[Part2,RFC,v4,17/40] crypto: ccp: Add the SNP_PLATFORM_STATUS command

Commit Message

Brijesh Singh July 7, 2021, 6:35 p.m. UTC

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 <[e-mail]>
---
 Documentation/virt/coco/sevguest.rst | 27 ++++++++++++++++++++++++
 drivers/crypto/ccp/sev-dev.c         | 31 ++++++++++++++++++++++++++++
 drivers/crypto/ccp/sev-dev.h         |  1 +
 include/uapi/linux/psp-sev.h         |  1 +
 4 files changed, 60 insertions(+)

Patch

diff --git a/Documentation/virt/coco/sevguest.rst b/Documentation/virt/coco/sevguest.rst
index 7acb8696fca4..7c51da010039 100644
--- a/Documentation/virt/coco/sevguest.rst
+++ b/Documentation/virt/coco/sevguest.rst
@@ -52,6 +52,22 @@  to execute due to the firmware error, then fw_err code will be set.
                 __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
 ------------------
 
@@ -107,3 +123,14 @@  length of the blob is lesser than expected then snp_ext_report_req.certs_len wil
 be updated with the expected value.
 
 See GHCB specification for further detail on how to parse the certificate blob.
+
+2.3 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.
diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index 16f0d9211739..65003aba807a 100644
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -1056,6 +1056,7 @@  static int __sev_snp_init_locked(int *error)
 	dev_dbg(sev->dev, "SEV-SNP firmware initialized\n");
 
 	sev_es_tmr_size = SEV_SNP_ES_TMR_SIZE;
+	sev->snp_plat_status_page = __snp_alloc_firmware_pages(GFP_KERNEL_ACCOUNT, 0, true);
 
 	return rc;
 }
@@ -1083,6 +1084,9 @@  static int __sev_snp_shutdown_locked(int *error)
 	if (!sev->snp_inited)
 		return 0;
 
+	/* Free the status page */
+	__snp_free_firmware_pages(sev->snp_plat_status_page, 0, true);
+
 	/* SHUTDOWN requires the DF_FLUSH */
 	wbinvd_on_all_cpus();
 	__sev_do_cmd_locked(SEV_CMD_SNP_DF_FLUSH, NULL, NULL);
@@ -1345,6 +1349,30 @@  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;
+	int ret;
+
+	if (!sev->snp_inited || !argp->data)
+		return -EINVAL;
+
+	if (!sev->snp_plat_status_page)
+		return -ENOMEM;
+
+	buf.status_paddr = __psp_pa(page_address(sev->snp_plat_status_page));
+	ret = __sev_do_cmd_locked(SEV_CMD_SNP_PLATFORM_STATUS, &buf, &argp->error);
+	if (ret)
+		return ret;
+
+	if (copy_to_user((void __user *)argp->data, page_address(sev->snp_plat_status_page),
+			sizeof(struct sev_user_data_snp_status)))
+		return -EFAULT;
+
+	return 0;
+}
+
 static long sev_ioctl(struct file *file, unsigned int ioctl, unsigned long arg)
 {
 	void __user *argp = (void __user *)arg;
@@ -1396,6 +1424,9 @@  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/drivers/crypto/ccp/sev-dev.h b/drivers/crypto/ccp/sev-dev.h
index fe5d7a3ebace..5efe162ad82d 100644
--- a/drivers/crypto/ccp/sev-dev.h
+++ b/drivers/crypto/ccp/sev-dev.h
@@ -66,6 +66,7 @@  struct sev_device {
 
 	bool snp_inited;
 	struct snp_host_map snp_host_map[MAX_SNP_HOST_MAP_BUFS];
+	struct page *snp_plat_status_page;
 };
 
 int sev_dev_init(struct psp_device *psp);
diff --git a/include/uapi/linux/psp-sev.h b/include/uapi/linux/psp-sev.h
index 226de6330a18..0c383d322097 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 = 256,
 
 	SEV_MAX,
 };