From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ivanoab7.miniserver.com ([37.128.132.42]:45340 "EHLO www.kot-begemot.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727339AbfKZLVR (ORCPT ); Tue, 26 Nov 2019 06:21:17 -0500 Subject: Re: [RFC v2 17/37] lkl tools: host lib: virtio devices References: <1531c5f16a00b608635c9a62fa3951807075f950.1573179553.git.thehajime@gmail.com> <1662825264.98055.1574758225905.JavaMail.zimbra@nod.at> <4ebb14dc67ccb70543617ce1f7066f3f27cd11a8.camel@sipsolutions.net> <243342257.98153.1574762974057.JavaMail.zimbra@nod.at> <98acf77a7c6f6cba7f76c12a850ac2929b9e5a48.camel@sipsolutions.net> From: Anton Ivanov Message-ID: Date: Tue, 26 Nov 2019 10:49:48 +0000 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-arch-owner@vger.kernel.org List-ID: To: Octavian Purdila , Johannes Berg Cc: linux-arch , cem , Richard Weinberger , linux-um , retrage01 , liuyuan , pscollins , linux-kernel-library , sigmaepsilon92 , Hajime Tazaki On 26/11/2019 10:42, Octavian Purdila wrote: > On Tue, Nov 26, 2019 at 12:16 PM Johannes Berg > wrote: >> >> On Tue, 2019-11-26 at 11:09 +0100, Richard Weinberger wrote: >>> ----- Ursprüngliche Mail ----- >>>>> My point is that UML and LKL should try to do use the same concept/code >>>>> regarding virtio. At the end of day both use virtual devices which use >>>>> facilities from the host. >>>>> If this is really not possible it needs a good explanation. >>>> >>>> I think it isn't possible, unless you use vhost-user over a unix domain >>>> socket internally to talk between the kernel (virtio_uml) and hypervisor >>>> (device) components. >>>> >>>> In virtio_uml, the device implementation is assumed to be a separate >>>> process with a vhost-user connection. Here in LKL, the virtio device is >>>> part of the "hypervisor", i.e. in the same process. >>> >>> Exactly, currently UML and LKL solve same things differently, but do we need to? >> >> It's not the same thing though :-) >> >> UML right now doesn't have or support virtio devices in the built-in >> hypervisor, what we wanted to use virtio for was explicitly for the >> vhost-user devices. >> >> LKL clearly wants to have device implementations in the hypervisor, >> perhaps for networking or console etc.? That _might_ be useful since it >> makes the device implementation more general, unlike the UML approach >> where all devices come with