Paolo Bonzini <pbonzini@xxxxxxxxxx> writes: > On 13/07/2016 00:18, Bandan Das wrote: >> v1 of this series posted at https://lkml.org/lkml/2016/6/28/7 >> >> Changes since v1: >> - 1/5 : modify is_shadow_present_pte to check against 0xffffffff >> Reasoning provided in commit message. >> - 2/5 : Removed 2/5 from v1 since kvm doesn't use execute only. >> 3/5 from v1 is now 2/5. Introduce shadow_present_mask that >> signifies whether ept execute only is supported. Add/remove some >> comments as suggested in v1. >> - 3/5 : 4/5 from v1 is now 3/5. >> - 4/5 : update_permission_bitmask now sets u=1 only if host doesn't >> support ept execute only. >> - 5/5 : No change > > These are the diffs I have after review, do they look okay? > > diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c > index 190c0559c221..bd2535fdb9eb 100644 > --- a/arch/x86/kvm/mmu.c > +++ b/arch/x86/kvm/mmu.c > @@ -2524,11 +2524,10 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep, > return 0; > > /* > - * In the non-EPT case, execonly is not valid and so > - * the following line is equivalent to spte |= PT_PRESENT_MASK. > * For the EPT case, shadow_present_mask is 0 if hardware > - * supports it and we honor whatever way the guest set it. > - * See: FNAME(gpte_access) in paging_tmpl.h > + * supports exec-only page table entries. In that case, > + * ACC_USER_MASK and shadow_user_mask are used to represent > + * read access. See FNAME(gpte_access) in paging_tmpl.h. > */ I would still prefer a note about the non-EPT case, makes it easy to understand. > spte |= shadow_present_mask; > if (!speculative) > @@ -3923,9 +3922,6 @@ static void update_permission_bitmask(struct kvm_vcpu *vcpu, > * clearer. > */ > smap = cr4_smap && u && !uf && !ff; > - } else { > - if (shadow_present_mask) > - u = 1; > } > > fault = (ff && !x) || (uf && !u) || (wf && !w) || > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 576c47cda1a3..dfef081e76c0 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -6120,12 +6120,14 @@ static int handle_ept_violation(struct kvm_vcpu *vcpu) > gpa = vmcs_read64(GUEST_PHYSICAL_ADDRESS); > trace_kvm_page_fault(gpa, exit_qualification); > > - /* It is a write fault? */ > + /* it is a read fault? */ > + error_code = (exit_qualification << 2) & PFERR_USER_MASK; > + /* it is a write fault? */ > error_code = exit_qualification & PFERR_WRITE_MASK; > /* It is a fetch fault? */ > error_code |= (exit_qualification << 2) & PFERR_FETCH_MASK; > /* ept page table is present? */ > - error_code |= (exit_qualification >> 3) & PFERR_PRESENT_MASK; > + error_code |= (exit_qualification & 0x38) != 0; > Thank you for the thorough review here. I missed that we didn't set the read bit at all. I am still a little unclear how permission_fault works though... > vcpu->arch.exit_qualification = exit_qualification; > > @@ -6474,8 +6476,7 @@ static __init int hardware_setup(void) > (enable_ept_ad_bits) ? VMX_EPT_DIRTY_BIT : 0ull, > 0ull, VMX_EPT_EXECUTABLE_MASK, > cpu_has_vmx_ept_execute_only() ? > - 0ull : PT_PRESENT_MASK); > - BUILD_BUG_ON(PT_PRESENT_MASK != VMX_EPT_READABLE_MASK); > + 0ull : VMX_EPT_READABLE_MASK); I wanted to keep it the former way because "PT_PRESENT_MASK is equal to VMX_EPT_READABLE_MASK" is an assumption all throughout. I wanted to use this section to catch mismatches. Bandan > ept_set_mmio_spte_mask(); > kvm_enable_tdp(); > } else -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
