[PATCH v2 5/6] KVM: selftests: dirty-log: Upgrade flag accesses to acquire/release semantics

Marc Zyngier
2022-09-26T16:04:09Z

In order to preserve ordering, make sure that the flag accesses
in the dirty log are done using acquire/release accessors.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
tools/testing/selftests/kvm/dirty_log_test.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/kvm/dirty_log_test.c b/tools/testing/selftests/kvm/dirty_log_test.c
index 9c883c94d478..53627add8a7c 100644
--- a/tools/testing/selftests/kvm/dirty_log_test.c
+++ b/tools/testing/selftests/kvm/dirty_log_test.c
@@ -17,6 +17,7 @@
#include <linux/bitmap.h>
#include <linux/bitops.h>
#include <linux/atomic.h>
+#include <asm/barrier.h>

#include "kvm_util.h"
#include "test_util.h"
@@ -279,12 +280,12 @@ static void dirty_ring_create_vm_done(struct kvm_vm *vm)

static inline bool dirty_gfn_is_dirtied(struct kvm_dirty_gfn *gfn)
{
- return gfn->flags == KVM_DIRTY_GFN_F_DIRTY;
+ return smp_load_acquire(&gfn->flags) == KVM_DIRTY_GFN_F_DIRTY;
}

static inline void dirty_gfn_set_collected(struct kvm_dirty_gfn *gfn)
{
- gfn->flags = KVM_DIRTY_GFN_F_RESET;
+ smp_store_release(&gfn->flags, KVM_DIRTY_GFN_F_RESET);
}

static uint32_t dirty_ring_collect_one(struct kvm_dirty_gfn *dirty_gfns,
--
2.34.1