From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 79695C7618B for ; Thu, 25 Jul 2019 11:56:42 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 525DE22BED for ; Thu, 25 Jul 2019 11:56:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 525DE22BED Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:59082 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hqcMT-0004fD-Ap for qemu-devel@archiver.kernel.org; Thu, 25 Jul 2019 07:56:41 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:56133) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hqcMA-0003Ym-T0 for qemu-devel@nongnu.org; Thu, 25 Jul 2019 07:56:24 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hqcM9-0005wR-Jb for qemu-devel@nongnu.org; Thu, 25 Jul 2019 07:56:22 -0400 Received: from mx1.redhat.com ([209.132.183.28]:37014) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hqcM9-0005w4-A8; Thu, 25 Jul 2019 07:56:21 -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 1E6E5307845E; Thu, 25 Jul 2019 11:56:20 +0000 (UTC) Received: from [10.36.117.70] (ovpn-117-70.ams2.redhat.com [10.36.117.70]) by smtp.corp.redhat.com (Postfix) with ESMTP id F0F8F1001E75; Thu, 25 Jul 2019 11:56:13 +0000 (UTC) To: "Michael S. Tsirkin" References: <20190725113638.4702-1-david@redhat.com> <20190725113638.4702-7-david@redhat.com> <20190725075054-mutt-send-email-mst@kernel.org> From: David Hildenbrand Openpgp: preference=signencrypt Autocrypt: addr=david@redhat.com; prefer-encrypt=mutual; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwX4EEwECACgFAljj9eoCGwMFCQlmAYAGCwkI BwMCBhUIAgkKCwQWAgMBAh4BAheAAAoJEE3eEPcA/4Na5IIP/3T/FIQMxIfNzZshIq687qgG 8UbspuE/YSUDdv7r5szYTK6KPTlqN8NAcSfheywbuYD9A4ZeSBWD3/NAVUdrCaRP2IvFyELj xoMvfJccbq45BxzgEspg/bVahNbyuBpLBVjVWwRtFCUEXkyazksSv8pdTMAs9IucChvFmmq3 jJ2vlaz9lYt/lxN246fIVceckPMiUveimngvXZw21VOAhfQ+/sofXF8JCFv2mFcBDoa7eYob s0FLpmqFaeNRHAlzMWgSsP80qx5nWWEvRLdKWi533N2vC/EyunN3HcBwVrXH4hxRBMco3jvM m8VKLKao9wKj82qSivUnkPIwsAGNPdFoPbgghCQiBjBe6A75Z2xHFrzo7t1jg7nQfIyNC7ez MZBJ59sqA9EDMEJPlLNIeJmqslXPjmMFnE7Mby/+335WJYDulsRybN+W5rLT5aMvhC6x6POK z55fMNKrMASCzBJum2Fwjf/VnuGRYkhKCqqZ8gJ3OvmR50tInDV2jZ1DQgc3i550T5JDpToh dPBxZocIhzg+MBSRDXcJmHOx/7nQm3iQ6iLuwmXsRC6f5FbFefk9EjuTKcLMvBsEx+2DEx0E UnmJ4hVg7u1PQ+2Oy+Lh/opK/BDiqlQ8Pz2jiXv5xkECvr/3Sv59hlOCZMOaiLTTjtOIU7Tq 7ut6OL64oAq+zsFNBFXLn5EBEADn1959INH2cwYJv0tsxf5MUCghCj/CA/lc/LMthqQ773ga uB9mN+F1rE9cyyXb6jyOGn+GUjMbnq1o121Vm0+neKHUCBtHyseBfDXHA6m4B3mUTWo13nid 0e4AM71r0DS8+KYh6zvweLX/LL5kQS9GQeT+QNroXcC1NzWbitts6TZ+IrPOwT1hfB4WNC+X 2n4AzDqp3+ILiVST2DT4VBc11Gz6jijpC/KI5Al8ZDhRwG47LUiuQmt3yqrmN63V9wzaPhC+ xbwIsNZlLUvuRnmBPkTJwwrFRZvwu5GPHNndBjVpAfaSTOfppyKBTccu2AXJXWAE1Xjh6GOC 8mlFjZwLxWFqdPHR1n2aPVgoiTLk34LR/bXO+e0GpzFXT7enwyvFFFyAS0Nk1q/7EChPcbRb hJqEBpRNZemxmg55zC3GLvgLKd5A09MOM2BrMea+l0FUR+PuTenh2YmnmLRTro6eZ/qYwWkC u8FFIw4pT0OUDMyLgi+GI1aMpVogTZJ70FgV0pUAlpmrzk/bLbRkF3TwgucpyPtcpmQtTkWS gDS50QG9DR/1As3LLLcNkwJBZzBG6PWbvcOyrwMQUF1nl4SSPV0LLH63+BrrHasfJzxKXzqg rW28CTAE2x8qi7e/6M/+XXhrsMYG+uaViM7n2je3qKe7ofum3s4vq7oFCPsOgwARAQABwsFl BBgBAgAPBQJVy5+RAhsMBQkJZgGAAAoJEE3eEPcA/4NagOsP/jPoIBb/iXVbM+fmSHOjEshl KMwEl/m5iLj3iHnHPVLBUWrXPdS7iQijJA/VLxjnFknhaS60hkUNWexDMxVVP/6lbOrs4bDZ NEWDMktAeqJaFtxackPszlcpRVkAs6Msn9tu8hlvB517pyUgvuD7ZS9gGOMmYwFQDyytpepo YApVV00P0u3AaE0Cj/o71STqGJKZxcVhPaZ+LR+UCBZOyKfEyq+ZN311VpOJZ1IvTExf+S/5 lqnciDtbO3I4Wq0ArLX1gs1q1XlXLaVaA3yVqeC8E7kOchDNinD3hJS4OX0e1gdsx/e6COvy qNg5aL5n0Kl4fcVqM0LdIhsubVs4eiNCa5XMSYpXmVi3HAuFyg9dN+x8thSwI836FoMASwOl C7tHsTjnSGufB+D7F7ZBT61BffNBBIm1KdMxcxqLUVXpBQHHlGkbwI+3Ye+nE6HmZH7IwLwV