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From: Marc Zyngier <maz@kernel.org>
To: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org
Cc: will@kernel.org, catalin.marinas@arm.com, andrew.jones@linux.dev,
	shan.gavin@gmail.com, bgardon@google.com, dmatlack@google.com,
	pbonzini@redhat.com, zhenyzha@redhat.com, shuah@kernel.org
Subject: [PATCH v2 5/6] KVM: selftests: dirty-log: Upgrade flag accesses to acquire/release semantics
Date: Mon, 26 Sep 2022 15:51:19 +0100	[thread overview]
Message-ID: <20220926145120.27974-6-maz@kernel.org> (raw)
In-Reply-To: <20220926145120.27974-1-maz@kernel.org>

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

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  parent reply	other threads:[~2022-09-26 14:51 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-26 14:51 [PATCH v2 0/6] KVM: Fix dirty-ring ordering on weakly ordered architectures Marc Zyngier
2022-09-26 14:51 ` [PATCH v2 1/6] KVM: Use acquire/release semantics when accessing dirty ring GFN state Marc Zyngier
2022-09-26 14:51 ` [PATCH v2 2/6] KVM: Add KVM_CAP_DIRTY_LOG_RING_ACQ_REL capability and config option Marc Zyngier
2022-09-26 14:51 ` [PATCH v2 3/6] KVM: x86: Select CONFIG_HAVE_KVM_DIRTY_RING_ACQ_REL Marc Zyngier
2022-09-26 14:51 ` [PATCH v2 4/6] KVM: Document weakly ordered architecture requirements for dirty ring Marc Zyngier
2022-09-26 14:51 ` Marc Zyngier [this message]
2022-09-26 14:51 ` [PATCH v2 6/6] KVM: selftests: dirty-log: Use KVM_CAP_DIRTY_LOG_RING_ACQ_REL if available Marc Zyngier
2022-09-27  0:58 ` [PATCH v2 0/6] KVM: Fix dirty-ring ordering on weakly ordered architectures Gavin Shan
2022-09-27 15:54 ` Peter Xu
2022-09-29  9:58 ` Marc Zyngier

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