[RFC PATCH v2 31/32] kvm: svm: Add support for SEV LAUNCH_MEASURE command

From: Brijesh Singh
Date: Thu Mar 02 2017 - 10:44:49 EST


The command is used to retrieve the measurement of memory encrypted through
the LAUNCH_UPDATE_DATA command. This measurement can be used for attestation
purposes.

Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx>
---
arch/x86/kvm/svm.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 52 insertions(+)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 64899ed..13996d6 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -6141,6 +6141,54 @@ static int sev_dbg_encrypt(struct kvm *kvm, struct kvm_sev_cmd *argp)
return ret;
}

+static int sev_launch_measure(struct kvm *kvm, struct kvm_sev_cmd *argp)
+{
+ int ret;
+ void *addr = NULL;
+ struct kvm_sev_launch_measure params;
+ struct sev_data_launch_measure *data;
+
+ if (!sev_guest(kvm))
+ return -ENOTTY;
+
+ if (copy_from_user(&params, (void *)argp->data,
+ sizeof(struct kvm_sev_launch_measure)))
+ return -EFAULT;
+
+ data = kzalloc(sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ if (params.address && params.length) {
+ ret = -EFAULT;
+ addr = kzalloc(params.length, GFP_KERNEL);
+ if (!addr)
+ goto err_1;
+ data->address = __psp_pa(addr);
+ data->length = params.length;
+ }
+
+ data->handle = sev_get_handle(kvm);
+ ret = sev_issue_cmd(kvm, SEV_CMD_LAUNCH_MEASURE, data, &argp->error);
+
+ /* copy the measurement to userspace */
+ if (addr &&
+ copy_to_user((void *)params.address, addr, params.length)) {
+ ret = -EFAULT;
+ goto err_1;
+ }
+
+ params.length = data->length;
+ if (copy_to_user((void *)argp->data, &params,
+ sizeof(struct kvm_sev_launch_measure)))
+ ret = -EFAULT;
+
+ kfree(addr);
+err_1:
+ kfree(data);
+ return ret;
+}
+
static int amd_memory_encryption_cmd(struct kvm *kvm, void __user *argp)
{
int r = -ENOTTY;
@@ -6176,6 +6224,10 @@ static int amd_memory_encryption_cmd(struct kvm *kvm, void __user *argp)
r = sev_dbg_encrypt(kvm, &sev_cmd);
break;
}
+ case KVM_SEV_LAUNCH_MEASURE: {
+ r = sev_launch_measure(kvm, &sev_cmd);
+ break;
+ }
default:
break;
}