linux-kernel - Re: [PATCH v4 0/6] virtio core DMA API conversion

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 10 Nov 2015 20:46:57 -0800
From:	Andy Lutomirski <luto@...capital.net>
To:	Benjamin Herrenschmidt <benh@...nel.crashing.org>
Cc:	Christian Borntraeger <borntraeger@...ibm.com>,
	David Woodhouse <dwmw2@...radead.org>,
	Paolo Bonzini <pbonzini@...hat.com>,
	Martin Schwidefsky <schwidefsky@...ibm.com>,
	"Michael S. Tsirkin" <mst@...hat.com>,
	"David S. Miller" <davem@...emloft.net>,
	Sebastian Ott <sebott@...ux.vnet.ibm.com>,
	linux-s390 <linux-s390@...r.kernel.org>,
	Joerg Roedel <jroedel@...e.de>,
	Cornelia Huck <cornelia.huck@...ibm.com>,
	KVM <kvm@...r.kernel.org>, Christoph Hellwig <hch@....de>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Linux Virtualization <virtualization@...ts.linux-foundation.org>,
	sparclinux@...r.kernel.org
Subject: Re: [PATCH v4 0/6] virtio core DMA API conversion

On Nov 10, 2015 4:44 PM, "Benjamin Herrenschmidt"
<benh@...nel.crashing.org> wrote:
>
> On Tue, 2015-11-10 at 15:44 -0800, Andy Lutomirski wrote:
> >
> > > What about partition <-> partition virtio such as what we could do on
> > > PAPR systems. That would have the weak barrier bit.
> > >
> >
> > Is it partition <-> partition, bypassing IOMMU?
>
> No.
>
> > I think I'd settle for just something that doesn't regress
> > non-experimental setups that actually work today and that allow new
> > setups (x86 with fixed QEMU and maybe something more complicated on
> > powerpc and/or sparc) to work in all cases.
> >
> > We could certainly just make powerpc and sparc continue bypassing the
> > IOMMU until someone comes up with a way to fix it.  I'll send out some
> > patches that do that, and maybe that'll help this make progress.
>
> But we haven't found a solution that works. All we have come up with is
> a quirk that will force bypass on virtio always and will not allow us
> to operate non-bypassing devices on either of those architectures in
> the future.
>
> I'm not too happy about this.

Me neither.  At least it wouldn't be a regression, but it's still crappy.

I think that arm is fine, at least.  I was unable to find an arm QEMU
config that has any problems with my patches.

--Andy
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/