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authorAvi Kivity <avi@qumranet.com>2008-08-22 19:24:38 +0300
committerAvi Kivity <avi@qumranet.com>2008-10-15 10:15:23 +0200
commit3d000db5688c8beff6319fb9ff4b98dcac32f798 (patch)
tree75e8464d300c232efa1793477c555e1a5b7e0a80
parent6c41f428b72afe5a581b967590c12538db31d399 (diff)
KVM: MMU: Add generic shadow walker
We currently walk the shadow page tables in two places: direct map (for real mode and two dimensional paging) and paging mode shadow. Since we anticipate requiring a third walk (for invlpg), it makes sense to have a generic facility for shadow walk. This patch adds such a shadow walker, walks the page tables and calls a method for every spte encountered. The method can examine the spte, modify it, or even instantiate it. The walk can be aborted by returning nonzero from the method. Signed-off-by: Avi Kivity <avi@qumranet.com>
-rw-r--r--arch/x86/kvm/mmu.c34
1 files changed, 34 insertions, 0 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 72f739aa862..8b95cf748b5 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -142,6 +142,11 @@ struct kvm_rmap_desc {
struct kvm_rmap_desc *more;
};
+struct kvm_shadow_walk {
+ int (*entry)(struct kvm_shadow_walk *walk, struct kvm_vcpu *vcpu,
+ gva_t addr, u64 *spte, int level);
+};
+
static struct kmem_cache *pte_chain_cache;
static struct kmem_cache *rmap_desc_cache;
static struct kmem_cache *mmu_page_header_cache;
@@ -935,6 +940,35 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
return sp;
}
+static int walk_shadow(struct kvm_shadow_walk *walker,
+ struct kvm_vcpu *vcpu, gva_t addr)
+{
+ hpa_t shadow_addr;
+ int level;
+ int r;
+ u64 *sptep;
+ unsigned index;
+
+ shadow_addr = vcpu->arch.mmu.root_hpa;
+ level = vcpu->arch.mmu.shadow_root_level;
+ if (level == PT32E_ROOT_LEVEL) {
+ shadow_addr = vcpu->arch.mmu.pae_root[(addr >> 30) & 3];
+ shadow_addr &= PT64_BASE_ADDR_MASK;
+ --level;
+ }
+
+ while (level >= PT_PAGE_TABLE_LEVEL) {
+ index = SHADOW_PT_INDEX(addr, level);
+ sptep = ((u64 *)__va(shadow_addr)) + index;
+ r = walker->entry(walker, vcpu, addr, sptep, level);
+ if (r)
+ return r;
+ shadow_addr = *sptep & PT64_BASE_ADDR_MASK;
+ --level;
+ }
+ return 0;
+}
+
static void kvm_mmu_page_unlink_children(struct kvm *kvm,
struct kvm_mmu_page *sp)
{