[Qemu-devel] [RFC PATCH v1 01/10] KVM: SVM: Add KVM_SEV SEND_START command

[Singh, Brijesh]

The command is used to create an outgoing SEV guest encryption context.

Cc: Thomas Gleixner <address@hidden>
Cc: Ingo Molnar <address@hidden>
Cc: "H. Peter Anvin" <address@hidden>
Cc: Paolo Bonzini <address@hidden>
Cc: "Radim Krčmář" <address@hidden>
Cc: Joerg Roedel <address@hidden>
Cc: Borislav Petkov <address@hidden>
Cc: Tom Lendacky <address@hidden>
Cc: address@hidden
Cc: address@hidden
Cc: address@hidden
Signed-off-by: Brijesh Singh <address@hidden>
---
 .../virtual/kvm/amd-memory-encryption.rst     |  24 +++++
 arch/x86/kvm/svm.c                            | 101 ++++++++++++++++++
 include/uapi/linux/kvm.h                      |  12 +++
 3 files changed, 137 insertions(+)

diff --git a/Documentation/virtual/kvm/amd-memory-encryption.rst 
b/Documentation/virtual/kvm/amd-memory-encryption.rst
index 659bbc093b52..340ac4f87321 100644
--- a/Documentation/virtual/kvm/amd-memory-encryption.rst
+++ b/Documentation/virtual/kvm/amd-memory-encryption.rst
@@ -238,6 +238,30 @@ Returns: 0 on success, -negative on error
                 __u32 trans_len;
         };
 
+10. KVM_SEV_SEND_START
+----------------------
+
+The KVM_SEV_SEND_START command can be used by the hypervisor to create an
+outgoing guest encryption context.
+
+Parameters (in): struct kvm_sev_send_start
+
+Returns: 0 on success, -negative on error
+
+::
+        struct kvm_sev_send_start {
+                __u32 policy;                 /* guest policy */
+
+                __u64 pdh_cert_uaddr;         /* platform Diffie-Hellman 
certificate */
+                __u32 pdh_cert_len;
+
+                __u64 plat_cert_uaddr;        /* platform certificate chain */
+                __u32 plat_cert_len;
+
+                __u64 amd_cert_uaddr;         /* AMD certificate */
+                __u32 amd_cert_len;
+        };
+
 References
 ==========
 
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 406b558abfef..4c2a225ba546 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -6955,6 +6955,104 @@ static int sev_launch_secret(struct kvm *kvm, struct 
kvm_sev_cmd *argp)
        return ret;
 }
 
+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(&params, (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;
+
+       /* copy the certificate blobs from userspace */
+       pdh_cert = psp_copy_user_blob(params.pdh_cert_uaddr, 
params.pdh_cert_len);
+       if (IS_ERR(pdh_cert)) {
+               ret = PTR_ERR(pdh_cert);
+               goto e_free;
+       }
+
+       data->pdh_cert_address = __psp_pa(pdh_cert);
+       data->pdh_cert_len = params.pdh_cert_len;
+
+       plat_cert = psp_copy_user_blob(params.plat_cert_uaddr, 
params.plat_cert_len);
+       if (IS_ERR(plat_cert)) {
+               ret = PTR_ERR(plat_cert);
+               goto e_free_pdh;
+       }
+
+       data->plat_cert_address = __psp_pa(plat_cert);
+       data->plat_cert_len = params.plat_cert_len;
+
+       amd_cert = psp_copy_user_blob(params.amd_cert_uaddr, 
params.amd_cert_len);
+       if (IS_ERR(amd_cert)) {
+               ret = PTR_ERR(amd_cert);
+               goto e_free_plat_cert;
+       }
+
+       data->amd_cert_address = __psp_pa(amd_cert);
+       data->amd_cert_len = params.amd_cert_len;
+
+       ret = -ENOMEM;
+       session_data = kmalloc(params.session_len, GFP_KERNEL);
+       if (!session_data)
+               goto e_free_amd_cert;
+
+       data->session_address = __psp_pa(session_data);
+       data->session_len = params.session_len;
+cmd:
+       data->handle = sev->handle;
+       ret = sev_issue_cmd(kvm, SEV_CMD_SEND_START, data, &argp->error);
+
+       /* if we queried the session length, FW responded with expected data */
+       if (!params.session_len)
+               goto done;
+
+       if (copy_to_user((void __user *)(uintptr_t) params.session_uaddr,
+                       session_data, params.session_len)) {
+               ret = -EFAULT;
+               goto e_free_session;
+       }
+
+       params.policy = data->policy;
+
+done:
+       params.session_len = data->session_len;
+       if (copy_to_user((void __user *)(uintptr_t)argp->data, &params,
+                               sizeof(struct kvm_sev_send_start)))
+               ret = -EFAULT;
+
+e_free_session:
+       kfree(session_data);
+e_free_amd_cert:
+       kfree(amd_cert);
+e_free_plat_cert:
+       kfree(plat_cert);
+e_free_pdh:
+       kfree(pdh_cert);
+e_free:
+       kfree(data);
+       return ret;
+}
+
 static int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
 {
        struct kvm_sev_cmd sev_cmd;
@@ -6996,6 +7094,9 @@ static int svm_mem_enc_op(struct kvm *kvm, void __user 
*argp)
        case KVM_SEV_LAUNCH_SECRET:
                r = sev_launch_secret(kvm, &sev_cmd);
                break;
+       case KVM_SEV_SEND_START:
+               r = sev_send_start(kvm, &sev_cmd);
+               break;
        default:
                r = -EINVAL;
                goto out;
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 6d4ea4b6c922..f425418bec13 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1520,6 +1520,18 @@ struct kvm_sev_dbg {
        __u32 len;
 };
 
+struct kvm_sev_send_start {
+       __u32 policy;
+       __u64 pdh_cert_uaddr;
+       __u32 pdh_cert_len;
+       __u64 plat_cert_uaddr;
+       __u32 plat_cert_len;
+       __u64 amd_cert_uaddr;
+       __u32 amd_cert_len;
+       __u64 session_uaddr;
+       __u32 session_len;
+};
+
 #define KVM_DEV_ASSIGN_ENABLE_IOMMU    (1 << 0)
 #define KVM_DEV_ASSIGN_PCI_2_3         (1 << 1)
 #define KVM_DEV_ASSIGN_MASK_INTX       (1 << 2)
-- 
2.17.1