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From: Jason Gunthorpe <jgg@nvidia.com>
To: Yan Zhao <yan.y.zhao@intel.com>
Cc: iommu@lists.linux.dev, kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org, alex.williamson@redhat.com,
	pbonzini@redhat.com, seanjc@google.com, joro@8bytes.org,
	will@kernel.org, robin.murphy@arm.com, kevin.tian@intel.com,
	baolu.lu@linux.intel.com, dwmw2@infradead.org,
	yi.l.liu@intel.com
Subject: Re: [RFC PATCH 11/42] iommu: Add new domain op cache_invalidate_kvm
Date: Tue, 5 Dec 2023 10:52:27 -0400	[thread overview]
Message-ID: <20231205145227.GD2787277@nvidia.com> (raw)
In-Reply-To: <ZW7F3AJZe7vrqzcy@yzhao56-desk.sh.intel.com>

On Tue, Dec 05, 2023 at 02:40:28PM +0800, Yan Zhao wrote:
> On Mon, Dec 04, 2023 at 11:09:45AM -0400, Jason Gunthorpe wrote:
> > On Sat, Dec 02, 2023 at 05:20:41PM +0800, Yan Zhao wrote:
> > > On KVM invalidates mappings that are shared to IOMMU stage 2 paging
> > > structures, IOMMU driver needs to invalidate hardware TLBs accordingly.
> > > 
> > > The new op cache_invalidate_kvm is called from IOMMUFD to invalidate
> > > hardware TLBs upon receiving invalidation notifications from KVM.
> > 
> > Why?
> > 
> > SVA hooks the invalidation directly to the mm, shouldn't KVM also hook
> > the invalidation directly from the kvm? Why do we need to call a chain
> > of function pointers? iommufd isn't adding any value in the chain
> > here.
> Do you prefer IOMMU vendor driver to register as importer to KVM directly?
> Then IOMMUFD just passes "struct kvm_tdp_fd" to IOMMU vendor driver for domain
> creation.

Yes, this is what we did for SVA

Function pointers are slow these days, so it is preferred to go
directly.

Jason

  reply	other threads:[~2023-12-05 14:52 UTC|newest]

