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From: "Huang\, Ying" <ying.huang@intel.com>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Lu Baolu <baolu.lu@linux.intel.com>, Bob Liu <liubo95@huawei.com>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H . Peter Anvin" <hpa@zytor.com>,
	Alex Williamson <alex.williamson@redhat.com>,
	"Joerg Roedel" <joro@8bytes.org>,
	David Woodhouse <dwmw2@infradead.org>,
	Rik van Riel <riel@redhat.com>, Michal Hocko <mhocko@suse.com>,
	Dave Jiang <dave.jiang@intel.com>, <x86@kernel.org>,
	<linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>,
	<iommu@lists.linux-foundation.org>,
	Vegard Nossum <vegard.nossum@oracle.com>,
	Andy Lutomirski <luto@kernel.org>,
	Matthew Wilcox <willy@linux.intel.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	"Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
	"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
	Kees Cook <keescook@chromium.org>,
	"xieyisheng \(A\)" <xieyisheng1@huawei.com>
Subject: Re: [PATCH 1/2] mm: Add kernel MMU notifier to manage IOTLB/DEVTLB
Date: Thu, 14 Dec 2017 14:43:27 +0800	[thread overview]
Message-ID: <87efnxn71s.fsf@yhuang-dev.intel.com> (raw)
In-Reply-To: <4466eac3-c4f5-47e4-e568-912a560240c1@intel.com> (Dave Hansen's message of "Wed, 13 Dec 2017 22:28:37 -0800")

Hi, Dave,

Dave Hansen <dave.hansen@intel.com> writes:

> On 12/13/2017 07:38 PM, Lu Baolu wrote:
>> 2. When vmalloc/vfree interfaces are called, the page mappings
>>     for kernel memory might get changed. And current code calls
>>     flush_tlb_kernel_range() to flush CPU TLBs only. The IOTLB or
>>     DevTLB will be stale compared to that on the cpu for kernel
>>     mappings.
>
> What's the plan to deal with all of the ways other than vmalloc() that
> the kernel changes the page tables?

The kernel MMU notifier is called in flush_tlb_kernel_range().  So IOMMU
will be notified for TLB flushing caused by all ways that the kernel
changes the page tables including vmalloc, kmap, etc.

Best Regards,
Huang, Ying

WARNING: multiple messages have this Message-ID (diff)
From: "Huang\, Ying" <ying.huang@intel.com>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Lu Baolu <baolu.lu@linux.intel.com>, Bob Liu <liubo95@huawei.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H . Peter Anvin" <hpa@zytor.com>,
	Alex Williamson <alex.williamson@redhat.com>,
	Joerg Roedel <joro@8bytes.org>,
	David Woodhouse <dwmw2@infradead.org>,
	Rik van Riel <riel@redhat.com>, Michal Hocko <mhocko@suse.com>,
	Dave Jiang <dave.jiang@intel.com>,
	x86@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	iommu@lists.linux-foundation.org,
	Vegard Nossum <vegard.nossum@oracle.com>,
	Andy Lutomirski <luto@kernel.org>,
	Matthew Wilcox <willy@linux.intel.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	"Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
	"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
	Kees Cook <keescook@chromium.org>,
	"xieyisheng (A)" <xieyisheng1@huawei.com>
Subject: Re: [PATCH 1/2] mm: Add kernel MMU notifier to manage IOTLB/DEVTLB
Date: Thu, 14 Dec 2017 14:43:27 +0800	[thread overview]
Message-ID: <87efnxn71s.fsf@yhuang-dev.intel.com> (raw)
In-Reply-To: <4466eac3-c4f5-47e4-e568-912a560240c1@intel.com> (Dave Hansen's message of "Wed, 13 Dec 2017 22:28:37 -0800")

Hi, Dave,

Dave Hansen <dave.hansen@intel.com> writes:

> On 12/13/2017 07:38 PM, Lu Baolu wrote:
>> 2. When vmalloc/vfree interfaces are called, the page mappings
>>     for kernel memory might get changed. And current code calls
>>     flush_tlb_kernel_range() to flush CPU TLBs only. The IOTLB or
>>     DevTLB will be stale compared to that on the cpu for kernel
>>     mappings.
>
> What's the plan to deal with all of the ways other than vmalloc() that
> the kernel changes the page tables?

