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Date: Thu, 13 Dec 2012 14:17:34 +0000
Message-ID: <CAFEAcA-WS0t5egP=LwVVBRPH0Lu4FCT4pP2Wh-eQ2=dM7Ed_fw@mail.gmail.com>
From: Peter Maydell <peter.maydell@linaro.org>
Content-Type: text/plain; charset=UTF-8
Subject: Re: [Qemu-devel] [PATCH 13/13] target-ppc: Give a meaningful error
 if too many threads are specified
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To: Alexander Graf <agraf@suse.de>
Cc: qemu-ppc@nongnu.org, Mike Qiu <qiudayu@linux.vnet.ibm.com>, qemu-devel@nongnu.org, David Gibson <dwg@au1.ibm.com>

On 13 December 2012 13:19, Alexander Graf <agraf@suse.de> wrote:
>
> On 13.12.2012, at 14:17, David Gibson wrote:
>
>> On Thu, Dec 13, 2012 at 01:57:16PM +0100, Alexander Graf wrote:
>>> What if I am using TCG on PPC?
>>
>> Then the stub version of kvmppc_smt_threads() returns 1, and since the
>> PPC TCG doesn't do any SMT emulation, that would seem to be correct...
>
> int kvmppc_smt_threads(void)
> {
>     return cap_ppc_smt ? cap_ppc_smt : 1;
> }
>
> So because we don't call kvm_arch_init, the cap is 0 and thus we return 1?

No, if we aren't CONFIG_KVM then that source file and version of
the function aren't compiled at all. David means the stub
function, which is in kvm_ppc.h:
static inline int kvmppc_smt_threads(void)
{
    return 1;
}

(if you don't like stubs lurking in the header file you could
have a target-ppc/kvm-stub.c by analogy with the i386 one I suppose)

-- PMM