From nobody Sun Feb 8 18:29:49 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1563803008; cv=none; d=zoho.com; s=zohoarc; b=Pln/a6UKIe7yZuqBSz/sBCDArI43TBW/gbtWRgGSt6yJeDq+8GSK5m527PmGoIjCchibzci/imS4KpE21KyTxDXEjxaveSaPE1x4nOHhRco/2jGZ3wDD9BU0nMEMvQNuUXV/61QqX8KUCChj+rk46UQTrj8+OsWgsUj0MfV23Ts= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zoho.com; s=zohoarc; t=1563803008; h=Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To:ARC-Authentication-Results; bh=//6u8pPfju18c4rU8GsMJs5CziYcW6eQ95JP0ojABBM=; b=HskLqJ3cSY42fmr5Mb0BrHaedSL03Yf6PYEdNs1DCg3Ep6m1cjSyzl868aqokbio2Mgksy7M13wDHza1fdZ7p89XofX3CcKXGX0T5+u7e7KxHAHKtQChA/ezXvjYAvlgPYuqlyiD0CxVMxEFCj+Tdnj3xhLZCqEwuJ6p8hRKw3Y= ARC-Authentication-Results: i=1; mx.zoho.com; spf=pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1563803008275194.90789328817596; Mon, 22 Jul 2019 06:43:28 -0700 (PDT) Received: from localhost ([::1]:33792 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hpYb9-0007dM-Av for importer@patchew.org; Mon, 22 Jul 2019 09:43:27 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:54927) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hpYZP-00008Q-Qz for qemu-devel@nongnu.org; Mon, 22 Jul 2019 09:41:41 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hpYZO-0005VH-IS for qemu-devel@nongnu.org; Mon, 22 Jul 2019 09:41:39 -0400 Received: from mx1.redhat.com ([209.132.183.28]:3559) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hpYZO-0005St-Ao; Mon, 22 Jul 2019 09:41:38 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 95E1C30C133C; Mon, 22 Jul 2019 13:41:37 +0000 (UTC) Received: from t460s.redhat.com (ovpn-116-75.ams2.redhat.com [10.36.116.75]) by smtp.corp.redhat.com (Postfix) with ESMTP id 48DA610021B2; Mon, 22 Jul 2019 13:41:31 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Date: Mon, 22 Jul 2019 15:41:08 +0200 Message-Id: <20190722134108.22151-7-david@redhat.com> In-Reply-To: <20190722134108.22151-1-david@redhat.com> References: <20190722134108.22151-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.45]); Mon, 22 Jul 2019 13:41:37 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH-for-4.1 v3 6/6] virtio-balloon: Use temporary PBP only X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Michael S . Tsirkin" , David Hildenbrand , qemu-stable@nongnu.org, Stefan Hajnoczi , Igor Mammedov , David Gibson Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Type: text/plain; charset="utf-8" We still have multiple issues in the current code - The PBP is not freed during unrealize() - The PBP is not reset on device resets: After a reset, the PBP is stale. - We are not indicating VIRTIO_BALLOON_F_MUST_TELL_HOST, therefore guests (esp. legacy guests) will reuse pages without deflating, turning the PBP stale. Adding that would require compat handling. Instead, let's use the PBP only temporarily, when processing one bulk of inflation requests. This will keep guest_page_size > 4k working (with Linux guests). There is nothing to do for deflation requests anymore. The pbp is only used for a limited amount of time. Fixes: ed48c59875b6 ("virtio-balloon: Safely handle BALLOON_PAGE_SIZE < host page size") Cc: qemu-stable@nongnu.org #v4.0.0 Suggested-by: Michael S. Tsirkin Signed-off-by: David Hildenbrand Acked-by: David Gibson --- hw/virtio/virtio-balloon.c | 21 +++++++++------------ include/hw/virtio/virtio-balloon.h | 3 --- 