From: Joerg Roedel <joro@8bytes.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: Tom Murphy <tmurphy@arista.com>,
iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
Tom Murphy <murphyt7@tcd.ie>
Subject: Re: [PATCH] iommu/amd: flush not present cache in iommu_map_page
Date: Wed, 24 Apr 2019 17:55:06 +0200 [thread overview]
Message-ID: <20190424155505.GA6731@8bytes.org> (raw)
In-Reply-To: <20190424145819.GA16141@infradead.org>
On Wed, Apr 24, 2019 at 07:58:19AM -0700, Christoph Hellwig wrote:
> I'd be tempted to do that. But lets just ask Joerg if he has
> any opinion..
The reason was that it is an unlikely path, as hardware implementations
are not allowed to set this bit. It is purely for emulated AMD IOMMUs.
I have not measured whether this annotation has any performance
benefit, but I find it more readable at least.
Regards,
Joerg
PS: Why did you drop me from the Cc list of the previous replies?
WARNING: multiple messages have this Message-ID (diff)
From: Joerg Roedel <joro@8bytes.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: Tom Murphy <tmurphy@arista.com>,
iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
Tom Murphy <murphyt7@tcd.ie>
Subject: Re: [PATCH] iommu/amd: flush not present cache in iommu_map_page
Date: Wed, 24 Apr 2019 17:55:06 +0200 [thread overview]
Message-ID: <20190424155505.GA6731@8bytes.org> (raw)
Message-ID: <20190424155506.sGHjpr7aLtjNqciPrdOzwnFc0_pXaWMvWWTV2IA-S7A@z> (raw)
In-Reply-To: <20190424145819.GA16141@infradead.org>
On Wed, Apr 24, 2019 at 07:58:19AM -0700, Christoph Hellwig wrote:
> I'd be tempted to do that. But lets just ask Joerg if he has
> any opinion..
The reason was that it is an unlikely path, as hardware implementations
are not allowed to set this bit. It is purely for emulated AMD IOMMUs.
I have not measured whether this annotation has any performance
benefit, but I find it more readable at least.
Regards,
Joerg
PS: Why did you drop me from the Cc list of the previous replies?
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next prev parent reply other threads:[~2019-04-24 15:55 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-24 14:18 [PATCH] iommu/amd: flush not present cache in iommu_map_page Tom Murphy
2019-04-24 14:18 ` Tom Murphy via iommu
[not found] ` <20190424141900.8883-1-tmurphy-nzgTgzXrdUbQT0dZR+AlfA@public.gmane.org>
2019-04-24 14:32 ` Christoph Hellwig
2019-04-24 14:32 ` Christoph Hellwig
2019-04-24 14:32 ` Christoph Hellwig
[not found] ` <20190424143246.GA24079-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
2019-04-24 14:47 ` Tom Murphy via iommu
2019-04-24 14:47 ` Tom Murphy
2019-04-24 14:47 ` Tom Murphy via iommu
[not found] ` <CAPL0++7w0wR+hid=0XkGtH2wR0qvL1oNheEMQOM=8CtyhNLmag-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2019-04-24 14:58 ` Christoph Hellwig
2019-04-24 14:58 ` Christoph Hellwig
2019-04-24 14:58 ` Christoph Hellwig
2019-04-24 15:55 ` Joerg Roedel [this message]
2019-04-24 15:55 ` Joerg Roedel
2019-04-24 16:25 ` Tom Murphy
2019-04-24 16:25 ` Tom Murphy via iommu
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