The kernel MMU notifier is called in flush_tlb_kernel_range().  So IOMMU
will be notified for TLB flushing caused by all ways that the kernel
changes the page tables including vmalloc, kmap, etc.

Best Regards,
Huang, Ying

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

WARNING: multiple messages have this Message-ID (diff)
From: "Huang\, Ying" <ying.huang@intel.com>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Lu Baolu <baolu.lu@linux.intel.com>, Bob Liu <liubo95@huawei.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H . Peter Anvin" <hpa@zytor.com>,
	Alex Williamson <alex.williamson@redhat.com>,
	Joerg Roedel <joro@8bytes.org>,
	David Woodhouse <dwmw2@infradead.org>,
	Rik van Riel <riel@redhat.com>, Michal Hocko <mhocko@suse.com>,
	Dave Jiang <dave.jiang@intel.com>,
	x86@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	iommu@lists.linux-foundation.org,
	Vegard Nossum <vegard.nossum@oracle.com>,
	Andy Lutomirski <luto@kernel.org>,
	Matthew Wilcox <willy@linux.intel.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	"Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
	"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
	Kees Coo k <keescook@chromium.org>,
	"xieyisheng (A)" <xieyisheng1@huawei.com>
Subject: Re: [PATCH 1/2] mm: Add kernel MMU notifier to manage IOTLB/DEVTLB
Date: Thu, 14 Dec 2017 14:43:27 +0800	[thread overview]
Message-ID: <87efnxn71s.fsf@yhuang-dev.intel.com> (raw)
In-Reply-To: <4466eac3-c4f5-47e4-e568-912a560240c1@intel.com> (Dave Hansen's message of "Wed, 13 Dec 2017 22:28:37 -0800")

Hi, Dave,

Dave Hansen <dave.hansen@intel.com> writes:

> On 12/13/2017 07:38 PM, Lu Baolu wrote:
>> 2. When vmalloc/vfree interfaces are called, the page mappings
>>     for kernel memory might get changed. And current code calls
>>     flush_tlb_kernel_range() to flush CPU TLBs only. The IOTLB or
>>     DevTLB will be stale compared to that on the cpu for kernel
>>     mappings.
>
> What's the plan to deal with all of the ways other than vmalloc() that
> the kernel changes the page tables?

The kernel MMU notifier is called in flush_tlb_kernel_range().  So IOMMU
will be notified for TLB flushing caused by all ways that the kernel
changes the page tables including vmalloc, kmap, etc.

Best Regards,
Huang, Ying

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

  reply	other threads:[~2017-12-14  6:43 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-14  1:02 [PATCH 0/2] Kernel MMU notifier for IOTLB/DEVTLB management Lu Baolu
2017-12-14  1:02 ` Lu Baolu
2017-12-14  1:02 ` [PATCH 1/2] mm: Add kernel MMU notifier to manage IOTLB/DEVTLB Lu Baolu
2017-12-14  1:02   ` Lu Baolu
2017-12-14  1:02   ` Lu Baolu
2017-12-14  3:10   ` Bob Liu
2017-12-14  3:10     ` Bob Liu
2017-12-14  3:10     ` Bob Liu
2017-12-14  3:38     ` Lu Baolu
2017-12-14  3:38       ` Lu Baolu
2017-12-14  6:07       ` Bob Liu
2017-12-14  6:07         ` Bob Liu
2017-12-14  6:07         ` Bob Liu
2017-12-15  3:08         ` Raj, Ashok
2017-12-15  3:08           ` Raj, Ashok
2017-12-15  3:08           ` Raj, Ashok
2017-12-14  6:28       ` Dave Hansen
2017-12-14  6:28         ` Dave Hansen
2017-12-14  6:43         ` Huang, Ying [this message]
2017-12-14  6:43           ` Huang, Ying
2017-12-14  6:43           ` Huang, Ying
2017-12-14  1:02 ` [PATCH 2/2] iommu/vt-d: Register " Lu Baolu
2017-12-14  1:02   ` Lu Baolu
2017-12-14  1:02   ` Lu Baolu

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