Patch "KVM: selftests: Fix number of pages for memory slot in memslot_modification_stress_test" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

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

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     kvm-selftests-fix-number-of-pages-for-memory-slot-in.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 4bf7e8247e3de1b8972c6bff504764aee7593650
Author: Gavin Shan <gshan@xxxxxxxxxx>
Date:   Thu Oct 13 14:30:20 2022 +0800

    KVM: selftests: Fix number of pages for memory slot in memslot_modification_stress_test
    
    [ Upstream commit 05c2224d4b049406b0545a10be05280ff4b8ba0a ]
    
    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>
    Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/20221013063020.201856-1-gshan@xxxxxxxxxx
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/tools/testing/selftests/kvm/memslot_modification_stress_test.c b/tools/testing/selftests/kvm/memslot_modification_stress_test.c
index 4cfcafea9f5a..1d806b8ffee2 100644
--- a/tools/testing/selftests/kvm/memslot_modification_stress_test.c
+++ b/tools/testing/selftests/kvm/memslot_modification_stress_test.c
@@ -72,7 +72,7 @@ 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;