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Google Says CPU Patches Cause 'Negligible Impact On Performance' With New 'Retpoline' Technique (theverge.com)

In a post on Google's Online Security Blog, two engineers described a novel chip-level patch that has been deployed across the company's entire infrastructure, resulting in only minor declines in performance in most cases. "The company has also posted details of the new technique, called Retpoline, in the hopes that other companies will be able to follow the same technique," reports The Verge. "If the claims hold, it would mean Intel and others have avoided the catastrophic slowdowns that many had predicted." From the report: "There has been speculation that the deployment of KPTI causes significant performance slowdowns," the post reads, referring to the company's "Kernel Page Table Isolation" technique. "Performance can vary, as the impact of the KPTI mitigations depends on the rate of system calls made by an application. On most of our workloads, including our cloud infrastructure, we see negligible impact on performance." "Of course, Google recommends thorough testing in your environment before deployment," the post continues. "We cannot guarantee any particular performance or operational impact."

Notably, the new technique only applies to one of the three variants involved in the new attacks. However, it's the variant that is arguably the most difficult to address. The other two vulnerabilities -- "bounds check bypass" and "rogue data cache load" -- would be addressed at the program and operating system level, respectively, and are unlikely to result in the same system-wide slowdowns.

120 comments

  1. You can't "patch" hardware by Anonymous Coward · · Score: 1, Interesting

    This is a hardware level problem. This will be continued to be exploited pretty much indefinitely. In my estimation this is the single biggest security problem ever created. My advice? Mortgage your house, cash out the retirement fund, and dump it all into AMD. Because Intel is going to be destroyed by lawsuit after lawsuit.

    1. Re: You can't "patch" hardware by Anonymous Coward · · Score: 2, Informative

      You can fix the microcode. You can also include software workarounds for hardware flaws. An example was the Pentium F00F bug, which was addressed by the operating system.

    2. Re:You can't "patch" hardware by supremebob · · Score: 5, Informative

      Geez... You make it sound like this is the first ever time someone has had to write a software patch to bypass a hardware flaw. Driver developers have had to come up with clever workarounds to hardware defects since the the dawn of computing.

      These Intel firmware fixes are just going to become part of yet another security update that will be required to keep systems secure.

    3. Re:You can't "patch" hardware by 110010001000 · · Score: 3, Insightful

      Again: there are no Intel firmware fixes for Meldown. It cannot be fixed without replacing the processor. There are only mitigation workarounds.

    4. Re:You can't "patch" hardware by Anonymous Coward · · Score: 1

      This is a hardware level problem. This will be continued to be exploited pretty much indefinitely.

      Have you looked at the actual retopline patches rather than simply inserting foot? It is an interesting approach to block speculative fetching by using indirect jumps/calls/returns.

    5. Re:You can't "patch" hardware by AvitarX · · Score: 1

      Based in the summary, this is a fix that dramatically reduces the impact of meltdown (too lazy to read up as it doesn't directly impact me), if they found a way to keep meltdown in the lower bound, they're doing alright.

      Lower bound being about 5% (initial patch on a pcid supporting processor was 7% in an artificial postgress benchmark that was more prone to slowdown than real life), if they found a way to get ok'd chips to that point, and shave a little bit off their, it dramatically reduces the problem.

      It pulls them ahead of AMD for single thread at sane price at the very least.

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    6. Re:You can't "patch" hardware by supremebob · · Score: 1

      Sure, but it's kind of like the Intel Pentium F00F bug. The underlying hardware issue will always be there, but the OS kernel can prevent that instruction from being run on the system.

    7. Re:You can't "patch" hardware by Anonymous Coward · · Score: 0

      It's an old tactic

      Someone threw a brick and broke your window and then came and apologize, and offer to fix your windows for you

      Unbeknownst to you while they were inside your installing a new window, they also installed tons of bugging devices, hidden all over your house

      On the 'Intel Meltdown' affair the same thing happens

      Intel's chips are 'broken', and 'walla!', there is a fix!

      So they offer a patch and you download and install it

      Unbeknownst to you, that patch came with all kinds of surveillance bugs inside

      Ultimately THE BIG BROTHER WINS

    8. Re:You can't "patch" hardware by Anonymous Coward · · Score: 0

      It's hardly a big deal. There have always been hardware bugs. It's like you're a little kid who has never seen anything like this before.

