Re: [PATCH v10 4/4] tpm_vpm_proxy: Use stack for TPM_CC_SET_LOCALITY

Stefano Garzarella
2025-09-22T08:46:48Z

On Sun, Sep 21, 2025 at 05:08:04AM +0300, Jarkko Sakkinen wrote:
>From: Jarkko Sakkinen <jarkko.sakkinen@opinsys.com>
>
>Use stack allocation for TPM_CC_SET_LOCALITY, as it has known fixed size.
>
>Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@opinsys.com>
>---
> drivers/char/tpm/tpm1-cmd.c | 2 +-
> drivers/char/tpm/tpm_vtpm_proxy.c | 12 +++++-------
> 2 files changed, 6 insertions(+), 8 deletions(-)
>
>diff --git a/drivers/char/tpm/tpm1-cmd.c b/drivers/char/tpm/tpm1-cmd.c
>index 11c16ad9b2a7..433908cfb4a9 100644
>--- a/drivers/char/tpm/tpm1-cmd.c
>+++ b/drivers/char/tpm/tpm1-cmd.c
>@@ -328,7 +328,7 @@ static int tpm1_startup(struct tpm_chip *chip)
> int rc;
>
> dev_info(&chip->dev, "TPM_Startup\n");
>- tpm_buf_init(buf, TPM_BUF_INT_SIZE);
>+ tpm_buf_init(buf, TPM_BUF_MIN_SIZE);

This change should be squashed in patch 2, right?

Thanks,
Stefano

> tpm_buf_reset(buf, TPM_TAG_RQU_COMMAND, TPM_ORD_STARTUP);
> tpm_buf_append_u16(buf, TPM_ST_CLEAR);
> rc = tpm_transmit_cmd(chip, buf, 0, "TPM_Startup");
>diff --git a/drivers/char/tpm/tpm_vtpm_proxy.c b/drivers/char/tpm/tpm_vtpm_proxy.c
>index e5de14379eb2..0f1b1b67ed4e 100644
>--- a/drivers/char/tpm/tpm_vtpm_proxy.c
>+++ b/drivers/char/tpm/tpm_vtpm_proxy.c
>@@ -395,15 +395,13 @@ static bool vtpm_proxy_tpm_req_canceled(struct tpm_chip *chip, u8 status)
>
> static int vtpm_proxy_request_locality(struct tpm_chip *chip, int locality)
> {
>- int rc;
>- const struct tpm_header *header;
> struct proxy_dev *proxy_dev = dev_get_drvdata(&chip->dev);
>+ u8 buf_data[TPM_BUF_MIN_SIZE];
>+ struct tpm_buf *buf = (struct tpm_buf *)buf_data;
>+ const struct tpm_header *header;
>+ int rc;
>
>- struct tpm_buf *buf __free(kfree) = kzalloc(PAGE_SIZE, GFP_KERNEL);
>- if (!buf)
>- return -ENOMEM;
>-
>- tpm_buf_init(buf, TPM_BUF_MAX_SIZE);
>+ tpm_buf_init(buf, TPM_BUF_MIN_SIZE);
> if (chip->flags & TPM_CHIP_FLAG_TPM2)
> tpm_buf_reset(buf, TPM2_ST_SESSIONS, TPM2_CC_SET_LOCALITY);
> else
>--
>2.39.5
>