[Part2 PATCH v8 29/38] KVM: SVM: Add support for KVM_SEV_LAUNCH_MEASURE command

[Brijesh Singh]

The command is used to retrieve the measurement of contents encrypted
through the KVM_SEV_LAUNCH_UPDATE_DATA command.

Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Ingo Molnar <mi...@redhat.com>
Cc: "H. Peter Anvin" <h...@zytor.com>
Cc: Paolo Bonzini <pbonz...@redhat.com>
Cc: "Radim Krčmář" <rkrc...@redhat.com>
Cc: Joerg Roedel <j...@8bytes.org>
Cc: Borislav Petkov <b...@suse.de>
Cc: Tom Lendacky <thomas.lenda...@amd.com>
Cc: x...@kernel.org
Cc: k...@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Brijesh Singh <brijesh.si...@amd.com>
Reviewed-by: Borislav Petkov <b...@suse.de>
---
 arch/x86/kvm/svm.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 74 insertions(+)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 8f2a676b5553..3a5ae4fd7103 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -6002,6 +6002,77 @@ static int sev_launch_update_data(struct kvm *kvm, 
struct kvm_sev_cmd *argp)
        return ret;
 }
 
+static int sev_launch_measure(struct kvm *kvm, struct kvm_sev_cmd *argp)
+{
+       struct kvm_sev_info *sev = &kvm->arch.sev_info;
+       struct sev_data_launch_measure *data;
+       struct kvm_sev_launch_measure params;
+       void *blob = NULL;
+       int ret;
+
+       if (!sev_guest(kvm))
+               return -ENOTTY;
+
+       if (copy_from_user(&params, (void __user *)(uintptr_t)argp->data, 
sizeof(params)))
+               return -EFAULT;
+
+       data = kzalloc(sizeof(*data), GFP_KERNEL);
+       if (!data)
+               return -ENOMEM;
+
+       /* User wants to query the blob length */
+       if (!params.len)
+               goto cmd;
+
+       if (params.uaddr) {
+               if (params.len > SEV_FW_BLOB_MAX_SIZE) {
+                       ret = -EINVAL;
+                       goto e_free;
+               }
+
+               if (!access_ok(VERIFY_WRITE, params.uaddr, params.len)) {
+                       ret = -EFAULT;
+                       goto e_free;
+               }
+
+               ret = -ENOMEM;
+               blob = kmalloc(params.len, GFP_KERNEL);
+               if (!blob)
+                       goto e_free;
+
+               data->address = __psp_pa(blob);
+               data->len = params.len;
+       }
+
+cmd:
+       data->handle = sev->handle;
+       ret = sev_issue_cmd(kvm, SEV_CMD_LAUNCH_MEASURE, data, &argp->error);
+
+       /*
+        * If we query the session length, FW responded with expected data.
+        */
+       if (!params.len)
+               goto done;
+
+       if (ret)
+               goto e_free_blob;
+
+       if (blob) {
+               if (copy_to_user((void __user *)(uintptr_t)params.uaddr, blob, 
params.len))
+                       ret = -EFAULT;
+       }
+
+done:
+       params.len = data->len;
+       if (copy_to_user((void __user *)(uintptr_t)argp->data, &params, 
sizeof(params)))
+               ret = -EFAULT;
+e_free_blob:
+       kfree(blob);
+e_free:
+       kfree(data);
+       return ret;
+}
+
 static int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
 {
        struct kvm_sev_cmd sev_cmd;
@@ -6025,6 +6096,9 @@ static int svm_mem_enc_op(struct kvm *kvm, void __user 
*argp)
        case KVM_SEV_LAUNCH_UPDATE_DATA:
                r = sev_launch_update_data(kvm, &sev_cmd);
                break;
+       case KVM_SEV_LAUNCH_MEASURE:
+               r = sev_launch_measure(kvm, &sev_cmd);
+               break;
        default:
                r = -EINVAL;
                goto out;
-- 
2.9.5