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From:   Ashish Kalra <Ashish.Kalra@amd.com>
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Subject: [PATCH Part2 v6 12/49] crypto: ccp: Add support to initialize the AMD-SP for SEV-SNP
Date:   Mon, 20 Jun 2022 23:04:29 +0000
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From: Brijesh Singh <brijesh.singh@amd.com>

Before SNP VMs can be launched, the platform must be appropriately
configured and initialized. Platform initialization is accomplished via
the SNP_INIT command. Make sure to do a WBINVD and issue DF_FLUSH command
to prepare for the first SNP guest launch after INIT.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off by: Ashish Kalra <ashish.kalra@amd.com>
---
 drivers/crypto/ccp/sev-dev.c | 121 +++++++++++++++++++++++++++++++++++
 drivers/crypto/ccp/sev-dev.h |   2 +
 include/linux/psp-sev.h      |  16 +++++
 3 files changed, 139 insertions(+)

diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index 9cb3265f3bef..f1173221d0b9 100644
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -33,6 +33,10 @@
 #define SEV_FW_FILE		"amd/sev.fw"
 #define SEV_FW_NAME_SIZE	64
 
+/* Minimum firmware version required for the SEV-SNP support */
+#define SNP_MIN_API_MAJOR	1
+#define SNP_MIN_API_MINOR	51
+
 static DEFINE_MUTEX(sev_cmd_mutex);
 static struct sev_misc_dev *misc_dev;
 
@@ -775,6 +779,98 @@ static int sev_update_firmware(struct device *dev)
 	return ret;
 }
 
+static void snp_set_hsave_pa(void *arg)
+{
+	wrmsrl(MSR_VM_HSAVE_PA, 0);
+}
+
+static int __sev_snp_init_locked(int *error)
+{
+	struct psp_device *psp = psp_master;
+	struct sev_device *sev;
+	int rc = 0;
+
+	if (!psp || !psp->sev_data)
+		return -ENODEV;
+
+	sev = psp->sev_data;
+
+	if (sev->snp_inited)
+		return 0;
+
+	/*
+	 * The SNP_INIT requires the MSR_VM_HSAVE_PA must be set to 0h
+	 * across all cores.
+	 */
+	on_each_cpu(snp_set_hsave_pa, NULL, 1);
+
+	/* Issue the SNP_INIT firmware command. */
+	rc = __sev_do_cmd_locked(SEV_CMD_SNP_INIT, NULL, error);
+	if (rc)
+		return rc;
+
+	/* Prepare for first SNP guest launch after INIT */
+	wbinvd_on_all_cpus();
+	rc = __sev_do_cmd_locked(SEV_CMD_SNP_DF_FLUSH, NULL, error);
+	if (rc)
+		return rc;
+
+	sev->snp_inited = true;
+	dev_dbg(sev->dev, "SEV-SNP firmware initialized\n");
+
+	return rc;
+}
+
+int sev_snp_init(int *error)
+{
+	int rc;
+
+	if (!cpu_feature_enabled(X86_FEATURE_SEV_SNP))
+		return -ENODEV;
+
+	mutex_lock(&sev_cmd_mutex);
+	rc = __sev_snp_init_locked(error);
+	mutex_unlock(&sev_cmd_mutex);
+
+	return rc;
+}
+EXPORT_SYMBOL_GPL(sev_snp_init);
+
+static int __sev_snp_shutdown_locked(int *error)
+{
+	struct sev_device *sev = psp_master->sev_data;
+	int ret;
+
+	if (!sev->snp_inited)
+		return 0;
+
+	/* SHUTDOWN requires the DF_FLUSH */
+	wbinvd_on_all_cpus();
+	__sev_do_cmd_locked(SEV_CMD_SNP_DF_FLUSH, NULL, NULL);
+
+	ret = __sev_do_cmd_locked(SEV_CMD_SNP_SHUTDOWN, NULL, error);
+	if (ret) {
+		dev_err(sev->dev, "SEV-SNP firmware shutdown failed\n");
+		return ret;
+	}
+
+	sev->snp_inited = false;
+	dev_dbg(sev->dev, "SEV-SNP firmware shutdown\n");
+
+	return ret;
+}
+
+static int sev_snp_shutdown(int *error)
+{
+	int rc;
+
+	mutex_lock(&sev_cmd_mutex);
+	rc = __sev_snp_shutdown_locked(NULL);
+	mutex_unlock(&sev_cmd_mutex);
+
+	return rc;
+}
+
 static int sev_ioctl_do_pek_import(struct sev_issue_cmd *argp, bool writable)
 {
 	struct sev_device *sev = psp_master->sev_data;
@@ -1231,6 +1327,8 @@ static void sev_firmware_shutdown(struct sev_device *sev)
 			   get_order(NV_LENGTH));
 		sev_init_ex_buffer = NULL;
 	}
+
+	sev_snp_shutdown(NULL);
 }
 
