KVM: selftests: Clear dirty ring states between two modes in dirty_log_test
There are two states, which need to be cleared before next mode
is executed. Otherwise, we will hit failure as the following messages
indicate.
- The variable 'dirty_ring_vcpu_ring_full' shared by main and vcpu
thread. It's indicating if the vcpu exit due to full ring buffer.
The value can be carried from previous mode (VM_MODE_P40V48_4K) to
current one (VM_MODE_P40V48_64K) when VM_MODE_P40V48_16K isn't
supported.
- The current ring buffer index needs to be reset before next mode
(VM_MODE_P40V48_64K) is executed. Otherwise, the stale value is
carried from previous mode (VM_MODE_P40V48_4K).
# ./dirty_log_test -M dirty-ring
Setting log mode to: 'dirty-ring'
Test iterations: 32, interval: 10 (ms)
Testing guest mode: PA-bits:40, VA-bits:48, 4K pages
guest physical test memory offset: 0xffbfffc000
:
Dirtied 995328 pages
Total bits checked: dirty (
1012434), clear (
7114123), track_next (966700)
Testing guest mode: PA-bits:40, VA-bits:48, 64K pages
guest physical test memory offset: 0xffbffc0000
vcpu stops because vcpu is kicked out...
vcpu continues now.
Notifying vcpu to continue
Iteration 1 collected 0 pages
vcpu stops because dirty ring is full...
vcpu continues now.
vcpu stops because dirty ring is full...
vcpu continues now.
vcpu stops because dirty ring is full...
==== Test Assertion Failure ====
dirty_log_test.c:369: cleared == count
pid=10541 tid=10541 errno=22 - Invalid argument
1 0x0000000000403087: dirty_ring_collect_dirty_pages at dirty_log_test.c:369
2 0x0000000000402a0b: log_mode_collect_dirty_pages at dirty_log_test.c:492
3 (inlined by) run_test at dirty_log_test.c:795
4 (inlined by) run_test at dirty_log_test.c:705
5 0x0000000000403a37: for_each_guest_mode at guest_modes.c:100
6 0x0000000000401ccf: main at dirty_log_test.c:938
7 0x0000ffff9ecd279b: ?? ??:0
8 0x0000ffff9ecd286b: ?? ??:0
9 0x0000000000401def: _start at ??:?
Reset dirty pages (0) mismatch with collected (35566)
Fix the issues by clearing 'dirty_ring_vcpu_ring_full' and the ring
buffer index before next new mode is to be executed.
Signed-off-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221110104914.31280-7-gshan@redhat.com