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
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next prev parent reply other threads:[~2023-12-05 17:33 UTC|newest]
Thread overview: 39+ 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 9:21 ` Marc Zyngier
2023-12-05 11:40 ` Catalin Marinas
2023-12-05 13:05 ` Jason Gunthorpe
2023-12-05 14:37 ` Lorenzo Pieralisi
2023-12-05 14:44 ` Jason Gunthorpe
2023-12-05 16:24 ` Catalin Marinas
2023-12-05 17:10 ` Jason Gunthorpe
2023-12-05 16:22 ` Catalin Marinas
2023-12-05 16:43 ` Jason Gunthorpe
2023-12-05 17:01 ` Marc Zyngier
2023-12-05 17:33 ` Catalin Marinas [this message]
2023-12-05 17:50 ` Marc Zyngier
2023-12-05 18:40 ` Catalin Marinas
2023-12-06 11:39 ` Marc Zyngier
2023-12-06 12:14 ` Catalin Marinas
2023-12-06 15:16 ` Jason Gunthorpe
2023-12-06 16:31 ` Catalin Marinas
2023-12-06 17:20 ` Jason Gunthorpe
2023-12-06 18:58 ` Catalin Marinas
2023-12-06 19:03 ` Jason Gunthorpe
2023-12-06 19:06 ` Catalin Marinas
2023-12-07 2:53 ` Ankit Agrawal
2023-12-06 11:52 ` Lorenzo Pieralisi
2023-12-05 19:24 ` Catalin Marinas
2023-12-05 19:48 ` Jason Gunthorpe
2023-12-06 14:49 ` Catalin Marinas
2023-12-06 15:05 ` Jason Gunthorpe
2023-12-06 15:18 ` Lorenzo Pieralisi
2023-12-06 15:38 ` Jason Gunthorpe
2023-12-06 16:23 ` Catalin Marinas
2023-12-06 16:48 ` Jason Gunthorpe
2023-12-07 10:13 ` Lorenzo Pieralisi
2023-12-07 13:38 ` Jason Gunthorpe
2023-12-07 14:50 ` Lorenzo Pieralisi
2023-12-05 13:28 ` Lorenzo Pieralisi
2023-12-05 14:16 ` Shameerali Kolothum Thodi
2023-12-06 8:17 ` Shameerali Kolothum Thodi
2023-12-05 11:48 ` Catalin Marinas
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