From: Paolo Bonzini <pbonzini@redhat.com>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: Amos Kong <akong@redhat.com>,
QEMU Developers <qemu-devel@nongnu.org>,
Anthony Liguori <anthony@codemonkey.ws>
Subject: Re: [Qemu-devel] [PATCH] extend limit of physical sections number
Date: Tue, 05 Nov 2013 13:27:57 +0100 [thread overview]
Message-ID: <5278E44D.80800@redhat.com> (raw)
In-Reply-To: <CAFEAcA8N5Oe70SZzgO-HiHv1uOBpGOfq-=sBn0aCjn5t1DVsnw@mail.gmail.com>
Il 05/11/2013 13:23, Peter Maydell ha scritto:
>>> >> This looks really weird. Why should the memory subsystem
>>> >> care whether we're using TCG or KVM or Xen?
>> >
>> > Because only TCG stores the section number in the low bits of the iotlb
>> > entry. This is exactly what is explained in the comments.
> So presumably we still crash if there are more than
> 32 virtio-blk disks on TCG (and indeed if more than 256
> on KVM)? That doesn't seem very satisfactory...
It isn't, do you have any idea on how to make the threshold equal for
TCG and KVM?
I guess the code could be made clearer like this:
assert (... < SHRT_MAX);
if (tcg_enabled()) {
/* TCG has a stricter limit due to iotlb etc. etc. */
assert (... < TARGET_PAGE_SIZE);
}
but that's pretty much it...
Paolo
next prev parent reply other threads:[~2013-11-05 12:28 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-27 16:49 [Qemu-devel] [PATCH] extend limit of physical sections number Amos Kong
2013-09-27 16:52 ` Paolo Bonzini
2013-11-05 0:21 ` Amos Kong
2013-11-05 0:36 ` Peter Maydell
2013-11-05 9:00 ` Paolo Bonzini
2013-11-05 12:23 ` Peter Maydell
2013-11-05 12:27 ` Paolo Bonzini [this message]
2013-11-19 11:11 ` Amos Kong
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