On 16/05/2019 13.30, David Hildenbrand wrote:
On 16.05.19 13:12, Thomas Huth wrote:
On s390x, there is a constraint that memory regions have to be aligned to 1M (or running the VM will fail). Introduce a new "alignment" variable in the vm_userspace_mem_region_add() function which now can be used for both, huge page and s390x alignment requirements.
Signed-off-by: Thomas Huth thuth@redhat.com
tools/testing/selftests/kvm/lib/kvm_util.c | 21 +++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-)
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c index 8d63ccb93e10..64a0da6efe3d 100644 --- a/tools/testing/selftests/kvm/lib/kvm_util.c +++ b/tools/testing/selftests/kvm/lib/kvm_util.c @@ -559,6 +559,7 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm, unsigned long pmem_size = 0; struct userspace_mem_region *region; size_t huge_page_size = KVM_UTIL_PGS_PER_HUGEPG * vm->page_size;
- size_t alignment;
TEST_ASSERT((guest_paddr % vm->page_size) == 0, "Guest physical " "address not on a page boundary.\n" @@ -608,9 +609,20 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm, TEST_ASSERT(region != NULL, "Insufficient Memory"); region->mmap_size = npages * vm->page_size;
- /* Enough memory to align up to a huge page. */
+#ifdef __s390x__
- /* On s390x, the host address must be aligned to 1M (due to PGSTEs) */
- alignment = 0x100000;
This corresponds to huge_page_size, maybe you can exploit this fact here.
Something like
alignment = 1;
/* On s390x, the host address must always be aligned to the THP size */ #ifndef __s390x__ if (src_type == VM_MEM_SRC_ANONYMOUS_THP) #endif alignment = huge_page_size;
Maybe in a nicer fashion. Not sure.
Hmm, but if I've got your explanation on IRC right, it's rather a coincidence that the huge page size matches the alignment requirements for KVM memslots, isn't it? So I think the code would look rather confusing if I'd try to shorten it this way...?
Thomas