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authorStefan Berger <stefanb@linux.vnet.ibm.com>2017-11-08 15:30:18 -0500
committerStefan Berger <stefanb@linux.vnet.ibm.com>2017-12-22 09:01:09 -0500
commit0b4c7c65f882fac328f2c97398f06f16fe6d3f12 (patch)
tree179f0a59462463928e77bf9367874777bbaacb92
parent281f327487c9c9b1599f93c589a408bbf4a651b8 (diff)
tpm_emulator: Add a caching layer for the TPM Established flag
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>
-rw-r--r--hw/tpm/tpm_emulator.c17
1 files changed, 14 insertions, 3 deletions
diff --git a/hw/tpm/tpm_emulator.c b/hw/tpm/tpm_emulator.c
index 38b6f175a1..35c78de5a9 100644
--- a/hw/tpm/tpm_emulator.c
+++ b/hw/tpm/tpm_emulator.c
@@ -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);
+
+ 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,
@@ -389,6 +398,8 @@ static int tpm_emulator_reset_tpm_established_flag(TPMBackend *tb,
return -1;
}
+ tpm_emu->established_flag_cached = 0;
+
return 0;
}