    9. Re: You can't "patch" hardware by Anonymous Coward · · Score: 0

      Hard to believe;, speculative execution is the cornerstone ofCPU/RAM performance, not just a faulty instruction. May be it can be somewhat mitigated but it is yet to see if the fix works for every attack vector or if the fix costs too much performance for each particular workload. Think about all this Deep Learning that is probably quite memory intensive.

    10. Re: You can't "patch" hardware by Anonymous Coward · · Score: 0

      It is on the level of bug that "internal combustion engine produces CO2". More like a design feature.

    11. Re:You can't "patch" hardware by admin7087 · · Score: 1

      I don't understand this talk about 'dramatically reducing the problem'. Either there is an exploitable flaw or not. If the fix only makes implementing the type of exploit harder, then it's not going to help at all. Some assembler freak and malware author somewhere in the world will still make it work.

      I'm not claiming that there is no fix, only that mere workarounds may be of limited value. What I've read so far hasn't really reassured me. The same can be said about rowhammer, btw. What's so worrying about these types of attacks is that best practices will not help you against them.

    12. Re: You can't "patch" hardware by Anonymous Coward · · Score: 0

      Well, if you think about the literal definition, you can. You're just stapling on a cover that prevents it from interfering with the function, but it's still there.

    13. Re: You can't "patch" hardware by Anonymous Coward · · Score: 0

      It's on the level of FDIV or F00F. A bunch of FUD and people with tinfoil hats running around in circles screaming but in the end it won't affect anyone, just like it hasn't affected anyone for the past 23 years that it's existed.

    14. Re: You can't "patch" hardware by Anonymous Coward · · Score: 0

      Nay, when everything is in Cloud and you can possibly break out of your VM and have fun with Google or Amazon digital infrastructure that hosts just about everything, it is much more exciting than some bad division on your desktop PC. Did Washington outsource their top secret data to the could already ?

      And the performance hit by the fixes has a potential to make the clouds way slower. Someone is in for a huuuge infrastructure upgrade to the newest CPUs that are not yet around.

    15. Re: You can't "patch" hardware by Anonymous Coward · · Score: 0

      I won't be patching my kernel and I bet you a hundred bucks that I won't suffer any security breaches.

      This "flaw" has existed for more than two decades and not a single recorded incident of exploitation has ever arisen due to it. Your computer would first have to be infected with malware to even begin to think about exploiting it and I have never had a system infected in forty years.

    16. Re: You can't "patch" hardware by Anonymous Coward · · Score: 0

      https://io9.gizmodo.com/5804116/why-every-human-has-a-blind-spot---and-how-to-find-yours

      Life can fix hardware problems in software too!

    17. Re: You can't "patch" hardware by Anonymous Coward · · Score: 0

      This "flaw" has existed for more than two decades and not a single recorded incident of exploitation has ever arisen due to it.

      Duh, because nobody found it, now it has been found and documented so malware writers can exploit it.

    18. Re: You can't "patch" hardware by Anonymous Coward · · Score: 0

      Whoop-de-fuckin-doo. It's not a serious flaw. Why are they so afraid to PROVE that this is an issue? Even Google won't provide source code to demonstrate this working and even if it did, you'd have to be infected by malware, which is already bad regardless of anything, and you'd have to be running without any kind of firewall in place in order for collected data to be transferred anywhere.

      Colour me completely unconcerned. I won't be patching and it won't cause any problems whatsoever. I suspect all of this FUD is to get people to install spyware patches that end up being far worse than the "problem".

      Have you ever played Deus Ex: Human Revolution? Remember the part where the global "flaw" was discovered and FUD was spread to get everyone to upgrade to a "fixed" chip which ended up allowing Tai-Yong Medical to turn everyone into zombies? That's eerily similar to what is happening here. I'm not falling for it. Twenty three years of being totally safe and suffering zero ill effects from this "flaw" tells me that I have nothing to worry about.

  2. How to protect your PC... by Anonymous Coward · · Score: 0

    From https://www.pcworld.com/article/3245810/security/how-to-protect-your-pc-meltdown-spectre-cpu-flaws.html

    Microsoft updated Edge and Internet Explorer alongside Windows 10. Firefox 57 also wraps in some Spectre safeguards. Chrome 63 made “Site Isolation” an optional experimental feature. You can activate it right now by entering chrome://flags/#enable-site-per-process into your URL bar, then clicking Enable next to “Strict site isolation.” Chrome 64 will have more protections in place when it launches on January 23.

