From: Peter Gonda <pgonda@google.com>
Date: Tue, 7 Mar 2023 20:24:39 +0100
Subject: crypto: ccp - Name -1 return value as SEV_RET_NO_FW_CALL
Git-commit: efb339a83368ab25de1a18c0fdff85e01c13a1ea
Patch-mainline: v6.4-rc1
References: jsc#PED-7167
The PSP can return a "firmware error" code of -1 in circumstances where
the PSP has not actually been called. To make this protocol unambiguous,
name the value SEV_RET_NO_FW_CALL.
[ bp: Massage a bit. ]
Signed-off-by: Peter Gonda <pgonda@google.com>
Signed-off-by: Dionna Glaze <dionnaglaze@google.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20221207010210.2563293-2-dionnaglaze@google.com
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
Documentation/virt/coco/sev-guest.rst | 4 ++--
drivers/crypto/ccp/sev-dev.c | 8 +++++---
include/uapi/linux/psp-sev.h | 7 +++++++
3 files changed, 14 insertions(+), 5 deletions(-)
--- a/Documentation/virt/coco/sev-guest.rst
+++ b/Documentation/virt/coco/sev-guest.rst
@@ -40,8 +40,8 @@ along with a description:
The guest ioctl should be issued on a file descriptor of the /dev/sev-guest device.
The ioctl accepts struct snp_user_guest_request. The input and output structure is
specified through the req_data and resp_data field respectively. If the ioctl fails
-to execute due to a firmware error, then fw_err code will be set otherwise the
-fw_err will be set to 0x00000000000000ff.
+to execute due to a firmware error, then fw_err code will be set. Otherwise, fw_err
+will be set to 0x00000000ffffffff, i.e., the lower 32-bits are -1.
The firmware checks that the message sequence counter is one greater than
the guests message sequence counter. If guest driver fails to increment message
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -443,10 +443,10 @@ static int __sev_init_ex_locked(int *err
static int __sev_platform_init_locked(int *error)
{
+ int rc = 0, psp_ret = SEV_RET_NO_FW_CALL;
struct psp_device *psp = psp_master;
- struct sev_device *sev;
- int rc = 0, psp_ret = -1;
int (*init_function)(int *error);
+ struct sev_device *sev;
if (!psp || !psp->sev_data)
return -ENODEV;
@@ -474,9 +474,11 @@ static int __sev_platform_init_locked(in
* initialization function should succeed by replacing the state
* with a reset state.
*/
- dev_err(sev->dev, "SEV: retrying INIT command because of SECURE_DATA_INVALID error. Retrying once to reset PSP SEV state.");
+ dev_err(sev->dev,
+"SEV: retrying INIT command because of SECURE_DATA_INVALID error. Retrying once to reset PSP SEV state.");
rc = init_function(&psp_ret);
}
+
if (error)
*error = psp_ret;
--- a/include/uapi/linux/psp-sev.h
+++ b/include/uapi/linux/psp-sev.h
@@ -36,6 +36,13 @@ enum {
* SEV Firmware status code
*/
typedef enum {
+ /*
+ * This error code is not in the SEV spec. Its purpose is to convey that
+ * there was an error that prevented the SEV firmware from being called.
+ * The SEV API error codes are 16 bits, so the -1 value will not overlap
+ * with possible values from the specification.
+ */
+ SEV_RET_NO_FW_CALL = -1,
SEV_RET_SUCCESS = 0,
SEV_RET_INVALID_PLATFORM_STATE,
SEV_RET_INVALID_GUEST_STATE,