From: Keir Fraser <keir@xen.org>
To: Christoph Egger <Christoph.Egger@amd.com>,
"xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>
Subject: Re: [PATCH] nestedhvm: ASID emulation
Date: Wed, 13 Apr 2011 14:27:02 +0100 [thread overview]
Message-ID: <C9CB6336.2C9FB%keir@xen.org> (raw)
In-Reply-To: <4DA57CD0.9040704@amd.com>
On 13/04/2011 11:37, "Christoph Egger" <Christoph.Egger@amd.com> wrote:
>
> Implement ASID emulation.
> This allows the l1 guest to run the l2 guest using hw ASID.
>
> Signed-off-by: Christoph Egger <Christoph.Egger@amd.com>
First, how much of a win is this compared with what we do currently?
Second, the two-asids-per-vcpu allocation scheme in
hvm_asid_handle_vmenter() looks broken. I mean, consider this comment:
/* When asid generation changed last time when we were
* were going to run l1 guest then next_asid <= nv->nv_n2asid. */
I don't see how you can assert this to be true. Arbitrary generations can
have passed, and next_asid incremented to an arbitrary value, since the last
time you allocated nv_n2asid.
I wouldn't bother fixing #2 unless there's a convincing answer for #1.
-- Keir
next prev parent reply other threads:[~2011-04-13 13:27 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-13 10:37 [PATCH] nestedhvm: ASID emulation Christoph Egger
2011-04-13 13:27 ` Keir Fraser [this message]
2011-04-13 14:26 ` Christoph Egger
2011-04-13 15:05 ` Keir Fraser
2011-04-13 15:19 ` Christoph Egger
2011-04-13 16:22 ` Keir Fraser
2011-04-14 9:26 ` Christoph Egger
2011-04-14 10:28 ` Keir Fraser
2011-04-14 14:01 ` Christoph Egger
2011-04-14 14:43 ` Keir Fraser
2011-04-15 8:20 ` Christoph Egger
2011-04-15 9:05 ` Keir Fraser
2011-04-15 9:08 ` Christoph Egger
2011-04-15 9:24 ` Keir Fraser
2011-04-15 9:57 ` Christoph Egger
2011-04-15 12:53 ` Keir Fraser
2011-04-15 12:49 ` Christoph Egger
2011-04-15 13:40 ` Christoph Egger
2011-04-13 13:51 ` Christoph Egger
2011-04-13 14:48 ` Christoph Egger
-- strict thread matches above, loose matches on Subject: below --
2011-04-13 8:57 Christoph Egger
2011-04-13 9:18 ` Keir Fraser
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