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 Received: from lists1p.gnu.org (lists1p.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DCFF7C4452D for ; Tue, 21 Jul 2026 17:06:46 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wmDuR-0004mK-D7; Tue, 21 Jul 2026 13:05:35 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wmDuP-0004m9-Pe for qemu-devel@nongnu.org; Tue, 21 Jul 2026 13:05:33 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wmDuO-000735-Aj for qemu-devel@nongnu.org; Tue, 21 Jul 2026 13:05:33 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1784653531; 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=FvrvTez3Tth/d3RQhRxQnACm/KeEgvWlI9eFWupyO3M=; b=YTfalTuRVrjtl/YGbXNk5DxE+WMkrEh20lHhTRq6p5qe59+tUsJ4ZB+PuLoNhkCp7V4xSQ rYheP/oskO8tGmeunPoevBPN4tHpJgKyn5Ciiu8Wk4R6u55cApkTdZyYpgkE4DVw1tnVE/ dN/Dz9yeFvQve2gex/9jsSlc1u3yZAw= Received: from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-20-C1UmKPlsOzenJmloDoUHLQ-1; Tue, 21 Jul 2026 13:05:27 -0400 X-MC-Unique: C1UmKPlsOzenJmloDoUHLQ-1 X-Mimecast-MFC-AGG-ID: C1UmKPlsOzenJmloDoUHLQ_1784653526 Received: from mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.95]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id AD983195FCD6; Tue, 21 Jul 2026 17:05:26 +0000 (UTC) Received: from corto.redhat.com (unknown [10.44.48.82]) by mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 3D0821599; Tue, 21 Jul 2026 17:05:24 +0000 (UTC) From: =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= To: qemu-devel@nongnu.org Cc: =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= , Nicolin Chen , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= Subject: [PULL 02/13] vfio/region: Clarify dma-buf failure messages Date: Tue, 21 Jul 2026 19:05:07 +0200 Message-ID: <20260721170518.4160785-3-clg@redhat.com> In-Reply-To: <20260721170518.4160785-1-clg@redhat.com> References: <20260721170518.4160785-1-clg@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.6 on 10.30.177.95 Received-SPF: permerror client-ip=170.10.133.124; envelope-from=clg@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: 12 X-Spam_score: 1.2 X-Spam_bar: + X-Spam_report: (1.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, 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_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, RCVD_IN_SBL_CSS=3.335, SPF_HELO_PASS=-0.001, T_SPF_PERMERROR=0.01 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org The dma-buf failure messages in vfio_region_create_dma_buf() say "PCI BAR IOMMU mappings may fail", which suggests the BAR is broken. In practice, only P2P DMA is affected -- normal passthrough uses the mmap fallback. Reword both messages to mention P2P DMA explicitly and clarify that the mmap fallback is in use. Use warn_report_err_once() at the call site so per-BAR repetition on mdev devices is suppressed. Fixes: dcf1b77e834d ("hw/vfio/region: Create dmabuf for PCI BAR per region") Cc: Nicolin Chen Reviewed-by: Philippe Mathieu-Daudé Signed-off-by: Cédric Le Goater --- hw/vfio/region.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/hw/vfio/region.c b/hw/vfio/region.c index dbde3391802691888ca31d5e329aba5ba680feb4..54ad11a6c8ed8e04fa365262ccb8bd694bdb45f7 100644 --- a/hw/vfio/region.c +++ b/hw/vfio/region.c @@ -321,13 +321,12 @@ static bool vfio_region_create_dma_buf(VFIORegion *region, Error **errp) ret = vfio_device_get_feature(vbasedev, feature); if (ret < 0) { if (ret == -ENOTTY) { - warn_report_once("VFIO dma-buf not supported in kernel: " - "PCI BAR IOMMU mappings may fail"); + warn_report_once("VFIO dma-buf not supported in kernel, " + "using mmap fallback, P2P DMA will not work"); return true; } - /* P2P DMA or exposing device memory use cases are not supported. */ - error_setg_errno(errp, -ret, "%s: failed to create dma-buf: " - "PCI BAR IOMMU mappings may fail", + error_setg_errno(errp, -ret, "%s: dma-buf unavailable, " + "using mmap fallback, P2P DMA will not work", memory_region_name(region->mem)); return false; } @@ -448,7 +447,7 @@ int vfio_region_mmap(VFIORegion *region) } if (!vfio_region_create_dma_buf(region, &local_err)) { - error_report_err(local_err); + warn_report_err_once(local_err); } return 0; -- 2.55.0