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

Singh, Brijesh
2019-04-24T16:11:10Z

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: "Radim Krčmář" <rkrcmar@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
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
.../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