From f59c1d2ded54e4bd7a9126f4a32c9eca8b336457 Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Tue, 6 Jul 2010 16:20:43 +0300 Subject: KVM: MMU: Keep going on permission error Real hardware disregards permission errors when computing page fault error code bit 0 (page present). Do the same. Reviewed-by: Xiao Guangrong Signed-off-by: Avi Kivity --- arch/x86/kvm/paging_tmpl.h | 52 ++++++++++++++++++++++++++-------------------- 1 file changed, 30 insertions(+), 22 deletions(-) (limited to 'arch/x86/kvm/paging_tmpl.h') diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index 3a3f6d784d7..1cea41cad06 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -119,21 +119,25 @@ static int FNAME(walk_addr)(struct guest_walker *walker, { pt_element_t pte; gfn_t table_gfn; - unsigned index, pt_access, pte_access; + unsigned index, pt_access, uninitialized_var(pte_access); gpa_t pte_gpa; - int rsvd_fault = 0; + bool eperm, present, rsvd_fault; trace_kvm_mmu_pagetable_walk(addr, write_fault, user_fault, fetch_fault); walk: + present = true; + eperm = rsvd_fault = false; walker->level = vcpu->arch.mmu.root_level; pte = vcpu->arch.cr3; #if PTTYPE == 64 if (!is_long_mode(vcpu)) { pte = kvm_pdptr_read(vcpu, (addr >> 30) & 3); trace_kvm_mmu_paging_element(pte, walker->level); - if (!is_present_gpte(pte)) - goto not_present; + if (!is_present_gpte(pte)) { + present = false; + goto error; + } --walker->level; } #endif @@ -151,31 +155,36 @@ walk: walker->table_gfn[walker->level - 1] = table_gfn; walker->pte_gpa[walker->level - 1] = pte_gpa; - if (kvm_read_guest(vcpu->kvm, pte_gpa, &pte, sizeof(pte))) - goto not_present; + if (kvm_read_guest(vcpu->kvm, pte_gpa, &pte, sizeof(pte))) { + present = false; + break; + } trace_kvm_mmu_paging_element(pte, walker->level); - if (!is_present_gpte(pte)) - goto not_present; + if (!is_present_gpte(pte)) { + present = false; + break; + } - rsvd_fault = is_rsvd_bits_set(vcpu, pte, walker->level); - if (rsvd_fault) - goto access_error; + if (is_rsvd_bits_set(vcpu, pte, walker->level)) { + rsvd_fault = true; + break; + } if (write_fault && !is_writable_pte(pte)) if (user_fault || is_write_protection(vcpu)) - goto access_error; + eperm = true; if (user_fault && !(pte & PT_USER_MASK)) - goto access_error; + eperm = true; #if PTTYPE == 64 if (fetch_fault && (pte & PT64_NX_MASK)) - goto access_error; + eperm = true; #endif - if (!(pte & PT_ACCESSED_MASK)) { + if (!eperm && !rsvd_fault && !(pte & PT_ACCESSED_MASK)) { trace_kvm_mmu_set_accessed_bit(table_gfn, index, sizeof(pte)); if (FNAME(cmpxchg_gpte)(vcpu->kvm, table_gfn, @@ -214,6 +223,9 @@ walk: --walker->level; } + if (!present || eperm || rsvd_fault) + goto error; + if (write_fault && !is_dirty_gpte(pte)) { bool ret; @@ -233,14 +245,10 @@ walk: __func__, (u64)pte, pte_access, pt_access); return 1; -not_present: +error: walker->error_code = 0; - goto err; - -access_error: - walker->error_code = PFERR_PRESENT_MASK; - -err: + if (present) + walker->error_code |= PFERR_PRESENT_MASK; if (write_fault) walker->error_code |= PFERR_WRITE_MASK; if (user_fault) -- cgit v1.2.3-70-g09d2