diff options
Diffstat (limited to 'drivers/kvm/mmu.c')
-rw-r--r-- | drivers/kvm/mmu.c | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c index cace1e4..a91e05b 100644 --- a/drivers/kvm/mmu.c +++ b/drivers/kvm/mmu.c @@ -879,6 +879,89 @@ struct page *gva_to_page(struct kvm_vcpu *vcpu, gva_t gva) return gfn_to_page(vcpu->kvm, gpa >> PAGE_SHIFT); } +static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte, + unsigned pt_access, unsigned pte_access, + int user_fault, int write_fault, int dirty, + int *ptwrite, gfn_t gfn) +{ + u64 spte; + int was_rmapped = is_rmap_pte(*shadow_pte); + struct page *page; + + pgprintk("%s: spte %llx gpte %llx access %x write_fault %d" + " user_fault %d gfn %lx\n", + __FUNCTION__, *shadow_pte, (u64)gpte, pt_access, + write_fault, user_fault, gfn); + + /* + * We don't set the accessed bit, since we sometimes want to see + * whether the guest actually used the pte (in order to detect + * demand paging). + */ + spte = PT_PRESENT_MASK | PT_DIRTY_MASK; + if (!dirty) + pte_access &= ~ACC_WRITE_MASK; + if (!(pte_access & ACC_EXEC_MASK)) + spte |= PT64_NX_MASK; + + page = gfn_to_page(vcpu->kvm, gfn); + + spte |= PT_PRESENT_MASK; + if (pte_access & ACC_USER_MASK) + spte |= PT_USER_MASK; + + if (is_error_page(page)) { + set_shadow_pte(shadow_pte, + shadow_trap_nonpresent_pte | PT_SHADOW_IO_MARK); + kvm_release_page_clean(page); + return; + } + + spte |= page_to_phys(page); + + if ((pte_access & ACC_WRITE_MASK) + || (write_fault && !is_write_protection(vcpu) && !user_fault)) { + struct kvm_mmu_page *shadow; + + spte |= PT_WRITABLE_MASK; + if (user_fault) { + mmu_unshadow(vcpu->kvm, gfn); + goto unshadowed; + } + + shadow = kvm_mmu_lookup_page(vcpu->kvm, gfn); + if (shadow) { + pgprintk("%s: found shadow page for %lx, marking ro\n", + __FUNCTION__, gfn); + pte_access &= ~ACC_WRITE_MASK; + if (is_writeble_pte(spte)) { + spte &= ~PT_WRITABLE_MASK; + kvm_x86_ops->tlb_flush(vcpu); + } + if (write_fault) + *ptwrite = 1; + } + } + +unshadowed: + + if (pte_access & ACC_WRITE_MASK) + mark_page_dirty(vcpu->kvm, gfn); + + pgprintk("%s: setting spte %llx\n", __FUNCTION__, spte); + set_shadow_pte(shadow_pte, spte); + page_header_update_slot(vcpu->kvm, shadow_pte, gfn); + if (!was_rmapped) { + rmap_add(vcpu, shadow_pte, gfn); + if (!is_rmap_pte(*shadow_pte)) + kvm_release_page_clean(page); + } + else + kvm_release_page_clean(page); + if (!ptwrite || !*ptwrite) + vcpu->last_pte_updated = shadow_pte; +} + static void nonpaging_new_cr3(struct kvm_vcpu *vcpu) { } |