmap_pte(*shadow_pte)) { + if (host_pfn != page_to_pfn(page)) { + pgprintk("hfn old %lx new %lx\n", + host_pfn, page_to_pfn(page)); + rmap_remove(vcpu->kvm, shadow_pte); + } + else + was_rmapped = 1; + } + /* * We don't set the accessed bit, since we sometimes want to see * whether the guest actually used the pte (in order to detect -- 2.41.1