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[Qemu-devel] [PATCH v3 for-2.11 1/3] tpm_emulator: Add a caching layer f
From: |
Stefan Berger |
Subject: |
[Qemu-devel] [PATCH v3 for-2.11 1/3] tpm_emulator: Add a caching layer for the TPM Established flag |
Date: |
Tue, 14 Nov 2017 16:52:27 -0500 |
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 <address@hidden>
v1->v2:
- move the caching to the backend layer since detecting the
TPM 1.2 TSC_ResetEstablishmentBit() command is easier to do
here.
---
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 e1a6810..b293db7 100644
--- a/hw/tpm/tpm_emulator.c
+++ b/hw/tpm/tpm_emulator.c
@@ -73,6 +73,9 @@ typedef struct TPMEmulator {
Error *migration_blocker;
QemuMutex mutex;
+
+ unsigned int established_flag:1;
+ unsigned int established_flag_cached:1;
} TPMEmulator;
@@ -287,16 +290,22 @@ 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,
@@ -327,6 +336,8 @@ static int
tpm_emulator_reset_tpm_established_flag(TPMBackend *tb,
return -1;
}
+ tpm_emu->established_flag_cached = 0;
+
return 0;
}
--
2.5.5
[Qemu-devel] [PATCH v3 for-2.11 3/3] tpm_tis: Return 0 for every register in case of failure mode, Stefan Berger, 2017/11/14
[Qemu-devel] [PATCH v3 for-2.11 2/3] tpm_tis: Return TPM_VERSION_UNSPEC in case of BE failure, Stefan Berger, 2017/11/14