From: Jason Gunthorpe <jgg@ziepe.ca>
To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>
Cc: "kvmarm@lists.linux.dev" <kvmarm@lists.linux.dev>,
"iommu@lists.linux.dev" <iommu@lists.linux.dev>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
Linuxarm <linuxarm@huawei.com>,
"kevin.tian@intel.com" <kevin.tian@intel.com>,
"alex.williamson@redhat.com" <alex.williamson@redhat.com>,
"maz@kernel.org" <maz@kernel.org>,
"oliver.upton@linux.dev" <oliver.upton@linux.dev>,
"will@kernel.org" <will@kernel.org>,
"robin.murphy@arm.com" <robin.murphy@arm.com>,
"nicolinc@nvidia.com" <nicolinc@nvidia.com>,
"jean-philippe@linaro.org" <jean-philippe@linaro.org>,
Jonathan Cameron <jonathan.cameron@huawei.com>
Subject: Re: [RFC PATCH v3 4/5] iommu/arm-smmu-v3-iommufd: Use KVM VMID for s2 stage
Date: Thu, 20 Mar 2025 09:27:19 -0300 [thread overview]
Message-ID: <20250320122719.GI126678@ziepe.ca> (raw)
In-Reply-To: <f654ae10e55e4142acb83eb926bb80b2@huawei.com>
On Thu, Mar 20, 2025 at 09:30:45AM +0000, Shameerali Kolothum Thodi wrote:
> > Isn't kvm_get_kvm_safe() in modular KVM code most of the time? You can't
> > call it like this right?
>
> I think it is safe since KVM is not modular for ARM64. And that is one of the
> reasons I thought I will hold the KVM reference here as we don't have to go
> through the symbol_get/put calls here. Also IOMMUFD is not using the kvm
> pointer at the moment. Probably I should add some comments in IOMMUFD
> to make it clear.
Oh I didn't know that.. Interesting simplification
> > That more closely matches how this will eventually work when the VMID
> > allocation is properly made to be local to the viommu.
>
> Ok. Will update.
You should also block creating a VIOMMU without a KVM for the same
reason.. Really isolate the S2 to only being usable with the KVM
shared VMID.
Jason
next prev parent reply other threads:[~2025-03-20 12:27 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-19 17:31 [RFC PATCH v3 0/5] iommu/arm-smmu-v3: Use pinned KVM VMID for stage 2 Shameer Kolothum
2025-03-19 17:31 ` [RFC PATCH v3 1/5] KVM: arm64: Introduce support to pin VMIDs Shameer Kolothum
2025-03-19 17:31 ` [RFC PATCH v3 2/5] iommufd/device: Associate a kvm pointer to iommufd_device Shameer Kolothum
2025-03-19 23:28 ` Jason Gunthorpe
2025-03-19 17:32 ` [RFC PATCH v3 3/5] iommu/arm-smmu-v3-iommufd: Pass in kvm pointer to viommu_alloc Shameer Kolothum
2025-03-19 23:31 ` Jason Gunthorpe
2025-03-19 17:32 ` [RFC PATCH v3 4/5] iommu/arm-smmu-v3-iommufd: Use KVM VMID for s2 stage Shameer Kolothum
2025-03-19 23:39 ` Jason Gunthorpe
2025-03-20 9:30 ` Shameerali Kolothum Thodi
2025-03-20 12:27 ` Jason Gunthorpe [this message]
2025-03-19 17:32 ` [RFC PATCH v3 5/5] iommu/arm-smmu-v3: Enable broadcast TLB maintenance Shameer Kolothum
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