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tpm_emulator: Add a caching layer for the TPM Established flag

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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 <stefanb@linux.vnet.ibm.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
This commit is contained in:
Stefan Berger 2017-11-08 15:30:18 -05:00
parent 281f327487
commit 0b4c7c65f8
1 changed files with 14 additions and 3 deletions
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17
hw/tpm/tpm_emulator.c
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@ -72,6 +72,9 @@ typedef struct TPMEmulator {
Error *migration_blocker;
QemuMutex mutex;
unsigned int established_flag:1;
unsigned int established_flag_cached:1;
} TPMEmulator;
@ -349,16 +352,22 @@ 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, 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);
return (est.u.resp.bit != 0);
tpm_emu->established_flag_cached = 1;
tpm_emu->established_flag = (est.u.resp.bit != 0);
return tpm_emu->established_flag;
}
static int tpm_emulator_reset_tpm_established_flag(TPMBackend *tb,
@ -389,6 +398,8 @@ static int tpm_emulator_reset_tpm_established_flag(TPMBackend *tb,
return -1;
}
tpm_emu->established_flag_cached = 0;
return 0;
}