Thread overview: 73+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-12-02  9:12 [RFC PATCH 00/42] Sharing KVM TDP to IOMMU Yan Zhao
2023-12-02  9:13 ` [RFC PATCH 01/42] KVM: Public header for KVM to export TDP Yan Zhao
2023-12-02  9:15 ` [RFC PATCH 02/42] KVM: x86: Arch header for kvm to export TDP for Intel Yan Zhao
2023-12-02  9:15 ` [RFC PATCH 03/42] KVM: Introduce VM ioctl KVM_CREATE_TDP_FD Yan Zhao
2023-12-02  9:16 ` [RFC PATCH 04/42] KVM: Skeleton of KVM TDP FD object Yan Zhao
2023-12-02  9:16 ` [RFC PATCH 05/42] KVM: Embed "arch" object and call arch init/destroy in TDP FD Yan Zhao
2023-12-02  9:17 ` [RFC PATCH 06/42] KVM: Register/Unregister importers to KVM exported TDP Yan Zhao
2023-12-02  9:18 ` [RFC PATCH 07/42] KVM: Forward page fault requests to arch specific code for " Yan Zhao
2023-12-02  9:18 ` [RFC PATCH 08/42] KVM: Add a helper to notify importers that KVM exported TDP is flushed Yan Zhao
2023-12-02  9:19 ` [RFC PATCH 09/42] iommu: Add IOMMU_DOMAIN_KVM Yan Zhao
2023-12-02  9:20 ` [RFC PATCH 10/42] iommu: Add new iommu op to create domains managed by KVM Yan Zhao
2023-12-04 15:09   ` Jason Gunthorpe
2023-12-02  9:20 ` [RFC PATCH 11/42] iommu: Add new domain op cache_invalidate_kvm Yan Zhao
2023-12-04 15:09   ` Jason Gunthorpe
2023-12-05  6:40     ` Yan Zhao
2023-12-05 14:52       ` Jason Gunthorpe [this message]
2023-12-06  1:00         ` Yan Zhao
2023-12-02  9:21 ` [RFC PATCH 12/42] iommufd: Introduce allocation data info and flag for KVM managed HWPT Yan Zhao
2023-12-04 18:29   ` Jason Gunthorpe
2023-12-05  7:08     ` Yan Zhao
2023-12-05 14:53       ` Jason Gunthorpe
2023-12-06  0:58         ` Yan Zhao
2023-12-02  9:21 ` [RFC PATCH 13/42] iommufd: Add a KVM HW pagetable object Yan Zhao
2023-12-02  9:22 ` [RFC PATCH 14/42] iommufd: Enable KVM HW page table object to be proxy between KVM and IOMMU Yan Zhao
2023-12-04 18:34   ` Jason Gunthorpe
2023-12-05  7:09     ` Yan Zhao
2023-12-02  9:22 ` [RFC PATCH 15/42] iommufd: Add iopf handler to KVM hw pagetable Yan Zhao
2023-12-02  9:23 ` [RFC PATCH 16/42] iommufd: Enable device feature IOPF during device attachment to KVM HWPT Yan Zhao
2023-12-04 18:36   ` Jason Gunthorpe
2023-12-05  7:14     ` Yan Zhao
2023-12-05 14:53       ` Jason Gunthorpe
2023-12-06  0:55         ` Yan Zhao
2023-12-02  9:23 ` [RFC PATCH 17/42] iommu/vt-d: Make some macros and helpers to be extern Yan Zhao
2023-12-02  9:24 ` [RFC PATCH 18/42] iommu/vt-d: Support of IOMMU_DOMAIN_KVM domain in Intel IOMMU Yan Zhao
2023-12-02  9:24 ` [RFC PATCH 19/42] iommu/vt-d: Set bit PGSNP in PASIDTE if domain cache coherency is enforced Yan Zhao
2023-12-02  9:25 ` [RFC PATCH 20/42] iommu/vt-d: Support attach devices to IOMMU_DOMAIN_KVM domain Yan Zhao
2023-12-02  9:26 ` [RFC PATCH 21/42] iommu/vt-d: Check reserved bits for " Yan Zhao
2023-12-02  9:26 ` [RFC PATCH 22/42] iommu/vt-d: Support cache invalidate of " Yan Zhao
2023-12-02  9:26 ` [RFC PATCH 23/42] iommu/vt-d: Allow pasid 0 in IOPF Yan Zhao
2023-12-02  9:27 ` [RFC PATCH 24/42] KVM: x86/mmu: Move bit SPTE_MMU_PRESENT from bit 11 to bit 59 Yan Zhao
2023-12-02  9:27 ` [RFC PATCH 25/42] KVM: x86/mmu: Abstract "struct kvm_mmu_common" from "struct kvm_mmu" Yan Zhao
2023-12-02  9:28 ` [RFC PATCH 26/42] KVM: x86/mmu: introduce new op get_default_mt_mask to kvm_x86_ops Yan Zhao
2023-12-02  9:28 ` [RFC PATCH 27/42] KVM: x86/mmu: change param "vcpu" to "kvm" in kvm_mmu_hugepage_adjust() Yan Zhao
2023-12-02  9:29 ` [RFC PATCH 28/42] KVM: x86/mmu: change "vcpu" to "kvm" in page_fault_handle_page_track() Yan Zhao
2023-12-02  9:29 ` [RFC PATCH 29/42] KVM: x86/mmu: remove param "vcpu" from kvm_mmu_get_tdp_level() Yan Zhao
2023-12-02  9:30 ` [RFC PATCH 30/42] KVM: x86/mmu: remove param "vcpu" from kvm_calc_tdp_mmu_root_page_role() Yan Zhao
2023-12-02  9:30 ` [RFC PATCH 31/42] KVM: x86/mmu: add extra param "kvm" to kvm_faultin_pfn() Yan Zhao
2023-12-02  9:31 ` [RFC PATCH 32/42] KVM: x86/mmu: add extra param "kvm" to make_mmio_spte() Yan Zhao
2023-12-02  9:31 ` [RFC PATCH 33/42] KVM: x86/mmu: add extra param "kvm" to make_spte() Yan Zhao
2023-12-02  9:32 ` [RFC PATCH 34/42] KVM: x86/mmu: add extra param "kvm" to tdp_mmu_map_handle_target_level() Yan Zhao
2023-12-02  9:32 ` [RFC PATCH 35/42] KVM: x86/mmu: Get/Put TDP root page to be exported Yan Zhao
2023-12-02  9:33 ` [RFC PATCH 36/42] KVM: x86/mmu: Keep exported TDP root valid Yan Zhao
2023-12-02  9:33 ` [RFC PATCH 37/42] KVM: x86: Implement KVM exported TDP fault handler on x86 Yan Zhao
2023-12-02  9:35 ` [RFC PATCH 38/42] KVM: x86: "compose" and "get" interface for meta data of exported TDP Yan Zhao
2023-12-02  9:35 ` [RFC PATCH 39/42] KVM: VMX: add config KVM_INTEL_EXPORTED_EPT Yan Zhao
2023-12-02  9:36 ` [RFC PATCH 40/42] KVM: VMX: Compose VMX specific meta data for KVM exported TDP Yan Zhao
2023-12-02  9:36 ` [RFC PATCH 41/42] KVM: VMX: Implement ops .flush_remote_tlbs* in VMX when EPT is on Yan Zhao
2023-12-02  9:37 ` [RFC PATCH 42/42] KVM: VMX: Notify importers of exported TDP to flush TLBs on KVM flushes EPT Yan Zhao
2023-12-04 15:08 ` [RFC PATCH 00/42] Sharing KVM TDP to IOMMU Jason Gunthorpe
2023-12-04 16:38   ` Sean Christopherson
2023-12-05  1:31     ` Yan Zhao
2023-12-05  6:45       ` Tian, Kevin
2023-12-05  1:52   ` Yan Zhao
2023-12-05  6:30   ` Tian, Kevin
2023-12-04 17:00 ` Sean Christopherson
2023-12-04 17:30   ` Jason Gunthorpe
2023-12-04 19:22     ` Sean Christopherson
2023-12-04 19:50       ` Jason Gunthorpe
2023-12-04 20:11         ` Sean Christopherson
2023-12-04 23:49           ` Jason Gunthorpe
2023-12-05  7:17         ` Tian, Kevin
2023-12-05  5:53       ` Yan Zhao
2023-12-05  3:51   ` Yan Zhao

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