    1. Re: How to protect your PC... by Anonymous Coward · · Score: 0

      What a bs. Browser has not much to do with the problem. The mitigation requires at least OS modification or even CPU microcode modification. And the in terms of performance might get quite large. No one cares about your Windows PC, with your buggy browser shmowser, you don't have security there anyways; but the event is like, " Bye bye cloud security" and this is serious.

    2. Re: How to protect your PC... by Anonymous Coward · · Score: 0

      It is possible that there are ways to make it less remotely accessible, though. Restricting site capabilities could be useful.

    3. Re: How to protect your PC... by Anonymous Coward · · Score: 0

      The point of public IaaS is that it lets Anyone run Arbitrary OS images. Restricting that is good idea, let's turn back time and forget about all this Software Defined Datacetre fallacy.

  3. Re: But why? by Anonymous Coward · · Score: 0

    Cool, thanks.

  4. Re: But why? by Anonymous Coward · · Score: 0

    Any time!

    Testicles

  5. time flies by mapkinase · · Score: 4, Funny

    Pentium 4.99989 disaster seems like yesterday.

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    I do not believe in karma. "Funny"=-6. Do good and forbid evil. Yours, Oft-Offtopic Flamebaiting Troll.
  6. Or just Buy AMD & get no slow down with more p by Joe_Dragon · · Score: 5, Informative

    Or just Buy AMD & get no slow down with more pci-e lanes.

  7. More lies by 110010001000 · · Score: 1

    This isn't a "chip-level" patch. The spin control here is admirable.

    1. Re:More lies by nyet · · Score: 2

      I definitely don't see how requiring you to replace GCC and recompile every single binary is "chip-level".

    2. Re:More lies by 110010001000 · · Score: 4, Interesting

      It isn't "chip level". The Intel PR spin is out in full effect. Meltdown is a major flaw that can only be fixed by removing the flawed Intel processor and replacing it with a processor that doesn't contain the flaw. If you don't do that, the best you can do is mitigate the effects. There is no microcode fix either. What Google is doing is recompiling everything, which is fine, but hackers aren't going to do that.

    3. Re:More lies by whoever57 · · Score: 1

      Exactly, you can't provide a general fix to chip-level security problems by changes to "programs". People can compile their own programs and have root access on VMs that they control.

      However, Google controls the hypervisor and presumably, it's at this level that the attack can be blocked or mitigated.

      --
      The real "Libtards" are the Libertarians!
    4. Re:More lies by 110010001000 · · Score: 2

      Exactly. The funny thing is these "cloud companies" always control their own infrastructure, so these types of "fixes" make sense. Everyone else is screwed.

    5. Re:More lies by atrex · · Score: 1

      Technically, you'd have to replace the motherboard too. Really no such thing as just replacing the chip since all motherboards are pretty much designed for a specific chip series at this point, unless there exists a chip in the same series without the flaw. I certainly couldn't name a single motherboard where you could choose between installing an LGA 2066 Core i9 and a Socket sTR4 Ryzen Threadripper.

    6. Re:More lies by Anonymous Coward · · Score: 0

      [...] since all motherboards are pretty much designed for a specific chip series at this point [...]

      That's just current Intel motherboards, which many speculate is just for profit-taking. For comparison, AMD has for many years supported multiple processor architectures on the same motherboard socket, such as how current socket AM4 motherboards support chips made on the Zen and Excavator architectures. There's no reason that a company would be unable to release an updated chipset on the same socket to fix this particular issue, other than an unwillingness to foot the bill of doing so.

  8. Re: Or just Buy AMD & get no slow down with mo by Anonymous Coward · · Score: 0, Insightful

    This probably offers a false sense of security. It's very possible that there are bugs lurking in AMD hardware that are just as severe. Just because AMD processors aren't susceptible to Meltdown doesn't mean there aren't other vulnerabilities unique to AMD processors.

