From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AB1DA20305 for ; Mon, 6 Nov 2023 13:05:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="vjC/mr09" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 278F5C433C7; Mon, 6 Nov 2023 13:05:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1699275954; bh=cYH1lHayyxbOCMCMjN/1I6ACfomSjpnvIILpaAJ2kn8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vjC/mr09zEoj3iwB8AjLHpibaxZAm3a88/lDN2x41aW/WcTt3WXBp/RjVEGGTjSKw m74wU5dHeMCGADVQcy3VnVRd3m6+X9xLI9K9zjL/5TozaChH+RKOnBFQ75lzMIqGHF TxTi/D/S1Vywmf7MM6WifuIMmWsPfhou43Utommw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Gavin Shan , Zhenyu Zhang , "Michael S. Tsirkin" , David Hildenbrand Subject: [PATCH 4.14 03/48] virtio_balloon: Fix endless deflation and inflation on arm64 Date: Mon, 6 Nov 2023 14:02:54 +0100 Message-ID: <20231106130257.976698340@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231106130257.862199836@linuxfoundation.org> References: <20231106130257.862199836@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Gavin Shan commit 07622bd415639e9709579f400afd19e7e9866e5e upstream. The deflation request to the target, which isn't unaligned to the guest page size causes endless deflation and inflation actions. For example, we receive the flooding QMP events for the changes on memory balloon's size after a deflation request to the unaligned target is sent for the ARM64 guest, where we have 64KB base page size. /home/gavin/sandbox/qemu.main/build/qemu-system-aarch64 \ -accel kvm -machine virt,gic-version=host -cpu host \ -smp maxcpus=8,cpus=8,sockets=2,clusters=2,cores=2,threads=1 \ -m 1024M,slots=16,maxmem=64G \ -object memory-backend-ram,id=mem0,size=512M \ -object memory-backend-ram,id=mem1,size=512M \ -numa node,nodeid=0,memdev=mem0,cpus=0-3 \ -numa node,nodeid=1,memdev=mem1,cpus=4-7 \ : \ -device virtio-balloon-pci,id=balloon0,bus=pcie.10 { "execute" : "balloon", "arguments": { "value" : 1073672192 } } {"return": {}} {"timestamp": {"seconds": 1693272173, "microseconds": 88667}, \ "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}} {"timestamp": {"seconds": 1693272174, "microseconds": 89704}, \ "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}} {"timestamp": {"seconds": 1693272175, "microseconds": 90819}, \ "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}} {"timestamp": {"seconds": 1693272176, "microseconds": 91961}, \ "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}} {"timestamp": {"seconds": 1693272177, "microseconds": 93040}, \ "event": "BALLOON_CHANGE", "data": {"actual": 1073676288}} {"timestamp": {"seconds": 1693272178, "microseconds": 94117}, \ "event": "BALLOON_CHANGE", "data": {"actual": 1073676288}} {"timestamp": {"seconds": 1693272179, "microseconds": 95337}, \ "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}} {"timestamp": {"seconds": 1693272180, "microseconds": 96615}, \ "event": "BALLOON_CHANGE", "data": {"actual": 1073676288}} {"timestamp": {"seconds": 1693272181, "microseconds": 97626}, \ "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}} {"timestamp": {"seconds": 1693272182, "microseconds": 98693}, \ "event": "BALLOON_CHANGE", "data": {"actual": 1073676288}} {"timestamp": {"seconds": 1693272183, "microseconds": 99698}, \ "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}} {"timestamp": {"seconds": 1693272184, "microseconds": 100727}, \ "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}} {"timestamp": {"seconds": 1693272185, "microseconds": 90430}, \ "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}} {"timestamp": {"seconds": 1693272186, "microseconds": 102999}, \ "event": "BALLOON_CHANGE", "data": {"actual": 1073676288}} : Fix it by aligning the target up to the guest page size, 64KB in this specific case. With this applied, no flooding QMP events are observed and the memory balloon's size can be stablizied to 0x3ffe0000 soon after the deflation request is sent. { "execute" : "balloon", "arguments": { "value" : 1073672192 } } {"return": {}} {"timestamp": {"seconds": 1693273328, "microseconds": 793075}, \ "event": "BALLOON_CHANGE", "data": {"actual": 1073610752}} { "execute" : "query-balloon" } {"return": {"actual": 1073610752}} Cc: stable@vger.kernel.org Signed-off-by: Gavin Shan Tested-by: Zhenyu Zhang Message-Id: <20230831011007.1032822-1-gshan@redhat.com> Signed-off-by: Michael S. Tsirkin Reviewed-by: David Hildenbrand Signed-off-by: Greg Kroah-Hartman --- drivers/virtio/virtio_balloon.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -341,7 +341,11 @@ static inline s64 towards_target(struct if (!virtio_has_feature(vb->vdev, VIRTIO_F_VERSION_1)) num_pages = le32_to_cpu((__force __le32)num_pages); - target = num_pages; + /* + * Aligned up to guest page size to avoid inflating and deflating + * balloon endlessly. + */ + target = ALIGN(num_pages, VIRTIO_BALLOON_PAGES_PER_PAGE); return target - vb->num_pages; }