Messages in this thread | | | Date | Thu, 25 Jun 2020 14:28:17 -0700 | From | Jerry Snitselaar <> | Subject | Re: [PATCH v2] tpm: tpm2-space: Resize session and context buffers dynamically |
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On Thu Jun 25 20, Jarkko Sakkinen wrote: >Re-allocate context and session buffers when needed. Scale them in page >increments so that the reallocation is only seldomly required, and thus >causes minimal stress to the system. Add a static maximum limit of four >pages for buffer sizes. > >Cc: James Bottomley <James.Bottomley@HansenPartnership.com> >Suggested-by: Stefan Berger <stefanb@linux.ibm.com> >Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> >--- >Tested only for compilation. >v2: TPM2_SPACE_DEFAULT_BUFFER_SIZE > drivers/char/tpm/tpm2-space.c | 87 ++++++++++++++++++++++++----------- > include/linux/tpm.h | 6 ++- > 2 files changed, 64 insertions(+), 29 deletions(-) > >diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c >index 982d341d8837..b8ece01d6afb 100644 >--- a/drivers/char/tpm/tpm2-space.c >+++ b/drivers/char/tpm/tpm2-space.c >@@ -15,6 +15,9 @@ > #include <asm/unaligned.h> > #include "tpm.h" > >+#define TPM2_SPACE_DEFAULT_BUFFER_SIZE PAGE_SIZE >+#define TPM2_SPACE_MAX_BUFFER_SIZE (4 * PAGE_SIZE) >+ > enum tpm2_handle_types { > TPM2_HT_HMAC_SESSION = 0x02000000, > TPM2_HT_POLICY_SESSION = 0x03000000, >@@ -40,16 +43,21 @@ static void tpm2_flush_sessions(struct tpm_chip *chip, struct tpm_space *space) > > int tpm2_init_space(struct tpm_space *space) > { >- space->context_buf = kzalloc(PAGE_SIZE, GFP_KERNEL); >+ space->context_buf = kzalloc(TPM2_SPACE_DEFAULT_BUFFER_SIZE, >+ GFP_KERNEL); > if (!space->context_buf) > return -ENOMEM; > >- space->session_buf = kzalloc(PAGE_SIZE, GFP_KERNEL); >+ space->session_buf = kzalloc(TPM2_SPACE_DEFAULT_BUFFER_SIZE, >+ GFP_KERNEL); > if (space->session_buf == NULL) { > kfree(space->context_buf); >+ space->context_buf = NULL; > return -ENOMEM; > } > >+ space->context_size = TPM2_SPACE_DEFAULT_BUFFER_SIZE; >+ space->session_size = TPM2_SPACE_DEFAULT_BUFFER_SIZE; > return 0; > } > >@@ -116,11 +124,13 @@ static int tpm2_load_context(struct tpm_chip *chip, u8 *buf, > return 0; > } > >-static int tpm2_save_context(struct tpm_chip *chip, u32 handle, u8 *buf, >- unsigned int buf_size, unsigned int *offset) >+static int tpm2_save_context(struct tpm_chip *chip, u32 handle, u8 **buf, >+ unsigned int *buf_size, unsigned int *offset) > { >- struct tpm_buf tbuf; >+ unsigned int new_buf_size; > unsigned int body_size; >+ struct tpm_buf tbuf; >+ void *new_buf; > int rc; > > rc = tpm_buf_init(&tbuf, TPM2_ST_NO_SESSIONS, TPM2_CC_CONTEXT_SAVE); >@@ -131,31 +141,48 @@ static int tpm2_save_context(struct tpm_chip *chip, u32 handle, u8 *buf, > > rc = tpm_transmit_cmd(chip, &tbuf, 0, NULL); > if (rc < 0) { >- dev_warn(&chip->dev, "%s: failed with a system error %d\n", >- __func__, rc); >- tpm_buf_destroy(&tbuf); >- return -EFAULT; >+ rc = -EFAULT; >+ goto err; > } else if (tpm2_rc_value(rc) == TPM2_RC_REFERENCE_H0) { >- tpm_buf_destroy(&tbuf); >- return -ENOENT; >+ rc = -ENOENT; >+ goto out; > } else if (rc) { >- dev_warn(&chip->dev, "%s: failed with a TPM error 0x%04X\n", >- __func__, rc); >- tpm_buf_destroy(&tbuf); >- return -EFAULT; >+ rc = -EFAULT; >+ goto err; > } >
Would it be worthwhile to still output something here since it is changing the value of rc returned from tpm_transmit_cmd()? Wondering if it would be useful for debugging to know what the returned error was. Other than that question looks good to me pending what is decided on using PAGE_SIZE.
