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tpm: Clean up driver registration & lookup

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We have a strict separation between enum TpmType and be_drivers[]:

* TpmType may have any number of members.  It just happens to have one.

* tpm_register_driver() uses the first empty slot in be_drivers[].

  If you register more than tpm_models[] has space,
  tpm_register_driver() fails.  Its caller silently ignores the
  failure.

  If you register more than one with a given TpmType,
  tpm_display_backend_drivers() will shows all of them, but
  tpm_driver_find_by_type() and tpm_get_backend_driver() will find
  only the one one that registered first.

Since we only ever register one driver, and be_drivers[] has space for
just that one, this contraption even works.

Turn be_drivers[] into a straight map from enum TpmType to driver.
Much simpler, and has a decent chance to actually work should we ever
acquire additional drivers.

While there, use qapi_enum_parse() in tpm_get_backend_driver().

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20170822132255.23945-8-marcandre.lureau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Rebased, superfluous initializer dropped, commit message rewritten]
Cc: Stefan Berger <stefanb@us.ibm.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1503564371-26090-4-git-send-email-armbru@redhat.com>
This commit is contained in:
Marc-André Lureau 2017-08-24 10:45:58 +02:00 committed by Markus Armbruster
parent 06c60b6c46
commit a9a72aeefb
2 changed files with 14 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/sysemu/tpm_backend.h
View File

@ -227,6 +227,6 @@ TPMBackend *qemu_find_tpm(const char *id);
const TPMDriverOps *tpm_get_backend_driver(const char *type);
int tpm_register_model(enum TpmModel model);
int tpm_register_driver(const TPMDriverOps *tdo);
void tpm_register_driver(const TPMDriverOps *tdo);
#endif

45
tpm.c
View File

@ -14,6 +14,7 @@
#include "qemu/osdep.h"
#include "qapi/qmp/qerror.h"
#include "qapi/util.h"
#include "sysemu/tpm_backend.h"
#include "sysemu/tpm.h"
#include "qemu/config-file.h"
@ -25,11 +26,8 @@ static QLIST_HEAD(, TPMBackend) tpm_backends =
#define TPM_MAX_MODELS 1
#define TPM_MAX_DRIVERS 1
static TPMDriverOps const *be_drivers[TPM_MAX_DRIVERS] = {
NULL,
};
static TPMDriverOps const *be_drivers[TPM_TYPE__MAX];
static enum TpmModel tpm_models[TPM_MAX_MODELS] = {
TPM_MODEL__MAX,
@ -63,31 +61,18 @@ static bool tpm_model_is_registered(enum TpmModel model)
const TPMDriverOps *tpm_get_backend_driver(const char *type)
{
int i;
int i = qapi_enum_parse(TpmType_lookup, type, -1, NULL);
for (i = 0; i < TPM_MAX_DRIVERS && be_drivers[i] != NULL; i++) {
if (!strcmp(TpmType_lookup[be_drivers[i]->type], type)) {
return be_drivers[i];
}
}
return NULL;
return i >= 0 ? be_drivers[i] : NULL;
}
#ifdef CONFIG_TPM
int tpm_register_driver(const TPMDriverOps *tdo)
void tpm_register_driver(const TPMDriverOps *tdo)
{
int i;
assert(!be_drivers[tdo->type]);
for (i = 0; i < TPM_MAX_DRIVERS; i++) {
if (!be_drivers[i]) {
be_drivers[i] = tdo;
return 0;
}
}
error_report("Could not register TPM driver");
return 1;
be_drivers[tdo->type] = tdo;
}
/*
@ -100,9 +85,12 @@ static void tpm_display_backend_drivers(void)
fprintf(stderr, "Supported TPM types (choose only one):\n");
for (i = 0; i < TPM_MAX_DRIVERS && be_drivers[i] != NULL; i++) {
for (i = 0; i < TPM_TYPE__MAX; i++) {
if (be_drivers[i] == NULL) {
continue;
}
fprintf(stderr, "%12s %s\n",
TpmType_lookup[be_drivers[i]->type], be_drivers[i]->desc());
TpmType_lookup[i], be_drivers[i]->desc());
}
fprintf(stderr, "\n");
}
@ -239,14 +227,7 @@ int tpm_config_parse(QemuOptsList *opts_list, const char *optarg)
static const TPMDriverOps *tpm_driver_find_by_type(enum TpmType type)
{
int i;
for (i = 0; i < TPM_MAX_DRIVERS && be_drivers[i] != NULL; i++) {
if (be_drivers[i]->type == type) {
return be_drivers[i];
}
}
return NULL;
return be_drivers[type];
}
static TPMInfo *qmp_query_tpm_inst(TPMBackend *drv)