a kernel- and user-side and are special >> drivers in the kernel, vs. general virtio drivers. >> > > That is correct. Initially we used the same UML model, with dedicated > drivers for LKL, and later switched to using the built-in virtio > drivers (so far for network and block devices). > >> Now, arguably, since UML has all these already a combined UML/LKL >> doesn't actually *need* any virtio devices, since all (or at least most) >> of the things that could be covered by virtio today are already covered >> by UML devices (block, net, console, random). >> >> I'd probably say then that this can be removed from an initial "minimum >> viable product" of LKL, since once merged with UML you get the devices >> from that. Later, we could decide that UML devices actually are better >> done as virtio, and support something like this. >> > > I agree, I think it make sense to drop these since the problem of > dedicated vs generic / virtio drivers are orthogonal with regard to > UML and LKL unification and can later be worked on. This brings us back to the interrupt controller as noted by Richard earlier. UML devices are heavily dependent on the file io as an IRQ trigger paradigm and they need an interrupt controller which has an IO event feed into it. I did not see that in LKL on first read. So as a first step we should get it to work with existing UML IRQ controller and whatever incremental patches are needed on top of that. > > _______________________________________________ > linux-um mailing list > linux-um@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-um > -- Anton R. Ivanov https://www.kot-begemot.co.uk/ From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ivanoab7.miniserver.com ([37.128.132.42] helo=www.kot-begemot.co.uk) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1iZYPu-0006D6-7k for linux-um@lists.infradead.org; Tue, 26 Nov 2019 10:50:00 +0000 Subject: Re: [RFC v2 17/37] lkl tools: host lib: virtio devices References: <1531c5f16a00b608635c9a62fa3951807075f950.1573179553.git.thehajime@gmail.com> <1662825264.98055.1574758225905.JavaMail.zimbra@nod.at> <4ebb14dc67ccb70543617ce1f7066f3f27cd11a8.camel@sipsolutions.net> <243342257.98153.1574762974057.JavaMail.zimbra@nod.at> <98acf77a7c6f6cba7f76c12a850ac2929b9e5a48.camel@sipsolutions.net> From: Anton Ivanov Message-ID: Date: Tue, 26 Nov 2019 10:49:48 +0000 