Regards, Jerry
> body_size = tpm_buf_length(&tbuf) - TPM_HEADER_SIZE; >- if ((*offset + body_size) > buf_size) { >- dev_warn(&chip->dev, "%s: out of backing storage\n", __func__); >- tpm_buf_destroy(&tbuf); >- return -ENOMEM; >+ /* We grow the buffer in page increments. */ >+ new_buf_size = PFN_UP(*offset + body_size); >+ >+ if (new_buf_size > TPM2_SPACE_MAX_BUFFER_SIZE) { >+ rc = -ENOMEM; >+ goto err; > } > >- memcpy(&buf[*offset], &tbuf.data[TPM_HEADER_SIZE], body_size); >+ if (new_buf_size > *buf_size) { >+ new_buf = krealloc(*buf, new_buf_size, GFP_KERNEL); >+ if (!new_buf) { >+ rc = -ENOMEM; >+ goto err; >+ } >+ >+ *buf = new_buf; >+ *buf_size = new_buf_size; >+ } >+ >+ memcpy(*buf + *offset, &tbuf.data[TPM_HEADER_SIZE], body_size); > *offset += body_size; >+ >+out: > tpm_buf_destroy(&tbuf); >- return 0; >+ return rc; >+ >+err: >+ dev_warn(&chip->dev, "%s: ret=%d\n", __func__, rc); >+ >+ tpm_buf_destroy(&tbuf); >+ return rc; > } > > void tpm2_flush_space(struct tpm_chip *chip) >@@ -311,8 +338,10 @@ int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u8 *cmd, > sizeof(space->context_tbl)); > memcpy(&chip->work_space.session_tbl, &space->session_tbl, > sizeof(space->session_tbl)); >- memcpy(chip->work_space.context_buf, space->context_buf, PAGE_SIZE); >- memcpy(chip->work_space.session_buf, space->session_buf, PAGE_SIZE); >+ memcpy(chip->work_space.context_buf, space->context_buf, >+ space->context_size); >+ memcpy(chip->work_space.session_buf, space->session_buf, >+ space->session_size); > > rc = tpm2_load_space(chip); > if (rc) { >@@ -492,7 +521,8 @@ static int tpm2_save_space(struct tpm_chip *chip) > continue; > > rc = tpm2_save_context(chip, space->context_tbl[i], >- space->context_buf, PAGE_SIZE, >+ &space->context_buf, >+ &space->context_size, > &offset); > if (rc == -ENOENT) { > space->context_tbl[i] = 0; >@@ -509,7 +539,8 @@ static int tpm2_save_space(struct tpm_chip *chip) > continue; > > rc = tpm2_save_context(chip, space->session_tbl[i], >- space->session_buf, PAGE_SIZE, >+ &space->session_buf, >+ &space->session_size, > &offset); > > if (rc == -ENOENT) { >@@ -557,8 +588,10 @@ int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space, > sizeof(space->context_tbl)); > memcpy(&space->session_tbl, &chip->work_space.session_tbl, > sizeof(space->session_tbl)); >- memcpy(space->context_buf, chip->work_space.context_buf, PAGE_SIZE); >- memcpy(space->session_buf, chip->work_space.session_buf, PAGE_SIZE); >+ memcpy(space->context_buf, chip->work_space.context_buf, >+ space->context_size); >+ memcpy(space->session_buf, chip->work_space.session_buf, >+ space->session_size); > > return 0; > out: >diff --git a/include/linux/tpm.h b/include/linux/tpm.h >index 03e9b184411b..9ea39e8f7162 100644 >--- a/include/linux/tpm.h >+++ b/include/linux/tpm.h >@@ -92,10 +92,12 @@ enum tpm_duration { > #define TPM_PPI_VERSION_LEN 3 > > struct tpm_space { >+ u8 *context_buf; >+ u8 *session_buf; >+ u32 context_size; >+ u32 session_size; > u32 context_tbl[3]; >- u8 *context_buf; > u32 session_tbl[3]; >- u8 *session_buf; > }; > > struct tpm_bios_log { >-- >2.25.1 >
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