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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  • peterlobl - Thursday, August 30, 2018 - link

    power to the press is power to the people ! Reply
  • bug77 - Thursday, August 30, 2018 - link

    What's more interesting for me is whether hardware fixes for these vulnerabilities are anything but toned down data prefetching. Reply
  • Mr Perfect - Thursday, August 30, 2018 - link

    I'd like to know what a hardware fix consists of also. Have they found a way to secure prefetching? Rumors suggest that the next processor refresh won't have HT, which makes me wonder if fixing the security flaws means they have to just shut this stuff off. Reply
  • bug77 - Friday, August 31, 2018 - link

    Most likely it means just that. Reply
  • jaydee - Thursday, August 30, 2018 - link

    What's with the "Buy the Right CPU" video right in the middle of the article? Is this the new norm? Reply
  • DanNeely - Thursday, August 30, 2018 - link

    Looks like a video ad posing as anandtech content. Someone on Twitter should ping Ian or Ryan so they can go scream at Purch's ad buyers, because that's totally unacceptable. IMO Reply
  • Ryan Smith - Thursday, August 30, 2018 - link

    Actually it is AnandTech content.

    Our current publisher (and going forward, Future as well) is pushing into doing short-form video. Quick takes under 2 minutes or so. And AnandTech is part of that.

    So now in most articles, you will find a video player that goes through a list of AnandTech videos (Purch's systems try to best match the video's subject with the article). And attached to that is a pre-roll ad that will run first, before the video.

    As for the videos themselves, we're still working on those. These first videos are all approved by me, but they're essentially recycled from Tom's Hardware. This is due to timing and the fact that we're still getting our feet wet with the format. Going forward we will have more unique videos, but we need to experiment here and see how we can offer AnandTech depth in under 120 seconds (without going full-on blipvert).
    Reply
  • jaydee - Friday, August 31, 2018 - link

    The big "X" on the bottom doesn't seem to close the video... There's always "Reader View" on most browsers now (which I'm using more and more), but it doesn't handle tables particularly well. Reply
  • Ryan Smith - Friday, August 31, 2018 - link

    To clarify, the 'X' is to get the floating window to stop following you around. The video anchored in the middle of the article is not intended to go away and will always be there. Reply
  • bug77 - Sunday, September 2, 2018 - link

    Lol, there's a video? Thank you, NoScript. Reply

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