Mailinglist Archive: opensuse-factory (439 mails)

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Re: [opensuse-factory] Huge single-core performance loss with spectre v2 mitigation enabled (it's the default)
On 10. 04. 19, 17:56, Dario Faggioli wrote:
On Wed, 2019-04-10 at 13:31 +0200, Jiri Slaby wrote:
On 10. 04. 19, 12:31, Michael Pujos wrote:

spectre_v2=retpoline,generic should be the default in my opinion.
If
good guys at Fedora (and other distros) are using it, so can
openSUSE.

They don't even have IBRS support in their kernels AFAIR.

FWIW, they seem to have that now, at least, according to this:

Fedora default: http://termbin.com/0u7o
* Kernel is compiled with IBRS support: YES
* IBRS enabled and active: YES (for kernel and firmware code)

The check script contains a bug:
https://github.com/speed47/spectre-meltdown-checker/issues/275

It considers every occurence of "IBRS" as "IBRS is engaged". Even if it
is only "IBRS_FW".

STATUS: NOT VULNERABLE (Full retpoline + IBPB are mitigating the
vulnerability)

Which confirms (if there were any need for that) that it's our own
doing, e.g., in kernel-default...

Of course, it's my patches "to blame":

patches.suse/0001-x86-speculation-Add-basic-IBRS-support-infrastructur.patch

patches.suse/0002-x86-speculation-Add-inlines-to-control-Indirect-Bran.patch

patches.suse/0003-x86-idle-Control-Indirect-Branch-Speculation-in-idle.patch

patches.suse/0004-x86-enter-Create-macros-to-restrict-unrestrict-Indir.patch
patches.suse/0005-x86-enter-Use-IBRS-on-syscall-and-interrupts.patch

thanks,
--
js
suse labs

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