  9. Google's technique requires patching binaries/code by JoeyRox · · Score: 4, Interesting

    Google's technique is to patch binaries so that branches/calls don't use the branch prediction mechanism of the CPU, which has a small performance hit but much smaller than KPTI. I suppose the presumption is that harmful code which uses the technique would have to compile it into their binary since most OS's prevent the self-modification of code segments/TLB entries once they've been placed into memory by the OS loader. But what about code segments generated entirely at runtime, including from interpreters and libraries like libjit?

  10. amd needs desktop level server chips / ipmi boards by Joe_Dragon · · Score: 1

    amd needs desktop level server chips / ipmi boards. Like intel exon-e3

    Ryzen PRO chips fully support ECC so we just need a few boards with IPMI

    ThreadRipper is an nice workstation system.

      Threadripper boards with IPMI will be nice as it has higher clocks with less cores then epyc chips.

    an full eypc board is overkill for smaller site hosts.

  11. But what you can't fix... by Anonymous Coward · · Score: 0

    ...is your micropenis.

    1. Re: But what you can't fix... by Anonymous Coward · · Score: 0

      Agreed!

  12. Re:Google's technique requires patching binaries/c by Fly+Swatter · · Score: 1

    How is patching software a 'chip-level patch?' Is the summary that wrong?

  13. Re:Google's technique requires patching binaries/c by 110010001000 · · Score: 1

    It works for Google because they run everything on their own infrastructure and have full control over it. They don't run it on someone elses "cloud". Rather ironic.

  14. Re: amd needs desktop level server chips / ipmi bo by Anonymous Coward · · Score: 0

    Stop with the off-topic AMD spam. And yes, your post is spam, and completely irrelevant to the thread. AMD is also susceptible to the Spectre bug, and it's not a stretch at all to suspect there may be additional bugs in AMD hardware. Stop astroturfing.

  15. Re:Or just Buy AMD & get no slow down with mor by RhettLivingston · · Score: 1

    This incident highlights the importance of maintaining vendor diversity in data centers. Modern processors are complex enough that it is not unlikely that any given design has problems waiting to be discovered. It would seem wise for large-scale clients to hedge their bets by having a mix of devices carrying their workload. Imagine the damage if someone discovered a means of bricking Intel processors and added the payload to one of the better viruses.

  16. Re:Idiotic Moderation by 110010001000 · · Score: 5, Insightful

    Because it doesn't make sense: Intel has a KNOWN UNFIXABLE FLAW in Meltdown. It cannot be fixed. You are saying "don't switch to AMD because they might have a major flaw too at some point". Meltdown is a much larger problem than Spectre is.

  17. But just as backdoored thanks to Secure Processor! by Anonymous Coward · · Score: 0

    AMD's Trustzone based equivalent of Intel ME/TPM/DRM which you STILL DON'T CONTROL THE SIGNING KEY TO.

    Plus they were marketing Secure Processor as one of Vega's new features over Polaris, so why you would touch current generation AMD, Intel, or Nvidia hardware if you didn't have to is beyond me.

    VIA is apparently getting back in the game, but unless they got pressured to be the most openest company ever in order to carve away american x86 marketshare, they are going to fumble this attempt just like their last half dozen: By having an ok but slightly expensive batch of hardware and a complete and total refusal to disclose the hardware documentation necessary to make it actually work anywhere, probably even including under windows!

  18. Re: amd needs desktop level server chips / ipmi bo by 110010001000 · · Score: 5, Informative

    More Intel spin. Spectre and Meltdown are different flaws. Meltdown is severe and unfixable and only affects Intel.

  19. Re: Idiotic Moderation by Anonymous Coward · · Score: 0

    Great, more abusive moderation. Slashdot has really gone in the toilet. The shill gets modded up while posts get modded down for pointing out why the shill is giving bad advice.

    AMD PROCESSORS ARE NOT A MAGIC BULLET

    AMD PROCESSORS ARE VULNERABLE TO SPECTRE

  20. Re: Idiotic Moderation by 110010001000 · · Score: 2

    No one said AMD was a magic bullet, but Intel at this point is bullet ridden. I only use Intel processors myself, but this is a huge flaw.

  21. Re:Idiotic Moderation by Anonymous Coward · · Score: 0

    Why would you assume there aren't any other serious vulnerabilities in AMD hardware?