2 files changed, 9 insertions(+), 15 deletions(-) diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c index 40d493a31a..a6282d58d4 100644 --- a/hw/virtio/virtio-balloon.c +++ b/hw/virtio/virtio-balloon.c @@ -34,11 +34,11 @@ =20 #define BALLOON_PAGE_SIZE (1 << VIRTIO_BALLOON_PFN_SHIFT) =20 -struct PartiallyBalloonedPage { +typedef struct PartiallyBalloonedPage { ram_addr_t base_gpa; long subpages; unsigned long *bitmap; -}; +} PartiallyBalloonedPage; =20 static void virtio_balloon_pbp_free(PartiallyBalloonedPage *pbp) { @@ -68,11 +68,11 @@ static bool virtio_balloon_pbp_matches(PartiallyBalloon= edPage *pbp, } =20 static void balloon_inflate_page(VirtIOBalloon *balloon, - MemoryRegion *mr, hwaddr mr_offset) + MemoryRegion *mr, hwaddr mr_offset, + PartiallyBalloonedPage **pbp) { void *addr =3D memory_region_get_ram_ptr(mr) + mr_offset; ram_addr_t rb_offset, rb_aligned_offset, base_gpa; - PartiallyBalloonedPage **pbp =3D &balloon->pbp; RAMBlock *rb; size_t rb_page_size; int subpages; @@ -149,12 +149,6 @@ static void balloon_deflate_page(VirtIOBalloon *balloo= n, rb =3D qemu_ram_block_from_host(addr, false, &rb_offset); rb_page_size =3D qemu_ram_pagesize(rb); =20 - if (balloon->pbp) { - /* Let's play safe and always reset the pbp on deflation requests.= */ - virtio_balloon_pbp_free(balloon->pbp); - balloon->pbp =3D NULL; - } - host_addr =3D (void *)((uintptr_t)addr & ~(rb_page_size - 1)); =20 /* When a page is deflated, we hint the whole host page it lives @@ -336,6 +330,7 @@ static void balloon_stats_set_poll_interval(Object *obj= , Visitor *v, static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq) { VirtIOBalloon *s =3D VIRTIO_BALLOON(vdev); + PartiallyBalloonedPage *pbp =3D NULL; VirtQueueElement *elem; MemoryRegionSection section; =20 @@ -344,7 +339,7 @@ static void virtio_balloon_handle_output(VirtIODevice *= vdev, VirtQueue *vq) uint32_t pfn; elem =3D virtqueue_pop(vq, sizeof(VirtQueueElement)); if (!elem) { - return; + break; } =20 while (iov_to_buf(elem->out_sg, elem->out_num, offset, &pfn, 4) = =3D=3D 4) { @@ -373,7 +368,7 @@ static void virtio_balloon_handle_output(VirtIODevice *= vdev, VirtQueue *vq) if (!qemu_balloon_is_inhibited()) { if (vq =3D=3D s->ivq) { balloon_inflate_page(s, section.mr, - section.offset_within_region); + section.offset_within_region, &pb= p); } else if (vq =3D=3D s->dvq) { balloon_deflate_page(s, section.mr, section.offset_wit= hin_region); } else { @@ -387,6 +382,8 @@ static void virtio_balloon_handle_output(VirtIODevice *= vdev, VirtQueue *vq) virtio_notify(vdev, vq); g_free(elem); } + + virtio_balloon_pbp_free(pbp); } =20 static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq) diff --git a/include/hw/virtio/virtio-balloon.h b/include/hw/virtio/virtio-= balloon.h index 5a99293a45..d1c968d237 100644 --- a/include/hw/virtio/virtio-balloon.h +++ b/include/hw/virtio/virtio-balloon.h @@ -33,8 +33,6 @@ typedef struct virtio_balloon_stat_modern { uint64_t val; } VirtIOBalloonStatModern; =20 -typedef struct PartiallyBalloonedPage PartiallyBalloonedPage; - enum virtio_balloon_free_page_report_status { FREE_PAGE_REPORT_S_STOP =3D 0, FREE_PAGE_REPORT_S_REQUESTED =3D 1, @@ -70,7 +68,6 @@ typedef struct VirtIOBalloon { int64_t stats_last_update; int64_t stats_poll_interval; uint32_t host_features; - PartiallyBalloonedPage *pbp; =20 bool qemu_4_0_config_size; } VirtIOBalloon; --=20 2.21.0