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authorHeiko Carstens <heiko.carstens@de.ibm.com>2013-11-18 10:35:55 +0100
committerGleb Natapov <gleb@redhat.com>2013-11-21 11:19:32 +0200
commit8a3caa6d74597c2a083f7c87f866891a0b12540b (patch)
treeee4cfd5a3787c0da3c8e84519ace12cc83461cf6 /virt
parent521ee0cfb876dd31ce4e0878e1163fe0817a7acc (diff)
downloadlinux-8a3caa6d74597c2a083f7c87f866891a0b12540b.tar.gz
KVM: kvm_clear_guest_page(): fix empty_zero_page usage
Using the address of 'empty_zero_page' as source address in order to clear a page is wrong. On some architectures empty_zero_page is only the pointer to the struct page of the empty_zero_page. Therefore the clear page operation would copy the contents of a couple of struct pages instead of clearing a page. For kvm only arm/arm64 are affected by this bug. To fix this use the ZERO_PAGE macro instead which will return the struct page address of the empty_zero_page on all architectures. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Gleb Natapov <gleb@redhat.com>
Diffstat (limited to 'virt')
-rw-r--r--virt/kvm/kvm_main.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 662f34c3287..a0aa84b5941 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1615,8 +1615,9 @@ EXPORT_SYMBOL_GPL(kvm_read_guest_cached);
int kvm_clear_guest_page(struct kvm *kvm, gfn_t gfn, int offset, int len)
{
- return kvm_write_guest_page(kvm, gfn, (const void *) empty_zero_page,
- offset, len);
+ const void *zero_page = (const void *) __va(page_to_phys(ZERO_PAGE(0)));
+
+ return kvm_write_guest_page(kvm, gfn, zero_page, offset, len);
}
EXPORT_SYMBOL_GPL(kvm_clear_guest_page);