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From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
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Date: Mon, 26 Aug 2013 09:03:42 +0530
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Subject: Re: [Qemu-devel] [Qemu-ppc] [PATCH -V3 2/4] target-ppc: Fix page
	table lookup with kvm enabled
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To: Benjamin Herrenschmidt <benh@kernel.crashing.org>, Alexander Graf <agraf@suse.de>
Cc: Paul Mackerras <paulus@samba.org>, "qemu-ppc@nongnu.org list:PowerPC" <qemu-ppc@nongnu.org>, "qemu-devel@nongnu.org qemu-devel" <qemu-devel@nongnu.org>

Benjamin Herrenschmidt <benh@kernel.crashing.org> writes:

> On Sun, 2013-08-25 at 19:32 +0100, Alexander Graf wrote:
>> > +     * At this point we are only interested in reading only bolted
>> entries
>> > +     */
>> > +    ghf.flags = KVM_GET_HTAB_BOLTED_ONLY;
>> > +    ghf.start_index = index;
>> > +    htab_fd = kvm_vm_ioctl(kvm_state, KVM_PPC_GET_HTAB_FD, &ghf);
>> 
>> We should cache this.
>> 
> Also why bolted only ?

because non bolted entries could be invalidated and reused by the time
we look at the returned hpte values. I am not sure, whether it is ok or
we need to make sure such a thing doesn't happen. For the use case i am
looking at, ie, to dump the kernel address looking at bolted entries was
enough. 

-aneesh