 void sev_dev_destroy(struct psp_device *psp)
@@ -1287,6 +1385,26 @@ void sev_pci_init(void)
 		}
 	}
 
+	/*
+	 * If boot CPU supports the SNP, then first attempt to initialize
+	 * the SNP firmware.
+	 */
+	if (cpu_feature_enabled(X86_FEATURE_SEV_SNP)) {
+		if (!sev_version_greater_or_equal(SNP_MIN_API_MAJOR, SNP_MIN_API_MINOR)) {
+			dev_err(sev->dev, "SEV-SNP support requires firmware version >= %d:%d\n",
+				SNP_MIN_API_MAJOR, SNP_MIN_API_MINOR);
+		} else {
+			rc = sev_snp_init(&error);
+			if (rc) {
+				/*
+				 * If we failed to INIT SNP then don't abort the probe.
+				 * Continue to initialize the legacy SEV firmware.
+				 */
+				dev_err(sev->dev, "SEV-SNP: failed to INIT error %#x\n", error);
+			}
+		}
+	}
+
 	/* Obtain the TMR memory area for SEV-ES use */
 	sev_es_tmr = sev_fw_alloc(SEV_ES_TMR_SIZE);
 	if (!sev_es_tmr)
@@ -1302,6 +1420,9 @@ void sev_pci_init(void)
 		dev_err(sev->dev, "SEV: failed to INIT error %#x, rc %d\n",
 			error, rc);
 
+	dev_info(sev->dev, "SEV%s API:%d.%d build:%d\n", sev->snp_inited ?
+		"-SNP" : "", sev->api_major, sev->api_minor, sev->build);
+
 	return;
 
 err:
diff --git a/drivers/crypto/ccp/sev-dev.h b/drivers/crypto/ccp/sev-dev.h
index 666c21eb81ab..186ad20cbd24 100644
--- a/drivers/crypto/ccp/sev-dev.h
+++ b/drivers/crypto/ccp/sev-dev.h
@@ -52,6 +52,8 @@ struct sev_device {
 	u8 build;
 
 	void *cmd_buf;
+
+	bool snp_inited;
 };
 
 int sev_dev_init(struct psp_device *psp);
diff --git a/include/linux/psp-sev.h b/include/linux/psp-sev.h
index 01ba9dc46ca3..ef4d42e8c96e 100644
--- a/include/linux/psp-sev.h
+++ b/include/linux/psp-sev.h
@@ -769,6 +769,20 @@ struct sev_data_snp_init_ex {
  */
 int sev_platform_init(int *error);
 
+/**
+ * sev_snp_init - perform SEV SNP_INIT command
+ *
+ * @error: SEV command return code
+ *
+ * Returns:
+ * 0 if the SEV successfully processed the command
+ * -%ENODEV    if the SEV device is not available
+ * -%ENOTSUPP  if the SEV does not support SEV
+ * -%ETIMEDOUT if the SEV command timed out
+ * -%EIO       if the SEV returned a non-zero return code
+ */
+int sev_snp_init(int *error);
+
 /**
  * sev_platform_status - perform SEV PLATFORM_STATUS command
  *
@@ -876,6 +890,8 @@ sev_platform_status(struct sev_user_data_status *status, int *error) { return -E
 
 static inline int sev_platform_init(int *error) { return -ENODEV; }
 
+static inline int sev_snp_init(int *error) { return -ENODEV; }
+
 static inline int
 sev_guest_deactivate(struct sev_data_deactivate *data, int *error) { return -ENODEV; }
 
-- 
2.25.1