KVM: SVM: Add KVM_SEV SEND_START command

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

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: x86@kernel.org
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Steve Rutherford <srutherford@google.com>
Reviewed-by: Venu Busireddy <venu.busireddy@oracle.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Message-Id: <2f1686d0164e0f1b3d6a41d620408393e0a48376.1618498113.git.ashish.kalra@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/Documentation/virt/kvm/amd-memory-encryption.rst b/Documentation/virt/kvm/amd-memory-encryption.rst
index 34ce2d1..db5c3fb 100644 (file)
--- a/Documentation/virt/kvm/amd-memory-encryption.rst
+++ b/Documentation/virt/kvm/amd-memory-encryption.rst
@@ -290,6 +290,36 @@ Returns: 0 on success, -negative on error
                 __u32 len;
         };
 
+11. KVM_SEV_SEND_START
+----------------------
+
+The KVM_SEV_SEND_START command can be used by the hypervisor to create an
+outgoing guest encryption context.
+
+If session_len is zero on entry, the length of the guest session information is
+written to session_len and all other fields are not used.
+
+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_certs_uaddr;        /* platform certificate chain */
+                __u32 plat_certs_len;
+
+                __u64 amd_certs_uaddr;        /* AMD certificate */
+                __u32 amd_certs_len;
+
+                __u64 session_uaddr;          /* Guest session information */
+                __u32 session_len;
+        };
+
 References
 ==========
 

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 4bf79db..9f53129 100644 (file)
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -1111,6 +1111,131 @@ e_free:
        return ret;
 }
 
+/* Userspace wants to query session length. */
+static int
+__sev_send_start_query_session_length(struct kvm *kvm, struct kvm_sev_cmd *argp,
+                                     struct kvm_sev_send_start *params)
+{
+       struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+       struct sev_data_send_start *data;
+       int ret;
+
+       data = kzalloc(sizeof(*data), GFP_KERNEL_ACCOUNT);
+       if (data == NULL)
+               return -ENOMEM;
+
+       data->handle = sev->handle;
+       ret = sev_issue_cmd(kvm, SEV_CMD_SEND_START, data, &argp->error);
+       if (ret < 0)
+               goto out;
+
+       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;
+
+out:
+       kfree(data);
+       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;
+       struct sev_data_send_start *data;
+       struct kvm_sev_send_start params;
+       void *amd_certs, *session_data;
+       void *pdh_cert, *plat_certs;
+       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;
+
+       /* if session_len is zero, userspace wants to query the session length */
+       if (!params.session_len)
+               return __sev_send_start_query_session_length(kvm, argp,
+                               &params);
+
+       /* some sanity checks */
+       if (!params.pdh_cert_uaddr || !params.pdh_cert_len ||
+           !params.session_uaddr || params.session_len > SEV_FW_BLOB_MAX_SIZE)
+               return -EINVAL;
+
+       /* allocate the memory to hold the session data blob */
+       session_data = kmalloc(params.session_len, GFP_KERNEL_ACCOUNT);
+       if (!session_data)
+               return -ENOMEM;
+
+       /* 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_session;
+       }
+
+       plat_certs = psp_copy_user_blob(params.plat_certs_uaddr,
+                               params.plat_certs_len);
+       if (IS_ERR(plat_certs)) {
+               ret = PTR_ERR(plat_certs);
+               goto e_free_pdh;
+       }
+
+       amd_certs = psp_copy_user_blob(params.amd_certs_uaddr,
+                               params.amd_certs_len);
+       if (IS_ERR(amd_certs)) {
+               ret = PTR_ERR(amd_certs);
+               goto e_free_plat_cert;
+       }
+
+       data = kzalloc(sizeof(*data), GFP_KERNEL_ACCOUNT);
+       if (data == NULL) {
+               ret = -ENOMEM;
+               goto e_free_amd_cert;
+       }
+
+       /* populate the FW SEND_START field with system physical address */
+       data->pdh_cert_address = __psp_pa(pdh_cert);
+       data->pdh_cert_len = params.pdh_cert_len;
+       data->plat_certs_address = __psp_pa(plat_certs);
+       data->plat_certs_len = params.plat_certs_len;
+       data->amd_certs_address = __psp_pa(amd_certs);
+       data->amd_certs_len = params.amd_certs_len;
+       data->session_address = __psp_pa(session_data);
+       data->session_len = params.session_len;
+       data->handle = sev->handle;
+
+       ret = sev_issue_cmd(kvm, SEV_CMD_SEND_START, data, &argp->error);
+
+       if (!ret && copy_to_user((void __user *)(uintptr_t)params.session_uaddr,
+                       session_data, params.session_len)) {
+               ret = -EFAULT;
+               goto e_free;
+       }
+
+       params.policy = data->policy;
+       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:
+       kfree(data);
+e_free_amd_cert:
+       kfree(amd_certs);
+e_free_plat_cert:
+       kfree(plat_certs);
+e_free_pdh:
+       kfree(pdh_cert);
+e_free_session:
+       kfree(session_data);
+       return ret;
+}
+
 int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
 {
        struct kvm_sev_cmd sev_cmd;
@@ -1173,6 +1298,9 @@ int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
        case KVM_SEV_GET_ATTESTATION_REPORT:
                r = sev_get_attestation_report(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/linux/psp-sev.h b/include/linux/psp-sev.h
index b801ead..73da511 100644 (file)
--- a/include/linux/psp-sev.h
+++ b/include/linux/psp-sev.h
@@ -326,11 +326,11 @@ struct sev_data_send_start {
        u64 pdh_cert_address;                   /* In */
        u32 pdh_cert_len;                       /* In */
        u32 reserved1;
-       u64 plat_cert_address;                  /* In */
-       u32 plat_cert_len;                      /* In */
+       u64 plat_certs_address;                 /* In */
+       u32 plat_certs_len;                     /* In */
        u32 reserved2;
-       u64 amd_cert_address;                   /* In */
-       u32 amd_cert_len;                       /* In */
+       u64 amd_certs_address;                  /* In */
+       u32 amd_certs_len;                      /* In */
        u32 reserved3;
        u64 session_address;                    /* In */
        u32 session_len;                        /* In/Out */

diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 37f0a32..11b3e52 100644 (file)
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1732,6 +1732,18 @@ struct kvm_sev_attestation_report {
        __u32 len;
 };
 
+struct kvm_sev_send_start {
+       __u32 policy;
+       __u64 pdh_cert_uaddr;
+       __u32 pdh_cert_len;
+       __u64 plat_certs_uaddr;
+       __u32 plat_certs_len;
+       __u64 amd_certs_uaddr;
+       __u32 amd_certs_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)