From: Ankit Agrawal <ankita@nvidia.com> To: Catalin Marinas <catalin.marinas@arm.com>, Jason Gunthorpe <jgg@nvidia.com> Cc: "maz@kernel.org" <maz@kernel.org>, "oliver.upton@linux.dev" <oliver.upton@linux.dev>, "will@kernel.org" <will@kernel.org>, Aniket Agashe <aniketa@nvidia.com>, Neo Jia <cjia@nvidia.com>, Kirti Wankhede <kwankhede@nvidia.com>, "Tarun Gupta (SW-GPU)" <targupta@nvidia.com>, Vikram Sethi <vsethi@nvidia.com>, Andy Currid <acurrid@nvidia.com>, Alistair Popple <apopple@nvidia.com>, John Hubbard <jhubbard@nvidia.com>, Dan Williams <danw@nvidia.com>, "linux-arm-kernel@lists.infradead.org" <linux-arm-kernel@lists.infradead.org>, "kvmarm@lists.linux.dev" <kvmarm@lists.linux.dev>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org> Subject: Re: [PATCH v1 1/2] KVM: arm64: determine memory type from VMA Date: Sun, 10 Mar 2024 03:49:36 +0000 [thread overview] Message-ID: <SA1PR12MB7199AB860E0C76B80B421C66B0252@SA1PR12MB7199.namprd12.prod.outlook.com> (raw) In-Reply-To: <ZSgb0WBSsXHHYJT0@arm.com> Bringing this to the fore. >> Where does that leave us for this patch? We check the VM_MTE_ALLOWED >> and check for ZONE_MOVABLE struct pages as one of the conditions for >> NORMAL? > > I think we should keep it as simple as possible and, looking at it > again, maybe even ignore vm_page_prot. Two questions though: > > 1. Does VM_IO imply vm_page_prot never having MT_NORMAL or > MT_NORMAL_TAGGED? > > 2. Do all I/O ranges (side-effects, non-RAM) mapped into a guest (and > which end up in user_mem_abort()) imply VM_IO? > > If yes to both, I think something like below would do: How may we get the answer to these? It seems to be the logical behavior, but how can we confirm? While we discuss on that, I am considering to send out the next version of this patch (incorporating the feedbacks on the thread) that is rebased to a commit inclusive of the recently applied KVM patch series: [KVM: arm64: Allow the VM to select DEVICE_* and NORMAL_NC for IO memory] https://lore.kernel.org/all/20240224150546.368-1-ankita@nvidia.com/ > mte_allowed = kvm_vma_mte_allowed(vma); > noncacheable = false; // or 'device' as in user_mem_abort() > ... > if (vma->flags & VM_IO) // replaces !pfn_is_map_memory() > noncacheable = true; > else if (!mte_allowed && kvm_has_mte()) > noncaheable = true; > ... > if (noncacheable) > prot |= KVM_PGTABLE_PROT_DEVICE; // or the new KVM_PGTABLE_PROT_NC > > mte_allowed would cover DAX mappings (and, who knows, some future DAX > mapping may allow MTE and the driver explicitly set the flag). Anything > else hot-plugged into ZONE_MOVABLE should have VM_MTE_ALLOWED set or > MTE disabled altogether. -- Catalin
WARNING: multiple messages have this Message-ID (diff)
From: Ankit Agrawal <ankita@nvidia.com> To: Catalin Marinas <catalin.marinas@arm.com>, Jason Gunthorpe <jgg@nvidia.com> Cc: "maz@kernel.org" <maz@kernel.org>, "oliver.upton@linux.dev" <oliver.upton@linux.dev>, "will@kernel.org" <will@kernel.org>, Aniket Agashe <aniketa@nvidia.com>, Neo Jia <cjia@nvidia.com>, Kirti Wankhede <kwankhede@nvidia.com>, "Tarun Gupta (SW-GPU)" <targupta@nvidia.com>, Vikram Sethi <vsethi@nvidia.com>, Andy Currid <acurrid@nvidia.com>, Alistair Popple <apopple@nvidia.com>, John Hubbard <jhubbard@nvidia.com>, Dan Williams <danw@nvidia.com>, "linux-arm-kernel@lists.infradead.org" <linux-arm-kernel@lists.infradead.org>, "kvmarm@lists.linux.dev" <kvmarm@lists.linux.dev>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org> Subject: Re: [PATCH v1 1/2] KVM: arm64: determine memory type from VMA Date: Sun, 10 Mar 2024 03:49:36 +0000 [thread overview] Message-ID: <SA1PR12MB7199AB860E0C76B80B421C66B0252@SA1PR12MB7199.namprd12.prod.outlook.com> (raw) In-Reply-To: <ZSgb0WBSsXHHYJT0@arm.com> Bringing this to the fore. >> Where does that leave us for this patch? We check the VM_MTE_ALLOWED >> and check for ZONE_MOVABLE struct pages as one of the conditions for >> NORMAL? > > I think we should keep it as simple as possible and, looking at it > again, maybe even ignore vm_page_prot. Two questions though: > > 1. Does VM_IO imply vm_page_prot never having MT_NORMAL or > MT_NORMAL_TAGGED? > > 2. Do all I/O ranges (side-effects, non-RAM) mapped into a guest (and > which end up in user_mem_abort()) imply VM_IO? > > If yes to both, I think something like below would do: How may we get the answer to these? It seems to be the logical behavior, but how can we confirm? While we discuss on that, I am considering to send out the next version of this patch (incorporating the feedbacks on the thread) that is rebased to a commit inclusive of the recently applied KVM patch series: [KVM: arm64: Allow the VM to select DEVICE_* and NORMAL_NC for IO memory] https://lore.kernel.org/all/20240224150546.368-1-ankita@nvidia.com/ > mte_allowed = kvm_vma_mte_allowed(vma); > noncacheable = false; // or 'device' as in user_mem_abort() > ... > if (vma->flags & VM_IO) // replaces !pfn_is_map_memory() > noncacheable = true; > else if (!mte_allowed && kvm_has_mte()) > noncaheable = true; > ... > if (noncacheable) > prot |= KVM_PGTABLE_PROT_DEVICE; // or the new KVM_PGTABLE_PROT_NC > > mte_allowed would cover DAX mappings (and, who knows, some future DAX > mapping may allow MTE and the driver explicitly set the flag). Anything > else hot-plugged into ZONE_MOVABLE should have VM_MTE_ALLOWED set or > MTE disabled altogether. -- 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:[~2024-03-10 3:49 UTC|newest] Thread overview: 110+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-09-07 18:14 [PATCH v1 0/2] KVM: arm64: support write combining and cachable IO memory in VMs ankita 2023-09-07 18:14 ` ankita 2023-09-07 18:14 ` [PATCH v1 1/2] KVM: arm64: determine memory type from VMA ankita 2023-09-07 18:14 ` ankita 2023-09-07 19:12 ` Jason Gunthorpe 2023-09-07 19:12 ` Jason Gunthorpe 2023-10-05 16:15 ` Catalin Marinas 2023-10-05 16:15 ` Catalin Marinas 2023-10-05 16:54 ` Jason Gunthorpe 2023-10-05 16:54 ` Jason Gunthorpe 2023-10-10 14:25 ` Catalin Marinas 2023-10-10 14:25 ` Catalin Marinas 2023-10-10 15:05 ` Jason Gunthorpe 2023-10-10 15:05 ` Jason Gunthorpe 2023-10-10 17:19 ` Catalin Marinas 2023-10-10 17:19 ` Catalin Marinas 2023-10-10 18:23 ` Jason Gunthorpe 2023-10-10 18:23 ` Jason Gunthorpe 2023-10-11 17:45 ` Catalin Marinas 2023-10-11 17:45 ` Catalin Marinas 2023-10-11 18:38 ` Jason Gunthorpe 2023-10-11 18:38 ` Jason Gunthorpe 2023-10-12 16:16 ` Catalin Marinas 2023-10-12 16:16 ` Catalin Marinas 2024-03-10 3:49 ` Ankit Agrawal [this message] 2024-03-10 3:49 ` Ankit Agrawal 2024-03-19 13:38 ` Jason Gunthorpe 2024-03-19 13:38 ` Jason Gunthorpe 2023-10-23 13:20 ` Shameerali Kolothum Thodi 2023-10-23 13:20 ` Shameerali Kolothum Thodi 2023-09-07 18:14 ` [PATCH v1 2/2] KVM: arm64: allow the VM to select DEVICE_* and NORMAL_NC for IO memory ankita 2023-09-07 18:14 ` ankita 2023-09-08 16:40 ` Catalin Marinas 2023-09-08 16:40 ` Catalin Marinas 2023-09-11 14:57 ` Lorenzo Pieralisi 2023-09-11 14:57 ` Lorenzo Pieralisi 2023-09-11 17:20 ` Jason Gunthorpe 2023-09-11 17:20 ` Jason Gunthorpe 2023-09-13 15:26 ` Lorenzo Pieralisi 2023-09-13 15:26 ` Lorenzo Pieralisi 2023-09-13 18:54 ` Jason Gunthorpe 2023-09-13 18:54 ` Jason Gunthorpe 2023-09-26 8:31 ` Lorenzo Pieralisi 2023-09-26 8:31 ` Lorenzo Pieralisi 2023-09-26 12:25 ` Jason Gunthorpe 2023-09-26 12:25 ` Jason Gunthorpe 2023-09-26 13:52 ` Catalin Marinas 2023-09-26 13:52 ` Catalin Marinas 2023-09-26 16:12 ` Lorenzo Pieralisi 2023-09-26 16:12 ` Lorenzo Pieralisi 2023-10-05 9:56 ` Lorenzo Pieralisi 2023-10-05 9:56 ` Lorenzo Pieralisi 2023-10-05 11:56 ` Jason Gunthorpe 2023-10-05 11:56 ` Jason Gunthorpe 2023-10-05 14:08 ` Lorenzo Pieralisi 2023-10-05 14:08 ` Lorenzo Pieralisi 2023-10-12 12:35 ` Will Deacon 2023-10-12 12:35 ` Will Deacon 2023-10-12 13:20 ` Jason Gunthorpe 2023-10-12 13:20 ` Jason Gunthorpe 2023-10-12 14:29 ` Lorenzo Pieralisi 2023-10-12 14:29 ` Lorenzo Pieralisi 2023-10-12 13:53 ` Catalin Marinas 2023-10-12 13:53 ` Catalin Marinas 2023-10-12 14:48 ` Will Deacon 2023-10-12 14:48 ` Will Deacon 2023-10-12 15:44 ` Jason Gunthorpe 2023-10-12 15:44 ` Jason Gunthorpe 2023-10-12 16:39 ` Will Deacon 2023-10-12 16:39 ` Will Deacon 2023-10-12 18:36 ` Jason Gunthorpe 2023-10-12 18:36 ` Jason Gunthorpe 2023-10-13 9:29 ` Will Deacon 2023-10-13 9:29 ` Will Deacon 2023-10-12 17:26 ` Catalin Marinas 2023-10-12 17:26 ` Catalin Marinas 2023-10-13 9:29 ` Will Deacon 2023-10-13 9:29 ` Will Deacon 2023-10-13 13:08 ` Catalin Marinas 2023-10-13 13:08 ` Catalin Marinas 2023-10-13 13:45 ` Jason Gunthorpe 2023-10-13 13:45 ` Jason Gunthorpe 2023-10-19 11:07 ` Catalin Marinas 2023-10-19 11:07 ` Catalin Marinas 2023-10-19 11:51 ` Jason Gunthorpe 2023-10-19 11:51 ` Jason Gunthorpe 2023-10-20 11:21 ` Catalin Marinas 2023-10-20 11:21 ` Catalin Marinas 2023-10-20 11:47 ` Jason Gunthorpe 2023-10-20 11:47 ` Jason Gunthorpe 2023-10-20 14:03 ` Lorenzo Pieralisi 2023-10-20 14:03 ` Lorenzo Pieralisi 2023-10-20 14:28 ` Jason Gunthorpe 2023-10-20 14:28 ` Jason Gunthorpe 2023-10-19 13:35 ` Lorenzo Pieralisi 2023-10-19 13:35 ` Lorenzo Pieralisi 2023-10-13 15:28 ` Lorenzo Pieralisi 2023-10-13 15:28 ` Lorenzo Pieralisi 2023-10-19 11:12 ` Catalin Marinas 2023-10-19 11:12 ` Catalin Marinas 2023-11-09 15:34 ` Lorenzo Pieralisi 2023-11-09 15:34 ` Lorenzo Pieralisi 2023-11-10 14:26 ` Jason Gunthorpe 2023-11-10 14:26 ` Jason Gunthorpe 2023-11-13 0:42 ` Lorenzo Pieralisi 2023-11-13 0:42 ` Lorenzo Pieralisi 2023-11-13 17:41 ` Catalin Marinas 2023-11-13 17:41 ` Catalin Marinas 2023-10-12 12:27 ` Will Deacon 2023-10-12 12:27 ` Will Deacon
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