From nobody Tue Feb 10 01:35:20 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.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 Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1648034590813853.6992313605801; Wed, 23 Mar 2022 04:23:10 -0700 (PDT) Received: from localhost ([::1]:42028 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nWz53-0000pS-Ig for importer@patchew.org; Wed, 23 Mar 2022 07:23:09 -0400 Received: from eggs.gnu.org ([209.51.188.92]:36950) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nWyzk-0000xm-UO for qemu-devel@nongnu.org; Wed, 23 Mar 2022 07:17:41 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:49396) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nWyzi-0001z3-FA for qemu-devel@nongnu.org; Wed, 23 Mar 2022 07:17:40 -0400 Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-661-R2df_69oOT2X0T-Og4rU-Q-1; Wed, 23 Mar 2022 07:17:34 -0400 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 618A3899EC2; Wed, 23 Mar 2022 11:17:34 +0000 (UTC) Received: from localhost (unknown [10.39.194.72]) by smtp.corp.redhat.com (Postfix) with ESMTP id EB36656D191; Wed, 23 Mar 2022 11:17:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1648034257; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=GuhMYgQSjvwA+WE+0m5ZgSh1iQlddJXFUZbFhus+bSY=; b=d84y8KNHdhce4XN2zxvddxIC5ARPxRnwVsfna1CqoZUW9n5ap8OmCyhL2VYSsmxJ/wEyGX r6+/NI0t2oyx6CkIzQbf6Fo3BF/PbC+xzZqwTHW8jnaiQ5U3S0c00luWnslGWZ54Smzq3f FexbGlwYB03g9q0efcnT1Xp53WoZ/kQ= X-MC-Unique: R2df_69oOT2X0T-Og4rU-Q-1 From: Stefan Hajnoczi To: qemu-devel@nongnu.org Subject: [RFC 3/8] block: pass size to bdrv_unregister_buf() Date: Wed, 23 Mar 2022 11:17:22 +0000 Message-Id: <20220323111727.1100209-4-stefanha@redhat.com> In-Reply-To: <20220323111727.1100209-1-stefanha@redhat.com> References: <20220323111727.1100209-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.85 on 10.11.54.9 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=stefanha@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.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; Received-SPF: pass client-ip=170.10.129.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Laurent Vivier , Kevin Wolf , Thomas Huth , Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org, "Michael S. Tsirkin" , John Snow , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Alberto Faria , Markus Armbruster , Yanan Wang , Eduardo Habkost , Hanna Reitz , Stefan Hajnoczi , Paolo Bonzini , Fam Zheng , Eric Blake , sgarzare@redhat.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) X-ZM-MESSAGEID: 1648034593238100001 Content-Type: text/plain; charset="utf-8" The only implementor of bdrv_register_buf() is block/nvme.c, where the size is not needed when unregistering a buffer. This is because util/vfio-helpers.c can look up mappings by address. Future block drivers that implement bdrv_register_buf() may not be able to do their job given only the buffer address. Add a size argument to bdrv_unregister_buf(). Also document the assumptions about bdrv_register_buf()/bdrv_unregister_buf() calls. The same values that were given to bdrv_register_buf() must be given to bdrv_unregister_buf(). gcc 11.2.1 emits a spurious warning that img_bench()'s buf_size local variable might be uninitialized, so it's necessary to silence the compiler. Signed-off-by: Stefan Hajnoczi --- include/block/block-global-state.h | 5 ++++- include/block/block_int-common.h | 2 +- include/sysemu/block-backend-global-state.h | 2 +- block/block-backend.c | 4 ++-- block/io.c | 6 +++--- block/nvme.c | 2 +- qemu-img.c | 4 ++-- 7 files changed, 14 insertions(+), 11 deletions(-) diff --git a/include/block/block-global-state.h b/include/block/block-globa= l-state.h index 25bb69bbef..2295a7c767 100644 --- a/include/block/block-global-state.h +++ b/include/block/block-global-state.h @@ -244,9 +244,12 @@ void bdrv_del_child(BlockDriverState *parent, BdrvChil= d *child, Error **errp); * Register/unregister a buffer for I/O. For example, VFIO