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From: Catalin Marinas <catalin.marinas@arm.com>
To: ankita@nvidia.com
Cc: jgg@nvidia.com, maz@kernel.org, oliver.upton@linux.dev,
	james.morse@arm.com, suzuki.poulose@arm.com,
	yuzenghui@huawei.com, reinette.chatre@intel.com,
	surenb@google.com, stefanha@redhat.com, brauner@kernel.org,
	will@kernel.org, mark.rutland@arm.com,
	alex.williamson@redhat.com, kevin.tian@intel.com,
	yi.l.liu@intel.com, ardb@kernel.org, akpm@linux-foundation.org,
	andreyknvl@gmail.com, wangjinchao@xfusion.com, gshan@redhat.com,
	shahuang@redhat.com, ricarkol@google.com, linux-mm@kvack.org,
	lpieralisi@kernel.org, rananta@google.com, ryan.roberts@arm.com,
	david@redhat.com, linus.walleij@linaro.org, bhe@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,
	kvmarm@lists.linux.dev, mochs@nvidia.com, zhiw@nvidia.com,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v8 4/4] vfio: convey kvm that the vfio-pci device is wc safe
Date: Tue, 20 Feb 2024 09:56:00 +0000	[thread overview]
Message-ID: <ZdR3MI_4pqV0EZcR@arm.com> (raw)
In-Reply-To: <20240220072926.6466-5-ankita@nvidia.com>

On Tue, Feb 20, 2024 at 12:59:26PM +0530, ankita@nvidia.com wrote:
> diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
> index 1cbc990d42e0..c93bea18fc4b 100644
> --- a/drivers/vfio/pci/vfio_pci_core.c
> +++ b/drivers/vfio/pci/vfio_pci_core.c
> @@ -1862,8 +1862,24 @@ int vfio_pci_core_mmap(struct vfio_device *core_vdev, struct vm_area_struct *vma
>  	/*
>  	 * See remap_pfn_range(), called from vfio_pci_fault() but we can't
>  	 * change vm_flags within the fault handler.  Set them now.
> +	 *
> +	 * VM_ALLOW_ANY_UNCACHED: The VMA flag is implemented for ARM64,
> +	 * allowing KVM stage 2 device mapping attributes to use Normal-NC
> +	 * rather than DEVICE_nGnRE, which allows guest mappings
> +	 * supporting combining attributes (WC). ARM does not

Nitpick: "supporting write-combining" (if you plan to respin).

-- 
Catalin

WARNING: multiple messages have this Message-ID (diff)
From: Catalin Marinas <catalin.marinas@arm.com>
To: ankita@nvidia.com
Cc: jgg@nvidia.com, maz@kernel.org, oliver.upton@linux.dev,
	james.morse@arm.com, suzuki.poulose@arm.com,
	yuzenghui@huawei.com, reinette.chatre@intel.com,
	surenb@google.com, stefanha@redhat.com, brauner@kernel.org,
	will@kernel.org, mark.rutland@arm.com,
	alex.williamson@redhat.com, kevin.tian@intel.com,
	yi.l.liu@intel.com, ardb@kernel.org, akpm@linux-foundation.org,
	andreyknvl@gmail.com, wangjinchao@xfusion.com, gshan@redhat.com,
	shahuang@redhat.com, ricarkol@google.com, linux-mm@kvack.org,
	lpieralisi@kernel.org, rananta@google.com, ryan.roberts@arm.com,
	david@redhat.com, linus.walleij@linaro.org, bhe@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,
	kvmarm@lists.linux.dev, mochs@nvidia.com, zhiw@nvidia.com,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v8 4/4] vfio: convey kvm that the vfio-pci device is wc safe
Date: Tue, 20 Feb 2024 09:56:00 +0000	[thread overview]
Message-ID: <ZdR3MI_4pqV0EZcR@arm.com> (raw)
In-Reply-To: <20240220072926.6466-5-ankita@nvidia.com>

On Tue, Feb 20, 2024 at 12:59:26PM +0530, ankita@nvidia.com wrote:
> diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
> index 1cbc990d42e0..c93bea18fc4b 100644
> --- a/drivers/vfio/pci/vfio_pci_core.c
> +++ b/drivers/vfio/pci/vfio_pci_core.c
> @@ -1862,8 +1862,24 @@ int vfio_pci_core_mmap(struct vfio_device *core_vdev, struct vm_area_struct *vma
>  	/*
>  	 * See remap_pfn_range(), called from vfio_pci_fault() but we can't
>  	 * change vm_flags within the fault handler.  Set them now.
> +	 *
> +	 * VM_ALLOW_ANY_UNCACHED: The VMA flag is implemented for ARM64,
> +	 * allowing KVM stage 2 device mapping attributes to use Normal-NC
> +	 * rather than DEVICE_nGnRE, which allows guest mappings
> +	 * supporting combining attributes (WC). ARM does not

Nitpick: "supporting write-combining" (if you plan to respin).

-- 
Catalin

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2024-02-20  9:56 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-20  7:29 [PATCH v8 0/4] kvm: arm64: allow the VM to select DEVICE_* and NORMAL_NC for IO memory ankita
2024-02-20  7:29 ` ankita
2024-02-20  7:29 ` [PATCH v8 1/4] kvm: arm64: introduce new flag for non-cacheable " ankita
2024-02-20  7:29   ` ankita
2024-02-20 12:21   ` Will Deacon
2024-02-20 12:21     ` Will Deacon
2024-02-20 14:27   ` Lorenzo Pieralisi
2024-02-20 14:27     ` Lorenzo Pieralisi
2024-02-21  6:01     ` Ankit Agrawal
2024-02-21  6:01       ` Ankit Agrawal
2024-02-20  7:29 ` [PATCH v8 2/4] mm: introduce new flag to indicate wc safe ankita
2024-02-20  7:29   ` ankita
2024-02-20  8:26   ` Zhi Wang
2024-02-20  8:26     ` Zhi Wang
2024-02-20  8:51     ` Ankit Agrawal
2024-02-20  8:51       ` Ankit Agrawal
2024-02-20  9:07       ` Zhi Wang
2024-02-20  9:07         ` Zhi Wang
2024-02-20  9:08         ` Ankit Agrawal
2024-02-20  9:08           ` Ankit Agrawal
2024-02-20  9:09       ` David Hildenbrand
2024-02-20  9:09         ` David Hildenbrand
2024-02-20  9:33         ` Zhi Wang
2024-02-20  9:33           ` Zhi Wang
2024-02-20  9:40           ` Ankit Agrawal
2024-02-20  9:40             ` Ankit Agrawal
2024-02-20  7:29 ` [PATCH v8 3/4] kvm: arm64: set io memory s2 pte as normalnc for vfio pci device ankita
2024-02-20  7:29   ` ankita
2024-02-23 17:07   ` Marc Zyngier
2024-02-23 17:07     ` Marc Zyngier
2024-02-20  7:29 ` [PATCH v8 4/4] vfio: convey kvm that the vfio-pci device is wc safe ankita
2024-02-20  7:29   ` ankita
2024-02-20  9:56   ` Catalin Marinas [this message]
2024-02-20  9:56     ` Catalin Marinas
2024-02-20 12:11     ` Ankit Agrawal
2024-02-20 12:11       ` Ankit Agrawal
2024-02-22 20:52   ` Alex Williamson
2024-02-22 20:52     ` Alex Williamson
2024-02-23 17:02 ` [PATCH v8 0/4] kvm: arm64: allow the VM to select DEVICE_* and NORMAL_NC for IO memory Marc Zyngier
2024-02-23 17:02   ` Marc Zyngier

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