The SEV_PEK_CSR command can be used to generate a PEK certificate
signing request. The command is defined in SEV spec section 5.7.

Cc: Paolo Bonzini <pbonz...@redhat.com>
Cc: "Radim Krčmář" <rkrc...@redhat.com>
Cc: Borislav Petkov <b...@suse.de>
Cc: Herbert Xu <herb...@gondor.apana.org.au>
Cc: Gary Hook <gary.h...@amd.com>
Cc: Tom Lendacky <thomas.lenda...@amd.com>
Cc: linux-crypto@vger.kernel.org
Cc: k...@vger.kernel.org
Cc: linux-ker...@vger.kernel.org
Signed-off-by: Brijesh Singh <brijesh.si...@amd.com>
---

Changes since v6:
 * when sev_do_cmd() and sev_platform_shutdown() fails then propogate
   the error status code from sev_do_cmd() because it can give us
   much better reason for the failure.

 drivers/crypto/ccp/psp-dev.c | 81 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)

diff --git a/drivers/crypto/ccp/psp-dev.c b/drivers/crypto/ccp/psp-dev.c
index 3672435150cf..aaf1c5cf821d 100644
--- a/drivers/crypto/ccp/psp-dev.c
+++ b/drivers/crypto/ccp/psp-dev.c
@@ -223,6 +223,84 @@ static int sev_ioctl_do_pek_pdh_gen(int cmd, struct 
sev_issue_cmd *argp)
        return ret;
 }
 
+static int sev_ioctl_do_pek_csr(struct sev_issue_cmd *argp)
+{
+       struct sev_user_data_pek_csr input;
+       struct sev_data_pek_csr *data;
+       void *blob = NULL;
+       int ret, err;
+
+       if (copy_from_user(&input, (void __user *)argp->data, sizeof(input)))
+               return -EFAULT;
+
+       data = kzalloc(sizeof(*data), GFP_KERNEL);
+       if (!data)
+               return -ENOMEM;
+
+       /* userspace wants to query CSR length */
+       if (!input.address || !input.length)
+               goto cmd;
+
+       /* allocate a physically contiguous buffer to store the CSR blob */
+       if (!access_ok(VERIFY_WRITE, input.address, input.length) ||
+           input.length > SEV_FW_BLOB_MAX_SIZE) {
+               ret = -EFAULT;
+               goto e_free;
+       }
+
+       blob = kmalloc(input.length, GFP_KERNEL);
+       if (!blob) {
+               ret = -ENOMEM;
+               goto e_free;
+       }
+
+       data->address = __psp_pa(blob);
+       data->len = input.length;
+
+cmd:
+       ret = sev_platform_init(NULL, &argp->error);
+       if (ret)
+               goto e_free_blob;
+
+       ret = sev_do_cmd(SEV_CMD_PEK_CSR, data, &argp->error);
+
+       /*
+        * If we query the CSR length, FW responded with expected data
+        */
+       input.length = data->len;
+
+       if (sev_platform_shutdown(&err)) {
+               /*
+                * If both sev_do_cmd() and sev_platform_shutdown() commands
+                * failed then propogate the error code from the sev_do_cmd()
+                * because it contains a useful status code for the command
+                * failure.
+                */
+               if (ret)
+                       goto e_free_blob;
+
+               ret = -EIO;
+               argp->error = err;
+               goto e_free_blob;
+       }
+
+       if (copy_to_user((void __user *)argp->data, &input, sizeof(input))) {
+               ret = -EFAULT;
+               goto e_free_blob;
+       }
+
+       if (blob) {
+               if (copy_to_user((void __user *)input.address, blob, 
input.length))
+                       ret = -EFAULT;
+       }
+
+e_free_blob:
+       kfree(blob);
+e_free:
+       kfree(data);
+       return ret;
+}
+
 static long sev_ioctl(struct file *file, unsigned int ioctl, unsigned long arg)
 {
        void __user *argp = (void __user *)arg;
@@ -252,6 +330,9 @@ static long sev_ioctl(struct file *file, unsigned int 
ioctl, unsigned long arg)
        case SEV_PDH_GEN:
                ret = sev_ioctl_do_pek_pdh_gen(SEV_CMD_PDH_GEN, &input);
                break;
+       case SEV_PEK_CSR:
+               ret = sev_ioctl_do_pek_csr(&input);
+               break;
        default:
                ret = -EINVAL;
                goto out;
-- 
2.9.5

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