drivers are * interested to know the memory areas that would later be used for I/O, so * that they can prepare IOMMU mapping etc., to get better performance. + * + * Buffers must not overlap and they must be unregistered with the same values that they were registered with. */ void bdrv_register_buf(BlockDriverState *bs, void *host, size_t size); -void bdrv_unregister_buf(BlockDriverState *bs, void *host); +void bdrv_unregister_buf(BlockDriverState *bs, void *host, size_t size); =20 void bdrv_cancel_in_flight(BlockDriverState *bs); =20 diff --git a/include/block/block_int-common.h b/include/block/block_int-com= mon.h index 8947abab76..b7a7cbd3a5 100644 --- a/include/block/block_int-common.h +++ b/include/block/block_int-common.h @@ -435,7 +435,7 @@ struct BlockDriver { * DMA mapping for hot buffers. */ void (*bdrv_register_buf)(BlockDriverState *bs, void *host, size_t siz= e); - void (*bdrv_unregister_buf)(BlockDriverState *bs, void *host); + void (*bdrv_unregister_buf)(BlockDriverState *bs, void *host, size_t s= ize); =20 /* * This field is modified only under the BQL, and is part of diff --git a/include/sysemu/block-backend-global-state.h b/include/sysemu/b= lock-backend-global-state.h index 2e93a74679..989ec0364b 100644 --- a/include/sysemu/block-backend-global-state.h +++ b/include/sysemu/block-backend-global-state.h @@ -107,7 +107,7 @@ void blk_io_limits_update_group(BlockBackend *blk, cons= t char *group); void blk_set_force_allow_inactivate(BlockBackend *blk); =20 void blk_register_buf(BlockBackend *blk, void *host, size_t size); -void blk_unregister_buf(BlockBackend *blk, void *host); +void blk_unregister_buf(BlockBackend *blk, void *host, size_t size); =20 const BdrvChild *blk_root(BlockBackend *blk); =20 diff --git a/block/block-backend.c b/block/block-backend.c index e0e1aff4b1..8af00d8a36 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -2591,10 +2591,10 @@ void blk_register_buf(BlockBackend *blk, void *host= , size_t size) bdrv_register_buf(blk_bs(blk), host, size); } =20 -void blk_unregister_buf(BlockBackend *blk, void *host) +void blk_unregister_buf(BlockBackend *blk, void *host, size_t size) { GLOBAL_STATE_CODE(); - bdrv_unregister_buf(blk_bs(blk), host); + bdrv_unregister_buf(blk_bs(blk), host, size); } =20 int coroutine_fn blk_co_copy_range(BlockBackend *blk_in, int64_t off_in, diff --git a/block/io.c b/block/io.c index 3280144a17..a8a7920e29 100644 --- a/block/io.c +++ b/block/io.c @@ -3365,16 +3365,16 @@ void bdrv_register_buf(BlockDriverState *bs, void *= host, size_t size) } } =20 -void bdrv_unregister_buf(BlockDriverState *bs, void *host) +void bdrv_unregister_buf(BlockDriverState *bs, void *host, size_t size) { BdrvChild *child; =20 GLOBAL_STATE_CODE(); if (bs->drv && bs->drv->bdrv_unregister_buf) { - bs->drv->bdrv_unregister_buf(bs, host); + bs->drv->bdrv_unregister_buf(bs, host, size); } QLIST_FOREACH(child, &bs->children, next) { - bdrv_unregister_buf(child->bs, host); + bdrv_unregister_buf(child->bs, host, size); } } =20 diff --git a/block/nvme.c b/block/nvme.c index 552029931d..88485e77f1 100644 --- a/block/nvme.c +++ b/block/nvme.c @@ -1592,7 +1592,7 @@ static void nvme_register_buf(BlockDriverState *bs, v= oid *host, size_t size) } } =20 -static void nvme_unregister_buf(BlockDriverState *bs, void *host) +static void nvme_unregister_buf(BlockDriverState *bs, void *host, size_t s= ize) { BDRVNVMeState *s =3D bs->opaque; =20 diff --git a/qemu-img.c b/qemu-img.c index 1caddfb23a..493fad758a 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -4363,7 +4363,7 @@ static int img_bench(int argc, char **argv) struct timeval t1, t2; int i; bool force_share =3D false; - size_t buf_size; + size_t buf_size =3D 0; =20 for (;;) { static const struct option long_options[] =3D { @@ -4585,7 +4585,7 @@ static int img_bench(int argc, char **argv) =20 out: if (data.buf) { - blk_unregister_buf(blk, data.buf); + blk_unregister_buf(blk, data.buf, buf_size); } qemu_vfree(data.buf); blk_unref(blk); --=20 2.35.1