diff options
author | Avi Kivity <avi@qumranet.com> | 2008-08-22 19:24:38 +0300 |
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committer | Avi Kivity <avi@qumranet.com> | 2008-10-15 10:15:23 +0200 |
commit | 3d000db5688c8beff6319fb9ff4b98dcac32f798 (patch) | |
tree | 75e8464d300c232efa1793477c555e1a5b7e0a80 /arch/x86/kvm/mmu.c | |
parent | 6c41f428b72afe5a581b967590c12538db31d399 (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>
Diffstat (limited to 'arch/x86/kvm/mmu.c')
-rw-r--r-- | arch/x86/kvm/mmu.c | 34 |
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) { |