From: Scott Wood <scottwood@freescale.com>
To: Alexander Graf <agraf@suse.de>
Cc: "“tiejun.chen”" <tiejun.chen@windriver.com>,
"Bhushan Bharat-R65777" <R65777@freescale.com>,
"kvm-ppc@vger.kernel.org" <kvm-ppc@vger.kernel.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"Wood Scott-B07421" <B07421@freescale.com>
Subject: Re: [PATCH 2/2] kvm: powerpc: set cache coherency only for kernel managed pages
Date: Thu, 18 Jul 2013 11:11:49 -0500 [thread overview]
Message-ID: <1374163909.5357.3@snotra> (raw)
In-Reply-To: <BBB1CC9D-3D21-4971-9659-8C885E9478A6@suse.de> (from agraf@suse.de on Thu Jul 18 05:00:42 2013)
On 07/18/2013 05:00:42 AM, Alexander Graf wrote:
> Now why is setting invalid flags a problem? If I understand Scott
> correctly, it can break the host if you access certain host devices
> with caching enabled. But to be sure I'd say we ask him directly :).
The architecture makes it illegal to mix cacheable and cache-inhibited
mappings to the same physical page. Mixing W or M bits is generally
bad as well. I've seen it cause machine checks, error interrupts, etc.
-- not just corrupting the page in question.
-Scott
WARNING: multiple messages have this Message-ID (diff)
From: Scott Wood <scottwood@freescale.com>
To: Alexander Graf <agraf@suse.de>
Cc: "“tiejun.chen”" <tiejun.chen@windriver.com>,
"Bhushan Bharat-R65777" <R65777@freescale.com>,
"kvm-ppc@vger.kernel.org" <kvm-ppc@vger.kernel.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"Wood Scott-B07421" <B07421@freescale.com>
Subject: Re: [PATCH 2/2] kvm: powerpc: set cache coherency only for kernel managed pages
Date: Thu, 18 Jul 2013 16:11:49 +0000 [thread overview]
Message-ID: <1374163909.5357.3@snotra> (raw)
In-Reply-To: <BBB1CC9D-3D21-4971-9659-8C885E9478A6@suse.de> (from agraf@suse.de on Thu Jul 18 05:00:42 2013)
On 07/18/2013 05:00:42 AM, Alexander Graf wrote:
> Now why is setting invalid flags a problem? If I understand Scott
> correctly, it can break the host if you access certain host devices
> with caching enabled. But to be sure I'd say we ask him directly :).
The architecture makes it illegal to mix cacheable and cache-inhibited
mappings to the same physical page. Mixing W or M bits is generally
bad as well. I've seen it cause machine checks, error interrupts, etc.
-- not just corrupting the page in question.
-Scott
next prev parent reply other threads:[~2013-07-18 16:11 UTC|newest]
Thread overview: 82+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-18 6:04 [PATCH 1/2] kvm: powerpc: Do not ignore "E" attribute in mas2 Bharat Bhushan
2013-07-18 6:16 ` Bharat Bhushan
2013-07-18 6:04 ` [PATCH 2/2] kvm: powerpc: set cache coherency only for kernel managed pages Bharat Bhushan
2013-07-18 6:16 ` Bharat Bhushan
