From: Anthony Liguori <anthony@codemonkey.ws>
To: Andrea Arcangeli <andrea@qumranet.com>
Cc: Carsten Otte <cotte@de.ibm.com>,
Hollis Blanchard <hollisb@us.ibm.com>,
kvm-devel@lists.sourceforge.net, Avi Kivity <avi@qumranet.com>,
Ben-Ami Yassour <benami@il.ibm.com>,
"Zhang, Xiantao" <xiantao.zhang@intel.com>
Subject: Re: [PATCH] Handle vma regions with no backing page (v2)
Date: Wed, 30 Apr 2008 10:37:24 -0500 [thread overview]
Message-ID: <48189234.6050502@codemonkey.ws> (raw)
In-Reply-To: <20080430070039.GA12501@duo.random>
Andrea Arcangeli wrote:
> On Tue, Apr 29, 2008 at 06:12:51PM -0500, Anthony Liguori wrote:
>
>> IIUC PPC correctly, all IO pages have corresponding struct pages. This
>> means that get_user_pages() would succeed and you can reference count them?
>> In this case, we would never take the VM_PFNMAP path.
>>
>
> get_user_pages only works on vmas where only pfn with struct page can
> be mapped, but if a struct page exists it doesn't mean get_user_pages
> will succeed. All mmio regions should be marked VM_IO as reading on
> them affects hardware somehow and that prevents get_user_pages to work
> on them regardless if a struct page exists.
>
Ah, thanks for the clarification.
Regards,
Anthony Liguori
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next prev parent reply other threads:[~2008-04-30 15:37 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-04-29 19:09 [PATCH] Handle vma regions with no backing page (v2) Anthony Liguori
2008-04-29 22:17 ` Avi Kivity
2008-04-29 22:25 ` Anthony Liguori
2008-04-29 22:42 ` Avi Kivity
2008-04-29 22:51 ` Anthony Liguori
2008-04-29 22:52 ` Avi Kivity
2008-04-29 22:57 ` Hollis Blanchard
2008-04-29 23:12 ` Anthony Liguori
2008-04-30 7:00 ` Andrea Arcangeli
2008-04-30 15:37 ` Anthony Liguori [this message]
2008-04-30 15:11 ` Hollis Blanchard
2008-04-30 7:59 ` Carsten Otte
2008-04-30 6:11 ` Muli Ben-Yehuda
2008-04-30 8:59 ` Avi Kivity
2008-04-30 9:13 ` Andrea Arcangeli
2008-04-30 9:15 ` Avi Kivity
2008-04-30 12:24 ` Anthony Liguori
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