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Subject: Re: Is 2nd Generation Intel(R) Xeon(R) Processors (Formerly Cascade Lake) affected by MDS
From:   Tony Luck <tony.luck@gmail.com>
In-Reply-To: <20190524141732.GA4412@kroah.com>
Date:   Fri, 24 May 2019 07:45:31 -0700
Cc:     Jinpu Wang <jinpu.wang@cloud.ionos.com>,
        Thomas Gleixner <tglx@linutronix.de>, tony.luck@intel.com,
        Arjan van de Ven <arjan@linux.intel.com>,
        linux-kernel@vger.kernel.org,
        Elmar Gerdes <elmar.gerdes@cloud.ionos.com>
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References: <CAMGffEkQmdrrH3+UChZx_Af6WcFFQFw6fz3Ti4CRUau-wq7jow@mail.gmail.com> <20190524141732.GA4412@kroah.com>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Sender: linux-kernel-owner@vger.kernel.org
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Stepping 5 is preproduction of cascade lake. MDS mitigation is in production=
 parts (stepping >=3D 6)

Sent from my iPhone

> On May 24, 2019, at 07:17, Greg Kroah-Hartman <gregkh@linuxfoundation.org>=
 wrote:
>=20
>> On Fri, May 24, 2019 at 03:19:34PM +0200, Jinpu Wang wrote:
>> Resend with plain text, and remove confidential unnecessary signature.
>> sorry for spam.
>>=20
>> Hi Thomas, hi Greg, hi Tony, hi Arjan, hi other expert on the list
>>=20
>> I noticed on our Cascade lake with 4.14.120,  the kernel is reporting
>> vulnerable:
>> jwang@ps401a-912:~$ head /sys/devices/system/cpu/vulnerabilities/mds
>> Vulnerable: Clear CPU buffers attempted, no microcode; SMT vulnerable
>>=20
>> But according to INTEL,  they have built the mitigation in hardware
>> for Cascade Lake:
>> https://www.intel.com/content/www/us/en/architecture-and-technology/engin=
eering-new-protections-into-hardware.html
>>=20
>> We are using latest microcode from debian:
>> https://metadata.ftp-master.debian.org/changelogs//non-free/i/intel-micro=
code/intel-microcode_3.20190514.1~deb9u1_changelog
>> lscpu:
>> jwang@ps401a-912:~$ lscpu
>> Architecture:          x86_64
>> CPU op-mode(s):        32-bit, 64-bit
>> Byte Order:            Little Endian
>> CPU(s):                96
>> On-line CPU(s) list:   0-95
>> Thread(s) per core:    2
>> Core(s) per socket:    24
>> Socket(s):             2
>> NUMA node(s):          2
>> Vendor ID:             GenuineIntel
>> CPU family:            6
>> Model:                 85
>> Model name:            Intel(R) Xeon(R) Platinum 8268 CPU @ 2.90GHz
>> Stepping:              5
>> CPU MHz:               3228.226
>> CPU max MHz:           3900.0000
>> CPU min MHz:           1000.0000
>> BogoMIPS:              5800.00
>> Virtualization:        VT-x
>> L1d cache:             32K
>> L1i cache:             32K
>> L2 cache:              1024K
>> L3 cache:              33792K
>> NUMA node0 CPU(s):     0-23,48-71
>> NUMA node1 CPU(s):     24-47,72-95
>> Flags:                 fpu vme de pse tsc msr pae mce cx8 apic sep
>> mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht
>> tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc art arch_perfmon pebs
>> bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf pni pclmulqdq
>> dtes64 monitor ds_cpl vmx smx est tm2 ssse3 sdbg fma cx16 xtpr pdcm
>> pcid dca sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes
>> xsave avx f16c rdrand lahf_lm abm 3dnowprefetch cpuid_fault epb cat_l3
>> cdp_l3 invpcid_single intel_ppin ssbd mba ibrs ibpb stibp tpr_shadow
>> vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2
>> erms invpcid rtm cqm mpx rdt_a avx512f avx512dq rdseed adx smap
>> clflushopt clwb intel_pt avx512cd avx512bw avx512vl xsaveopt xsavec
>> xgetbv1 xsaves cqm_llc cqm_occup_llc cqm_mbm_total cqm_mbm_local
>> dtherm ida arat pln pts pku ospke flush_l1d arch_capabilities
>>=20
>> Clearly we want to buy Cascade Lake if the hardware mitigations are in
>> place, but the information on the internet is quite limited and
>> misleading.
>>=20
>> Could anyone of you could clarify it for us?
>> Does it mean 4.14.120 is missing patches for detecting Cascade Lake
>> mitigation, Or maybe only small set of cascade lake has mitigation?
>> Or the community/intel are not sure about it yet?
>=20
> Did you try 4.19 or 5.1?  Try those and see if anything changes.
>=20
> If not, odds are you need a microcode update from Intel, please contact
> them, nothing we can do about that.
>=20
> If 4.14 works different from 4.19 or 5.1, please let us know.
>=20
> thanks,
>=20
> greg k-h