From: Paul Mackerras <paulus@samba.org>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: kvm-ppc@vger.kernel.org, kvm@vger.kernel.org,
Alexander Graf <agraf@suse.de>
Subject: Re: [PATCH 1/7] powerpc/kvm: Fix updates of vcpu->cpu on HV KVM
Date: Fri, 17 Aug 2012 20:42:27 +1000 [thread overview]
Message-ID: <20120817104227.GC19296@bloggs.ozlabs.ibm.com> (raw)
In-Reply-To: <1345192683.11751.66.camel@pasglop>
On Fri, Aug 17, 2012 at 06:38:03PM +1000, Benjamin Herrenschmidt wrote:
> This patch removes the powerpc "generic" updates of vcpu->cpu in
> load and put, and moves them to the various backends.
>
> The reason is that "HV" KVM does its own sauce with that field
> and the generic updates might corrupt it. The field contains the
> CPU# of the -first- HW CPU of the core always for all the VCPU
> threads of a core (the one that's online from a host Linux
> perspective).
>
> However, the preempt notifiers are going to be called on the
> threads VCPUs when they are running (due to them sleeping on our
> private waitqueue) causing unload to be called, potentially
> clobbering the value.
>
> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Paul Mackerras <paulus@samba.org>
prev parent reply other threads:[~2012-08-17 10:42 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-17 8:38 [PATCH 1/7] powerpc/kvm: Fix updates of vcpu->cpu on HV KVM Benjamin Herrenschmidt
2012-08-17 10:42 ` Paul Mackerras [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20120817104227.GC19296@bloggs.ozlabs.ibm.com \
--to=paulus@samba.org \
--cc=agraf@suse.de \
--cc=benh@kernel.crashing.org \
--cc=kvm-ppc@vger.kernel.org \
--cc=kvm@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox