On Wed, Mar 15, 2023 at 02:17:36AM +0000, Anish Moorthy wrote: > When a memslot has the KVM_MEM_MEMORY_FAULT_EXIT flag set, exit to > userspace upon encountering a page fault for which the userspace > page tables do not contain a present mapping. > > Signed-off-by: Anish Moorthy <amoorthy@xxxxxxxxxx> > Acked-by: James Houghton <jthoughton@xxxxxxxxxx> > --- > arch/arm64/kvm/arm.c | 1 + > arch/arm64/kvm/mmu.c | 14 ++++++++++++-- > 2 files changed, 13 insertions(+), 2 deletions(-) > > diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c > index 3bd732eaf0872..f8337e757c777 100644 > --- a/arch/arm64/kvm/arm.c > +++ b/arch/arm64/kvm/arm.c > @@ -220,6 +220,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) > case KVM_CAP_VCPU_ATTRIBUTES: > case KVM_CAP_PTP_KVM: > case KVM_CAP_ARM_SYSTEM_SUSPEND: > + case KVM_CAP_MEMORY_FAULT_NOWAIT: > r = 1; > break; > case KVM_CAP_SET_GUEST_DEBUG2: > diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c > index 735044859eb25..0d04ffc81f783 100644 > --- a/arch/arm64/kvm/mmu.c > +++ b/arch/arm64/kvm/mmu.c > @@ -1206,6 +1206,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, > unsigned long vma_pagesize, fault_granule; > enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_R; > struct kvm_pgtable *pgt; > + bool exit_on_memory_fault = kvm_slot_fault_on_absent_mapping(memslot); > > fault_granule = 1UL << ARM64_HW_PGTABLE_LEVEL_SHIFT(fault_level); > write_fault = kvm_is_write_fault(vcpu); > @@ -1303,8 +1304,17 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, > */ > smp_rmb(); > > - pfn = __gfn_to_pfn_memslot(memslot, gfn, false, false, NULL, > - write_fault, &writable, NULL); > + pfn = __gfn_to_pfn_memslot( > + memslot, gfn, exit_on_memory_fault, false, NULL, > + write_fault, &writable, NULL); As stated before [*], this google3-esque style does not match the kernel style guide. You may want to check if your work machine is setting up a G3-specific editor configuration behind your back. [*] https://lore.kernel.org/kvm/Y+0QRsZ4yWyUdpnc@xxxxxxxxxx/ > + if (exit_on_memory_fault && pfn == KVM_PFN_ERR_FAULT) { nit: I don't think the local is explicitly necessary. I still find this readable: if (pfn == KVM_PFN_ERR_FAULT && kvm_slot_fault_on_absent_mapping(memslot)) > + vcpu->run->exit_reason = KVM_EXIT_MEMORY_FAULT; > + vcpu->run->memory_fault.flags = 0; > + vcpu->run->memory_fault.gpa = gfn << PAGE_SHIFT; > + vcpu->run->memory_fault.len = vma_pagesize; > + return 0; > + } > if (pfn == KVM_PFN_ERR_HWPOISON) { > kvm_send_hwpoison_signal(hva, vma_shift); > return 1; > -- > 2.40.0.rc1.284.g88254d51c5-goog > > -- Thanks, Oliver
