On Fri, Mar 01, 2024, isaku.yamahata@xxxxxxxxx wrote: > From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx> > > Introduce a helper function to call kvm fault handler. This allows > a new ioctl to invoke kvm fault handler to populate without seeing > RET_PF_* enums or other KVM MMU internal definitions. > > Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx> > --- > arch/x86/kvm/mmu.h | 3 +++ > arch/x86/kvm/mmu/mmu.c | 30 ++++++++++++++++++++++++++++++ > 2 files changed, 33 insertions(+) > > diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h > index 60f21bb4c27b..48870c5e08ec 100644 > --- a/arch/x86/kvm/mmu.h > +++ b/arch/x86/kvm/mmu.h > @@ -183,6 +183,9 @@ static inline void kvm_mmu_refresh_passthrough_bits(struct kvm_vcpu *vcpu, > __kvm_mmu_refresh_passthrough_bits(vcpu, mmu); > } > > +int kvm_mmu_map_page(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code, > + u8 max_level, u8 *goal_level); > + > /* > * Check if a given access (described through the I/D, W/R and U/S bits of a > * page fault error code pfec) causes a permission fault with the given PTE > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > index e4cc7f764980..7d5e80d17977 100644 > --- a/arch/x86/kvm/mmu/mmu.c > +++ b/arch/x86/kvm/mmu/mmu.c > @@ -4659,6 +4659,36 @@ int kvm_tdp_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault) > return direct_page_fault(vcpu, fault); > } > > +int kvm_mmu_map_page(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code, > + u8 max_level, u8 *goal_level) > +{ > + struct kvm_page_fault fault = KVM_PAGE_FAULT_INIT(vcpu, gpa, error_code, > + false, max_level); > + int r; > + > + r = __kvm_mmu_do_page_fault(vcpu, &fault); > + > + if (is_error_noslot_pfn(fault.pfn) || vcpu->kvm->vm_bugged) > + return -EFAULT; This clobbers a non-zero 'r'. And KVM return -EIO if the VM is bugged/dead, not -EFAULT. I also don't see why KVM needs to explicitly check is_error_noslot_pfn(), that should be funneled to RET_PF_EMULATE. > + > + switch (r) { > + case RET_PF_RETRY: > + return -EAGAIN; > + > + case RET_PF_FIXED: > + case RET_PF_SPURIOUS: > + *goal_level = fault.goal_level; > + return 0; > + > + case RET_PF_CONTINUE: > + case RET_PF_EMULATE: -EINVAL woud be more appropriate for RET_PF_EMULATE. > + case RET_PF_INVALID: CONTINUE and INVALID should be WARN conditions. > + default: > + return -EIO; > + } > +} > +EXPORT_SYMBOL_GPL(kvm_mmu_map_page); Unnecessary export. > + > static void nonpaging_init_context(struct kvm_mmu *context) > { > context->page_fault = nonpaging_page_fault; > -- > 2.25.1 >