Commit fc5659c8 authored Feb 18, 2009 by Joerg Roedel Committed by Avi Kivity Mar 24, 2009

KVM: MMU: handle compound pages in kvm_is_mmio_pfn



The function kvm_is_mmio_pfn is called before put_page is called on a
page by KVM. This is a problem when when this function is called on some
struct page which is part of a compund page. It does not test the
reserved flag of the compound page but of the struct page within the
compount page. This is a problem when KVM works with hugepages allocated
at boot time. These pages have the reserved bit set in all tail pages.
Only the flag in the compount head is cleared. KVM would not put such a
page which results in a memory leak.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Acked-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

parent c8076604

virt/kvm/kvm_main.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -535,8 +535,10 @@ static inline int valid_vcpu(int n)

		inline int kvm_is_mmio_pfn(pfn_t pfn)
		{
		if (pfn_valid(pfn))
		return PageReserved(pfn_to_page(pfn));
		if (pfn_valid(pfn)) {
		struct page *page = compound_head(pfn_to_page(pfn));
		return PageReserved(page);
		}

		return true;
		}

Admin message