crypto: ccp - Add support for SEV-ES to the PSP driver

To provide support for SEV-ES, the hypervisor must provide an area of
memory to the PSP. Once this Trusted Memory Region (TMR) is provided to
the PSP, the contents of this area of memory are no longer available to
the x86.

Update the PSP driver to allocate a 1MB region for the TMR that is 1MB
aligned and then provide it to the PSP through the SEV INIT command.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 43 insertions, 0 deletions

diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index 896f190b9a50..439cd737076e 100644
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -20,6 +20,7 @@
 #include <linux/hw_random.h>
 #include <linux/ccp.h>
 #include <linux/firmware.h>
+#include <linux/gfp.h>
 
 #include <asm/smp.h>
 
@@ -44,6 +45,14 @@ MODULE_PARM_DESC(psp_probe_timeout, " default timeout value, in seconds, during
 static bool psp_dead;
 static int psp_timeout;
 
+/* Trusted Memory Region (TMR):
+ *   The TMR is a 1MB area that must be 1MB aligned.  Use the page allocator
+ *   to allocate the memory, which will return aligned memory for the specified
+ *   allocation order.
+ */
+#define SEV_ES_TMR_SIZE		(1024 * 1024)
+static void *sev_es_tmr;
+
 static inline bool sev_version_greater_or_equal(u8 maj, u8 min)
 {
 	struct sev_device *sev = psp_master->sev_data;
@@ -214,6 +223,20 @@ static int __sev_platform_init_locked(int *error)
 	if (sev->state == SEV_STATE_INIT)
 		return 0;
 
+	if (sev_es_tmr) {
+		u64 tmr_pa;
+
+		/*
+		 * Do not include the encryption mask on the physical
+		 * address of the TMR (firmware should clear it anyway).
+		 */
+		tmr_pa = __pa(sev_es_tmr);
+
+		sev->init_cmd_buf.flags |= SEV_INIT_FLAGS_SEV_ES;
+		sev->init_cmd_buf.tmr_address = tmr_pa;
+		sev->init_cmd_buf.tmr_len = SEV_ES_TMR_SIZE;
+	}
+
 	rc = __sev_do_cmd_locked(SEV_CMD_INIT, &sev->init_cmd_buf, error);
 	if (rc)
 		return rc;
@@ -1012,6 +1035,7 @@ EXPORT_SYMBOL_GPL(sev_issue_cmd_external_user);
 void sev_pci_init(void)
 {
 	struct sev_device *sev = psp_master->sev_data;
+	struct page *tmr_page;
 	int error, rc;
 
 	if (!sev)
@@ -1041,6 +1065,16 @@ void sev_pci_init(void)
 	    sev_update_firmware(sev->dev) == 0)
 		sev_get_api_version();
 
+	/* Obtain the TMR memory area for SEV-ES use */
+	tmr_page = alloc_pages(GFP_KERNEL, get_order(SEV_ES_TMR_SIZE));
+	if (tmr_page) {
+		sev_es_tmr = page_address(tmr_page);
+	} else {
+		sev_es_tmr = NULL;
+		dev_warn(sev->dev,
+			 "SEV: TMR allocation failed, SEV-ES support unavailable\n");
+	}
+
 	/* Initialize the platform */
 	rc = sev_platform_init(&error);
 	if (rc && (error == SEV_RET_SECURE_DATA_INVALID)) {
@@ -1075,4 +1109,13 @@ void sev_pci_exit(void)
 		return;
 
 	sev_platform_shutdown(NULL);
+
+	if (sev_es_tmr) {
+		/* The TMR area was encrypted, flush it from the cache */
+		wbinvd_on_all_cpus();
+
+		free_pages((unsigned long)sev_es_tmr,
+			   get_order(SEV_ES_TMR_SIZE));
+		sev_es_tmr = NULL;
+	}
 }