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KVM: MMU: Keep going on permission error

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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>
This commit is contained in:
Avi Kivity 2010-07-06 16:20:43 +03:00
parent b0eeec29fe
commit f59c1d2ded
1 changed files with 30 additions and 22 deletions
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52
arch/x86/kvm/paging_tmpl.h
View File

@ -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)