[Qemu-devel] [RFC PATCH 2/3] kvm: Use inhibit to prevent ballooning without synchronous mmu

[Alex Williamson <alex.williamson@redhat.com>]

Remove KVM specific tests in balloon_page(), instead marking
ballooning as inhibited without KVM_CAP_SYNC_MMU support.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
 accel/kvm/kvm-all.c        |    4 ++++
 hw/virtio/virtio-balloon.c |    4 +---
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index eb7db92a5e3b..38f468d8e2b1 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -39,6 +39,7 @@
 #include "trace.h"
 #include "hw/irq.h"
 #include "sysemu/sev.h"
+#include "sysemu/balloon.h"
 
 #include "hw/boards.h"
 
@@ -1698,6 +1699,9 @@ static int kvm_init(MachineState *ms)
     s->many_ioeventfds = kvm_check_many_ioeventfds();
 
     s->sync_mmu = !!kvm_vm_check_extension(kvm_state, KVM_CAP_SYNC_MMU);
+    if (!s->sync_mmu) {
+        qemu_balloon_inhibit(true);
+    }
 
     return 0;
 
diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
index 1f7a87f09429..b5425080c5fb 100644
--- a/hw/virtio/virtio-balloon.c
+++ b/hw/virtio/virtio-balloon.c
@@ -21,7 +21,6 @@
 #include "hw/mem/pc-dimm.h"
 #include "sysemu/balloon.h"
 #include "hw/virtio/virtio-balloon.h"
-#include "sysemu/kvm.h"
 #include "exec/address-spaces.h"
 #include "qapi/error.h"
 #include "qapi/qapi-events-misc.h"
@@ -36,8 +35,7 @@
 
 static void balloon_page(void *addr, int deflate)
 {
-    if (!qemu_balloon_is_inhibited() && (!kvm_enabled() ||
-                                         kvm_has_sync_mmu())) {
+    if (!qemu_balloon_is_inhibited()) {
         qemu_madvise(addr, BALLOON_PAGE_SIZE,
                 deflate ? QEMU_MADV_WILLNEED : QEMU_MADV_DONTNEED);
     }