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[Qemu-devel] [PATCH] tpm: Add a caching layer for the TPM Established fl
From: |
Stefan Berger |
Subject: |
[Qemu-devel] [PATCH] tpm: Add a caching layer for the TPM Established flag |
Date: |
Wed, 8 Nov 2017 14:45:56 -0500 |
Add a caching layer for the TPM established flag so that we don't
need to go to the backend every time the flag is read by accessing
the REG_ACCESS register.
Signed-off-by: Stefan Berger <address@hidden>
---
hw/tpm/tpm_tis.c | 27 +++++++++++++++++++++++++--
1 file changed, 25 insertions(+), 2 deletions(-)
diff --git a/hw/tpm/tpm_tis.c b/hw/tpm/tpm_tis.c
index 7402528..6b81bbf 100644
--- a/hw/tpm/tpm_tis.c
+++ b/hw/tpm/tpm_tis.c
@@ -95,6 +95,9 @@ struct TPMState {
char *backend;
TPMBackend *be_driver;
TPMVersion be_tpm_version;
+
+ unsigned int established_flag:1;
+ unsigned int established_flag_cached:1;
};
#define TPM(obj) OBJECT_CHECK(TPMState, (obj), TYPE_TPM_TIS)
@@ -529,6 +532,26 @@ static void tpm_tis_dump_state(void *opaque, hwaddr addr)
}
#endif
+static void tpm_tis_reset_tpm_established_flag(TPMState *s,
+ uint8_t locty)
+{
+ s->established_flag_cached = 0;
+
+ tpm_backend_reset_tpm_established_flag(s->be_driver, locty);
+}
+
+static unsigned int tpm_tis_get_tpm_established_flag(TPMState *s)
+{
+ if (s->established_flag_cached) {
+ return s->established_flag;
+ }
+
+ s->established_flag = !tpm_backend_get_tpm_established_flag(s->be_driver);
+ s->established_flag_cached = 1;
+
+ return s->established_flag;
+}
+
/*
* Read a register of the TIS interface
* See specs pages 33-63 for description of the registers
@@ -556,7 +579,7 @@ static uint64_t tpm_tis_mmio_read(void *opaque, hwaddr addr,
if (tpm_tis_check_request_use_except(s, locty)) {
val |= TPM_TIS_ACCESS_PENDING_REQUEST;
}
- val |= !tpm_backend_get_tpm_established_flag(s->be_driver);
+ val |= tpm_tis_get_tpm_established_flag(s);
break;
case TPM_TIS_REG_INT_ENABLE:
val = s->loc[locty].inte;
@@ -840,7 +863,7 @@ static void tpm_tis_mmio_write(void *opaque, hwaddr addr,
if (val & TPM_TIS_STS_RESET_ESTABLISHMENT_BIT) {
if (locty == 3 || locty == 4) {
- tpm_backend_reset_tpm_established_flag(s->be_driver,
locty);
+ tpm_tis_reset_tpm_established_flag(s, locty);
}
}
}
--
2.5.5
- [Qemu-devel] [PATCH] tpm: Add a caching layer for the TPM Established flag,
Stefan Berger <=