From: Sean Christopherson <seanjc@google.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: Yan Zhao <yan.y.zhao@intel.com>,
iommu@lists.linux.dev, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org, alex.williamson@redhat.com,
pbonzini@redhat.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 00/42] Sharing KVM TDP to IOMMU
Date: Mon, 4 Dec 2023 12:11:46 -0800 [thread overview]
Message-ID: <ZW4ygoqOq2JpXml3@google.com> (raw)
In-Reply-To: <20231204195055.GA2692119@nvidia.com>
On Mon, Dec 04, 2023, Jason Gunthorpe wrote:
> On Mon, Dec 04, 2023 at 11:22:49AM -0800, Sean Christopherson wrote:
> > I'm not suggesting full blown mirroring, all I'm suggesting is a fire-and-forget
> > notifier for KVM to tell IOMMUFD "I've faulted in GFN A, you might want to do the
> > same".
>
> If we say the only thing this works with is the memfd version of KVM,
That's likely a big "if", as guest_memfd is not and will not be a wholesale
replacement of VMA-based guest memory, at least not in the forseeable future.
I would be quite surprised if the target use cases for this could be moved to
guest_memfd without losing required functionality.
> could we design the memfd stuff to not have the same challenges with
> mirroring as normal VMAs?
What challenges in particular are you concerned about? And maybe also define
"mirroring"? E.g. ensuring that the CPU and IOMMU page tables are synchronized
is very different than ensuring that the IOMMU page tables can only map memory
that is mappable by the guest, i.e. that KVM can map into the CPU page tables.
next prev parent reply other threads:[~2023-12-04 20:11 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
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 [this message]
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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