From 1b0973bd8f788178f21d9eebdd879203464f8528 Mon Sep 17 00:00:00 2001
From: Avi Kivity <avi@qumranet.com>
Date: Fri, 5 Jan 2007 16:36:41 -0800
Subject: [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 <avi@qumranet.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---
drivers/kvm/kvm_main.c | 2 ++
drivers/kvm/paging_tmpl.h | 28 ++++++++++++++++++----------
2 files changed, 20 insertions(+), 10 deletions(-)
(limited to 'drivers/kvm')
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 4512d8c..68e121e 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 963d80e..3ade944 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,
--
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