With the launch of Intel’s latest 8th Generation Core mobile processors, the 15W Whiskey Lake U-series and the 5W Amber Lake Y-series, questions were left on the table as to the state of the Spectre and Meltdown mitigations. Intel had, previously in the year, promised that there would be hardware fixes for some of these issues in consumer hardware by the end of the year. Nothing was mentioned in our WHL/AML briefing, so we caught up with Intel to find out the situation.

There Are Some Hardware Mitigations in Whiskey Lake

The takeaway message from our discussions with Intel is that there are some hardware mitigations in the new Whiskey Lake processors. In fact, there are almost as many as the upcoming Cascade Lake enterprise parts. Intel told us that while the goal was to be transparent in general with how these mitigations were being fixed - we think Intel misread the level of interest in the specifics in advance of the Whiskey Lake launch, especially when the situation is not a simple yes/no.

For the mitigations, here is the current status:

Spectre and Meltdown on Intel
AnandTech Cascade
Lake
Whiskey
Lake
Amber
Lake
Spectre Variant 1 Bounds Check Bypass OS/VMM OS/VMM OS/VMM
Spectre Variant 2 Branch Target Injection Hardware + OS Firmware + OS Firmware + OS
Meltdown Variant 3 Rogue Data Cache Load Hardware Hardware Firmware
Meltdown Variant 3a Rogue System Register Read Firmware Firmware Firmware
  Variant 4 Speculative Store Bypass Firmware + OS Firmware + OS Firmware + OS
  Variant 5 L1 Terminal Fault Hardware Hardware Firmware

What this means is that Whiskey Lake is a new spin of silicon compared to Kaby Lake Refresh, but is still built on that Kaby Lake microarchitecture. Intel confirmed to us that Whiskey Lake is indeed built on the 14++ process node technology, indicating a respin of silicon.

As a result, both CPU families have the all-important (and most performance degrading) Meltdown vulnerability fixed. What remains unfixed in Whiskey Lake and differentiates it from Cascade Lake CPUs is Spectre variant 2, the Branch Target Injection. This vulnerability has its own performance costs when mitigated in software, and it has taken longer to develop a hardware fix.

What About Amber Lake?

The situation with Amber Lake is a little different. Intel confirmed to us that Amber Lake is still Kaby Lake – including being built on the 14+ process node – making it identical to Kaby Lake Refresh as far as the CPU die is concerned. In essence, these parts are binned to go within the 5W TDP at base frequency. But as a result, Amber Lake shares the same situation as Kaby Lake Refresh: all side channel attacks and mitigations are done in firmware and operating system fixes. Nothing in Amber Lake is protected against in hardware.

Performance

The big performance marker is tackling Spectre Variant 2. When fixed in software, Intel expects a 3-10% drop in performance depending on the workload – when fixed in hardware, Intel says that performance drop is a lot less, but expects new platforms (like Cascade Lake) to offer better overall performance anyway. Neither Whiskey Lake nor Amber Lake have mitigations for v2, but Whiskey Lake is certainly well on its way with fixes to some of the more dangerous attacks, such as v3 and L1TF. Whiskey Lake is also offering new performance bins as the platform is also on 14++, which will help with performance and power.

Intel’s Disclosure in the Future

Speaking with Intel, it is clear (and they recognise) that they appreciate the level of interest in the scope of these fixes. We’re pushing hard to make sure that with all future launches, detailed tables about the process of fixes will occur. Progress on these issues, if anything, is a good thing.

Related Reading

Title image from PC Watch

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  • NuclearArmament - Thursday, August 30, 2018 - link

    Use Fujitsu SPARC64/Solaris; IBM POWER 9/AIX, z/OS; Elbrus; IA-64/HP-UX; SX/Super UX; MIPS IV/IRIX; Alpha/OSF/1. Ditch x86, ARM, and never look back. Reply
  • NuclearArmament - Thursday, August 30, 2018 - link

    IBM's Cell (Broadband Engine Architecture), specifically the venerable QS22 variant is also still a decent option. Hitachi's SuperH, Apollo Computer's PRISM, and Fujitsu's FR-V, used in conjunction with a direct descendant of UNIX--System V, BSD, OSF/1--are also possible alternatives to the x86/ARM hardware and NT, GNU/Linux software hegemony. Reply
  • Senti - Thursday, August 30, 2018 - link

    Typical article of Ian: Variant 3 (Meltdown) mitigation on Amber Lake (=Kaby Lake) by Firmware? Yeah... (And many other squares are also incorrect.)
    Please, just don't write about things you don't understand at all.

    Tom's has much less such errors in their articles.
    Reply
  • Ian Cutress - Thursday, August 30, 2018 - link

    All squares confirmed by Intel. Reply
  • Senti - Thursday, August 30, 2018 - link

    Then how about using common sense and asking someone who understands the matter in case Intel PR says such things?

    If there is really a pure Firmware Meltdown (and other squares) mitigation (= don't require OS support at all) for Meltdown for Kaby Lake - THAT is interesting.
    Reply
  • Senti - Thursday, August 30, 2018 - link

    Then how about using common sense and asking someone who understands the matter in case Intel PR says such things?

    If there is really a pure Firmware Meltdown (and other squares) mitigation (= don't require OS support at all) for Meltdown for Kaby Lake - THAT is interesting.
    Reply
  • HStewart - Thursday, August 30, 2018 - link

    Ian,

    Did Intel provide any specific information about Hardware fixes provided? I also be curious if AMD or ARM has similar changes coming for cpu's - are they just relying on Firmware / Microcode
    Reply
  • HStewart - Thursday, August 30, 2018 - link

    One more thing, in following web site - it was mention that Smartphones also could be effected and curious if anybody has more information on that

    https://meltdownattack.com/
    Reply
  • dynamis31 - Thursday, August 30, 2018 - link

    the price to pay if you have xeons :
    https://www.phoronix.com/scan.php?page=article&...
    aws, google, hpc supercomputer owners must be happy
    Reply
  • Dr.X - Monday, September 3, 2018 - link

    @dynamis31 Great contribution here! Thanks! I forgot about that great review. Reply

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