KVM: arm64: Add ioctl to fetch/store tags in a guest

[linux-2.6-microblaze.git] / arch / arm64 / kvm / guest.c

diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index 5cb4a1c..4ddb200 100644 (file)
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -995,3 +995,85 @@ int kvm_arm_vcpu_arch_has_attr(struct kvm_vcpu *vcpu,
 
        return ret;
 }
+
+long kvm_vm_ioctl_mte_copy_tags(struct kvm *kvm,
+                               struct kvm_arm_copy_mte_tags *copy_tags)
+{
+       gpa_t guest_ipa = copy_tags->guest_ipa;
+       size_t length = copy_tags->length;
+       void __user *tags = copy_tags->addr;
+       gpa_t gfn;
+       bool write = !(copy_tags->flags & KVM_ARM_TAGS_FROM_GUEST);
+       int ret = 0;
+
+       if (!kvm_has_mte(kvm))
+               return -EINVAL;
+
+       if (copy_tags->reserved[0] || copy_tags->reserved[1])
+               return -EINVAL;
+
+       if (copy_tags->flags & ~KVM_ARM_TAGS_FROM_GUEST)
+               return -EINVAL;
+
+       if (length & ~PAGE_MASK || guest_ipa & ~PAGE_MASK)
+               return -EINVAL;
+
+       gfn = gpa_to_gfn(guest_ipa);
+
+       mutex_lock(&kvm->slots_lock);
+
+       while (length > 0) {
+               kvm_pfn_t pfn = gfn_to_pfn_prot(kvm, gfn, write, NULL);
+               void *maddr;
+               unsigned long num_tags;
+               struct page *page;
+
+               if (is_error_noslot_pfn(pfn)) {
+                       ret = -EFAULT;
+                       goto out;
+               }
+
+               page = pfn_to_online_page(pfn);
+               if (!page) {
+                       /* Reject ZONE_DEVICE memory */
+                       ret = -EFAULT;
+                       goto out;
+               }
+               maddr = page_address(page);
+
+               if (!write) {
+                       if (test_bit(PG_mte_tagged, &page->flags))
+                               num_tags = mte_copy_tags_to_user(tags, maddr,
+                                                       MTE_GRANULES_PER_PAGE);
+                       else
+                               /* No tags in memory, so write zeros */
+                               num_tags = MTE_GRANULES_PER_PAGE -
+                                       clear_user(tags, MTE_GRANULES_PER_PAGE);
+                       kvm_release_pfn_clean(pfn);
+               } else {
+                       num_tags = mte_copy_tags_from_user(maddr, tags,
+                                                       MTE_GRANULES_PER_PAGE);
+                       kvm_release_pfn_dirty(pfn);
+               }
+
+               if (num_tags != MTE_GRANULES_PER_PAGE) {
+                       ret = -EFAULT;
+                       goto out;
+               }
+
+               /* Set the flag after checking the write completed fully */
+               if (write)
+                       set_bit(PG_mte_tagged, &page->flags);
+
+               gfn++;
+               tags += num_tags;
+               length -= PAGE_SIZE;
+       }
+
+out:
+       mutex_unlock(&kvm->slots_lock);
+       /* If some data has been copied report the number of bytes copied */
+       if (length != copy_tags->length)
+               return copy_tags->length - length;
+       return ret;
+}