    Nobody is assuming that, but certainly this bug isn't present in AMD's microarchitecture. Maybe AMD's microarchitecture has serious undiscovered vulnerabilities and maybe Intel's microarchitecture has even more serious undiscovered vulnerabilities but we can only make decisions based on what we know.

    What we know is that Intel's chips have a serious security vulnerability that requires a performance-crippling fix. AMD's do not have this vulnerability, they may have others that we don't know about and Intel may also have others that we don't know about beyond the serious one we already know about.

    The two posts in this article from the poster of the original comment both appear to be AMD astroturfing. It would appear that another AMD shill has mod points.

    Do you also go around complaining that people suggesting a switch to Linux from Windows for security reasons are Linux astroturfing because Linux might contain serious undiscovered vulnerabilities?

    I suppose you just suck it up and be vulnerable or performance crippled because of the possibility that an alternative might have an undiscovered problem.

  22. Retpoline is for Spectre by Anonymous Coward · · Score: 1

    Meltdown patch (KPTI) will still hurt applications with lots of syscalls, or lots of userspace->kernel context switches.

    1. Re: Retpoline is for Spectre by Anonymous Coward · · Score: 0

      Yup. Mod parent up!

  23. Re:Idiotic Moderation by Anonymous Coward · · Score: 1, Interesting

    A flaw has just been discovered in my car where it has a 20% chance of spontaneously bursting into flames when you turn on the ignition. However, I've decided to keep buying the same model of car because other cars likely have equally severe issues that just haven't been discovered yet.

    Be smart - keep buying shit.

  24. Re: But why? by Anonymous Coward · · Score: 0

    You've got balls to post this drivel.

  25. You can't "scope" hardware by Anonymous Coward · · Score: 0

    True, but few have been this big in scope.

  26. Summary not very helpful, here's my attempt. by PhrostyMcByte · · Score: 5, Informative

    Google has created "retpoline", a technique which allows an indirect branch (e.g. a vtable call) to occur in a way that effectively disables speculative execution by isolating branch target prediction into a safe effectless loop. This addresses Variant 2 (aka Spectre).

    Retpoline does not depend on or assist a CPU or an OS patch: it is done purely at the software level, per-app, by a compiler. There is no simple OS-wide patch.

    Google says a retpoline call has performance "within cycles" of a regular old mispredicted branch. The zero-cost predictions we're used to are a thing of the past, because it effectively forces misprediction. I'd be curious to see a benchmark of an indirection-heavy platform like .NET.

    This does not help address or optimize Variant 3, which is what the big kernel patches for Page Table Isolation are needed for. So, your I/O-dependent apps like databases are still going to take a big performance hit. Nor does it address Variant 1.

    1. Re: Summary not very helpful, here's my attempt. by pop+ebp · · Score: 1

      EXACTLY. The summary is horrible. It made it sound like Google invented a novel technique that makes the KPTI/Variant 3 (Meltdown) mitigation slowdown "negligible". But actually the blog post simply says:

      • They invented a technique called Retpoline that mitigates Variant 2, with negligible performance impact; and
      • When testing KPTI/Variant 3 (Meltdown) mitigation on their own workflows, they found the performance impact negligible.
  27. Google is connected to Intel at the hip by bongey · · Score: 4, Insightful

    Google is dependant on Intel CPUs at the moment and has a vested interest in not saying well our cloud just got 5-30% percent slower.

    1. Re:Google is connected to Intel at the hip by Anonymous Coward · · Score: 0

      Except that the '30% slower' is totally speculative at the moment. Not to mention that the circumstances when the statement would apply are left completely undefined.

    2. Re:Google is connected to Intel at the hip by swillden · · Score: 1

      Google is dependant on Intel CPUs at the moment and has a vested interest in not saying well our cloud just got 5-30% percent slower.

      Exactly the same as their competitors, including in-house data centers as well as other cloud providers.

      --
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  28. Re: Idiotic Moderation by Anonymous Coward · · Score: 0

    Your example of Linux and Windows is not equivalent. Both certainly can have serious bugs, and avoiding a single bug is not the best justification for switching from Windows to Linux.

    There is a fundamental difference between Linux and Windows, one that is not present between AMD and Intel. The difference is the open source versus closed source development models. There is a very valid reason to think that open source is more secure, because it's much harder to hide backdoors in open source.