2013-07-18 6:26 ` "“tiejun.chen”"
2013-07-18 6:26 ` "“tiejun.chen”"
2013-07-18 7:12 ` Bhushan Bharat-R65777
2013-07-18 7:12 ` Bhushan Bharat-R65777
2013-07-18 7:31 ` "“tiejun.chen”"
2013-07-18 7:31 ` "“tiejun.chen”"
2013-07-18 8:08 ` Bhushan Bharat-R65777
2013-07-18 8:08 ` Bhushan Bharat-R65777
2013-07-18 8:21 ` "“tiejun.chen”"
2013-07-18 8:21 ` "“tiejun.chen”"
2013-07-18 8:22 ` Bhushan Bharat-R65777
2013-07-18 8:22 ` Bhushan Bharat-R65777
2013-07-18 8:25 ` Bhushan Bharat-R65777
2013-07-18 8:25 ` Bhushan Bharat-R65777
2013-07-18 8:55 ` "“tiejun.chen”"
2013-07-18 8:55 ` "“tiejun.chen”"
2013-07-18 9:44 ` Alexander Graf
2013-07-18 9:44 ` Alexander Graf
2013-07-18 9:56 ` "“tiejun.chen”"
2013-07-18 9:56 ` "“tiejun.chen”"
2013-07-18 10:00 ` Alexander Graf
2013-07-18 10:00 ` Alexander Graf
2013-07-18 10:14 ` "“tiejun.chen”"
2013-07-18 10:14 ` "“tiejun.chen”"
2013-07-18 16:11 ` Scott Wood [this message]
2013-07-18 16:11 ` Scott Wood
2013-07-18 9:48 ` Alexander Graf
2013-07-18 9:48 ` Alexander Graf
2013-07-18 9:51 ` Bhushan Bharat-R65777
2013-07-18 10:08 ` "“tiejun.chen”"
2013-07-18 10:08 ` "“tiejun.chen”"
2013-07-18 10:12 ` Alexander Graf
2013-07-18 10:12 ` Alexander Graf
2013-07-18 10:19 ` "“tiejun.chen”"
2013-07-18 10:19 ` "“tiejun.chen”"
2013-07-18 10:27 ` Alexander Graf
2013-07-18 10:27 ` Alexander Graf
2013-07-24 2:26 ` "“tiejun.chen”"
2013-07-24 2:26 ` "“tiejun.chen”"
2013-07-24 8:25 ` Alexander Graf
2013-07-24 8:25 ` Alexander Graf
2013-07-24 9:11 ` Bhushan Bharat-R65777
2013-07-24 9:11 ` Bhushan Bharat-R65777
2013-07-24 9:21 ` Alexander Graf
2013-07-24 9:21 ` Alexander Graf
2013-07-24 9:35 ` Gleb Natapov
2013-07-24 9:35 ` Gleb Natapov
2013-07-24 9:39 ` Alexander Graf
2013-07-24 9:39 ` Alexander Graf
2013-07-24 20:32 ` Scott Wood
2013-07-24 20:32 ` Scott Wood
2013-07-24 20:32 ` Scott Wood
2013-07-25 8:50 ` Gleb Natapov
2013-07-25 8:50 ` Gleb Natapov
2013-07-25 8:50 ` Gleb Natapov
2013-07-25 16:07 ` Alexander Graf
2013-07-25 16:07 ` Alexander Graf
2013-07-25 16:07 ` Alexander Graf
2013-07-25 16:14 ` Gleb Natapov
2013-07-25 16:14 ` Gleb Natapov
2013-07-25 16:14 ` Gleb Natapov
2013-07-26 22:27 ` Scott Wood
2013-07-26 22:27 ` Scott Wood
2013-07-26 22:27 ` Scott Wood
2013-07-24 10:01 ` Gleb Natapov
2013-07-24 10:01 ` Gleb Natapov
2013-07-24 10:09 ` Alexander Graf
2013-07-24 10:09 ` Alexander Graf
2013-07-24 10:19 ` Gleb Natapov
2013-07-24 10:19 ` Gleb Natapov
2013-07-24 10:25 ` Alexander Graf
2013-07-24 10:25 ` Alexander Graf
2013-07-24 10:30 ` Gleb Natapov
2013-07-24 10:30 ` Gleb Natapov
2013-07-25 1:04 ` Andrea Arcangeli
2013-07-25 1:04 ` Andrea Arcangeli
2013-07-18 8:27 ` "“tiejun.chen”"
2013-07-18 8:27 ` "“tiejun.chen”"
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