Hi
On Wed, Nov 8, 2017 at 9:37 PM, Stefan Berger
<stef...@linux.vnet.ibm.com> wrote:
> Add a caching layer for the TPM established flag so that we don't
> need to go to the emulator every time the flag is read by accessing
> the REG_ACCESS register.
>
> Signed-off-by: Stefan Berger <stef...@linux.vnet.ibm.com>
>
> v1->v2:
> - move the caching to the backend layer since detecting the
> TPM 1.2 TSC_ResetEstablishmentBit() command is easier to do
> here.
What about the HASH_START? Is this not supported by qemu TIS? Is the
function gone or done differently with TPM2 or CRB?
> ---
> hw/tpm/tpm_emulator.c | 17 ++++++++++++++---
> 1 file changed, 14 insertions(+), 3 deletions(-)
>
> diff --git a/hw/tpm/tpm_emulator.c b/hw/tpm/tpm_emulator.c
> index 9aaec8e..507e2cb 100644
> --- a/hw/tpm/tpm_emulator.c
> +++ b/hw/tpm/tpm_emulator.c
> @@ -71,6 +71,9 @@ typedef struct TPMEmulator {
> ptm_cap caps; /* capabilities of the TPM */
> uint8_t cur_locty_number; /* last set locality */
> Error *migration_blocker;
> +
> + unsigned int established_flag:1;
> + unsigned int established_flag_cached:1;
> } TPMEmulator;
>
>
> @@ -277,16 +280,22 @@ static bool
> tpm_emulator_get_tpm_established_flag(TPMBackend *tb)
> TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
> ptm_est est;
>
> - DPRINTF("%s", __func__);
> + if (tpm_emu->established_flag_cached) {
> + return tpm_emu->established_flag;
> + }
> +
> if (tpm_emulator_ctrlcmd(&tpm_emu->ctrl_chr, CMD_GET_TPMESTABLISHED,
> &est,
> 0, sizeof(est)) < 0) {
> error_report("tpm-emulator: Could not get the TPM established flag:
> %s",
> strerror(errno));
> return false;
> }
> - DPRINTF("established flag: %0x", est.u.resp.bit);
> + DPRINTF("got established flag: %0x", est.u.resp.bit);
> +
> + tpm_emu->established_flag_cached = 1;
> + tpm_emu->established_flag = (est.u.resp.bit != 0);
>
> - return (est.u.resp.bit != 0);
> + return tpm_emu->established_flag;
> }
>
> static int tpm_emulator_reset_tpm_established_flag(TPMBackend *tb,
> @@ -317,6 +326,8 @@ static int
> tpm_emulator_reset_tpm_established_flag(TPMBackend *tb,
> return -1;
> }
>
> + tpm_emu->established_flag_cached = 0;
> +
> return 0;
> }
>
> --
> 2.5.5
>
>
--
Marc-André Lureau
