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Commit 15aaa819 authored by Marcelo Tosatti's avatar Marcelo Tosatti Committed by Avi Kivity
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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: default avatarMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
parent 4b1a80fa

arch/x86/kvm/mmu.c

+12 −1
Original line number Diff line number Diff line
@@ -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