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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no 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 663CAC07E9C for ; Wed, 14 Jul 2021 06:47:47 +0000 (UTC) Received: from smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (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 236E1613B6 for ; Wed, 14 Jul 2021 06:47:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 236E1613B6 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id 851CB606D6; Wed, 14 Jul 2021 06:47:46 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id SkXunSX4_vZq; Wed, 14 Jul 2021 06:47:45 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [IPv6:2605:bc80:3010:104::8cd3:938]) by smtp3.osuosl.org (Postfix) with ESMTPS id 652D8606DB; Wed, 14 Jul 2021 06:47:45 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id BE3E1C0020; Wed, 14 Jul 2021 06:47:44 +0000 (UTC) Received: from smtp1.osuosl.org (smtp1.osuosl.org [140.211.166.138]) by lists.linuxfoundation.org (Postfix) with ESMTP id 51C75C000E; Wed, 14 Jul 2021 06:47:43 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp1.osuosl.org (Postfix) with ESMTP id 2C65482BE5; Wed, 14 Jul 2021 06:47:43 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Authentication-Results: smtp1.osuosl.org (amavisd-new); dkim=pass (1024-bit key) header.d=linuxfoundation.org Received: from smtp1.osuosl.org ([127.0.0.1]) by localhost (smtp1.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Vct1NVew3bV7; Wed, 14 Jul 2021 06:47:42 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.8.0 X-Greylist: from auto-whitelisted by SQLgrey-1.8.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp1.osuosl.org (Postfix) with ESMTPS id 9C72082BD6; Wed, 14 Jul 2021 06:47:42 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 96EA5613AA; Wed, 14 Jul 2021 06:47:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626245261; bh=YNUqH8SXbCanLQzbk4axEfesSFurixvhv/5EA0zfQNs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=wAUkEGuaJJ+xyTOr/3CDeDn85Emf2yTZJe5ZHYx0VnNfvTbl7kecruHBrIiXB9tD4 hOTnqvfdmfYs99MmWfQCGkqgZRAEQaJUr3W2yvScHeXWy0hWoFfBhRxFqDrGmW4RKY pl0XDR1Yzvo9UeO+3Eo4T4k0nBkLz7h3AOHxAbt0= Date: Wed, 14 Jul 2021 08:47:36 +0200 From: Greg KH To: Jason Wang Subject: Re: [PATCH v9 16/17] vduse: Introduce VDUSE - vDPA Device in Userspace Message-ID: References: <20210713084656.232-1-xieyongji@bytedance.com> <20210713084656.232-17-xieyongji@bytedance.com> <26116714-f485-eeab-4939-71c4c10c30de@redhat.com> <20210714014817-mutt-send-email-mst@kernel.org> <0565ed6c-88e2-6d93-7cc6-7b4afaab599c@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <0565ed6c-88e2-6d93-7cc6-7b4afaab599c@redhat.com> Cc: kvm@vger.kernel.org, "Michael