[PATCH Part2 v6 16/49] crypto: ccp: Add the SNP_PLATFORM_STATUS command

Ashish Kalra
2022-06-20T23:07:01Z

From: Brijesh Singh <brijesh.singh@amd.com>

The command can be used by the userspace to query the SNP platform status
report. See the SEV-SNP spec for more details.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
Documentation/virt/coco/sevguest.rst | 27 +++++++++++++++++
drivers/crypto/ccp/sev-dev.c | 45 ++++++++++++++++++++++++++++
include/uapi/linux/psp-sev.h | 1 +
3 files changed, 73 insertions(+)

diff --git a/Documentation/virt/coco/sevguest.rst b/Documentation/virt/coco/sevguest.rst
index bf593e88cfd9..11ea67c944df 100644
--- a/Documentation/virt/coco/sevguest.rst
+++ b/Documentation/virt/coco/sevguest.rst
@@ -61,6 +61,22 @@ counter (e.g. counter overflow), then -EIO will be returned.
__u64 fw_err;
};

+The host ioctl should be called to /dev/sev device. The ioctl accepts command
+id and command input structure.
+
+::
+ struct sev_issue_cmd {
+ /* Command ID */
+ __u32 cmd;
+
+ /* Command request structure */
+ __u64 data;
+
+ /* firmware error code on failure (see psp-sev.h) */
+ __u32 error;
+ };
+
+
2.1 SNP_GET_REPORT
------------------

@@ -118,6 +134,17 @@ be updated with the expected value.

See GHCB specification for further detail on how to parse the certificate blob.

+2.4 SNP_PLATFORM_STATUS
+-----------------------
+:Technology: sev-snp
+:Type: hypervisor ioctl cmd
+:Parameters (in): struct sev_data_snp_platform_status
+:Returns (out): 0 on success, -negative on error
+
+The SNP_PLATFORM_STATUS command is used to query the SNP platform status. The
+status includes API major, minor version and more. See the SEV-SNP
+specification for further details.
+
3. SEV-SNP CPUID Enforcement
============================

diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index 75f5c4ed9ac3..b9b6fab31a82 100644
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -1574,6 +1574,48 @@ static int sev_ioctl_do_pdh_export(struct sev_issue_cmd *argp, bool writable)
return ret;
}

+static int sev_ioctl_snp_platform_status(struct sev_issue_cmd *argp)
+{
+ struct sev_device *sev = psp_master->sev_data;
+ struct sev_data_snp_platform_status_buf buf;
+ struct page *status_page;
+ void *data;
+ int ret;
+
+ if (!sev->snp_inited || !argp->data)
+ return -EINVAL;
+
+ status_page = alloc_page(GFP_KERNEL_ACCOUNT);
+ if (!status_page)
+ return -ENOMEM;
+
+ data = page_address(status_page);
+ if (snp_set_rmp_state(__pa(data), 1, true, true, false)) {
+ __free_pages(status_page, 0);
+ return -EFAULT;
+ }
+
+ buf.status_paddr = __psp_pa(data);
+ ret = __sev_do_cmd_locked(SEV_CMD_SNP_PLATFORM_STATUS, &buf, &argp->error);
+
+ /* Change the page state before accessing it */
+ if (snp_set_rmp_state(__pa(data), 1, false, true, true)) {
+ snp_leak_pages(__pa(data) >> PAGE_SHIFT, 1);
+ return -EFAULT;
+ }
+
+ if (ret)
+ goto cleanup;
+
+ if (copy_to_user((void __user *)argp->data, data,
+ sizeof(struct sev_user_data_snp_status)))
+ ret = -EFAULT;
+
+cleanup:
+ __free_pages(status_page, 0);
+ return ret;
+}
+
static long sev_ioctl(struct file *file, unsigned int ioctl, unsigned long arg)
{
void __user *argp = (void __user *)arg;
@@ -1625,6 +1667,9 @@ static long sev_ioctl(struct file *file, unsigned int ioctl, unsigned long arg)
case SEV_GET_ID2:
ret = sev_ioctl_do_get_id2(&input);
break;
+ case SNP_PLATFORM_STATUS:
+ ret = sev_ioctl_snp_platform_status(&input);
+ break;
default:
ret = -EINVAL;
goto out;
diff --git a/include/uapi/linux/psp-sev.h b/include/uapi/linux/psp-sev.h
index bed65a891223..ffd60e8b0a31 100644
--- a/include/uapi/linux/psp-sev.h
+++ b/include/uapi/linux/psp-sev.h
@@ -28,6 +28,7 @@ enum {
SEV_PEK_CERT_IMPORT,
SEV_GET_ID, /* This command is deprecated, use SEV_GET_ID2 */
SEV_GET_ID2,
+ SNP_PLATFORM_STATUS,

SEV_MAX,
};
--
2.25.1