linux-kernel - [PATCH Part2 v6 16/49] crypto: ccp: Add the SNP_PLATFORM

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Message-ID: <218510ae39b529e19570c1af57bef86775e28c7e.1655761627.git.ashish.kalra@amd.com>
Date:   Mon, 20 Jun 2022 23:05:35 +0000
From:   Ashish Kalra <Ashish.Kalra@....com>
To:     <x86@...nel.org>, <linux-kernel@...r.kernel.org>,
        <kvm@...r.kernel.org>, <linux-coco@...ts.linux.dev>,
        <linux-mm@...ck.org>, <linux-crypto@...r.kernel.org>
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        <thomas.lendacky@....com>, <hpa@...or.com>, <ardb@...nel.org>,
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Subject: [PATCH Part2 v6 16/49] crypto: ccp: Add the SNP_PLATFORM_STATUS command

From: Brijesh Singh <brijesh.singh@....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@....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