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 <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 3a3f6d7..1cea41c 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -119,21 +119,25 @@
{
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 @@
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 @@
--walker->level;
}
+ if (!present || eperm || rsvd_fault)
+ goto error;
+
if (write_fault && !is_dirty_gpte(pte)) {
bool ret;
@@ -233,14 +245,10 @@
__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)