S. Tsirkin" , virtualization@lists.linux-foundation.org, christian.brauner@canonical.com, corbet@lwn.net, willy@infradead.org, hch@infradead.org, Xie Yongji , dan.carpenter@oracle.com, sgarzare@redhat.com, xiaodong.liu@intel.com, viro@zeniv.linux.org.uk, stefanha@redhat.com, songmuchun@bytedance.com, axboe@kernel.dk, zhe.he@windriver.com, netdev@vger.kernel.org, rdunlap@infradead.org, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, bcrl@kvack.org, linux-fsdevel@vger.kernel.org, mika.penttila@nextfour.com X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" T24gV2VkLCBKdWwgMTQsIDIwMjEgYXQgMDI6MDI6NTBQTSArMDgwMCwgSmFzb24gV2FuZyB3cm90 ZToKPiAKPiDlnKggMjAyMS83LzE0IOS4i+WNiDE6NTQsIE1pY2hhZWwgUy4gVHNpcmtpbiDlhpnp gZM6Cj4gPiBPbiBXZWQsIEp1bCAxNCwgMjAyMSBhdCAwMTo0NTozOVBNICswODAwLCBKYXNvbiBX YW5nIHdyb3RlOgo+ID4gPiA+ICtzdGF0aWMgaW50IHZkdXNlX2Rldl9tc2dfc3luYyhzdHJ1Y3Qg dmR1c2VfZGV2ICpkZXYsCj4gPiA+ID4gKwkJCSAgICAgIHN0cnVjdCB2ZHVzZV9kZXZfbXNnICpt c2cpCj4gPiA+ID4gK3sKPiA+ID4gPiArCWludCByZXQ7Cj4gPiA+ID4gKwo+ID4gPiA+ICsJaW5p dF93YWl0cXVldWVfaGVhZCgmbXNnLT53YWl0cSk7Cj4gPiA+ID4gKwlzcGluX2xvY2soJmRldi0+ bXNnX2xvY2spOwo+ID4gPiA+ICsJbXNnLT5yZXEucmVxdWVzdF9pZCA9IGRldi0+bXNnX3VuaXF1 ZSsrOwo+ID4gPiA+ICsJdmR1c2VfZW5xdWV1ZV9tc2coJmRldi0+c2VuZF9saXN0LCBtc2cpOwo+ ID4gPiA+ICsJd2FrZV91cCgmZGV2LT53YWl0cSk7Cj4gPiA+ID4gKwlzcGluX3VubG9jaygmZGV2 LT5tc2dfbG9jayk7Cj4gPiA+ID4gKwo+ID4gPiA+ICsJd2FpdF9ldmVudF9raWxsYWJsZV90aW1l b3V0KG1zZy0+d2FpdHEsIG1zZy0+Y29tcGxldGVkLAo+ID4gPiA+ICsJCQkJICAgIFZEVVNFX1JF UVVFU1RfVElNRU9VVCAqIEhaKTsKPiA+ID4gPiArCXNwaW5fbG9jaygmZGV2LT5tc2dfbG9jayk7 Cj4gPiA+ID4gKwlpZiAoIW1zZy0+Y29tcGxldGVkKSB7Cj4gPiA+ID4gKwkJbGlzdF9kZWwoJm1z Zy0+bGlzdCk7Cj4gPiA+ID4gKwkJbXNnLT5yZXNwLnJlc3VsdCA9IFZEVVNFX1JFUV9SRVNVTFRf RkFJTEVEOwo+ID4gPiA+ICsJfQo+ID4gPiA+ICsJcmV0ID0gKG1zZy0+cmVzcC5yZXN1bHQgPT0g VkRVU0VfUkVRX1JFU1VMVF9PSykgPyAwIDogLUVJTzsKPiA+ID4gCj4gPiA+IEkgdGhpbmsgd2Ug c2hvdWxkIG1hcmsgdGhlIGRldmljZSBhcyBtYWxmdW5jdGlvbiB3aGVuIHRoZXJlIGlzIGEgdGlt ZW91dCBhbmQKPiA+ID4gZm9yYmlkIGFueSB1c2Vyc3BhY2Ugb3BlcmF0aW9ucyBleGNlcHQgZm9y IHRoZSBkZXN0cm95IGFmdHdhcmRzIGZvciBzYWZldHkuCj4gPiBUaGlzIGxvb2tzIGxpa2UgaWYg b25lIHRyaWVkIHRvIHJ1biBnZGIgb24gdGhlIHByb2dyYW0gdGhlIGJlaGF2aW91cgo+ID4gd2ls bCBjaGFuZ2UgY29tcGxldGVseSBiZWNhdXNlIGtlcm5lbCB3YW50cyBpdCB0byByZXNwb25kIHdp dGhpbgo+ID4gc3BlY2lmaWMgdGltZS4gTG9va3MgbGlrZSBhIHJlY2VpcGUgZm9yIGhlaXNlbmJ1 Z3MuCj4gPiAKPiA+IExldCdzIG5vdCBidWlsZCBpbnRlcmZhY2VzIHdpdGggYXJiaXRyYXJ5IHRp bWVvdXRzIGxpa2UgdGhhdC4KPiA+IEludGVycnVwdGlibGUgd2FpdCBleGlzdHMgZm9yIHRoaXMg dmVyeSByZWFzb24uCj4gCj4gCj4gVGhlIHByb2JsZW0gaXMuIERvIHdlIHdhbnQgdXNlcnNwYWNl IHByb2dyYW0gbGlrZSBtb2Rwcm9iZSB0byBiZSBzdHVjayBmb3IKPiBpbmRlZmluaXRlIHRpbWUg YW5kIGV4cGVjdCB0aGUgYWRtaW5pc3RyYXRvciB0byBraWxsIHRoYXQ/CgpXaHkgd291bGQgbW9k cHJvYmUgYmUgc3R1Y2sgZm9yIGZvcmV2ZXI/CgpJcyB0aGlzIG9uIHRoZSBtb2R1bGUgcHJvYmUg