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[PATCH] KVM: MMU: Implement child shadow unlinking 

When removing a page table, we must maintain the parent_pte field all child
shadow page tables.

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>
hifive-unleashed-5.1
Avi Kivity 2007-01-05 16:36:46 -08:00 committed by Linus Torvalds
parent a436036baf
commit 697fe2e24a
1 changed files with 38 additions and 4 deletions
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42
drivers/kvm/mmu.c
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@ -402,12 +402,21 @@ static void mmu_page_remove_parent_pte(struct kvm_mmu_page *page,
break;
if (pte_chain->parent_ptes[i] != parent_pte)
continue;
while (i + 1 < NR_PTE_CHAIN_ENTRIES) {
while (i + 1 < NR_PTE_CHAIN_ENTRIES
&& pte_chain->parent_ptes[i + 1]) {
pte_chain->parent_ptes[i]
= pte_chain->parent_ptes[i + 1];
++i;
}
pte_chain->parent_ptes[i] = NULL;
if (i == 0) {
hlist_del(&pte_chain->link);
kfree(pte_chain);
if (hlist_empty(&page->parent_ptes)) {
page->multimapped = 0;
page->parent_pte = NULL;
}
}
return;
}
BUG();
@ -481,7 +490,30 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
static void kvm_mmu_page_unlink_children(struct kvm_vcpu *vcpu,
struct kvm_mmu_page *page)
{
BUG();
unsigned i;
u64 *pt;
u64 ent;
pt = __va(page->page_hpa);
if (page->role.level == PT_PAGE_TABLE_LEVEL) {
for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
if (pt[i] & PT_PRESENT_MASK)
rmap_remove(vcpu->kvm, &pt[i]);
pt[i] = 0;
}
return;
}
for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
ent = pt[i];
pt[i] = 0;
if (!(ent & PT_PRESENT_MASK))
continue;
ent &= PT64_BASE_ADDR_MASK;
mmu_page_remove_parent_pte(page_header(ent), &pt[i]);
}
}
static void kvm_mmu_put_page(struct kvm_vcpu *vcpu,
@ -489,8 +521,7 @@ static void kvm_mmu_put_page(struct kvm_vcpu *vcpu,
u64 *parent_pte)
{
mmu_page_remove_parent_pte(page, parent_pte);
if (page->role.level > PT_PAGE_TABLE_LEVEL)
kvm_mmu_page_unlink_children(vcpu, page);
kvm_mmu_page_unlink_children(vcpu, page);
hlist_del(&page->hash_link);
list_del(&page->link);
list_add(&page->link, &vcpu->free_pages);
@ -511,6 +542,7 @@ static void kvm_mmu_zap_page(struct kvm_vcpu *vcpu,
struct kvm_pte_chain, link);
parent_pte = chain->parent_ptes[0];
}
BUG_ON(!parent_pte);
kvm_mmu_put_page(vcpu, page, parent_pte);
*parent_pte = 0;
}
@ -530,6 +562,8 @@ static int kvm_mmu_unprotect_page(struct kvm_vcpu *vcpu, gfn_t gfn)
bucket = &vcpu->kvm->mmu_page_hash[index];
hlist_for_each_entry_safe(page, node, n, bucket, hash_link)
if (page->gfn == gfn && !page->role.metaphysical) {
pgprintk("%s: gfn %lx role %x\n", __FUNCTION__, gfn,
page->role.word);
kvm_mmu_zap_page(vcpu, page);
r = 1;
}