Re: [PATCH v2 7/8] crypto: ccp: Use the stack and common buffer for INIT command

[Christophe Leroy]

Le 07/04/2021 à 00:49, Sean Christopherson a écrit :

Drop the dedicated init_cmd_buf and instead use a local variable.  Now
that the low level helper uses an internal buffer for all commands,
using the stack for the upper layers is safe even when running with
CONFIG_VMAP_STACK=y.

Signed-off-by: Sean Christopherson <sea...@google.com>
---
  drivers/crypto/ccp/sev-dev.c | 10 ++++++----
  drivers/crypto/ccp/sev-dev.h |  1 -
  2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index e54774b0d637..9ff28df03030 100644
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -233,6 +233,7 @@ static int sev_do_cmd(int cmd, void *data, int *psp_ret)
  static int __sev_platform_init_locked(int *error)
  {
        struct psp_device *psp = psp_master;
+       struct sev_data_init data;

struct sev_data_init data = {0, 0, 0, 0};

        struct sev_device *sev;
        int rc = 0;

@@ -244,6 +245,7 @@ static int __sev_platform_init_locked(int *error)

        if (sev->state == SEV_STATE_INIT)
                return 0;

+ memset(&data, 0, sizeof(data));

Not needed.

        if (sev_es_tmr) {
                u64 tmr_pa;

@@ -253,12 +255,12 @@ static int __sev_platform_init_locked(int *error)

                 */
                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;
+               data.flags |= SEV_INIT_FLAGS_SEV_ES;
+               data.tmr_address = tmr_pa;
+               data.tmr_len = SEV_ES_TMR_SIZE;
        }

- rc = __sev_do_cmd_locked(SEV_CMD_INIT, &sev->init_cmd_buf, error);

+       rc = __sev_do_cmd_locked(SEV_CMD_INIT, &data, error);
        if (rc)
                return rc;

diff --git a/drivers/crypto/ccp/sev-dev.h b/drivers/crypto/ccp/sev-dev.h

index 0fd21433f627..666c21eb81ab 100644
--- a/drivers/crypto/ccp/sev-dev.h
+++ b/drivers/crypto/ccp/sev-dev.h
@@ -46,7 +46,6 @@ struct sev_device {
        unsigned int int_rcvd;
        wait_queue_head_t int_queue;
        struct sev_misc_dev *misc;
-       struct sev_data_init init_cmd_buf;

u8 api_major;

        u8 api_minor;