From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: Wei Liu <wei.liu2@citrix.com>,
Xen-devel <xen-devel@lists.xen.org>,
Brian Woods <brian.woods@amd.com>,
Roger Pau Monne <roger.pau@citrix.com>
Subject: Re: [PATCH 4/9] x86/amd: Introduce CPUID/MSR definitions for per-vcpu SSBD support
Date: Thu, 6 Dec 2018 18:35:51 +0000 [thread overview]
Message-ID: <1ed7caa1-a78f-afec-6978-626178b5d710@citrix.com> (raw)
In-Reply-To: <5C08E2B402000078002036DA@prv1-mh.provo.novell.com>
On 06/12/2018 08:49, Jan Beulich wrote:
>>>> + {"amd_stibp", 0x80000008, NA, CPUID_REG_EBX, 15, 1},
>>>> + {"amd_ssbd", 0x80000008, NA, CPUID_REG_EBX, 24, 1},
>>>> + {"virt_sc_ssbd", 0x80000008, NA, CPUID_REG_EBX, 25, 1},
>>>> + {"amd_ssb_no", 0x80000008, NA, CPUID_REG_EBX, 26, 1},
>>> Since you're at it, why not also introduce names for bits 16-18
>>> at this occasion?
>> I haven't previously filled in names for the sake of it.
>>
>> The reason that ibrs/stibp/ssbd are here is because they're related and
>> I've also got a followon few patches to support MSR_VIRT_SPEC_CTRL on
>> Rome hardware via MSR_SPEC_CTRL, but I need an SDP and some
>> experimentation time before I'd be happy posting them.
>>
>> But to address your question, I can't locate those bits at all. Not
>> even in the NDA docs or Linux source.
> Hmm, that's certainly odd. I've found them quite some time ago in this
> public whitepaper:
> https://developer.amd.com/wp-content/resources/Architecture_Guidelines_Update_Indirect_Branch_Control.pdf
> They're all clearly IBRS/STIBP related.
Oh - I'd completely forgotten about that whitepaper. Some of the
details are superseded by the SSBD paper.
For now, I'll drop the bit names for features not used in this series.
One way or another, doing anything with the others will require some
experimentation on hardware which supports them.
~Andrew
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next prev parent reply other threads:[~2018-12-06 18:35 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-03 16:18 [PATCH 0/9] xen/amd: Support for guest MSR_VIRT_SPEC_CTRL support Andrew Cooper
2018-12-03 16:18 ` [PATCH 1/9] x86/spec-ctrl: Drop the bti= command line option Andrew Cooper
2018-12-04 16:19 ` Jan Beulich
2018-12-03 16:18 ` [PATCH 2/9] x86/cpuid: Drop the synthetic X86_FEATURE_XEN_IBPB Andrew Cooper
2018-12-04 16:21 ` Jan Beulich
2018-12-03 16:18 ` [PATCH 3/9] x86/cpuid: Extend the cpuid= command line option to support all named features Andrew Cooper
2018-12-04 16:28 ` Jan Beulich
2018-12-06 12:52 ` Wei Liu
2018-12-03 16:18 ` [PATCH 4/9] x86/amd: Introduce CPUID/MSR definitions for per-vcpu SSBD support Andrew Cooper
2018-12-04 16:06 ` Woods, Brian
2018-12-05 16:39 ` Jan Beulich
2018-12-05 17:50 ` Andrew Cooper
2018-12-06 8:49 ` Jan Beulich
2018-12-06 18:35 ` Andrew Cooper [this message]
2018-12-03 16:18 ` [PATCH 5/9] x86/amd: Probe for legacy SSBD interfaces on boot Andrew Cooper
2018-12-04 16:15 ` Woods, Brian
2018-12-05 16:50 ` Jan Beulich
2018-12-05 17:09 ` Andrew Cooper
2018-12-06 8:53 ` Jan Beulich
2018-12-06 10:59 ` Jan Beulich
2018-12-28 16:30 ` Andrew Cooper
2019-01-04 8:58 ` Jan Beulich
2018-12-03 16:18 ` [PATCH 6/9] x86/amd: Allocate resources to cope with LS_CFG being per-core on Fam17h Andrew Cooper
2018-12-04 16:38 ` Woods, Brian
2018-12-05 16:57 ` Jan Beulich
2018-12-05 17:05 ` Andrew Cooper
2018-12-06 8:54 ` Jan Beulich
2018-12-06 18:46 ` Andrew Cooper
2018-12-06 19:25 ` Woods, Brian
2018-12-07 10:17 ` Jan Beulich
2018-12-03 16:18 ` [PATCH 7/9] x86/amd: Support context switching legacy SSBD interface Andrew Cooper
2018-12-04 20:27 ` Woods, Brian
2018-12-06 10:51 ` Jan Beulich
2018-12-06 18:55 ` Andrew Cooper
2018-12-07 10:25 ` Jan Beulich
2018-12-03 16:18 ` [PATCH 8/9] x86/amd: Virtualise MSR_VIRT_SPEC_CTRL for guests Andrew Cooper
2018-12-04 21:35 ` Woods, Brian
2018-12-05 8:41 ` Jan Beulich
2018-12-05 19:09 ` Andrew Cooper
2018-12-06 8:59 ` Jan Beulich
2018-12-06 19:41 ` Woods, Brian
2018-12-06 10:55 ` Jan Beulich
2018-12-03 16:18 ` [PATCH 9/9] x86/amd: Offer MSR_VIRT_SPEC_CTRL to guests Andrew Cooper
2018-12-06 10:57 ` Jan Beulich
2018-12-03 16:24 ` [PATCH 0/9] xen/amd: Support for guest MSR_VIRT_SPEC_CTRL support Jan Beulich
2018-12-03 16:31 ` Andrew Cooper
2018-12-04 9:45 ` Jan Beulich
2018-12-04 11:26 ` Andrew Cooper
2018-12-04 12:45 ` Jan Beulich
2018-12-04 13:41 ` Andrew Cooper
2018-12-04 14:07 ` Jan Beulich
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