linux-kernel - [PATCH v10 19/50] crypto: ccp: Add the SNP_PLATFORM

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Date:   Mon, 16 Oct 2023 08:27:48 -0500
From:   Michael Roth <michael.roth@....com>
To:     <kvm@...r.kernel.org>
CC:     <linux-coco@...ts.linux.dev>, <linux-mm@...ck.org>,
        <linux-crypto@...r.kernel.org>, <x86@...nel.org>,
        <linux-kernel@...r.kernel.org>, <tglx@...utronix.de>,
        <mingo@...hat.com>, <jroedel@...e.de>, <thomas.lendacky@....com>,
        <hpa@...or.com>, <ardb@...nel.org>, <pbonzini@...hat.com>,
        <seanjc@...gle.com>, <vkuznets@...hat.com>, <jmattson@...gle.com>,
        <luto@...nel.org>, <dave.hansen@...ux.intel.com>, <slp@...hat.com>,
        <pgonda@...gle.com>, <peterz@...radead.org>,
        <srinivas.pandruvada@...ux.intel.com>, <rientjes@...gle.com>,
        <dovmurik@...ux.ibm.com>, <tobin@....com>, <bp@...en8.de>,
        <vbabka@...e.cz>, <kirill@...temov.name>, <ak@...ux.intel.com>,
        <tony.luck@...el.com>, <marcorr@...gle.com>,
        <sathyanarayanan.kuppuswamy@...ux.intel.com>,
        <alpergun@...gle.com>, <jarkko@...nel.org>, <ashish.kalra@....com>,
        <nikunj.dadhania@....com>, <pankaj.gupta@....com>,
        <liam.merwick@...cle.com>, <zhi.a.wang@...el.com>,
        Brijesh Singh <brijesh.singh@....com>
Subject: [PATCH v10 19/50] 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>
Signed-off-by: Ashish Kalra <ashish.kalra@....com>
---
 Documentation/virt/coco/sev-guest.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/sev-guest.rst b/Documentation/virt/coco/sev-guest.rst
index 68b0d2363af8..e828c5326936 100644
--- a/Documentation/virt/coco/sev-guest.rst
+++ b/Documentation/virt/coco/sev-guest.rst
@@ -67,6 +67,22 @@ counter (e.g. counter overflow), then -EIO will be returned.
                 };
         };
 
+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
 ------------------
 
@@ -124,6 +140,17 @@ 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 b574b0ef2b1f..679b8d6fc09a 100644
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -1772,6 +1772,48 @@ 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_addr buf;
+	struct page *status_page;
+	void *data;
+	int ret;
+
+	if (!sev->snp_initialized || !argp->data)
+		return -EINVAL;
+
+	status_page = alloc_page(GFP_KERNEL_ACCOUNT);
+	if (!status_page)
+		return -ENOMEM;
+
+	data = page_address(status_page);
+	if (rmp_mark_pages_firmware(__pa(data), 1, true)) {
+		__free_pages(status_page, 0);
+		return -EFAULT;
+	}
+
+	buf.gctx_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_reclaim_pages(__pa(data), 1, 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;
@@ -1823,6 +1865,9 @@ 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 48e3ef91559c..b94b3687edbb 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