(cc Muchun)
On Wed, 10 Jan 2024 14:03:35 +0530 Donet Tom <donettom@xxxxxxxxxxxxxxxxxx> wrote:
> The kernel sefltest mm/hugepage-vmemmap fails on architectures
> which has different page size other than 4K. In hugepage-vmemmap
> page size used is 4k so the pfn calculation will go wrong on systems
> which has different page size .The length of MAP_HUGETLB memory must
> be hugepage aligned but in hugepage-vmemmap map length is 2M so this
> will not get aligned if the system has differnet hugepage size.
>
> Added psize() to get the page size and default_huge_page_size() to
> get the default hugepage size at run time, hugepage-vmemmap test pass
> on powerpc with 64K page size and x86 with 4K page size.
>
> Result on powerpc without patch (page size 64K)
> *# ./hugepage-vmemmap
> Returned address is 0x7effff000000 whose pfn is 0
> Head page flags (100000000) is invalid
> check_page_flags: Invalid argument
> *#
>
> Result on powerpc with patch (page size 64K)
> *# ./hugepage-vmemmap
> Returned address is 0x7effff000000 whose pfn is 600
> *#
>
> Result on x86 with patch (page size 4K)
> *# ./hugepage-vmemmap
> Returned address is 0x7fc7c2c00000 whose pfn is 1dac00
> *#
>
> Signed-off-by: Donet Tom <donettom@xxxxxxxxxxxxxxxxxx>
> Reported-by : Geetika Moolchandani (geetika@xxxxxxxxxxxxx)
> Tested-by : Geetika Moolchandani (geetika@xxxxxxxxxxxxx)
I'll add
Fixes: b147c89cd429 ("selftests: vm: add a hugetlb test case")
Cc: <stable@xxxxxxxxxxxxxxx>
>
> diff --git a/tools/testing/selftests/mm/hugepage-vmemmap.c b/tools/testing/selftests/mm/hugepage-vmemmap.c
> index 5b354c209e93..894d28c3dd47 100644
> --- a/tools/testing/selftests/mm/hugepage-vmemmap.c
> +++ b/tools/testing/selftests/mm/hugepage-vmemmap.c
> @@ -10,10 +10,7 @@
> #include <unistd.h>
> #include <sys/mman.h>
> #include <fcntl.h>
> -
> -#define MAP_LENGTH (2UL * 1024 * 1024)
> -
> -#define PAGE_SIZE 4096
> +#include "vm_util.h"
>
> #define PAGE_COMPOUND_HEAD (1UL << 15)
> #define PAGE_COMPOUND_TAIL (1UL << 16)
> @@ -39,6 +36,9 @@
> #define MAP_FLAGS (MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB)
> #endif
>
> +static size_t pagesize;
> +static size_t maplength;
> +
> static void write_bytes(char *addr, size_t length)
> {
> unsigned long i;
> @@ -56,7 +56,7 @@ static unsigned long virt_to_pfn(void *addr)
> if (fd < 0)
> return -1UL;
>
> - lseek(fd, (unsigned long)addr / PAGE_SIZE * sizeof(pagemap), SEEK_SET);
> + lseek(fd, (unsigned long)addr / pagesize * sizeof(pagemap), SEEK_SET);
> read(fd, &pagemap, sizeof(pagemap));
> close(fd);
>
> @@ -86,7 +86,7 @@ static int check_page_flags(unsigned long pfn)
> * this also verifies kernel has correctly set the fake page_head to tail
> * while hugetlb_free_vmemmap is enabled.
> */
> - for (i = 1; i < MAP_LENGTH / PAGE_SIZE; i++) {
> + for (i = 1; i < maplength / pagesize; i++) {
> read(fd, &pageflags, sizeof(pageflags));
> if ((pageflags & TAIL_PAGE_FLAGS) != TAIL_PAGE_FLAGS ||
> (pageflags & HEAD_PAGE_FLAGS) == HEAD_PAGE_FLAGS) {
> @@ -106,18 +106,25 @@ int main(int argc, char **argv)
> void *addr;
> unsigned long pfn;
>
> - addr = mmap(MAP_ADDR, MAP_LENGTH, PROT_READ | PROT_WRITE, MAP_FLAGS, -1, 0);
> + pagesize = psize();
> + maplength = default_huge_page_size();
> + if (!maplength) {
> + printf("Unable to determine huge page size\n");
> + exit(1);
> + }
> +
> + addr = mmap(MAP_ADDR, maplength, PROT_READ | PROT_WRITE, MAP_FLAGS, -1, 0);
> if (addr == MAP_FAILED) {
> perror("mmap");
> exit(1);
> }
>
> /* Trigger allocation of HugeTLB page. */
> - write_bytes(addr, MAP_LENGTH);
> + write_bytes(addr, maplength);
>
> pfn = virt_to_pfn(addr);
> if (pfn == -1UL) {
> - munmap(addr, MAP_LENGTH);
> + munmap(addr, maplength);
> perror("virt_to_pfn");
> exit(1);
> }
> @@ -125,13 +132,13 @@ int main(int argc, char **argv)
> printf("Returned address is %p whose pfn is %lx\n", addr, pfn);
>
> if (check_page_flags(pfn) < 0) {
> - munmap(addr, MAP_LENGTH);
> + munmap(addr, maplength);
> perror("check_page_flags");
> exit(1);
> }
>
> /* munmap() length of MAP_HUGETLB memory must be hugepage aligned */
> - if (munmap(addr, MAP_LENGTH)) {
> + if (munmap(addr, maplength)) {
> perror("munmap");
> exit(1);
> }
> --
> 2.43.0
