From: Keir Fraser <keir.xen@gmail.com>
To: Christoph Egger <Christoph.Egger@amd.com>
Cc: "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>
Subject: Re: [PATCH] nestedhvm: ASID emulation
Date: Thu, 14 Apr 2011 11:28:54 +0100 [thread overview]
Message-ID: <C9CC8AF6.1655E%keir.xen@gmail.com> (raw)
In-Reply-To: <4DA6BDAD.9040300@amd.com>
On 14/04/2011 10:26, "Christoph Egger" <Christoph.Egger@amd.com> wrote:
>> What if nv_n2asid wast last assigned on a previous generation, but nv_n1asid
>> was assigned from the current generation? Then you'd have next_asid>
>> nv_n2asid, but nv_n2asid is stale.
>
> When the generation changes, next_asid is set back to 1 and the hw TLB
> flushed.
>
> If next_asid is larger than nv_n2asid then it is reused and this is ok
> since the hw TLB got flushed. It is just important that nv_n1asid never
> gets the same hw ASID assigned and that is what the do { } while loop
> ensures.
What if some other vcpu's nv_n1asid or nv_n2asid got assigned the same HW
asid in this generation as this vcpu's (now stale, as it's from a previous
generation's) nv_n2asid? This PCPU can be interleaving execution of other
HVM VCPUs after all.
-- Keir
next prev parent reply other threads:[~2011-04-14 10:28 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
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 [this message]
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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