On Wed, Sep 28, 2022, David Matlack wrote:
> @@ -114,6 +115,36 @@ void print_skip(const char *fmt, ...)
> puts(", skipping test");
> }
>
> +bool get_module_param_bool(const char *module_name, const char *param)
> +{
> + const int path_size = 1024;
> + char path[path_size];
> + char value;
> + FILE *f;
> + int r;
> +
> + r = snprintf(path, path_size, "/sys/module/%s/parameters/%s",
> + module_name, param);
> + TEST_ASSERT(r < path_size,
> + "Failed to construct sysfs path in %d bytes.", path_size);
> +
> + f = fopen(path, "r");
Any particular reason for using fopen()? Oh, because that's what the existing
code does. More below.
> + TEST_ASSERT(f, "fopen(%s) failed", path);
I don't actually care myself, but for consistency this should probably be a
skip condition. The easiest thing would be to use open_path_or_exit().
At that point, assuming read() instead of fread() does the right thin, that seems
like the easiest solution.
> + TEST_FAIL("Unrecognized value: %c", value);
Maybe be slightly more verbose? E.g.
TEST_FAIL("Unrecognized value '%c' for boolean module param", value);
> +}
> +
> bool thp_configured(void)
> {
> int ret;
> diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
> index 2e6e61bbe81b..522d3e2009fb 100644
> --- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
> +++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
> @@ -1294,20 +1294,9 @@ unsigned long vm_compute_max_gfn(struct kvm_vm *vm)
> /* Returns true if kvm_intel was loaded with unrestricted_guest=1. */
> bool vm_is_unrestricted_guest(struct kvm_vm *vm)
> {
> - char val = 'N';
> - size_t count;
> - FILE *f;
> -
> /* Ensure that a KVM vendor-specific module is loaded. */
> if (vm == NULL)
> close(open_kvm_dev_path_or_exit());
>
> - f = fopen("/sys/module/kvm_intel/parameters/unrestricted_guest", "r");
> - if (f) {
> - count = fread(&val, sizeof(char), 1, f);
> - TEST_ASSERT(count == 1, "Unable to read from param file.");
> - fclose(f);
> - }
> -
> - return val == 'Y';
> + return get_module_param_bool("kvm_intel", "unrestricted_guest");
Since there are only three possible modules, what about providing wrappers to
handle "kvm", "kvm_amd", and "kvm_intel"? I'm guessing we'll end up with wrappers
for each param we care about, but one fewer strings to get right would be nice.
