From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f177.google.com (mail-wi0-f177.google.com [209.85.212.177]) by dpdk.org (Postfix) with ESMTP id 76A1C8DAD for ; Wed, 30 Sep 2015 21:10:59 +0200 (CEST) Received: by wicgb1 with SMTP id gb1so209508585wic.1 for ; Wed, 30 Sep 2015 12:10:59 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:subject:to:references:cc:from:message-id:date :user-agent:mime-version:in-reply-to:content-type :content-transfer-encoding; bh=Gkrmk9eUyH11HgE/RKVQgFc/G/yxZgAnIbPyxmF6L0A=; b=L4qoBOPTaf04m9pG4oK1QU8vpATXfO7HFF1XZevRIU90qp2N74mkb9N98w68KeU7fk X8EaOmPE/s3/VAPgj4hQZxUdljyJ5w6Pl+TBSgQIG58OJ3N+/RAHMyIate3NWVL1kJvK G4P2Yg+kNLp2nOBrIOeUB2UFcYJOw03kST7pSkPtnJyLFxr4zvy7SFz/RKsLkcb6wAJY bGh/tgVS1IOoKS8nApViMd4QVeSsIROHLym6F8gDhJ85z22ZUsw9hhEpwE8TrZhbutHU d/Uirt2cqMfzO5S4F4cN+XtQXzXD5/ewg1Wz6TJcixb80UAhiMnPBNjxnUNpv8G1+3G1 nV4Q== X-Gm-Message-State: ALoCoQm5yHEI/bmKVXXf5Zs+mqXGl4FooBav0X/rUT/ZNHW+hOKfdOEvIVkPlZ535fAqBCYKOlHk X-Received: by 10.181.8.72 with SMTP id di8mr6809891wid.62.1443640259236; Wed, 30 Sep 2015 12:10:59 -0700 (PDT) Received: from [10.0.0.2] (bzq-79-180-197-252.red.bezeqint.net. [79.180.197.252]) by smtp.googlemail.com with ESMTPSA id xa5sm2143070wjc.20.2015.09.30.12.10.58 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 30 Sep 2015 12:10:58 -0700 (PDT) To: "Michael S. Tsirkin" References: <20150930134533-mutt-send-email-mst@redhat.com> <560BC6C9.4020505@cloudius-systems.com> <20150930143927-mutt-send-email-mst@redhat.com> <560BCD2F.5060505@cloudius-systems.com> <20150930150115-mutt-send-email-mst@redhat.com> <560BD284.7040505@cloudius-systems.com> <20150930151632-mutt-send-email-mst@redhat.com> <560BDA81.6070807@cloudius-systems.com> <20150930182155-mutt-send-email-mst@redhat.com> <560C26DC.80209@cloudius-systems.com> <20150930215027-mutt-send-email-mst@redhat.com> <560C32CC.90708@cloudius-systems.com> From: Vlad Zolotarov Message-ID: <560C33C1.7030202@cloudius-systems.com> Date: Wed, 30 Sep 2015 22:10:57 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.1.0 MIME-Version: 1.0 In-Reply-To: <560C32CC.90708@cloudius-systems.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Cc: "dev@dpdk.org" Subject: Re: [dpdk-dev] Having troubles binding an SR-IOV VF to uio_pci_generic on Amazon instance X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 30 Sep 2015 19:10:59 -0000 On 09/30/15 22:06, Vlad Zolotarov wrote: > > > On 09/30/15 21:55, Michael S. Tsirkin wrote: >> On Wed, Sep 30, 2015 at 09:15:56PM +0300, Vlad Zolotarov wrote: >>> >>> On 09/30/15 18:26, Michael S. Tsirkin wrote: >>>> On Wed, Sep 30, 2015 at 03:50:09PM +0300, Vlad Zolotarov wrote: >>>>> How not virtualizing iommu forces "all or nothing" approach? >>>> Looks like you can't limit an assigned device to only access part of >>>> guest memory that belongs to a given process. Either let it access >>>> all >>>> of guest memory ("all") or don't assign the device ("nothing"). >>> Ok. A question then: can u limit the assigned device to only access >>> part of >>> the guest memory even if iommu was virtualized? >> That's exactly what an iommu does - limit the device io access to >> memory. > > If it does - it will continue to do so with or without the patch and > if it doesn't (for any reason) it won't do it even without the patch. > So, again, the above (rhetorical) question stands. ;) > > I think Avi has already explained quite in detail why security is > absolutely a non issue in regard to this patch or in regard to UIO in > general. Security has to be enforced by some other means like iommu. > >> >>> How would iommu >>> virtualization change anything? >> Kernel can use an iommu to limit device access to memory of >> the controlling application. > > Ok, this is obvious but what it has to do with enabling using > MSI/MSI-X interrupts support in uio_pci_generic? kernel may continue > to limit the above access with this support as well. > >> >>> And why do we care about an assigned device >>> to be able to access all Guest memory? >> Because we want to be reasonably sure a kernel memory corruption >> is not a result of a bug in a userspace application. > > Corrupting Guest's memory due to any SW misbehavior (including bugs) > is a non-issue by design - this is what HV and Guest machines were > invented for. So, like Avi also said, instead of trying to enforce > nobody cares about Let me rephrase: by pretending enforcing some security promise that u don't actually fulfill... ;) > we'd rather make the developers life easier instead (by applying the > not-yet-completed patch I'm working on). >> >