[PATCH] KVM: selftests: Fix number of pages for memory slot in memslot_modification_stress_test

From: Gavin Shan
Date: Thu Oct 13 2022 - 02:30:45 EST


It's required by vm_userspace_mem_region_add() that memory size
should be aligned to host page size. However, one guest page is
provided by memslot_modification_stress_test. It triggers failure
in the scenario of 64KB-page-size-host and 4KB-page-size-guest,
as the following messages indicate.

# ./memslot_modification_stress_test
Testing guest mode: PA-bits:40, VA-bits:48, 4K pages
guest physical test memory: [0xffbfff0000, 0xffffff0000)
Finished creating vCPUs
Started all vCPUs
==== Test Assertion Failure ====
lib/kvm_util.c:824: vm_adjust_num_guest_pages(vm->mode, npages) == npages
pid=5712 tid=5712 errno=0 - Success
1 0x0000000000404eeb: vm_userspace_mem_region_add at kvm_util.c:822
2 0x0000000000401a5b: add_remove_memslot at memslot_modification_stress_test.c:82
3 (inlined by) run_test at memslot_modification_stress_test.c:110
4 0x0000000000402417: for_each_guest_mode at guest_modes.c:100
5 0x00000000004016a7: main at memslot_modification_stress_test.c:187
6 0x0000ffffb8cd4383: ?? ??:0
7 0x0000000000401827: _start at :?
Number of guest pages is not compatible with the host. Try npages=16

Fix the issue by providing 16 guest pages to the memory slot for this
particular combination of 64KB-page-size-host and 4KB-page-size-guest
on aarch64.

Fixes: ef4c9f4f65462 ("KVM: selftests: Fix 32-bit truncation of vm_get_max_gfn()")
Signed-off-by: Gavin Shan <gshan@xxxxxxxxxx>
---
tools/testing/selftests/kvm/memslot_modification_stress_test.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/kvm/memslot_modification_stress_test.c b/tools/testing/selftests/kvm/memslot_modification_stress_test.c
index 6ee7e1dde404..bb1d17a1171b 100644
--- a/tools/testing/selftests/kvm/memslot_modification_stress_test.c
+++ b/tools/testing/selftests/kvm/memslot_modification_stress_test.c
@@ -67,7 +67,7 @@ struct memslot_antagonist_args {
static void add_remove_memslot(struct kvm_vm *vm, useconds_t delay,
uint64_t nr_modifications)
{
- const uint64_t pages = 1;
+ uint64_t pages = max_t(int, vm->page_size, getpagesize()) / vm->page_size;
uint64_t gpa;
int i;

--
2.23.0