Commit efb339a8 authored by Peter Gonda's avatar Peter Gonda Committed by Borislav Petkov (AMD)
Browse files

crypto: ccp - Name -1 return value as SEV_RET_NO_FW_CALL 



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: default avatarPeter Gonda <pgonda@google.com>
Signed-off-by: default avatarDionna Glaze <dionnaglaze@google.com>
Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20221207010210.2563293-2-dionnaglaze@google.com
parent e8d018dd

Documentation/virt/coco/sev-guest.rst

+2 −2
Original line number Diff line number Diff line
@@ -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

drivers/crypto/ccp/sev-dev.c

+5 −3
Original line number Diff line number Diff line
@@ -444,10 +444,10 @@ static int __sev_init_ex_locked(int *error) 


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;
@@ -475,9 +475,11 @@ static int __sev_platform_init_locked(int *error) 
		 * 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;

include/uapi/linux/psp-sev.h

+7 −0
Original line number Diff line number Diff line
@@ -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,