Re: [Qemu-devel] [PATCH v3 2/4] kvm: Use inhibit to prevent ballooning without synchronous mmu

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

On Tue,  7 Aug 2018 13:31:23 -0600
Alex Williamson <alex.williamson@redhat.com> wrote:

> Remove KVM specific tests in balloon_page(), instead marking
> ballooning as inhibited without KVM_CAP_SYNC_MMU support.
> 
> Reviewed-by: David Hildenbrand <david@redhat.com>
> Reviewed-by: Peter Xu <peterx@redhat.com>
> Reviewed-by: Cornelia Huck <cohuck@redhat.com>
> 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(-)

Paolo and Michael, can I get an ack for this one?  Otherwise I can drop
it from the series and let this continue to be a special case.  Thanks,

Alex
 
> 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);
>      }