Messages in this thread | | | Subject | Re: [PATCH] tpm: tpm2-space: Resize session and context buffers dynamically | From | Stefan Berger <> | Date | Thu, 25 Jun 2020 08:13:09 -0400 |
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On 6/25/20 12:24 AM, 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. > drivers/char/tpm/tpm2-space.c | 80 ++++++++++++++++++++++++----------- > include/linux/tpm.h | 6 ++- > 2 files changed, 59 insertions(+), 27 deletions(-) > > diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c > index 982d341d8837..acb9e82bf9e8 100644 > --- a/drivers/char/tpm/tpm2-space.c > +++ b/drivers/char/tpm/tpm2-space.c > @@ -15,6 +15,8 @@ > #include <asm/unaligned.h> > #include "tpm.h" > > +#define TPM2_SPACE_MAX_BUFFER_SIZE (4 * PAGE_SIZE)
PAGE_SIZE is 64k on ppc64. Rather use 4 * 4096?
Rest looks good.
> + > enum tpm2_handle_types { > TPM2_HT_HMAC_SESSION = 0x02000000, > TPM2_HT_POLICY_SESSION = 0x03000000, > @@ -47,9 +49,12 @@ int tpm2_init_space(struct tpm_space *space) > space->session_buf = kzalloc(PAGE_SIZE, GFP_KERNEL); > if (space->session_buf == NULL) { > kfree(space->context_buf); > + space->context_buf = NULL; > return -ENOMEM; > } > > + space->context_size = PAGE_SIZE; > + space->session_size = PAGE_SIZE; > return 0; > } > > @@ -116,11 +121,13 @@ 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 +138,48 @@ 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; > } > > 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 +335,10 @@ 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 +518,8 @@ 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 +536,8 @@ 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 +585,10 @@ 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 {
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