    If you could make the case that AMD processors were designed in a fundamentally different manner that made them less prone to some classes of vulnerabilities, you'd have a stronger argument. I have yet to see such a case be made. I'll be happy to listen, if you can make the case that AMD has a superior design philosophy or process.

  29. I think they're not looking at the big picture by Anonymous Coward · · Score: 1

    These three exploits are instances, not three different principles. The principle is the same, and there is no reason to suspect that there won't be more instances that follow that principle. CPUs speculatively execute code and load cache lines based on that execution. Intel CPUs can furthermore access privileged memory when unprivileged code is executed speculatively. That's the principle. The way the speculatively executed code is guarded and the speculative window is widened differs between the three exploits, but if you only protect against these three attacks, you leave the fundamental principle available to different exploitation. KPTI prevents privileged memory accesses from userland code no matter how the CPU is coaxed into making these speculative accesses. It does have a performance impact, but at least it addresses all as yet unknown ways of exploiting speculative execution.

  30. Re:Google's technique requires patching binaries/c by PhrostyMcByte · · Score: 5, Insightful

    Google's technique ... has a small performance hit but much smaller than KPTI.

    Keep in mind Google's technique (retpoline) is not an alternative to KPTI. Retpoline addresses Variant 2. KPTI addresses Variant 3. Both are required.

  31. Seriously misleading by jspenguin1 · · Score: 2

    Not only do they misspell the name of the mitigation technique, the "retpoline" technique only protects against the indirect branch variant of Spectre. The fix for Meltdown is still KPTI, with all the same overhead that involves. The "negligible inpact on performance" is on top of the KPTI changes.

    1. Re:Seriously misleading by Anonymous Coward · · Score: 0

      And you know all of this for sure, how? Trump told you?

    2. Re:Seriously misleading by ScentCone · · Score: 0, Flamebait

      And you know all of this for sure, how? Trump told you?

      No, he got it from Hillary Clinton. She's the server expert.

      --
      Don't disappoint your bird dog. Go to the range.
  32. Why patch on a closed farm? by Anonymous Coward · · Score: 0

    Why do a performance downgrade patch on a closed ecosystem farm? If you are not going to run outside code why would you bother patching?

  33. Re: Idiotic Moderation by Anonymous Coward · · Score: 0

    Is there a compelling reason to believe that AMD processors are less likely to be vulnerable in the future than Intel processors? If one manufacturer is cutting corners with the engineering and the other isn't, then there's a logical reason. Otherwise, there isn't a logical basis for using that as a reason to change your behavior in the future. It's also entirely possible that, faced with backlash and distrust, the manufacturer might take additional steps to ensure that no such similar issues occur in the future. If there was demonstable evidence of this, it might be a good reason not to switch.

    The important question is whether there is any reason to believe Intel processors will be more vulnerable in the future.

  34. Re: Or just Buy AMD & get no slow down with mo by Anonymous Coward · · Score: 0

    I made sure that damn Microsoft/intel patch was uninstalled and hidden from my updates. I run AMD processors, so take your FUD elsewhere.. This is an Intel problem!

  35. Re: Idiotic Moderation by Anonymous Coward · · Score: 1, Informative

    Forget about the future. What about NOW? If you run Intel you are vulnerable to Meltdown. If you run AMD, you aren't. Meldown is a major bug. And yes, AMD microarchitecture is superior. It isn't affected by Meltdown.

  36. Re: Idiotic Moderation by Anonymous Coward · · Score: 4, Interesting

    I take it you didn't read AMD's press release explaining exactly what you say you want to hear.

    It's true that all processors have errata and can have bugs/flaws/security weaknesses... but, the Meltdown flaw which does not affect AMD is a specific kind which can't affect AMD because of architecture differences. Specifically, AMD checks to make sure user land code doesn't try to access kernel data without the correct permissions before executing predictive branches on it. Intel doesn't -- it goes ahead and runs the illegal code before flagging an exception to dump the branch after the fact. So, for a short time, there's data in cache on an Intel chip that should NOT be there because it should never have been accessed by the system to begin with.... and a specially crafted program can read it before it's flushed. This is because Intel (and ARM and others) chose a certain optimization for their speculative engine while AMD chose a different, more secure architecture.

    https://www.pcgamesn.com/intel...

    AMD's fix is -- no fix needed b/c we weren't stupid enough to let even speculative code run without checking its permissions first.

