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    SubjectRe: [PATCHv8 09/11] selftests/x86/lam: Add mmap and SYSCALL test cases for linear-address masking
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    On Tue, 2022-08-30 at 04:01 +0300, Kirill A. Shutemov wrote:
    > From: Weihong Zhang <weihong.zhang@intel.com>
    >
    > Add mmap and SYSCALL test cases.
    >
    > SYSCALL test cases:
    >
    > - LAM supports set metadata in high bits 62:57 (LAM_U57) of a user
    > pointer, pass
    > the pointer to SYSCALL, SYSCALL can dereference the pointer and
    > return correct
    > result.
    >
    > - Disable LAM, pass a pointer with metadata in high bits to SYSCALL,
    > SYSCALL returns -1 (EFAULT).
    >
    > MMAP test cases:
    >
    > - Enable LAM_U57, MMAP with low address (below bits 47), set
    > metadata
    > in high bits of the address, dereference the address should be
    > allowed.
    >
    > - Enable LAM_U57, MMAP with high address (above bits 47), set
    > metadata
    > in high bits of the address, dereference the address should be
    > allowed.
    >
    > Signed-off-by: Weihong Zhang <weihong.zhang@intel.com>
    > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
    > Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
    > ---
    > tools/testing/selftests/x86/lam.c | 135
    > +++++++++++++++++++++++++++++-
    > 1 file changed, 132 insertions(+), 3 deletions(-)
    >
    > diff --git a/tools/testing/selftests/x86/lam.c
    > b/tools/testing/selftests/x86/lam.c
    > index 900a3a0fb709..b88e007ee0a3 100644
    > --- a/tools/testing/selftests/x86/lam.c
    > +++ b/tools/testing/selftests/x86/lam.c
    > @@ -7,6 +7,7 @@
    > #include <signal.h>
    > #include <setjmp.h>
    > #include <sys/mman.h>
    > +#include <sys/utsname.h>
    > #include <sys/wait.h>
    > #include <inttypes.h>
    >
    > @@ -29,11 +30,18 @@
    > /* Specified test function bits */
    > #define FUNC_MALLOC 0x1
    > #define FUNC_BITS 0x2
    > +#define FUNC_MMAP 0x4
    > +#define FUNC_SYSCALL 0x8
    >
    > -#define TEST_MASK 0x3
    > +#define TEST_MASK 0xf
    > +
    > +#define LOW_ADDR (0x1UL << 30)
    > +#define HIGH_ADDR (0x3UL << 48)
    >
    > #define MALLOC_LEN 32
    >
    > +#define PAGE_SIZE (4 << 10)
    > +
    > struct testcases {
    > unsigned int later;
    > int expected; /* 2: SIGSEGV Error; 1: other errors */
    > @@ -49,6 +57,7 @@ jmp_buf segv_env;
    > static void segv_handler(int sig)
    > {
    > ksft_print_msg("Get segmentation fault(%d).", sig);
    > +
    > siglongjmp(segv_env, 1);
    > }
    >
    > @@ -61,6 +70,16 @@ static inline int cpu_has_lam(void)
    > return (cpuinfo[0] & (1 << 26));
    > }
    >
    > +/* Check 5-level page table feature in CPUID.(EAX=07H,
    > ECX=00H):ECX.[bit 16] */
    > +static inline int cpu_has_la57(void)
    > +{
    > + unsigned int cpuinfo[4];
    > +
    > + __cpuid_count(0x7, 0, cpuinfo[0], cpuinfo[1], cpuinfo[2],
    > cpuinfo[3]);
    > +
    > + return (cpuinfo[2] & (1 << 16));
    > +}
    > +
    > /*
    > * Set tagged address and read back untag mask.
    > * check if the untagged mask is expected.
    > @@ -213,6 +232,68 @@ static int handle_malloc(struct testcases *test)
    > return ret;
    > }
    >
    > +static int handle_mmap(struct testcases *test)
    > +{
    > + void *ptr;
    > + unsigned int flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED;
    > + int ret = 0;
    > +
    > + if (test->later == 0 && test->lam != 0)
    > + if (set_lam(test->lam) != 0)
    > + return 1;
    > +
    > + ptr = mmap((void *)test->addr, PAGE_SIZE, PROT_READ |
    > PROT_WRITE,
    > + flags, -1, 0);
    > + if (ptr == MAP_FAILED) {
    > + if (test->addr == HIGH_ADDR)
    > + if (!cpu_has_la57())
    > + return 3; /* unsupport LA57 */

    I think here return 3 to indicate skip cases.

    Perhaps you can enable skip case like this? Just FYI, I'm not familiar
    with selftests yet.