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: base64 Content-Type: text/plain; charset="utf-8"; Format="flowed" Sender: "linux-um" Errors-To: linux-um-bounces+geert=linux-m68k.org@lists.infradead.org To: Octavian Purdila , Johannes Berg Cc: linux-arch , Hajime Tazaki , cem , Richard Weinberger , linux-um , retrage01 , linux-kernel-library , pscollins , sigmaepsilon92 , liuyuan CgpPbiAyNi8xMS8yMDE5IDEwOjQyLCBPY3RhdmlhbiBQdXJkaWxhIHdyb3RlOgo+IE9uIFR1ZSwg Tm92IDI2LCAyMDE5IGF0IDEyOjE2IFBNIEpvaGFubmVzIEJlcmcKPiA8am9oYW5uZXNAc2lwc29s dXRpb25zLm5ldD4gd3JvdGU6Cj4+Cj4+IE9uIFR1ZSwgMjAxOS0xMS0yNiBhdCAxMTowOSArMDEw MCwgUmljaGFyZCBXZWluYmVyZ2VyIHdyb3RlOgo+Pj4gLS0tLS0gVXJzcHLDvG5nbGljaGUgTWFp bCAtLS0tLQo+Pj4+PiBNeSBwb2ludCBpcyB0aGF0IFVNTCBhbmQgTEtMIHNob3VsZCB0cnkgdG8g ZG8gdXNlIHRoZSBzYW1lIGNvbmNlcHQvY29kZQo+Pj4+PiByZWdhcmRpbmcgdmlydGlvLiBBdCB0 aGUgZW5kIG9mIGRheSBib3RoIHVzZSB2aXJ0dWFsIGRldmljZXMgd2hpY2ggdXNlCj4+Pj4+IGZh Y2lsaXRpZXMgZnJvbSB0aGUgaG9zdC4KPj4+Pj4gSWYgdGhpcyBpcyByZWFsbHkgbm90IHBvc3Np YmxlIGl0IG5lZWRzIGEgZ29vZCBleHBsYW5hdGlvbi4KPj4+Pgo+Pj4+IEkgdGhpbmsgaXQgaXNu J3QgcG9zc2libGUsIHVubGVzcyB5b3UgdXNlIHZob3N0LXVzZXIgb3ZlciBhIHVuaXggZG9tYWlu Cj4+Pj4gc29ja2V0IGludGVybmFsbHkgdG8gdGFsayBiZXR3ZWVuIHRoZSBrZXJuZWwgKHZpcnRp b191bWwpIGFuZCBoeXBlcnZpc29yCj4+Pj4gKGRldmljZSkgY29tcG9uZW50cy4KPj4+Pgo+Pj4+ IEluIHZpcnRpb191bWwsIHRoZSBkZXZpY2UgaW1wbGVtZW50YXRpb24gaXMgYXNzdW1lZCB0byBi ZSBhIHNlcGFyYXRlCj4+Pj4gcHJvY2VzcyB3aXRoIGEgdmhvc3QtdXNlciBjb25uZWN0aW9uLiBI ZXJlIGluIExLTCwgdGhlIHZpcnRpbyBkZXZpY2UgaXMKPj4+PiBwYXJ0IG9mIHRoZSAiaHlwZXJ2 aXNvciIsIGkuZS4gaW4gdGhlIHNhbWUgcHJvY2Vzcy4KPj4+Cj4+PiBFeGFjdGx5LCBjdXJyZW50 bHkgVU1MIGFuZCBMS0wgc29sdmUgc2FtZSB0aGluZ3MgZGlmZmVyZW50bHksIGJ1dCBkbyB3ZSBu ZWVkIHRvPwo+Pgo+PiBJdCdzIG5vdCB0aGUgc2FtZSB0aGluZyB0aG91Z2ggOi0pCj4+Cj4+IFVN TCByaWdodCBub3cgZG9lc24ndCBoYXZlIG9yIHN1cHBvcnQgdmlydGlvIGRldmljZXMgaW4gdGhl IGJ1aWx0LWluCj4+IGh5cGVydmlzb3IsIHdoYXQgd2Ugd2FudGVkIHRvIHVzZSB2aXJ0aW8gZm9y IHdhcyBleHBsaWNpdGx5IGZvciB0aGUKPj4gdmhvc3QtdXNlciBkZXZpY2VzLgo+Pgo+PiBMS0wg Y2xlYXJseSB3YW50cyB0byBoYXZlIGRldmljZSBpbXBsZW1lbnRhdGlvbnMgaW4gdGhlIGh5cGVy dmlzb3IsCj4+IHBlcmhhcHMgZm9yIG5ldHdvcmtpbmcgb3IgY29uc29sZSBldGMuPyBUaGF0IF9t aWdodF8gYmUgdXNlZnVsIHNpbmNlIGl0Cj4+IG1ha2VzIHRoZSBkZXZpY2UgaW1wbGVtZW50YXRp b24gbW9yZSBnZW5lcmFsLCB1bmxpa2UgdGhlIFVNTCBhcHByb2FjaAo+PiB3aGVyZSBhbGwgZGV2 aWNlcyBjb21lIHdpdGggYSBrZXJuZWwtIGFuZCB1c2VyLXNpZGUgYW5kIGFyZSBzcGVjaWFsCj4+ IGRyaXZlcnMgaW4gdGhlIGtlcm5lbCwgdnMuIGdlbmVyYWwgdmlydGlvIGRyaXZlcnMuCj4+Cj4g Cj4gVGhhdCBpcyBjb3JyZWN0LiBJbml0aWFsbHkgd2UgdXNlZCB0aGUgc2FtZSBVTUwgbW9kZWws IHdpdGggZGVkaWNhdGVkCj4gZHJpdmVycyBmb3IgTEtMLCBhbmQgbGF0ZXIgc3dpdGNoZWQgdG8g dXNpbmcgdGhlIGJ1aWx0LWluIHZpcnRpbwo+IGRyaXZlcnMgKHNvIGZhciBmb3IgbmV0d29yayBh bmQgYmxvY2sgZGV2aWNlcykuCj4gCj4+IE5vdywgYXJndWFibHksIHNpbmNlIFVNTCBoYXMgYWxs IHRoZXNlIGFscmVhZHkgYSBjb21iaW5lZCBVTUwvTEtMCj4+IGRvZXNuJ3QgYWN0dWFsbHkgKm5l ZWQqIGFueSB2aXJ0aW8gZGV2aWNlcywgc2luY2UgYWxsIChvciBhdCBsZWFzdCBtb3N0KQo+PiBv ZiB0aGUgdGhpbmdzIHRoYXQgY291bGQgYmUgY292ZXJlZCBieSB2aXJ0aW8gdG9kYXkgYXJlIGFs cmVhZHkgY292ZXJlZAo+PiBieSBVTUwgZGV2aWNlcyAoYmxvY2ssIG5ldCwgY29uc29sZSwgcmFu ZG9tKS4KPj4KPj4gSSdkIHByb2JhYmx5IHNheSB0aGVuIHRoYXQgdGhpcyBjYW4gYmUgcmVtb3Zl ZCBmcm9tIGFuIGluaXRpYWwgIm1pbmltdW0KPj4gdmlhYmxlIHByb2R1Y3QiIG9mIExLTCwgc2lu Y2Ugb25jZSBtZXJnZWQgd2l0aCBVTUwgeW91IGdldCB0aGUgZGV2aWNlcwo+PiBmcm9tIHRoYXQu IExhdGVyLCB3ZSBjb3VsZCBkZWNpZGUgdGhhdCBVTUwgZGV2aWNlcyBhY3R1YWxseSBhcmUgYmV0 dGVyCj4+IGRvbmUgYXMgdmlydGlvLCBhbmQgc3VwcG9ydCBzb21ldGhpbmcgbGlrZSB0aGlzLgo+ Pgo+IAo+IEkgYWdyZWUsIEkgdGhpbmsgaXQgbWFrZSBzZW5zZSB0byBkcm9wIHRoZXNlIHNpbmNl IHRoZSBwcm9ibGVtIG9mCj4gZGVkaWNhdGVkIHZzIGdlbmVyaWMgLyB2aXJ0aW8gZHJpdmVycyBh cmUgb3J0aG9nb25hbCB3aXRoIHJlZ2FyZCB0bwo+IFVNTCBhbmQgTEtMIHVuaWZpY2F0aW9uIGFu ZCBjYW4gbGF0ZXIgYmUgd29ya2VkIG9uLgoKVGhpcyBicmluZ3MgdXMgYmFjayB0byB0aGUgaW50 ZXJydXB0IGNvbnRyb2xsZXIgYXMgbm90ZWQgYnkgUmljaGFyZCBlYXJsaWVyLgoKVU1MIGRldmlj ZXMgYXJlIGhlYXZpbHkgZGVwZW5kZW50IG9uIHRoZSBmaWxlIGlvIGFzIGFuIElSUSB0cmlnZ2Vy IApwYXJhZGlnbSBhbmQgdGhleSBuZWVkIGFuIGludGVycnVwdCBjb250cm9sbGVyIHdoaWNoIGhh cyBhbiBJTyBldmVudCAKZmVlZCBpbnRvIGl0LiBJIGRpZCBub3Qgc2VlIHRoYXQgaW4gTEtMIG9u IGZpcnN0IHJlYWQuCgpTbyBhcyBhIGZpcnN0IHN0ZXAgd2Ugc2hvdWxkIGdldCBpdCB0byB3b3Jr IHdpdGggZXhpc3RpbmcgVU1MIElSUSAKY29udHJvbGxlciBhbmQgd2hhdGV2ZXIgaW5jcmVtZW50 YWwgcGF0Y2hlcyBhcmUgbmVlZGVkIG9uIHRvcCBvZiB0aGF0LgoKPiAKPiBfX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fXwo+IGxpbnV4LXVtIG1haWxpbmcgbGlz dAo+IGxpbnV4LXVtQGxpc3RzLmluZnJhZGVhZC5vcmcKPiBodHRwOi8vbGlzdHMuaW5mcmFkZWFk Lm9yZy9tYWlsbWFuL2xpc3RpbmZvL2xpbnV4LXVtCj4gCgotLSAKQW50b24gUi4gSXZhbm92Cmh0 dHBzOi8vd3d3LmtvdC1iZWdlbW90LmNvLnVrLwoKX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX18KbGludXgtdW0gbWFpbGluZyBsaXN0CmxpbnV4LXVtQGxpc3Rz LmluZnJhZGVhZC5vcmcKaHR0cDovL2xpc3RzLmluZnJhZGVhZC5vcmcvbWFpbG1hbi9saXN0aW5m by9saW51eC11bQo=