The patch titled KVM: MMU: Handle misaligned accesses to write protected guest page tables has been removed from the -mm tree. Its filename was kvm-mmu-handle-misaligned-accesses-to-write-protected-guest-page-tables.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ Subject: KVM: MMU: Handle misaligned accesses to write protected guest page tables From: Avi Kivity <avi@xxxxxxxxxxxx> A misaligned access affects two shadow ptes instead of just one. Since a misaligned access is unlikely to occur on a real page table, just zap the page out of existence, avoiding further trouble. Signed-off-by: Avi Kivity <avi@xxxxxxxxxxxx> Acked-by: Ingo Molnar <mingo@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxx> --- drivers/kvm/mmu.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) diff -puN drivers/kvm/mmu.c~kvm-mmu-handle-misaligned-accesses-to-write-protected-guest-page-tables drivers/kvm/mmu.c --- a/drivers/kvm/mmu.c~kvm-mmu-handle-misaligned-accesses-to-write-protected-guest-page-tables +++ a/drivers/kvm/mmu.c @@ -954,21 +954,36 @@ void kvm_mmu_pre_write(struct kvm_vcpu * gfn_t gfn = gpa >> PAGE_SHIFT; struct kvm_mmu_page *page; struct kvm_mmu_page *child; - struct hlist_node *node; + struct hlist_node *node, *n; struct hlist_head *bucket; unsigned index; u64 *spte; u64 pte; unsigned offset = offset_in_page(gpa); + unsigned pte_size; unsigned page_offset; + unsigned misaligned; int level; pgprintk("%s: gpa %llx bytes %d\n", __FUNCTION__, gpa, bytes); index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES; bucket = &vcpu->kvm->mmu_page_hash[index]; - hlist_for_each_entry(page, node, bucket, hash_link) { + hlist_for_each_entry_safe(page, node, n, bucket, hash_link) { if (page->gfn != gfn || page->role.metaphysical) continue; + pte_size = page->role.glevels == PT32_ROOT_LEVEL ? 4 : 8; + misaligned = (offset ^ (offset + bytes - 1)) & ~(pte_size - 1); + if (misaligned) { + /* + * Misaligned accesses are too much trouble to fix + * up; also, they usually indicate a page is not used + * as a page table. + */ + pgprintk("misaligned: gpa %llx bytes %d role %x\n", + gpa, bytes, page->role.word); + kvm_mmu_zap_page(vcpu, page); + continue; + } page_offset = offset; level = page->role.level; if (page->role.glevels == PT32_ROOT_LEVEL) { _ Patches currently in -mm which might be from avi@xxxxxxxxxxxx are - To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html