KVM: VMX: Introduce KVM_SET_IDENTITY_MAP_ADDR ioctl

Now KVM allow guest to modify guest's physical address of EPT's identity mapping page.

(change from v1, discard unnecessary check, change ioctl to accept parameter
address rather than value)

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c7ec0c921c01..f4cb1baaa04b 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1206,6 +1206,7 @@ int kvm_dev_ioctl_check_extension(long ext)
         case KVM_CAP_IOEVENTFD:
         case KVM_CAP_PIT2:
         case KVM_CAP_PIT_STATE2:
+        case KVM_CAP_SET_IDENTITY_MAP_ADDR:
                 r = 1;
                 break;
         case KVM_CAP_COALESCED_MMIO:
@@ -1906,6 +1907,13 @@ static int kvm_vm_ioctl_set_tss_addr(struct kvm *kvm, unsigned long addr)
         return ret;
 }
 
+static int kvm_vm_ioctl_set_identity_map_addr(struct kvm *kvm,
+                                              u64 ident_addr)
+{
+        kvm->arch.ept_identity_map_addr = ident_addr;
+        return 0;
+}
+
 static int kvm_vm_ioctl_set_nr_mmu_pages(struct kvm *kvm,
                                           u32 kvm_nr_mmu_pages)
 {
@@ -2173,6 +2181,17 @@ long kvm_arch_vm_ioctl(struct file *filp,
                 if (r < 0)
                         goto out;
                 break;
+        case KVM_SET_IDENTITY_MAP_ADDR: {
+                u64 ident_addr;
+
+                r = -EFAULT;
+                if (copy_from_user(&ident_addr, argp, sizeof ident_addr))
+                        goto out;
+                r = kvm_vm_ioctl_set_identity_map_addr(kvm, ident_addr);
+                if (r < 0)
+                        goto out;
+                break;
+        }
         case KVM_SET_MEMORY_REGION: {
                 struct kvm_memory_region kvm_mem;
                 struct kvm_userspace_memory_region kvm_userspace_mem;