cGF0aD8KX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KaW9t bXUgbWFpbGluZyBsaXN0CmlvbW11QGxpc3RzLmxpbnV4LWZvdW5kYXRpb24ub3JnCmh0dHBzOi8v bGlzdHMubGludXhmb3VuZGF0aW9uLm9yZy9tYWlsbWFuL2xpc3RpbmZvL2lvbW11 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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no 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 B5546C07E9A for ; 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Wed, 14 Jul 2021 06:47:42 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 96EA5613AA; Wed, 14 Jul 2021 06:47:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626245261; bh=YNUqH8SXbCanLQzbk4axEfesSFurixvhv/5EA0zfQNs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=wAUkEGuaJJ+xyTOr/3CDeDn85Emf2yTZJe5ZHYx0VnNfvTbl7kecruHBrIiXB9tD4 hOTnqvfdmfYs99MmWfQCGkqgZRAEQaJUr3W2yvScHeXWy0hWoFfBhRxFqDrGmW4RKY pl0XDR1Yzvo9UeO+3Eo4T4k0nBkLz7h3AOHxAbt0= Date: Wed, 14 Jul 2021 08:47:36 +0200 From: Greg KH To: Jason Wang Subject: Re: [PATCH v9 16/17] vduse: Introduce VDUSE - vDPA Device in Userspace Message-ID: References: <20210713084656.232-1-xieyongji@bytedance.com> <20210713084656.232-17-xieyongji@bytedance.com> <26116714-f485-eeab-4939-71c4c10c30de@redhat.com> <20210714014817-mutt-send-email-mst@kernel.org> <0565ed6c-88e2-6d93-7cc6-7b4afaab599c@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <0565ed6c-88e2-6d93-7cc6-7b4afaab599c@redhat.com> Cc: kvm@vger.kernel.org, "Michael S. Tsirkin" , virtualization@lists.linux-foundation.org, christian.brauner@canonical.com, corbet@lwn.net, joro@8bytes.org, willy@infradead.org, hch@infradead.org, Xie Yongji , dan.carpenter@oracle.com, xiaodong.liu@intel.com, viro@zeniv.linux.org.uk, stefanha@redhat.com, songmuchun@bytedance.com, axboe@kernel.dk, zhe.he@windriver.com, netdev@vger.kernel.org, rdunlap@infradead.org, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, bcrl@kvack.org, linux-fsdevel@vger.kernel.org, mika.penttila@nextfour.com X-BeenThere: virtualization@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux virtualization List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" T24gV2VkLCBKdWwgMTQsIDIwMjEgYXQgMDI6MDI6NTBQTSArMDgwMCwgSmFzb24gV2FuZyB3cm90 ZToKPiAKPiDlnKggMjAyMS83LzE0IOS4i+WNiDE6NTQsIE1pY2hhZWwgUy4gVHNpcmtpbiDlhpnp gZM6Cj4gPiBPbiBXZWQsIEp1bCAxNCwgMjAyMSBhdCAwMTo0NTozOVBNICswODAwLCBKYXNvbiBX YW5nIHdyb3RlOgo+ID4gPiA+ICtzdGF0aWMgaW50IHZkdXNlX2Rldl9tc2dfc3luYyhzdHJ1Y3Qg dmR1c2VfZGV2ICpkZXYsCj4gPiA+ID4gKwkJCSAgICAgIHN0cnVjdCB2ZHVzZV9kZXZfbXNnICpt c2cpCj4gPiA+ID4gK3sKPiA+ID4gPiArCWludCByZXQ7Cj4gPiA+ID4gKwo+ID4gPiA+ICsJaW5p dF93YWl0cXVldWVfaGVhZCgmbXNnLT53YWl0cSk7Cj4gPiA+ID4gKwlzcGluX2xvY2soJmRldi0+ bXNnX2xvY2spOwo+ID4gPiA+ICsJbXNnLT5yZXEucmVxdWVzdF9pZCA9IGRldi0+bXNnX3VuaXF1 