From: Catalin Marinas <catalin.marinas@arm.com>
To: Marc Zyngier <maz@kernel.org>
Cc: Jason Gunthorpe <jgg@nvidia.com>,
ankita@nvidia.com,
Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>,
oliver.upton@linux.dev, suzuki.poulose@arm.com,
yuzenghui@huawei.com, will@kernel.org, ardb@kernel.org,
akpm@linux-foundation.org, gshan@redhat.com, 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, mochs@nvidia.com,
kvmarm@lists.linux.dev, kvm@vger.kernel.org,
lpieralisi@kernel.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 1/1] KVM: arm64: allow the VM to select DEVICE_* and NORMAL_NC for IO memory
Date: Tue, 5 Dec 2023 17:33:01 +0000 [thread overview]
Message-ID: <ZW9ezSGSDIvv5MsQ@arm.com> (raw)
In-Reply-To: <86bkb4bn2v.wl-maz@kernel.org>
On Tue, Dec 05, 2023 at 05:01:28PM +0000, Marc Zyngier wrote:
> On Tue, 05 Dec 2023 16:43:18 +0000,
> Jason Gunthorpe <jgg@nvidia.com> wrote:
> > On Tue, Dec 05, 2023 at 04:22:33PM +0000, Catalin Marinas wrote:
> > > That's an argument to restrict this feature to PCIe. It's really about
> > > fewer arguments on the behaviour of other devices. Marc did raise
> > > another issue with the GIC VCPU interface (does this even have a vma in
> > > the host VMM?). That's a class of devices where the mapping is
> > > context-switched, so the TLBI+DSB rules don't help.
>
> There is no vma. The CPU interface is entirely under control of KVM.
> Userspace only provides the IPA for the mapping.
That's good to know. We can solve the GIC issue by limiting the
relaxation to those mappings that have a user vma. Ideally we should do
this for vfio only but we don't have an easy way to convey this to KVM.
--
Catalin
WARNING: multiple messages have this Message-ID (diff)
From: Catalin Marinas <catalin.marinas@arm.com>
To: Marc Zyngier <maz@kernel.org>
Cc: Jason Gunthorpe <jgg@nvidia.com>,
ankita@nvidia.com,
Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>,
oliver.upton@linux.dev, suzuki.poulose@arm.com,
yuzenghui@huawei.com, will@kernel.org, ardb@kernel.org,
akpm@linux-foundation.org, gshan@redhat.com, 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, mochs@nvidia.com,
kvmarm@lists.linux.dev, kvm@vger.kernel.org,
lpieralisi@kernel.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 1/1] KVM: arm64: allow the VM to select DEVICE_* and NORMAL_NC for IO memory
Date: Tue, 5 Dec 2023 17:33:01 +0000 [thread overview]
Message-ID: <ZW9ezSGSDIvv5MsQ@arm.com> (raw)
In-Reply-To: <86bkb4bn2v.wl-maz@kernel.org>
On Tue, Dec 05, 2023 at 05:01:28PM +0000, Marc Zyngier wrote:
> On Tue, 05 Dec 2023 16:43:18 +0000,
> Jason Gunthorpe <jgg@nvidia.com> wrote:
> > On Tue, Dec 05, 2023 at 04:22:33PM +0000, Catalin Marinas wrote:
> > > That's an argument to restrict this feature to PCIe. It's really about
> > > fewer arguments on the behaviour of other devices. Marc did raise
> > > another issue with the GIC VCPU interface (does this even have a vma in
> > > the host VMM?). That's a class of devices where the mapping is
> > > context-switched, so the TLBI+DSB rules don't help.
>
> There is no vma. The CPU interface is entirely under control of KVM.
> Userspace only provides the IPA for the mapping.
That's good to know. We can solve the GIC issue by limiting the
relaxation to those mappings that have a user vma. Ideally we should do
this for vfio only but we don't have an easy way to convey this to KVM.
