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From: "Christian König" <christian.koenig@amd.com>
To: "Thomas Hellström (VMware)" <thomas_os@shipmail.org>,
	dri-devel@lists.freedesktop.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org,
	linux-graphics-maintainer@vmware.com
Cc: "Thomas Hellstrom" <thellstrom@vmware.com>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Michal Hocko" <mhocko@suse.com>,
	"Matthew Wilcox (Oracle)" <willy@infradead.org>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	"Ralph Campbell" <rcampbell@nvidia.com>,
	"Jérôme Glisse" <jglisse@redhat.com>
Subject: Re: [PATCH 2/2] drm/ttm: Fix vm page protection handling
Date: Wed, 27 Nov 2019 09:43:35 +0100
Message-ID: <04b5dae3-6e72-2c35-117a-a79421d274d9@amd.com> (raw)
In-Reply-To: <20191126202717.30762-2-thomas_os@shipmail.org>

Am 26.11.19 um 21:27 schrieb Thomas Hellström (VMware):
> From: Thomas Hellstrom <thellstrom@vmware.com>
>
> We were using an ugly hack to set the page protection correctly.
> Fix that and instead use vmf_insert_mixed_prot() and / or
> vmf_insert_pfn_prot().
> Also get the default page protection from
> struct vm_area_struct::vm_page_prot rather than using vm_get_page_prot().
> This way we catch modifications done by the vm system for drivers that
> want write-notification.
>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
> Cc: Ralph Campbell <rcampbell@nvidia.com>
> Cc: "Jérôme Glisse" <jglisse@redhat.com>
> Cc: "Christian König" <christian.koenig@amd.com>
> Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>

Reviewed-by: Christian König <christian.koenig@amd.com>

> ---
>   drivers/gpu/drm/ttm/ttm_bo_vm.c | 14 +++++++-------
>   1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c
> index e6495ca2630b..2098f8d4dfc5 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
> @@ -173,7 +173,6 @@ vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf,
>   				    pgoff_t num_prefault)
>   {
>   	struct vm_area_struct *vma = vmf->vma;
> -	struct vm_area_struct cvma = *vma;
>   	struct ttm_buffer_object *bo = vma->vm_private_data;
>   	struct ttm_bo_device *bdev = bo->bdev;
>   	unsigned long page_offset;
> @@ -244,7 +243,7 @@ vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf,
>   		goto out_io_unlock;
>   	}
>   
> -	cvma.vm_page_prot = ttm_io_prot(bo->mem.placement, prot);
> +	prot = ttm_io_prot(bo->mem.placement, prot);
>   	if (!bo->mem.bus.is_iomem) {
>   		struct ttm_operation_ctx ctx = {
>   			.interruptible = false,
> @@ -260,7 +259,7 @@ vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf,
>   		}
>   	} else {
>   		/* Iomem should not be marked encrypted */
> -		cvma.vm_page_prot = pgprot_decrypted(cvma.vm_page_prot);
> +		prot = pgprot_decrypted(prot);
>   	}
>   
>   	/*
> @@ -284,10 +283,11 @@ vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf,
>   		}
>   
>   		if (vma->vm_flags & VM_MIXEDMAP)
> -			ret = vmf_insert_mixed(&cvma, address,
> -					__pfn_to_pfn_t(pfn, PFN_DEV));
> +			ret = vmf_insert_mixed_prot(vma, address,
> +						    __pfn_to_pfn_t(pfn, PFN_DEV),
> +						    prot);
>   		else
> -			ret = vmf_insert_pfn(&cvma, address, pfn);
> +			ret = vmf_insert_pfn_prot(vma, address, pfn, prot);
>   
>   		/* Never error on prefaulted PTEs */
>   		if (unlikely((ret & VM_FAULT_ERROR))) {
> @@ -319,7 +319,7 @@ vm_fault_t ttm_bo_vm_fault(struct vm_fault *vmf)
>   	if (ret)
>   		return ret;
>   
> -	prot = vm_get_page_prot(vma->vm_flags);
> +	prot = vma->vm_page_prot;
>   	ret = ttm_bo_vm_fault_reserved(vmf, prot, TTM_BO_VM_NUM_PREFAULT);
>   	if (ret == VM_FAULT_RETRY && !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT))
>   		return ret;



  reply index

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-26 20:27 [PATCH 1/2] mm: Add and export vmf_insert_mixed_prot() Thomas Hellström (VMware)
2019-11-26 20:27 ` [PATCH 2/2] drm/ttm: Fix vm page protection handling Thomas Hellström (VMware)
2019-11-27  8:43   ` Christian König [this message]
2019-11-27  8:42 ` [PATCH 1/2] mm: Add and export vmf_insert_mixed_prot() Christian König
2019-12-03  7:54 [PATCH 0/2] mm, drm/ttm: Fix pte insertion with customized protection Thomas Hellström (VMware)
2019-12-03  7:54 ` [PATCH 2/2] drm/ttm: Fix vm page protection handling Thomas Hellström (VMware)
2019-12-03  9:55   ` Kirill A. Shutemov
2019-12-03  9:58     ` Christian König
2019-12-03 10:19       ` Thomas Hellström (VMware)

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