From: David Gibson <david@gibson.dropbear.id.au>
To: Sam Bobroff <sam.bobroff@au1.ibm.com>
Cc: qemu-ppc@nongnu.org, qemu-devel@nongnu.org, groug@kaod.org
Subject: Re: [Qemu-devel] [PATCH v4 1/1] PPC: KVM: Support machine option to set VSMT mode
Date: Wed, 30 Aug 2017 15:01:11 +1000 [thread overview]
Message-ID: <20170830050111.GH3386@umbus.fritz.box> (raw)
In-Reply-To: <b1865d81456e774567ab624a5b4ffde47772dd08.1503034743.git.sam.bobroff@au1.ibm.com>
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On Fri, Aug 18, 2017 at 03:50:22PM +1000, Sam Bobroff wrote:
> KVM now allows writing to KVM_CAP_PPC_SMT which has previously been
> read only. Doing so causes KVM to act, for that VM, as if the host's
> SMT mode was the given value. This is particularly important on Power
> 9 systems because their default value is 1, but they are able to
> support values up to 8.
>
> This patch introduces a way to control this capability via a new
> machine property called VSMT ("Virtual SMT"). If the value is not set
> on the command line a default is chosen that is, when possible,
> compatible with legacy systems.
>
> Note that the intialization of KVM_CAP_PPC_SMT has changed slightly
> because it has changed (in KVM) from a global capability to a
> VM-specific one. This won't cause a problem on older KVMs because VM
> capabilities fall back to global ones.
>
> Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
There are some things that could be tweaked, but I see no reason they
can't be done as followups.
Applied to ppc-for-2.11.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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prev parent reply other threads:[~2017-08-30 5:02 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-18 5:50 [Qemu-devel] [PATCH v4 0/1] Exploit settable KVM_CAP_PPC_SMT Sam Bobroff
2017-08-18 5:50 ` [Qemu-devel] [PATCH v4 1/1] PPC: KVM: Support machine option to set VSMT mode Sam Bobroff
2017-08-30 5:01 ` David Gibson [this message]
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