--
Catalin
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2023-12-05 17:33 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-05 3:30 [PATCH v2 1/1] KVM: arm64: allow the VM to select DEVICE_* and NORMAL_NC for IO memory ankita
2023-12-05 3:30 ` ankita
2023-12-05 9:21 ` Marc Zyngier
2023-12-05 9:21 ` Marc Zyngier
2023-12-05 11:40 ` Catalin Marinas
2023-12-05 11:40 ` Catalin Marinas
2023-12-05 13:05 ` Jason Gunthorpe
2023-12-05 13:05 ` Jason Gunthorpe
2023-12-05 14:37 ` Lorenzo Pieralisi
2023-12-05 14:37 ` Lorenzo Pieralisi
2023-12-05 14:44 ` Jason Gunthorpe
2023-12-05 14:44 ` Jason Gunthorpe
2023-12-05 16:24 ` Catalin Marinas
2023-12-05 16:24 ` Catalin Marinas
2023-12-05 17:10 ` Jason Gunthorpe
2023-12-05 17:10 ` Jason Gunthorpe
2023-12-05 16:22 ` Catalin Marinas
2023-12-05 16:22 ` Catalin Marinas
2023-12-05 16:43 ` Jason Gunthorpe
2023-12-05 16:43 ` Jason Gunthorpe
2023-12-05 17:01 ` Marc Zyngier
2023-12-05 17:01 ` Marc Zyngier
2023-12-05 17:33 ` Catalin Marinas [this message]
2023-12-05 17:33 ` Catalin Marinas
2023-12-05 17:50 ` Marc Zyngier
2023-12-05 17:50 ` Marc Zyngier
2023-12-05 18:40 ` Catalin Marinas
2023-12-05 18:40 ` Catalin Marinas
2023-12-06 11:39 ` Marc Zyngier
2023-12-06 11:39 ` Marc Zyngier
2023-12-06 12:14 ` Catalin Marinas
2023-12-06 12:14 ` Catalin Marinas
2023-12-06 15:16 ` Jason Gunthorpe
2023-12-06 15:16 ` Jason Gunthorpe
2023-12-06 16:31 ` Catalin Marinas
2023-12-06 16:31 ` Catalin Marinas
2023-12-06 17:20 ` Jason Gunthorpe
2023-12-06 17:20 ` Jason Gunthorpe
2023-12-06 18:58 ` Catalin Marinas
2023-12-06 18:58 ` Catalin Marinas
2023-12-06 19:03 ` Jason Gunthorpe
2023-12-06 19:03 ` Jason Gunthorpe
2023-12-06 19:06 ` Catalin Marinas
2023-12-06 19:06 ` Catalin Marinas
2023-12-07 2:53 ` Ankit Agrawal
2023-12-07 2:53 ` Ankit Agrawal
2023-12-06 11:52 ` Lorenzo Pieralisi
2023-12-06 11:52 ` Lorenzo Pieralisi
2023-12-05 19:24 ` Catalin Marinas
2023-12-05 19:24 ` Catalin Marinas
2023-12-05 19:48 ` Jason Gunthorpe
2023-12-05 19:48 ` Jason Gunthorpe
2023-12-06 14:49 ` Catalin Marinas
2023-12-06 14:49 ` Catalin Marinas
2023-12-06 15:05 ` Jason Gunthorpe
2023-12-06 15:05 ` Jason Gunthorpe
2023-12-06 15:18 ` Lorenzo Pieralisi
2023-12-06 15:18 ` Lorenzo Pieralisi
2023-12-06 15:38 ` Jason Gunthorpe
2023-12-06 15:38 ` Jason Gunthorpe
2023-12-06 16:23 ` Catalin Marinas
2023-12-06 16:23 ` Catalin Marinas
2023-12-06 16:48 ` Jason Gunthorpe
2023-12-06 16:48 ` Jason Gunthorpe
2023-12-07 10:13 ` Lorenzo Pieralisi
2023-12-07 10:13 ` Lorenzo Pieralisi
2023-12-07 13:38 ` Jason Gunthorpe
2023-12-07 13:38 ` Jason Gunthorpe
2023-12-07 14:50 ` Lorenzo Pieralisi
2023-12-07 14:50 ` Lorenzo Pieralisi
2023-12-05 13:28 ` Lorenzo Pieralisi
2023-12-05 13:28 ` Lorenzo Pieralisi
2023-12-05 14:16 ` Shameerali Kolothum Thodi
2023-12-05 14:16 ` Shameerali Kolothum Thodi
2023-12-06 8:17 ` Shameerali Kolothum Thodi
2023-12-06 8:17 ` Shameerali Kolothum Thodi
2023-12-05 11:48 ` Catalin Marinas
2023-12-05 11:48 ` Catalin Marinas
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=ZW9ezSGSDIvv5MsQ@arm.com \
--to=catalin.marinas@arm.com \
--cc=acurrid@nvidia.com \
--cc=akpm@linux-foundation.org \
--cc=aniketa@nvidia.com \
--cc=ankita@nvidia.com \
--cc=apopple@nvidia.com \
--cc=ardb@kernel.org \
--cc=cjia@nvidia.com \
--cc=danw@nvidia.com \
--cc=gshan@redhat.com \
--cc=jgg@nvidia.com \
--cc=jhubbard@nvidia.com \
--cc=kvm@vger.kernel.org \
--cc=kvmarm@lists.linux.dev \
--cc=kwankhede@nvidia.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=lpieralisi@kernel.org \
--cc=maz@kernel.org \
--cc=mochs@nvidia.com \
--cc=oliver.upton@linux.dev \
--cc=shameerali.kolothum.thodi@huawei.com \
--cc=suzuki.poulose@arm.com \
--cc=targupta@nvidia.com \
--cc=vsethi@nvidia.com \
--cc=will@kernel.org \
--cc=yuzenghui@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.