Add helpers to read integer module params, which is painfully non-trivial because the pain of dealing with strings in C is exacerbated by the kernel inserting a newline. Don't bother differentiating between int, uint, short, etc. They all fit in an int, and KVM (thankfully) doesn't have any integer params larger than an int. Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx> --- .../selftests/kvm/include/kvm_util_base.h | 4 ++ tools/testing/selftests/kvm/lib/kvm_util.c | 62 +++++++++++++++++-- 2 files changed, 60 insertions(+), 6 deletions(-) diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h index a18db6a7b3cf..46b71241216e 100644 --- a/tools/testing/selftests/kvm/include/kvm_util_base.h +++ b/tools/testing/selftests/kvm/include/kvm_util_base.h @@ -238,6 +238,10 @@ bool get_kvm_param_bool(const char *param); bool get_kvm_intel_param_bool(const char *param); bool get_kvm_amd_param_bool(const char *param); +int get_kvm_param_integer(const char *param); +int get_kvm_intel_param_integer(const char *param); +int get_kvm_amd_param_integer(const char *param); + unsigned int kvm_check_cap(long cap); static inline bool kvm_has_cap(long cap) diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c index 7a8af1821f5d..65101c7d1a1a 100644 --- a/tools/testing/selftests/kvm/lib/kvm_util.c +++ b/tools/testing/selftests/kvm/lib/kvm_util.c @@ -51,13 +51,13 @@ int open_kvm_dev_path_or_exit(void) return _open_kvm_dev_path_or_exit(O_RDONLY); } -static bool get_module_param_bool(const char *module_name, const char *param) +static ssize_t get_module_param(const char *module_name, const char *param, + void *buffer, size_t buffer_size) { const int path_size = 128; char path[path_size]; - char value; - ssize_t r; - int fd; + ssize_t bytes_read; + int fd, r; r = snprintf(path, path_size, "/sys/module/%s/parameters/%s", module_name, param); @@ -66,11 +66,46 @@ static bool get_module_param_bool(const char *module_name, const char *param) fd = open_path_or_exit(path, O_RDONLY); - r = read(fd, &value, 1); - TEST_ASSERT(r == 1, "read(%s) failed", path); + bytes_read = read(fd, buffer, buffer_size); + TEST_ASSERT(bytes_read > 0, "read(%s) returned %ld, wanted %ld bytes", + path, bytes_read, buffer_size); r = close(fd); TEST_ASSERT(!r, "close(%s) failed", path); + return bytes_read; +} + +static int get_module_param_integer(const char *module_name, const char *param) +{ + /* + * 16 bytes to hold a 64-bit value (1 byte per char), 1 byte for the + * NUL char, and 1 byte because the kernel sucks and inserts a newline + * at the end. + */ + char value[16 + 1 + 1]; + ssize_t r; + + memset(value, '\0', sizeof(value)); + + r = get_module_param(module_name, param, value, sizeof(value)); + TEST_ASSERT(value[r - 1] == '\n', + "Expected trailing newline, got char '%c'", value[r - 1]); + + /* + * Squash the newline, otherwise atoi_paranoid() will complain about + * trailing non-NUL characters in the string. + */ + value[r - 1] = '\0'; + return atoi_paranoid(value); +} + +static bool get_module_param_bool(const char *module_name, const char *param) +{ + char value; + ssize_t r; + + r = get_module_param(module_name, param, &value, sizeof(value)); + TEST_ASSERT_EQ(r, 1); if (value == 'Y') return true; @@ -95,6 +130,21 @@ bool get_kvm_amd_param_bool(const char *param) return get_module_param_bool("kvm_amd", param); } +int get_kvm_param_integer(const char *param) +{ + return get_module_param_integer("kvm", param); +} + +int get_kvm_intel_param_integer(const char *param) +{ + return get_module_param_integer("kvm_intel", param); +} + +int get_kvm_amd_param_integer(const char *param) +{ + return get_module_param_integer("kvm_amd", param); +} + /* * Capability * -- 2.42.0.869.gea05f2083d-goog