[PATCH RFC 4/4] kvm: No need to sync dirty bitmap before memslot removal any more

From: Peter Xu <peterx@redhat.com>
To: qemu-devel@nongnu.org
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	Tian Kevin <kevin.tian@intel.com>,
	"Dr . David Alan Gilbert" <dgilbert@redhat.com>,
	peterx@redhat.com, Juan Quintela <quintela@redhat.com>
Subject: [PATCH RFC 4/4] kvm: No need to sync dirty bitmap before memslot removal any more
Date: Tue, 28 Apr 2020 15:42:19 -0400	[thread overview]
Message-ID: <20200428194219.10963-5-peterx@redhat.com> (raw)
In-Reply-To: <20200428194219.10963-1-peterx@redhat.com>

With the system reset dirty sync in qemu_system_reset(), we should be able to
drop this operation now.  After all it doesn't really fix the problem cleanly
because logically we could still have a race [1].

[1] https://lore.kernel.org/qemu-devel/20200327150425.GJ422390@xz-x1/

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 accel/kvm/kvm-all.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 439a4efe52..e1c87fa4e1 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -1061,9 +1061,6 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml,
             if (!mem) {
                 goto out;
             }
-            if (mem->flags & KVM_MEM_LOG_DIRTY_PAGES) {
-                kvm_physical_sync_dirty_bitmap(kml, section);
-            }
 
             /* unregister the slot */
             g_free(mem->dirty_bmap);
-- 
2.24.1


