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From: Richard Henderson <richard.henderson@linaro.org>
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Date: Thu, 14 Jun 2018 09:52:55 -1000
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Subject: Re: [Qemu-devel] [PATCH 3/3] target/ppc: filter out non-zero PCR
 values when using TCG
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To: Greg Kurz <groug@kaod.org>, David Gibson <david@gibson.dropbear.id.au>
Cc: qemu-ppc@nongnu.org, qemu-devel@nongnu.org

On 06/12/2018 10:19 PM, Greg Kurz wrote:
> I'm confused... I don't see anything related to HTM in TCG. Also we have
> the following in cap_htm_apply():
> 
>     if (tcg_enabled()) {
>         error_setg(errp,
>                    "No Transactional Memory support in TCG, try cap-htm=off");
> 
> I'm probably missing something... can you enlighten me ?

One of the two IBM machines -- and I thought it was ppc not s390x, but the code
you quote seems to deny that memory -- has stub support for TM within TCG.

To wit, the instructions are recognized and transactions always fail.  Which is
not a bad way to test the required fallback paths that rarely fail on hardware.
 ;-)


r~