    @@ -321,8 +323,10 @@ static int handle_mmap(struct testcases *test)
    flags, -1, 0);
    if (ptr == MAP_FAILED) {
    if (test->addr == HIGH_ADDR)
    - if (!cpu_has_la57())
    + if (!cpu_has_la57()) {
    + perror("Unsupport LA57. Skip");
    return 3; /* unsupport LA57 */
    + }
    return 1;
    }

    @@ -746,12 +750,16 @@ static void run_test(struct testcases *test, int
    count)

    /* fork a process to run test case */
    ret = fork_test(t);
    + tests_cnt++;
    + if (ret == 3) {
    + ksft_test_result_skip(t->msg);
    + continue;
    + }
    if (ret != 0)
    ret = (t->expected == ret);
    else
    ret = !(t->expected);

    - tests_cnt++;
    ksft_test_result(ret, t->msg);
    }
    }
    > + return 1;
    > + }
    > +
    > + if (test->later != 0 && test->lam != 0)
    > + if (set_lam(test->lam) != 0)
    > + ret = 1;
    > +
    > + if (ret == 0) {
    > + if (sigsetjmp(segv_env, 1) == 0) {
    > + signal(SIGSEGV, segv_handler);
    > + ret = handle_lam_test(ptr, test->lam);
    > + } else {
    > + ret = 2;
    > + }
    > + }
    > +
    > + munmap(ptr, PAGE_SIZE);
    > + return ret;
    > +}
    > +
    > +static int handle_syscall(struct testcases *test)
    > +{
    > + struct utsname unme, *pu;
    > + int ret = 0;
    > +
    > + if (test->later == 0 && test->lam != 0)
    > + if (set_lam(test->lam) != 0)
    > + return 1;
    > +
    > + if (sigsetjmp(segv_env, 1) == 0) {
    > + signal(SIGSEGV, segv_handler);
    > + pu = (struct utsname *)set_metadata((uint64_t)&unme,
    > test->lam);
    > + ret = uname(pu);
    > + if (ret < 0)
    > + ret = 1;
    > + } else {
    > + ret = 2;
    > + }
    > +
    > + if (test->later != 0 && test->lam != 0)
    > + if (set_lam(test->lam) != -1 && ret == 0)
    > + ret = 1;
    > +
    > + return ret;
    > +}
    > +
    > static int fork_test(struct testcases *test)
    > {
    > int ret, child_ret;
    > @@ -268,7 +349,6 @@ static struct testcases malloc_cases[] = {
    > },
    > };
    >
    > -
    > static struct testcases bits_cases[] = {
    > {
    > .test_func = handle_max_bits,
    > @@ -276,11 +356,54 @@ static struct testcases bits_cases[] = {
    > },
    > };
    >
    > +static struct testcases syscall_cases[] = {
    > + {
    > + .later = 0,
    > + .lam = LAM_U57_BITS,
    > + .test_func = handle_syscall,
    > + .msg = "SYSCALL: LAM_U57. syscall with metadata\n",
    > + },
    > + {
    > + .later = 1,
    > + .expected = 1,
    > + .lam = LAM_U57_BITS,
    > + .test_func = handle_syscall,
    > + .msg = "SYSCALL:[Negative] Disable LAM. Dereferencing
    > pointer with metadata.\n",
    > + },
    > +};
    > +
    > +static struct testcases mmap_cases[] = {
    > + {
    > + .later = 1,
    > + .expected = 0,
    > + .lam = LAM_U57_BITS,
    > + .addr = HIGH_ADDR,
    > + .test_func = handle_mmap,
    > + .msg = "MMAP: First mmap high address, then set
    > LAM_U57.\n",
    > + },
    > + {
    > + .later = 0,
    > + .expected = 0,
    > + .lam = LAM_U57_BITS,
    > + .addr = HIGH_ADDR,
    > + .test_func = handle_mmap,
    > + .msg = "MMAP: First LAM_U57, then High address.\n",
    > + },
    > + {
    > + .later = 0,
    > + .expected = 0,
    > + .lam = LAM_U57_BITS,
    > + .addr = LOW_ADDR,
    > + .test_func = handle_mmap,
    > + .msg = "MMAP: First LAM_U57, then Low address.\n",
    > + },
    > +};
    > +
    > static void cmd_help(void)
    > {
    > printf("usage: lam [-h] [-t test list]\n");
    > printf("\t-t test list: run tests specified in the test list,
    > default:0x%x\n", TEST_MASK);
    > - printf("\t\t0x1:malloc; 0x2:max_bits;\n");
    > + printf("\t\t0x1:malloc; 0x2:max_bits; 0x4:mmap;
    > 0x8:syscall.\n");
    > printf("\t-h: help\n");
    > }
    >
    > @@ -320,6 +443,12 @@ int main(int argc, char **argv)
    > if (tests & FUNC_BITS)
    > run_test(bits_cases, ARRAY_SIZE(bits_cases));
    >
    > + if (tests & FUNC_MMAP)
    > + run_test(mmap_cases, ARRAY_SIZE(mmap_cases));
    > +
    > + if (tests & FUNC_SYSCALL)
    > + run_test(syscall_cases, ARRAY_SIZE(syscall_cases));
    > +
    > ksft_set_plan(tests_cnt);
    >
    > return ksft_exit_pass();

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