[PATCH 19/58] KVM: MMU: Store shadow page tables as kernel virtual addresses, not physical

Avi Kivity
2007-06-17T09:44:00Z

Simpifies things a bit.

Signed-off-by: Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
---
drivers/kvm/kvm.h | 2 +-
drivers/kvm/mmu.c | 32 +++++++++++++++-----------------
drivers/kvm/paging_tmpl.h | 2 +-
3 files changed, 17 insertions(+), 19 deletions(-)

diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index 5e6dac5..fc4a6c1 100644
--- a/drivers/kvm/kvm.h
+++ b/drivers/kvm/kvm.h
@@ -139,7 +139,7 @@ struct kvm_mmu_page {
gfn_t gfn;
union kvm_mmu_page_role role;

- hpa_t page_hpa;
+ u64 *spt;
unsigned long slot_bitmap; /* One bit set per slot which has memory
* in this shadow page.
*/
diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c
index a96c9ae..c85c664 100644
--- a/drivers/kvm/mmu.c
+++ b/drivers/kvm/mmu.c
@@ -439,13 +439,12 @@ static void rmap_write_protect(struct kvm_vcpu *vcpu, u64 gfn)
}

#ifdef MMU_DEBUG
-static int is_empty_shadow_page(hpa_t page_hpa)
+static int is_empty_shadow_page(u64 *spt)
{
u64 *pos;
u64 *end;

- for (pos = __va(page_hpa), end = pos + PAGE_SIZE / sizeof(u64);
- pos != end; pos++)
+ for (pos = spt, end = pos + PAGE_SIZE / sizeof(u64); pos != end; pos++)
if (*pos != 0) {
printk(KERN_ERR "%s: %p %llx\n", __FUNCTION__,
pos, *pos);
@@ -458,7 +457,7 @@ static int is_empty_shadow_page(hpa_t page_hpa)
static void kvm_mmu_free_page(struct kvm_vcpu *vcpu,
struct kvm_mmu_page *page_head)
{
- ASSERT(is_empty_shadow_page(page_head->page_hpa));
+ ASSERT(is_empty_shadow_page(page_head->spt));
list_move(&page_head->link, &vcpu->free_pages);
++vcpu->kvm->n_free_mmu_pages;
}
@@ -478,7 +477,7 @@ static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu,

page = list_entry(vcpu->free_pages.next, struct kvm_mmu_page, link);
list_move(&page->link, &vcpu->kvm->active_mmu_pages);
- ASSERT(is_empty_shadow_page(page->page_hpa));
+ ASSERT(is_empty_shadow_page(page->spt));
page->slot_bitmap = 0;
page->multimapped = 0;
page->parent_pte = parent_pte;
@@ -636,7 +635,7 @@ static void kvm_mmu_page_unlink_children(struct kvm_vcpu *vcpu,
u64 *pt;
u64 ent;

- pt = __va(page->page_hpa);
+ pt = page->spt;

if (page->role.level == PT_PAGE_TABLE_LEVEL) {
for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
@@ -803,7 +802,7 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, hpa_t p)
return -ENOMEM;
}

- table[index] = new_table->page_hpa | PT_PRESENT_MASK
+ table[index] = __pa(new_table->spt) | PT_PRESENT_MASK
| PT_WRITABLE_MASK | PT_USER_MASK;
}
table_addr = table[index] & PT64_BASE_ADDR_MASK;
@@ -855,7 +854,7 @@ static void mmu_alloc_roots(struct kvm_vcpu *vcpu)
ASSERT(!VALID_PAGE(root));
page = kvm_mmu_get_page(vcpu, root_gfn, 0,
PT64_ROOT_LEVEL, 0, 0, NULL);
- root = page->page_hpa;
+ root = __pa(page->spt);
++page->root_count;
vcpu->mmu.root_hpa = root;
return;
@@ -876,7 +875,7 @@ static void mmu_alloc_roots(struct kvm_vcpu *vcpu)
page = kvm_mmu_get_page(vcpu, root_gfn, i << 30,
PT32_ROOT_LEVEL, !is_paging(vcpu),
0, NULL);
- root = page->page_hpa;
+ root = __pa(page->spt);
++page->root_count;
vcpu->mmu.pae_root[i] = root | PT_PRESENT_MASK;
}
@@ -1220,8 +1219,7 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
if (quadrant != page->role.quadrant)
continue;
}
- spte = __va(page->page_hpa);
- spte += page_offset / sizeof(*spte);
+ spte = &page->spt[page_offset / sizeof(*spte)];
while (npte--) {
mmu_pte_write_zap_pte(vcpu, page, spte);
mmu_pte_write_new_pte(vcpu, page, spte, new, bytes);
@@ -1262,8 +1260,8 @@ static void free_mmu_pages(struct kvm_vcpu *vcpu)
page = list_entry(vcpu->free_pages.next,
struct kvm_mmu_page, link);
list_del(&page->link);
- __free_page(pfn_to_page(page->page_hpa >> PAGE_SHIFT));
- page->page_hpa = INVALID_PAGE;
+ free_page((unsigned long)page->spt);
+ page->spt = NULL;
}
free_page((unsigned long)vcpu->mmu.pae_root);
}
@@ -1282,8 +1280,8 @@ static int alloc_mmu_pages(struct kvm_vcpu *vcpu)
if ((page = alloc_page(GFP_KERNEL)) == NULL)
goto error_1;
set_page_private(page, (unsigned long)page_header);
- page_header->page_hpa = (hpa_t)page_to_pfn(page) << PAGE_SHIFT;
- memset(__va(page_header->page_hpa), 0, PAGE_SIZE);
+ page_header->spt = page_address(page);
+ memset(page_header->spt, 0, PAGE_SIZE);
list_add(&page_header->link, &vcpu->free_pages);
++vcpu->kvm->n_free_mmu_pages;
}
@@ -1346,7 +1344,7 @@ void kvm_mmu_slot_remove_write_access(struct kvm_vcpu *vcpu, int slot)
if (!test_bit(slot, &page->slot_bitmap))
continue;

- pt = __va(page->page_hpa);
+ pt = page->spt;
for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
/* avoid RMW */
if (pt[i] & PT_WRITABLE_MASK) {
@@ -1497,7 +1495,7 @@ static int count_writable_mappings(struct kvm_vcpu *vcpu)
int i;

list_for_each_entry(page, &vcpu->kvm->active_mmu_pages, link) {
- u64 *pt = __va(page->page_hpa);
+ u64 *pt = page->spt;

if (page->role.level != PT_PAGE_TABLE_LEVEL)
continue;
diff --git a/drivers/kvm/paging_tmpl.h b/drivers/kvm/paging_tmpl.h
index 10ba0a8..6dd0da9 100644
--- a/drivers/kvm/paging_tmpl.h
+++ b/drivers/kvm/paging_tmpl.h
@@ -304,7 +304,7 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
shadow_page = kvm_mmu_get_page(vcpu, table_gfn, addr, level-1,
metaphysical, hugepage_access,
shadow_ent);
- shadow_addr = shadow_page->page_hpa;
+ shadow_addr = __pa(shadow_page->spt);
shadow_pte = shadow_addr | PT_PRESENT_MASK | PT_ACCESSED_MASK
| PT_WRITABLE_MASK | PT_USER_MASK;
*shadow_ent = shadow_pte;