ZSsrOwo+ID4gPiA+ICsJdmR1c2VfZW5xdWV1ZV9tc2coJmRldi0+c2VuZF9saXN0LCBtc2cpOwo+ ID4gPiA+ICsJd2FrZV91cCgmZGV2LT53YWl0cSk7Cj4gPiA+ID4gKwlzcGluX3VubG9jaygmZGV2 LT5tc2dfbG9jayk7Cj4gPiA+ID4gKwo+ID4gPiA+ICsJd2FpdF9ldmVudF9raWxsYWJsZV90aW1l b3V0KG1zZy0+d2FpdHEsIG1zZy0+Y29tcGxldGVkLAo+ID4gPiA+ICsJCQkJICAgIFZEVVNFX1JF UVVFU1RfVElNRU9VVCAqIEhaKTsKPiA+ID4gPiArCXNwaW5fbG9jaygmZGV2LT5tc2dfbG9jayk7 Cj4gPiA+ID4gKwlpZiAoIW1zZy0+Y29tcGxldGVkKSB7Cj4gPiA+ID4gKwkJbGlzdF9kZWwoJm1z Zy0+bGlzdCk7Cj4gPiA+ID4gKwkJbXNnLT5yZXNwLnJlc3VsdCA9IFZEVVNFX1JFUV9SRVNVTFRf RkFJTEVEOwo+ID4gPiA+ICsJfQo+ID4gPiA+ICsJcmV0ID0gKG1zZy0+cmVzcC5yZXN1bHQgPT0g VkRVU0VfUkVRX1JFU1VMVF9PSykgPyAwIDogLUVJTzsKPiA+ID4gCj4gPiA+IEkgdGhpbmsgd2Ug c2hvdWxkIG1hcmsgdGhlIGRldmljZSBhcyBtYWxmdW5jdGlvbiB3aGVuIHRoZXJlIGlzIGEgdGlt ZW91dCBhbmQKPiA+ID4gZm9yYmlkIGFueSB1c2Vyc3BhY2Ugb3BlcmF0aW9ucyBleGNlcHQgZm9y IHRoZSBkZXN0cm95IGFmdHdhcmRzIGZvciBzYWZldHkuCj4gPiBUaGlzIGxvb2tzIGxpa2UgaWYg b25lIHRyaWVkIHRvIHJ1biBnZGIgb24gdGhlIHByb2dyYW0gdGhlIGJlaGF2aW91cgo+ID4gd2ls bCBjaGFuZ2UgY29tcGxldGVseSBiZWNhdXNlIGtlcm5lbCB3YW50cyBpdCB0byByZXNwb25kIHdp dGhpbgo+ID4gc3BlY2lmaWMgdGltZS4gTG9va3MgbGlrZSBhIHJlY2VpcGUgZm9yIGhlaXNlbmJ1 Z3MuCj4gPiAKPiA+IExldCdzIG5vdCBidWlsZCBpbnRlcmZhY2VzIHdpdGggYXJiaXRyYXJ5IHRp bWVvdXRzIGxpa2UgdGhhdC4KPiA+IEludGVycnVwdGlibGUgd2FpdCBleGlzdHMgZm9yIHRoaXMg dmVyeSByZWFzb24uCj4gCj4gCj4gVGhlIHByb2JsZW0gaXMuIERvIHdlIHdhbnQgdXNlcnNwYWNl IHByb2dyYW0gbGlrZSBtb2Rwcm9iZSB0byBiZSBzdHVjayBmb3IKPiBpbmRlZmluaXRlIHRpbWUg YW5kIGV4cGVjdCB0aGUgYWRtaW5pc3RyYXRvciB0byBraWxsIHRoYXQ/CgpXaHkgd291bGQgbW9k cHJvYmUgYmUgc3R1Y2sgZm9yIGZvcmV2ZXI/CgpJcyB0aGlzIG9uIHRoZSBtb2R1bGUgcHJvYmUg cGF0aD8KX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KVmly dHVhbGl6YXRpb24gbWFpbGluZyBsaXN0ClZpcnR1YWxpemF0aW9uQGxpc3RzLmxpbnV4LWZvdW5k YXRpb24ub3JnCmh0dHBzOi8vbGlzdHMubGludXhmb3VuZGF0aW9uLm9yZy9tYWlsbWFuL2xpc3Rp bmZvL3ZpcnR1YWxpemF0aW9u 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=-6.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 64F03C07E9C for ; Wed, 14 Jul 2021 06:47:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 458D5613AB for ; Wed, 14 Jul 2021 06:47:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238144AbhGNGud (ORCPT ); Wed, 14 Jul 2021 02:50:33 -0400 Received: from mail.kernel.org ([198.145.29.99]:50880 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237948AbhGNGud (ORCPT ); Wed, 14 Jul 2021 02:50:33 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 96EA5613AA; Wed, 14 Jul 2021 06:47:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626245261; bh=YNUqH8SXbCanLQzbk4axEfesSFurixvhv/5EA0zfQNs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=wAUkEGuaJJ+xyTOr/3CDeDn85Emf2yTZJe5ZHYx0VnNfvTbl7kecruHBrIiXB9tD4 hOTnqvfdmfYs99MmWfQCGkqgZRAEQaJUr3W2yvScHeXWy0hWoFfBhRxFqDrGmW4RKY