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| author | Heiko Carstens <heiko.carstens@de.ibm.com> | 2013-11-18 10:35:55 +0100 |
|---|---|---|
| committer | Gleb Natapov <gleb@redhat.com> | 2013-11-21 11:19:32 +0200 |
| commit | 8a3caa6d74597c2a083f7c87f866891a0b12540b (patch) | |
| tree | ee4cfd5a3787c0da3c8e84519ace12cc83461cf6 /virt/kvm | |
| parent | 521ee0cfb876dd31ce4e0878e1163fe0817a7acc (diff) | |
| download | lwn-8a3caa6d74597c2a083f7c87f866891a0b12540b.tar.gz lwn-8a3caa6d74597c2a083f7c87f866891a0b12540b.zip | |
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/kvm')
| -rw-r--r-- | virt/kvm/kvm_main.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 662f34c3287e..a0aa84b5941a 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); |