From: Joerg Roedel Date: Wed, 18 Feb 2009 13:08:58 +0000 (+0100) Subject: KVM: MMU: handle compound pages in kvm_is_mmio_pfn X-Git-Tag: v2.6.30-rc1~664^2~21 X-Git-Url: http://ftp.safe.ca/?p=safe%2Fjmp%2Flinux-2.6;a=commitdiff_plain;h=fc5659c8c6b6c4e02ac354b369017c1bf231f347 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 Acked-by: Marcelo Tosatti Signed-off-by: Avi Kivity --- diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 266bdaf..0ed662d 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -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; }