    Per AMD for the initial Linux kernel patch:

    AMD processors are not subject to the types of attacks that the kernel page table isolation feature protects against. The AMD microarchitecture does not allow memory references, including speculative references, that access higher privileged data when running in a lesser privileged mode when that access would result in a page fault.

    AMD is definitely vulnerable to lesser exploits -- some which are also patched others are mitigated... and some are obfuscated because they are processor generation specific. But, they are not vulnerable for Meltdown or any variant like it by design.

    Now remember... the fix for Meltdown is to flush the cache -- all levels -- when switching from user mode to kernel mode or vice versa.... every single time. That's a heck of a hit for some use cases. I believe Intel has found some ways to mitigate it with their 8th gen core series and will likely tinker with a better patch in the future.

    It is absolutely a great idea to purchase an AMD processor if it suits the needs of one's business for those use cases where it will perform better than an Intel chip that is crippled by this horrendous bug -- all things being equal. Obviously, businesses have contracts with 3rd party suppliers and don't necessarily get to pick and choose every aspect of hardware, nor is AMD a savior necessarily if their total cost of ownership is higher because of servicing more varieties of equipment, dealing with more motherboard types and vendors, electricity / Air conditioning costs, etc.

    One doesn't have to be a shill for AMD to notice it's obvious that Intel has a serious hardware flaw that AMD lacks and while any CPU can have errata, most can be patched with negligible effects. Intel having to flush caches between modes is a serious flaw if one runs programs that switch modes constantly. For average users and even gamers, there's not a huge impact. I'm running the patch right now for Windows and I can tell it affects Virtual Machines and a bit of file serving, but not enough for me to be too upset about it. If I had a high-end cluster for databases, a 20% hit to that would definitely make me want to check out AMD as an alternative... b/c even IF AMD has a bug that needs patching, it's unlikely to ever affect performance like this one does by requiring cache flushes to avoid having processes of user and kernel modes running at the same time for fear of one stealing data from the other.

  37. Patched OS tables? by Anonymous Coward · · Score: 0

    Everyone rightly talks about the 3-4 variants and what CPUs were hit.

    However, for those of use looking for a fix for what hardware we have, are there any tables listing by OS and OS version the earliest (and thus downstream likely) are patched?

    Especially for Android, since that's a cluster?uck. Besides the various versions, there are various manufacturers that stopped applying software updates. There are people that root their devices to run mods that are patched, derived from the latest updated versions from Google. It'd be nice to see when Google patched what and when so people can determine what they are running is likely patched or not. If Goole knew about these sort of vulnerabilities, did they update KitKat and Lollipop? When was, assuming, Marshmallow and Nougat updated?

    1. Re:Patched OS tables? by AvitarX · · Score: 1

      I don't think many ARM CPUs use out of order.

      Posting primarily to be corrected if I'm wrong.

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    2. Re: Patched OS tables? by Anonymous Coward · · Score: 0

      Arm64 which is the modern standard for high end Arms, surely does out of order execution and branch prediction. Low end models don't.

  38. Re: Idiotic Moderation by Anonymous Coward · · Score: 0

    Your example of Linux and Windows is not equivalent.

    No, it is an analogy.

    Both certainly can have serious bugs, and avoiding a single bug is not the best justification for switching from Windows to Linux.

    Wrong, that depends on the bug. Not all bugs are the same and in this case the entire system can be compromised and the fix is a significant performance penalty which is about as serious a bug as you can get.

    There is a fundamental difference between Linux and Windows, one that is not present between AMD and Intel. The difference is the open source versus closed source development models.

    Then substitute "Linux" with "macOS".

    I'll be happy to listen, if you can make the case that AMD has a superior design philosophy or process.

    No need, the point is they do not suffer from this specific bug nor do they have any known bug that even approaches the extreme level of severity of this one.

  39. Everyone is connected to Intel at the hip by Anonymous Coward · · Score: 0

    Is anyone running their cloud on AMD?

  40. Re: Or just Buy AMD & get no slow down with mo by Anonymous Coward · · Score: 2, Insightful

    This probably offers a false sense of security. It's very possible that there are bugs lurking in AMD hardware that are just as severe. Just because AMD processors aren't susceptible to Meltdown doesn't mean there aren't other vulnerabilities unique to AMD processors.

