Re: [PATCH v1 14/15] tools: add hmm gup tests for device coherent type

Alistair Popple
2022-05-16T08:07:00Z

Alex Sierra <alex.sierra@amd.com> writes:

> The intention is to test hmm device coherent type under different get
> user pages paths. Also, test gup with FOLL_LONGTERM flag set in
> device coherent pages. These pages should get migrated back to system
> memory.
>
> Signed-off-by: Alex Sierra <alex.sierra@amd.com>
> ---
> tools/testing/selftests/vm/hmm-tests.c | 104 +++++++++++++++++++++++++
> 1 file changed, 104 insertions(+)
>
> diff --git a/tools/testing/selftests/vm/hmm-tests.c b/tools/testing/selftests/vm/hmm-tests.c
> index 84ec8c4a1dc7..65e30ab6494c 100644
> --- a/tools/testing/selftests/vm/hmm-tests.c
> +++ b/tools/testing/selftests/vm/hmm-tests.c
> @@ -36,6 +36,7 @@
> * in the usual include/uapi/... directory.
> */
> #include "../../../../lib/test_hmm_uapi.h"
> +#include "../../../../mm/gup_test.h"
>
> struct hmm_buffer {
> void *ptr;
> @@ -60,6 +61,8 @@ enum {
> #define NTIMES 10
>
> #define ALIGN(x, a) (((x) + (a - 1)) & (~((a) - 1)))
> +/* Just the flags we need, copied from mm.h: */
> +#define FOLL_WRITE 0x01 /* check pte is writable */
>
> FIXTURE(hmm)
> {
> @@ -1766,4 +1769,105 @@ TEST_F(hmm, exclusive_cow)
> hmm_buffer_free(buffer);
> }
>
> +static int gup_test_exec(int gup_fd, unsigned long addr,
> + int cmd, int npages, int size)
> +{
> + struct gup_test gup = {
> + .nr_pages_per_call = npages,
> + .addr = addr,
> + .gup_flags = FOLL_WRITE,
> + .size = size,
> + };
> +
> + if (ioctl(gup_fd, cmd, &gup)) {
> + perror("ioctl on error\n");
> + return errno;
> + }
> +
> + return 0;
> +}
> +
> +/*
> + * Test get user device pages through gup_test. Setting PIN_LONGTERM flag.
> + * This should trigger a migration back to system memory for both, private
> + * and coherent type pages.
> + * This test makes use of gup_test module. Make sure GUP_TEST_CONFIG is added
> + * to your configuration before you run it.
> + */
> +TEST_F(hmm, hmm_gup_test)
> +{
> + struct hmm_buffer *buffer;
> + int gup_fd;
> + unsigned long npages;
> + unsigned long size;
> + unsigned long i;
> + int *ptr;
> + int ret;
> + unsigned char *m;
> +
> + gup_fd = open("/sys/kernel/debug/gup_test", O_RDWR);
> + if (gup_fd == -1)
> + SKIP(return, "Skipping test, could not find gup_test driver");
> +
> + npages = 3;
> + size = npages << self->page_shift;
> +
> + buffer = malloc(sizeof(*buffer));
> + ASSERT_NE(buffer, NULL);
> +
> + buffer->fd = -1;
> + buffer->size = size;
> + buffer->mirror = malloc(size);
> + ASSERT_NE(buffer->mirror, NULL);
> +
> + buffer->ptr = mmap(NULL, size,
> + PROT_READ | PROT_WRITE,
> + MAP_PRIVATE | MAP_ANONYMOUS,
> + buffer->fd, 0);
> + ASSERT_NE(buffer->ptr, MAP_FAILED);
> +
> + /* Initialize buffer in system memory. */
> + for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
> + ptr[i] = i;
> +
> + /* Migrate memory to device. */
> + ret = hmm_migrate_sys_to_dev(self->fd, buffer, npages);
> + ASSERT_EQ(ret, 0);
> + ASSERT_EQ(buffer->cpages, npages);
> + /* Check what the device read. */
> + for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i)
> + ASSERT_EQ(ptr[i], i);
> +
> + ASSERT_EQ(gup_test_exec(gup_fd,
> + (unsigned long)buffer->ptr,
> + GUP_BASIC_TEST, 1, self->page_size), 0);
> + ASSERT_EQ(gup_test_exec(gup_fd,
> + (unsigned long)buffer->ptr + 1 * self->page_size,
> + GUP_FAST_BENCHMARK, 1, self->page_size), 0);
> + ASSERT_EQ(gup_test_exec(gup_fd,
> + (unsigned long)buffer->ptr + 2 * self->page_size,
> + PIN_LONGTERM_BENCHMARK, 1, self->page_size), 0);
> +
> + /* Take snapshot to CPU pagetables */
> + ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_SNAPSHOT, buffer, npages);
> + ASSERT_EQ(ret, 0);
> + ASSERT_EQ(buffer->cpages, npages);
> + m = buffer->mirror;
> + if (hmm_is_coherent_type(variant->device_number)) {
> + ASSERT_EQ(HMM_DMIRROR_PROT_DEV_COHERENT_LOCAL | HMM_DMIRROR_PROT_WRITE, m[0]);
> + ASSERT_EQ(HMM_DMIRROR_PROT_DEV_COHERENT_LOCAL | HMM_DMIRROR_PROT_WRITE, m[1]);
> + } else {
> + ASSERT_EQ(HMM_DMIRROR_PROT_WRITE, m[0]);
> + ASSERT_EQ(HMM_DMIRROR_PROT_WRITE, m[1]);
> + }
> + ASSERT_EQ(HMM_DMIRROR_PROT_WRITE, m[2]);
> + /* Check again the content on the pages. Make sure there's no

Very minor nit-pick, but if you happen to be re-spinning anyway the
comment formatting needs fixing and a new line before the comment would
be nice. Otherwise:

Reviewed-by: Alistair Popple <apopple@nvidia.com>

> + * corrupted data.
> + */
> + for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
> + ASSERT_EQ(ptr[i], i);
> +
> + close(gup_fd);
> + hmm_buffer_free(buffer);
> +}
> TEST_HARNESS_MAIN