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KVM: selftests: add shared hugetlbfs backing source type

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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: Axel Rasmussen <axelrasmussen@google.com>
Message-Id: <20210519200339.829146-11-axelrasmussen@google.com>
Reviewed-by: Ben Gardon <bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Axel Rasmussen 2021-05-19 13:03:39 -07:00 committed by Paolo Bonzini
parent a4b9722a59
commit 33090a884d
4 changed files with 33 additions and 4 deletions
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6
tools/testing/selftests/kvm/demand_paging_test.c
View File

@ -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);

11
tools/testing/selftests/kvm/include/test_util.h
View File

@ -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 */

9
tools/testing/selftests/kvm/lib/kvm_util.c
View File

@ -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);

11
tools/testing/selftests/kvm/lib/test_util.c
View File

@ -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);