On 11/14/19 1:27 PM, Peter Gonda wrote:
On Tue, Nov 12, 2019 at 2:27 PM Brijesh Singh <brijesh.singh@xxxxxxx> wrote:
On 11/12/19 12:35 PM, Peter Gonda wrote:
On Wed, Jul 10, 2019 at 1:13 PM Singh, Brijesh <brijesh.singh@xxxxxxx> wrote:
+static int sev_send_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
+{
+ struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+ void *amd_cert = NULL, *session_data = NULL;
+ void *pdh_cert = NULL, *plat_cert = NULL;
+ struct sev_data_send_start *data = NULL;
+ struct kvm_sev_send_start params;
+ int ret;
+
+ if (!sev_guest(kvm))
+ return -ENOTTY;
+
+ if (copy_from_user(¶ms, (void __user *)(uintptr_t)argp->data,
+ sizeof(struct kvm_sev_send_start)))
+ return -EFAULT;
+
+ data = kzalloc(sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ /* userspace wants to query the session length */
+ if (!params.session_len)
+ goto cmd;
+
+ if (!params.pdh_cert_uaddr || !params.pdh_cert_len ||
+ !params.session_uaddr)
+ return -EINVAL;
I think pdh_cert is only required if the guest policy SEV bit is set.
Can pdh_cert be optional?
We don't cache the policy information in kernel, having said so we can
try caching it during the LAUNCH_START to optimize this case. I have to
check with FW folks but I believe all those fields are required. IIRC,
When I passed NULL then SEND_START failed for me. But I double check it
and update you on this.
I must have misinterpreted the this line of the spec:
"If GCTX.POLICY.SEV is 1, the PDH, PEK, CEK, ASK, and ARK certificates
are validated."
I thought that since they were not validated they were not needed.
I have confirmed that these fields are required by the SEND_START
even when GCTX.POLICY.SEV=0. The FW needs us to pass certificate
chain, if POLICY.SEV=1 then FW will validating the chain otherwise
ignore it.
