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

From: Brijesh Singh
Date: Mon Nov 06 2017 - 13:13:30 EST


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

Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: "Radim KrÄmÃÅ" <rkrcmar@xxxxxxxxxx>
Cc: Joerg Roedel <joro@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxx>
Cc: Tom Lendacky <thomas.lendacky@xxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: kvm@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx>
Reviewed-by: Borislav Petkov <bp@xxxxxxx>
---
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