From: Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
To: Nadav Amit <namit-pghWNbHTmq7QT0dZR+AlfA@public.gmane.org>
Cc: iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org
Subject: Re: [PATCH] iommu/vt-d: Remove unnecassary qi clflushes
Date: Mon, 27 Jun 2016 13:30:15 +0200 [thread overview]
Message-ID: <20160627113014.GL11432@8bytes.org> (raw)
In-Reply-To: <1466773994-242872-1-git-send-email-namit-pghWNbHTmq7QT0dZR+AlfA@public.gmane.org>
On Fri, Jun 24, 2016 at 06:13:14AM -0700, Nadav Amit wrote:
> According to the manual: "Hardware access to ... invalidation queue ...
> are always coherent."
>
> Remove unnecassary clflushes accordingly.
It is one thing what the spec says and another how hardware really
behaves. Have you tested this on (potentially really old) VT-d machines
to make sure the spec is _always_ right here?
Joerg
next prev parent reply other threads:[~2016-06-27 11:30 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-24 13:13 [PATCH] iommu/vt-d: Remove unnecassary qi clflushes Nadav Amit
[not found] ` <1466773994-242872-1-git-send-email-namit-pghWNbHTmq7QT0dZR+AlfA@public.gmane.org>
2016-06-27 11:30 ` Joerg Roedel [this message]
[not found] ` <20160627113014.GL11432-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
2016-06-27 16:17 ` Nadav Amit
[not found] ` <C78095BC-3BED-48DE-90CE-601DE40AA613-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2016-07-05 16:27 ` Nadav Amit
[not found] ` <926A8CFB-D22D-4DC6-9EE0-D912451365BB-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2016-07-05 16:40 ` Paolo Bonzini
[not found] ` <ac3ff8d4-e47b-e4d8-40ed-02811732526a-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2016-07-05 16:50 ` Nadav Amit
[not found] ` <5F48A3E6-99EE-4DC5-BF38-4F0338E9E8D0-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2016-07-05 16:57 ` Paolo Bonzini
2016-07-13 10:07 ` Joerg Roedel
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