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
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