KVM: allow userspace to adjust kvmclock offset

[pandora-kernel.git] / arch / x86 / kvm / x86.c

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 13f30aa..e16cdc9 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -680,7 +680,8 @@ static void kvm_write_guest_time(struct kvm_vcpu *v)
        /* With all the info we got, fill in the values */
 
        vcpu->hv_clock.system_time = ts.tv_nsec +
-                                    (NSEC_PER_SEC * (u64)ts.tv_sec);
+                                    (NSEC_PER_SEC * (u64)ts.tv_sec) + v->kvm->arch.kvmclock_offset;
+
        /*
         * The interface expects us to write an even number signaling that the
         * update is finished. Since the guest won't see the intermediate
@@ -1262,6 +1263,7 @@ int kvm_dev_ioctl_check_extension(long ext)
        case KVM_CAP_PIT_STATE2:
        case KVM_CAP_SET_IDENTITY_MAP_ADDR:
        case KVM_CAP_XEN_HVM:
+       case KVM_CAP_ADJUST_CLOCK:
                r = 1;
                break;
        case KVM_CAP_COALESCED_MMIO:
@@ -2468,6 +2470,44 @@ long kvm_arch_vm_ioctl(struct file *filp,
                r = 0;
                break;
        }
+       case KVM_SET_CLOCK: {
+               struct timespec now;
+               struct kvm_clock_data user_ns;
+               u64 now_ns;
+               s64 delta;
+
+               r = -EFAULT;
+               if (copy_from_user(&user_ns, argp, sizeof(user_ns)))
+                       goto out;
+
+               r = -EINVAL;
+               if (user_ns.flags)
+                       goto out;
+
+               r = 0;
+               ktime_get_ts(&now);
+               now_ns = timespec_to_ns(&now);
+               delta = user_ns.clock - now_ns;
+               kvm->arch.kvmclock_offset = delta;
+               break;
+       }
+       case KVM_GET_CLOCK: {
+               struct timespec now;
+               struct kvm_clock_data user_ns;
+               u64 now_ns;
+
+               ktime_get_ts(&now);
+               now_ns = timespec_to_ns(&now);
+               user_ns.clock = kvm->arch.kvmclock_offset + now_ns;
+               user_ns.flags = 0;
+
+               r = -EFAULT;
+               if (copy_to_user(argp, &user_ns, sizeof(user_ns)))
+                       goto out;
+               r = 0;
+               break;
+       }
+
        default:
                ;
        }