From: Paolo Bonzini <pbonzini@redhat.com>
To: "Kani, Toshimitsu" <toshi.kani@hpe.com>,
"karahmed@amazon.de" <karahmed@amazon.de>
Cc: "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"bp@suse.de" <bp@suse.de>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"x86@kernel.org" <x86@kernel.org>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"hpa@zytor.com" <hpa@zytor.com>,
"mingo@redhat.com" <mingo@redhat.com>,
"tony.luck@intel.com" <tony.luck@intel.com>,
"dvlasenk@redhat.com" <dvlasenk@redhat.com>,
"rkrcmar@redhat.com" <rkrcmar@redhat.com>
Subject: Re: [PATCH] kvm, x86: Properly check whether a pfn is an MMIO or not
Date: Thu, 15 Sep 2016 18:22:41 +0200 [thread overview]
Message-ID: <2ca7f677-723e-b96d-64aa-e2d858df7930@redhat.com> (raw)
In-Reply-To: <1473955392.2092.76.camel@hpe.com>
On 15/09/2016 18:04, Kani, Toshimitsu wrote:
> On Thu, 2016-09-15 at 08:22 +0200, Paolo Bonzini wrote:
>>
>> On 15/09/2016 07:54, Raslan, KarimAllah wrote:
>>>
>>>
>>>>
>>>> On Jun 22, 2016, at 3:41 PM, Paolo Bonzini <pbonzini@redhat.com>
>>>> wrote:
>>>>
>>>>
>>>>
>>>> On 22/06/2016 04:34, KarimAllah Ahmed wrote:
>>>>>
>>>>> pfn_valid check is not sufficient because it only checks if a
>>>>> page has a struct page or not, if for example "mem=" was passed
>>>>> to the kernel some valid pages won't have a struct page. This
>>>>> means that if guests were assigned valid memory that lies after
>>>>> the mem= boundary it will be passed uncached to the guest no
>>>>> matter what the guest caching attributes are for this memory.
>>>>
>>>> How can you pass memory after the mem= boundary to the guest?
>>>
>>> Does my previous reply answer your question?
>>
>> Yes, but I'm not sure it's the right way to do it. Looking at the
>> e820 memory map seems pretty hacky.
>
> Can you use region_intersects() for this check? See memremap() as an
> example using this interface.
This one seems more generic but very slow.
Paolo
prev parent reply other threads:[~2016-09-15 16:23 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-22 2:34 [PATCH] kvm, x86: Properly check whether a pfn is an MMIO or not KarimAllah Ahmed
2016-06-22 13:41 ` Paolo Bonzini
2016-06-22 14:11 ` Raslan, KarimAllah
2016-09-15 5:54 ` Raslan, KarimAllah
2016-09-15 6:22 ` Paolo Bonzini
2016-09-15 16:04 ` Kani, Toshimitsu
2016-09-15 16:22 ` Paolo Bonzini [this message]
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