On 06/03/2011 06:04 PM, Christoffer Dall wrote:
Handles the guest faults in KVM by mapping in corresponding user pages in the 2nd stage page tables. +static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, + gfn_t gfn, struct kvm_memory_slot *memslot) +{ + pfn_t pfn; + pgd_t *pgd; + pmd_t *pmd; + pte_t *pte, new_pte; + + pfn = gfn_to_pfn(vcpu->kvm, gfn); + + if (is_error_pfn(pfn)) { + kvm_err(-EFAULT, "Guest gfn %u (0x%08lx) does not have " + "corresponding host mapping", + gfn, gfn<< PAGE_SHIFT); + return -EFAULT; + } + + /* Create 2nd stage page table mapping - Level 1 */ + pgd = vcpu->kvm->arch.pgd + pgd_index(fault_ipa); + if (pgd_none(*pgd)) { + pmd = pmd_alloc_one(NULL, fault_ipa); + if (!pmd) { + kvm_err(-ENOMEM, "Cannot allocate 2nd stage pmd"); + return -ENOMEM; + } + pgd_populate(NULL, pgd, pmd); + pmd += pmd_index(fault_ipa); + } else + pmd = pmd_offset(pgd, fault_ipa); + + /* Create 2nd stage page table mapping - Level 2 */ + if (pmd_none(*pmd)) { + pte = pte_alloc_one_kernel(NULL, fault_ipa); + if (!pte) { + kvm_err(-ENOMEM, "Cannot allocate 2nd stage pte"); + return -ENOMEM; + } + pmd_populate_kernel(NULL, pmd, pte); + pte += pte_index(fault_ipa); + } else + pte = pte_offset_kernel(pmd, fault_ipa); + + /* Create 2nd stage page table mapping - Level 3 */ + new_pte = pfn_pte(pfn, PAGE_KVM_GUEST); + set_pte_ext(pte, new_pte, 0); + + return 0; +} + +#define HSR_ABT_FS (0x3f) +#define HPFAR_MASK (~0xf) int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run) { + unsigned long hsr_ec; + unsigned long fault_status; + phys_addr_t fault_ipa; + struct kvm_memory_slot *memslot = NULL; + bool is_iabt; + gfn_t gfn; + + hsr_ec = vcpu->arch.hsr>> HSR_EC_SHIFT; + is_iabt = (hsr_ec == HSR_EC_IABT); + + /* Check that the second stage fault is a translation fault */ + fault_status = vcpu->arch.hsr& HSR_ABT_FS; + if ((fault_status& 0x3c) != 0x4) { + kvm_err(-EFAULT, "Unsupported fault status: %x", + fault_status& 0x3c); + return -EFAULT; + } + + fault_ipa = ((phys_addr_t)vcpu->arch.hpfar& HPFAR_MASK)<< 8; + + gfn = fault_ipa>> PAGE_SHIFT; + if (!kvm_is_visible_gfn(vcpu->kvm, gfn)) + goto io_mem_abort; + + memslot = gfn_to_memslot(vcpu->kvm, gfn); + if (memslot->user_alloc) + return user_mem_abort(vcpu, fault_ipa, gfn, memslot);
Non-user_alloc should not exist for ARM (and are not supported for x86 these days, except for a few implementation internal slots).
+ +io_mem_abort: + if (is_iabt) { + kvm_err(-EFAULT, "Inst. abort on I/O address"); + return -EFAULT; + } + + kvm_msg("I/O address abort..."); KVMARM_NOT_IMPLEMENTED(); return -EINVAL; }
Okay, this is about a zillion times simpler than x86. Congratulations. What are your thoughts about mmu notifier support? -- error compiling committee.c: too many arguments to function -- 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