From 1b0973bd8f788178f21d9eebdd879203464f8528 Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Fri, 5 Jan 2007 16:36:41 -0800 Subject: [PATCH] [PATCH] KVM: MMU: Use the guest pdptrs instead of mapping cr3 in pae mode This lets us not write protect a partial page, and is anyway what a real processor does. Signed-off-by: Avi Kivity Acked-by: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/kvm/kvm_main.c | 2 ++ drivers/kvm/paging_tmpl.h | 28 ++++++++++++++++++---------- 2 files changed, 20 insertions(+), 10 deletions(-) diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c index 4512d8c39c..68e121eecc 100644 --- a/drivers/kvm/kvm_main.c +++ b/drivers/kvm/kvm_main.c @@ -1491,6 +1491,8 @@ static int kvm_dev_ioctl_set_sregs(struct kvm *kvm, struct kvm_sregs *sregs) mmu_reset_needed |= vcpu->cr4 != sregs->cr4; kvm_arch_ops->set_cr4(vcpu, sregs->cr4); + if (!is_long_mode(vcpu) && is_pae(vcpu)) + load_pdptrs(vcpu, vcpu->cr3); if (mmu_reset_needed) kvm_mmu_reset_context(vcpu); diff --git a/drivers/kvm/paging_tmpl.h b/drivers/kvm/paging_tmpl.h index 963d80e227..3ade9445ab 100644 --- a/drivers/kvm/paging_tmpl.h +++ b/drivers/kvm/paging_tmpl.h @@ -67,18 +67,28 @@ static void FNAME(walk_addr)(struct guest_walker *walker, hpa_t hpa; struct kvm_memory_slot *slot; pt_element_t *ptep; + pt_element_t root; walker->level = vcpu->mmu.root_level; - walker->table_gfn = (vcpu->cr3 & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT; + walker->table = NULL; + root = vcpu->cr3; +#if PTTYPE == 64 + if (!is_long_mode(vcpu)) { + walker->ptep = &vcpu->pdptrs[(addr >> 30) & 3]; + root = *walker->ptep; + if (!(root & PT_PRESENT_MASK)) + return; + --walker->level; + } +#endif + walker->table_gfn = (root & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT; slot = gfn_to_memslot(vcpu->kvm, walker->table_gfn); - hpa = safe_gpa_to_hpa(vcpu, vcpu->cr3 & PT64_BASE_ADDR_MASK); + hpa = safe_gpa_to_hpa(vcpu, root & PT64_BASE_ADDR_MASK); walker->table = kmap_atomic(pfn_to_page(hpa >> PAGE_SHIFT), KM_USER0); ASSERT((!is_long_mode(vcpu) && is_pae(vcpu)) || (vcpu->cr3 & ~(PAGE_MASK | CR3_FLAGS_MASK)) == 0); - walker->table = (pt_element_t *)( (unsigned long)walker->table | - (unsigned long)(vcpu->cr3 & ~(PAGE_MASK | CR3_FLAGS_MASK)) ); walker->inherited_ar = PT_USER_MASK | PT_WRITABLE_MASK; for (;;) { @@ -89,11 +99,8 @@ static void FNAME(walk_addr)(struct guest_walker *walker, ASSERT(((unsigned long)walker->table & PAGE_MASK) == ((unsigned long)ptep & PAGE_MASK)); - /* Don't set accessed bit on PAE PDPTRs */ - if (vcpu->mmu.root_level != 3 || walker->level != 3) - if ((*ptep & (PT_PRESENT_MASK | PT_ACCESSED_MASK)) - == PT_PRESENT_MASK) - *ptep |= PT_ACCESSED_MASK; + if (is_present_pte(*ptep) && !(*ptep & PT_ACCESSED_MASK)) + *ptep |= PT_ACCESSED_MASK; if (!is_present_pte(*ptep) || walker->level == PT_PAGE_TABLE_LEVEL || @@ -116,7 +123,8 @@ static void FNAME(walk_addr)(struct guest_walker *walker, static void FNAME(release_walker)(struct guest_walker *walker) { - kunmap_atomic(walker->table, KM_USER0); + if (walker->table) + kunmap_atomic(walker->table, KM_USER0); } static void FNAME(set_pte)(struct kvm_vcpu *vcpu, u64 guest_pte, -- 2.39.5