pl0XDR1Yzvo9UeO+3Eo4T4k0nBkLz7h3AOHxAbt0= Date: Wed, 14 Jul 2021 08:47:36 +0200 From: Greg KH To: Jason Wang Cc: "Michael S. Tsirkin" , Xie Yongji , stefanha@redhat.com, sgarzare@redhat.com, parav@nvidia.com, hch@infradead.org, christian.brauner@canonical.com, rdunlap@infradead.org, willy@infradead.org, viro@zeniv.linux.org.uk, axboe@kernel.dk, bcrl@kvack.org, corbet@lwn.net, mika.penttila@nextfour.com, dan.carpenter@oracle.com, joro@8bytes.org, zhe.he@windriver.com, xiaodong.liu@intel.com, songmuchun@bytedance.com, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, kvm@vger.kernel.org, linux-fsdevel@vger.kernel.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v9 16/17] vduse: Introduce VDUSE - vDPA Device in Userspace Message-ID: References: <20210713084656.232-1-xieyongji@bytedance.com> <20210713084656.232-17-xieyongji@bytedance.com> <26116714-f485-eeab-4939-71c4c10c30de@redhat.com> <20210714014817-mutt-send-email-mst@kernel.org> <0565ed6c-88e2-6d93-7cc6-7b4afaab599c@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <0565ed6c-88e2-6d93-7cc6-7b4afaab599c@redhat.com> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Wed, Jul 14, 2021 at 02:02:50PM +0800, Jason Wang wrote: > > 在 2021/7/14 下午1:54, Michael S. Tsirkin 写道: > > On Wed, Jul 14, 2021 at 01:45:39PM +0800, Jason Wang wrote: > > > > +static int vduse_dev_msg_sync(struct vduse_dev *dev, > > > > + struct vduse_dev_msg *msg) > > > > +{ > > > > + int ret; > > > > + > > > > + init_waitqueue_head(&msg->waitq); > > > > + spin_lock(&dev->msg_lock); > > > > + msg->req.request_id = dev->msg_unique++; > > > > + vduse_enqueue_msg(&dev->send_list, msg); > > > > + wake_up(&dev->waitq); > > > > + spin_unlock(&dev->msg_lock); > > > > + > > > > + wait_event_killable_timeout(msg->waitq, msg->completed, > > > > + VDUSE_REQUEST_TIMEOUT * HZ); > > > > + spin_lock(&dev->msg_lock); > > > > + if (!msg->completed) { > > > > + list_del(&msg->list); > > > > + msg->resp.result = VDUSE_REQ_RESULT_FAILED; > > > > + } > > > > + ret = (msg->resp.result == VDUSE_REQ_RESULT_OK) ? 0 : -EIO; > > > > > > I think we should mark the device as malfunction when there is a timeout and > > > forbid any userspace operations except for the destroy aftwards for safety. > > This looks like if one tried to run gdb on the program the behaviour > > will change completely because kernel wants it to respond within > > specific time. Looks like a receipe for heisenbugs. > > > > Let's not build interfaces with arbitrary timeouts like that. > > Interruptible wait exists for this very reason. > > > The problem is. Do we want userspace program like modprobe to be stuck for > indefinite time and expect the administrator to kill that? Why would modprobe be stuck for forever? Is this on the module probe path?