Re: [PATCH v4 04/10] KVM: selftests: Add memory size parameter to the demand paging test

Andrew Jones
2020-01-24T10:02:08Z

> diff --git a/tools/testing/selftests/kvm/lib/test_util.c b/tools/testing/selftests/kvm/lib/test_util.c
> new file mode 100644
> index 0000000000000..706e0f963a44b
> --- /dev/null
> +++ b/tools/testing/selftests/kvm/lib/test_util.c
> @@ -0,0 +1,61 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * tools/testing/selftests/kvm/lib/test_util.c
> + *
> + * Copyright (C) 2020, Google LLC.
> + */
> +
> +#include "test_util.h"
> +
> +#include <ctype.h>
> +
> +/*
> + * Parses "[0-9]+[kmgt]?".
> + */
> +size_t parse_size(const char *size)
> +{
> + size_t len = strlen(size);
> + size_t i;
> + size_t scale_shift = 0;
> + size_t base;
> +
> + TEST_ASSERT(len > 0, "Need at least 1 digit in '%s'", size);
> +
> + /* Find the first letter in the string, indicating scale. */
> + for (i = 0; i < len; i++) {
> + if (!isdigit(size[i])) {
> + TEST_ASSERT(i > 0, "Need at least 1 digit in '%s'",
> + size);
> + TEST_ASSERT(i == len - 1,
> + "Expected letter at the end in '%s'.",
> + size);
> + switch (tolower(size[i])) {
> + case 't':
> + scale_shift = 40;
> + break;
> + case 'g':
> + scale_shift = 30;
> + break;
> + case 'm':
> + scale_shift = 20;
> + break;
> + case 'k':
> + scale_shift = 10;
> + break;
> + default:
> + TEST_ASSERT(false, "Unknown size letter %c",
> + size[i]);
> + }
> + }
> + }
> +
> + TEST_ASSERT(scale_shift < 8 * sizeof(size_t),
> + "Overflow parsing scale!");
> +
> + base = atoi(size);

I'd use strtoull(size, NULL, 0), allowing the user to input full 0x...
sizes too. And, if the strtoull is done before the scale parsing, then
you could supply a non-null endptr and avoid the need for the for loop.

Thanks,
drew