From: Lorenzo Pieralisi <lpieralisi@kernel.org>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>, Jason Gunthorpe <jgg@nvidia.com>,
ankita@nvidia.com, maz@kernel.org, oliver.upton@linux.dev,
aniketa@nvidia.com, cjia@nvidia.com, kwankhede@nvidia.com,
targupta@nvidia.com, vsethi@nvidia.com, acurrid@nvidia.com,
apopple@nvidia.com, jhubbard@nvidia.com, danw@nvidia.com,
linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1 2/2] KVM: arm64: allow the VM to select DEVICE_* and NORMAL_NC for IO memory
Date: Fri, 13 Oct 2023 17:28:10 +0200 [thread overview]
Message-ID: <ZSliChc3poZNM4f9@lpieralisi> (raw)
In-Reply-To: <ZSlBOiebenPKXBY4@arm.com>
On Fri, Oct 13, 2023 at 02:08:10PM +0100, Catalin Marinas wrote:
[...]
> Yes, we end up with mismatched aliases but they only matter if the VMM
> also accesses the I/O range via its own mapping. So far I haven't seen
> case that suggests this.
>
> > > Things can go wrong but that's not because Device does anything better.
> > > Given the RAS implementation, external aborts caused on Device memory
> > > (e.g. wrong size access) is uncontainable. For Normal NC it can be
> > > contained (I can dig out the reasoning behind this if you want, IIUC
> > > something to do with not being able to cancel an already issued Device
> > > access since such accesses don't allow speculation due to side-effects;
> > > for Normal NC, it's just about the software not getting the data).
> >
> > I really think these details belong in the commit message.
>
> I guess another task for Lorenzo ;).
I will do, I start wondering though whether this documentation belongs
in this commit log only or at Documentation/arch/arm64 level (or both),
I am pretty sure this thread can turn out quite useful as a reference
(it is for me) if we manage to summarize it that would benefit
everyone.
Lorenzo
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next prev parent reply other threads:[~2023-10-13 15:28 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-07 18:14 [PATCH v1 0/2] KVM: arm64: support write combining and cachable IO memory in VMs ankita
2023-09-07 18:14 ` [PATCH v1 1/2] KVM: arm64: determine memory type from VMA ankita
2023-09-07 19:12 ` Jason Gunthorpe
2023-10-05 16:15 ` Catalin Marinas
2023-10-05 16:54 ` Jason Gunthorpe
2023-10-10 14:25 ` Catalin Marinas
2023-10-10 15:05 ` Jason Gunthorpe
2023-10-10 17:19 ` Catalin Marinas
2023-10-10 18:23 ` Jason Gunthorpe
2023-10-11 17:45 ` Catalin Marinas
2023-10-11 18:38 ` Jason Gunthorpe
2023-10-12 16:16 ` Catalin Marinas
2024-03-10 3:49 ` Ankit Agrawal
2024-03-19 13:38 ` Jason Gunthorpe
2023-10-23 13:20 ` Shameerali Kolothum Thodi
2023-09-07 18:14 ` [PATCH v1 2/2] KVM: arm64: allow the VM to select DEVICE_* and NORMAL_NC for IO memory ankita
2023-09-08 16:40 ` Catalin Marinas
2023-09-11 14:57 ` Lorenzo Pieralisi
2023-09-11 17:20 ` Jason Gunthorpe
2023-09-13 15:26 ` Lorenzo Pieralisi
2023-09-13 18:54 ` Jason Gunthorpe
2023-09-26 8:31 ` Lorenzo Pieralisi
2023-09-26 12:25 ` Jason Gunthorpe
2023-09-26 13:52 ` Catalin Marinas
2023-09-26 16:12 ` Lorenzo Pieralisi
2023-10-05 9:56 ` Lorenzo Pieralisi
2023-10-05 11:56 ` Jason Gunthorpe
2023-10-05 14:08 ` Lorenzo Pieralisi
2023-10-12 12:35 ` Will Deacon
2023-10-12 13:20 ` Jason Gunthorpe
2023-10-12 14:29 ` Lorenzo Pieralisi
2023-10-12 13:53 ` Catalin Marinas
2023-10-12 14:48 ` Will Deacon
2023-10-12 15:44 ` Jason Gunthorpe
2023-10-12 16:39 ` Will Deacon
2023-10-12 18:36 ` Jason Gunthorpe
2023-10-13 9:29 ` Will Deacon
2023-10-12 17:26 ` Catalin Marinas
2023-10-13 9:29 ` Will Deacon
2023-10-13 13:08 ` Catalin Marinas
2023-10-13 13:45 ` Jason Gunthorpe
2023-10-19 11:07 ` Catalin Marinas
2023-10-19 11:51 ` Jason Gunthorpe
2023-10-20 11:21 ` Catalin Marinas
2023-10-20 11:47 ` Jason Gunthorpe
2023-10-20 14:03 ` Lorenzo Pieralisi
2023-10-20 14:28 ` Jason Gunthorpe
2023-10-19 13:35 ` Lorenzo Pieralisi
2023-10-13 15:28 ` Lorenzo Pieralisi [this message]
2023-10-19 11:12 ` Catalin Marinas
2023-11-09 15:34 ` Lorenzo Pieralisi
2023-11-10 14:26 ` Jason Gunthorpe
2023-11-13 0:42 ` Lorenzo Pieralisi
2023-11-13 17:41 ` Catalin Marinas
2023-10-12 12:27 ` Will Deacon
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