Commit 33090a88 authored by Axel Rasmussen's avatar Axel Rasmussen Committed by Paolo Bonzini
Browse files

KVM: selftests: add shared hugetlbfs backing source type 



This lets us run the demand paging test on top of a shared
hugetlbfs-backed area. The "shared" is key, as this allows us to
exercise userfaultfd minor faults on hugetlbfs.

Signed-off-by: default avatarAxel Rasmussen <axelrasmussen@google.com>
Message-Id: <20210519200339.829146-11-axelrasmussen@google.com>
Reviewed-by: default avatarBen Gardon <bgardon@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent a4b9722a

tools/testing/selftests/kvm/demand_paging_test.c

+4 −2
Original line number Diff line number Diff line
@@ -484,8 +484,10 @@ int main(int argc, char *argv[]) 
		}

	}



	TEST_ASSERT(p.uffd_mode != UFFDIO_REGISTER_MODE_MINOR || p.src_type == VM_MEM_SRC_SHMEM,

		    "userfaultfd MINOR mode requires shared memory; pick a different -t");

	if (p.uffd_mode == UFFDIO_REGISTER_MODE_MINOR &&

	    !backing_src_is_shared(p.src_type)) {

		TEST_FAIL("userfaultfd MINOR mode requires shared memory; pick a different -t");

	}



	for_each_guest_mode(run_test, &p);

tools/testing/selftests/kvm/include/test_util.h

+11 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include <errno.h>

#include <unistd.h>

#include <fcntl.h>

#include <sys/mman.h>

#include "kselftest.h"



static inline int _no_printf(const char *format, ...) { return 0; }
@@ -85,6 +86,7 @@ enum vm_mem_backing_src_type { 
	VM_MEM_SRC_ANONYMOUS_HUGETLB_2GB,

	VM_MEM_SRC_ANONYMOUS_HUGETLB_16GB,

	VM_MEM_SRC_SHMEM,

	VM_MEM_SRC_SHARED_HUGETLB,

	NUM_SRC_TYPES,

};
@@ -101,4 +103,13 @@ size_t get_backing_src_pagesz(uint32_t i); 
void backing_src_help(void);

enum vm_mem_backing_src_type parse_backing_src_type(const char *type_name);



/*

 * Whether or not the given source type is shared memory (as opposed to

 * anonymous).

 */

static inline bool backing_src_is_shared(enum vm_mem_backing_src_type t)

{

	return vm_mem_backing_src_alias(t)->flag & MAP_SHARED;

}



#endif /* SELFTEST_KVM_TEST_UTIL_H */

tools/testing/selftests/kvm/lib/kvm_util.c

+7 −2
Original line number Diff line number Diff line
@@ -848,8 +848,13 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm, 
		region->mmap_size += alignment;



	region->fd = -1;

	if (src_type == VM_MEM_SRC_SHMEM) {

		region->fd = memfd_create("kvm_selftest", MFD_CLOEXEC);

	if (backing_src_is_shared(src_type)) {

		int memfd_flags = MFD_CLOEXEC;



		if (src_type == VM_MEM_SRC_SHARED_HUGETLB)

			memfd_flags |= MFD_HUGETLB;



		region->fd = memfd_create("kvm_selftest", memfd_flags);

		TEST_ASSERT(region->fd != -1,

			    "memfd_create failed, errno: %i", errno);

tools/testing/selftests/kvm/lib/test_util.c

+11 −0
Original line number Diff line number Diff line
@@ -240,6 +240,16 @@ const struct vm_mem_backing_src_alias *vm_mem_backing_src_alias(uint32_t i) 
			.name = "shmem",

			.flag = MAP_SHARED,

		},

		[VM_MEM_SRC_SHARED_HUGETLB] = {

			.name = "shared_hugetlb",

			/*

			 * No MAP_HUGETLB, we use MFD_HUGETLB instead. Since

			 * we're using "file backed" memory, we need to specify

			 * this when the FD is created, not when the area is

			 * mapped.

			 */

			.flag = MAP_SHARED,

		},

	};

	_Static_assert(ARRAY_SIZE(aliases) == NUM_SRC_TYPES,

		       "Missing new backing src types?");
@@ -262,6 +272,7 @@ size_t get_backing_src_pagesz(uint32_t i) 
	case VM_MEM_SRC_ANONYMOUS_THP:

		return get_trans_hugepagesz();

	case VM_MEM_SRC_ANONYMOUS_HUGETLB:

	case VM_MEM_SRC_SHARED_HUGETLB:

		return get_def_hugetlb_pagesz();

	default:

		return MAP_HUGE_PAGE_SIZE(flag);