From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54516) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aqhdE-00028o-7O for qemu-devel@nongnu.org; Thu, 14 Apr 2016 09:48:29 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aqhd9-0003R5-7v for qemu-devel@nongnu.org; Thu, 14 Apr 2016 09:48:28 -0400 Received: from mx1.redhat.com ([209.132.183.28]:45154) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aqhd9-0003Qz-1Z for qemu-devel@nongnu.org; Thu, 14 Apr 2016 09:48:23 -0400 Date: Thu, 14 Apr 2016 16:48:19 +0300 From: "Michael S. Tsirkin" Message-ID: <1460641658-18561-7-git-send-email-mst@redhat.com> References: <1460641658-18561-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1460641658-18561-1-git-send-email-mst@redhat.com> Subject: [Qemu-devel] [PULL 6/6] hw/virtio/balloon: Replace TARGET_PAGE_SIZE with BALLOON_PAGE_SIZE List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Peter Maydell , Thomas Huth From: Thomas Huth The balloon code currently calls madvise() with TARGET_PAGE_SIZE as length parameter. Since the virtio-balloon protocol is always based on 4k pages, no matter what the host and guest are using as page size, this could cause problems: If TARGET_PAGE_SIZE is bigger than 4k, the madvise call also destroys the 4k areas after the current one - which might be wrong since the guest did not want free that area yet (in case the guest used as smaller MMU page size than the hard-coded TARGET_PAGE_SIZE). So to fix this issue, introduce a proper define called BALLOON_PAGE_SIZE (which is 4096) to use this as the size parameter for the madvise() call instead. Signed-off-by: Thomas Huth Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/virtio/virtio-balloon.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c index c74101e..9dbe681 100644 --- a/hw/virtio/virtio-balloon.c +++ b/hw/virtio/virtio-balloon.c @@ -19,7 +19,6 @@ #include "qemu-common.h" #include "hw/virtio/virtio.h" #include "hw/i386/pc.h" -#include "cpu.h" #include "sysemu/balloon.h" #include "hw/virtio/virtio-balloon.h" #include "sysemu/kvm.h" @@ -35,12 +34,14 @@ #include "hw/virtio/virtio-bus.h" #include "hw/virtio/virtio-access.h" +#define BALLOON_PAGE_SIZE (1 << VIRTIO_BALLOON_PFN_SHIFT) + static void balloon_page(void *addr, int deflate) { #if defined(__linux__) if (!qemu_balloon_is_inhibited() && (!kvm_enabled() || kvm_has_sync_mmu())) { - qemu_madvise(addr, TARGET_PAGE_SIZE, + qemu_madvise(addr, BALLOON_PAGE_SIZE, deflate ? QEMU_MADV_WILLNEED : QEMU_MADV_DONTNEED); } #endif -- MST