W+Ajl7oYF+jeKaH4DZFtgLYGLtZ1LDwKPjX7VAsa4Yx7S5+EBAaZGxK510MjIx6SGrZWBrrV TEvdV00F2MnQoeXKzD7O4WFbL55hhyGgfWTHwZ457iN9SgYi1JLPqWkZB0JRXIEtjd4JEQcx +8Umfre0Xt4713VxMygW0PnQt5aSQdMD58jHFxTk092mU+yIHj5LeYgvwSgZN4airXk5yRXl SE+xAvmumFBY Organization: Red Hat GmbH Message-ID: <9852d84a-992e-9b7c-a55a-72183ebfbb97@redhat.com> Date: Thu, 25 Jul 2019 13:56:13 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: <20190725075054-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit 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 [10.5.110.41]); Thu, 25 Jul 2019 11:56:20 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH-for-4.1 v4 6/7] 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: Igor Mammedov , qemu-stable@nongnu.org, qemu-devel@nongnu.org, Stefan Hajnoczi , David Gibson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 25.07.19 13:53, Michael S. Tsirkin wrote: > On Thu, Jul 25, 2019 at 01:36:37PM +0200, David Hildenbrand wrote: >> 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 >> Acked-by: David Gibson >> Signed-off-by: David Hildenbrand >> --- >> 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 @@ >> >> #define BALLOON_PAGE_SIZE (1 << VIRTIO_BALLOON_PFN_SHIFT) >> >> -struct PartiallyBalloonedPage { >> +typedef struct PartiallyBalloonedPage { >> ram_addr_t base_gpa; >> long subpages; >> unsigned long *bitmap; >> -}; >> +} PartiallyBalloonedPage; >> >> static void virtio_balloon_pbp_free(PartiallyBalloonedPage *pbp) >> { >> @@ -68,11 +68,11 @@ static bool virtio_balloon_pbp_matches(PartiallyBalloonedPage *pbp, >> } >> >> static void balloon_inflate_page(VirtIOBalloon *balloon, >> - MemoryRegion *mr, hwaddr mr_offset) >> + MemoryRegion *mr, hwaddr mr_offset, >> + PartiallyBalloonedPage **pbp) >> { >> void *addr = memory_region_get_ram_ptr(mr) + mr_offset; >> ram_addr_t rb_offset, rb_aligned_offset, base_gpa; >> - PartiallyBalloonedPage **pbp = &balloon->pbp; >> RAMBlock *rb; >> size_t rb_page_size; >> int subpages; >> @@ -149,12 +149,6 @@ static void balloon_deflate_page(VirtIOBalloon *balloon, >> rb = qemu_ram_block_from_host(addr, false, &rb_offset); >> rb_page_size = qemu_ram_pagesize(rb); >> >> - if (balloon->pbp) { >> - /* Let's play safe and always reset the pbp on deflation requests. */ >> - virtio_balloon_pbp_free(balloon->pbp); >> - balloon->pbp = NULL; >> - } >> - >> host_addr = (void *)((uintptr_t)addr & ~(rb_page_size - 1)); >> >> /* 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 = VIRTIO_BALLOON(vdev); >> + PartiallyBalloonedPage *pbp = NULL; >> VirtQueueElement *elem; >> MemoryRegionSection section; >> >> @@ -344,7 +339,7 @@ static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq) >> uint32_t pfn; >> elem = virtqueue_pop(vq, sizeof(VirtQueueElement)); >> if (!elem) { >> - return; >> + break; >> } >> >> while (iov_to_buf(elem->out_sg, elem->out_num, offset, &pfn, 4) == 4) { >> @@ -373,7 +368,7 @@ static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq) >> if (!qemu_balloon_is_inhibited()) { >> if (vq == s->ivq) { >> balloon_inflate_page(s, section.mr, >> - section.offset_within_region); >> + section.offset_within_region, &pbp); >> } else if (vq == s->dvq) { >> balloon_deflate_page(s, section.mr, section.offset_within_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); >> } >> >> static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq) > > Oops this is not early enough. > We must not track pbp across elements: once we push an element > guest can reuse the page. > Right, it has to go into the loop. -- Thanks, David / dhildenb