    And sticking with Intel even after this patch probably offers a false sense of security. It's very possible that there are more bugs lurking in Intel hardware that are just as severe. Just because Intel processors have been patched for Meltdown doesn't mean there aren't other vulnerabilities unique to Intel processors.

  41. Re: Idiotic Moderation by Shikaku · · Score: 1

    They're both full of bullet holes but AMD at least has less holes in short.

  42. Re:Idiotic Moderation by jittles · · Score: 2

    Because it doesn't make sense: Intel has a KNOWN UNFIXABLE FLAW in Meltdown. It cannot be fixed. You are saying "don't switch to AMD because they might have a major flaw too at some point". Meltdown is a much larger problem than Spectre is.

    Except that I read the write-up by the team and it did NOT say that AMD was immune to Meltdown. It actually said that they were able to get AMD processors to execute the pipelines but were unable to read it before the cache was invalidated. They speculated that a more optimized attack may be able to read the cache but they did not know for sure if it was possible. Thus they were not able to use their existing attack against AMD but that does not mean that it is not possible. AMD claimed that those pipelines would never execute and Google's team claims otherwise.

    Intel claimed that they would have a patch available for 90% of the processors affected by next week. Whether that means they have found some byte code that mitigates the attack vector, or they meant OS level patches to flush the cache on system calls was not clear in the blurb that I read. Either way, Google is still claiming that their patch has negligible effect on their server farms. They have quite a few systems deployed doing all kinds of things. Odds are good that the patch will be negligible for many or most users.

  43. Re:Or just Buy AMD & get no slow down with mor by AHuxley · · Score: 1

    Think of the problem as a Venn diagram and the two CPU "vulnerabilities" as lists of CPU's within the diagram.
    Some cpu generations will have both issues. Some one issue. Very few will not have any problem.

    --
    Domestic spying is now "Benign Information Gathering"
  44. Re: Idiotic Moderation by jezwel · · Score: 4, Insightful

    Is there a compelling reason to believe that AMD processors are less likely to be vulnerable in the future than Intel processors?

    Right now only Intel is massively exposed on one security issue where other manufacturers are not. So yes - this makes it appear that AMD design philosophy values security over performance. Whether that is proved out remains to be seen.

    If one manufacturer is cutting corners with the engineering and the other isn't, then there's a logical reason.

    Intel seems to be the one cutting corners - for decades. You do remember the FDIV and FOOF bugs in early Pentiums? I don't recall other manufacturers having such severe problems (sure, mainly PR with FDIV) that a recall was required.

    Otherwise, there isn't a logical basis for using that as a reason to change your behaviour in the future.

    Intel cannot provide CPUs to retail without this flaw for another 18 months or so. That should most certainly influence short-term future behaviour IF the fix causes significant performance issues with your workload.

    It's also entirely possible that, faced with backlash and distrust, the manufacturer might take additional steps to ensure that no such similar issues occur in the future. If there was demonstrable evidence of this, it might be a good reason not to switch.

    Sounds strange to not switch to a vendor that doesn't suffer from this vulnerability, in the hope that Intel will fix it's processes to ensure this doesn't happen again. Right now though, there's no good reason to specify Intel for your CPUs.

    The important question is whether there is any reason to believe Intel processors will be more vulnerable in the future.

    Why is that important? All manufacturers will have problems. You make plans with known data today. Intel messed up big time, and until the problem is fixed they should absolutely have this issue in the 'known problems' pile when consideration of CPU choice is done.

  45. Re: amd needs desktop level server chips / ipmi bo by Anonymous Coward · · Score: 0

    It also applies to ARM.

  46. Re: Idiotic Moderation by Anonymous Coward · · Score: 1, Interesting

    The shill gets modded up while posts get modded down for pointing out why the shill is giving bad advice.

    Given the choice of buying one of two x86-64 processors you would choose the Intel one that has a known critical security flaw that can only be mitigated with a performance crippling software patch rather than the AMD one that does not have this flaw. I think it's quite obvious who the shill is on this one and he/she is in some pretty serious damage control at the moment.

  47. Re:Idiotic Moderation by AvitarX · · Score: 1

    Based on what I read.

    AMD said they're immune (to meltdown because they keep the protection of kernel memory more strict
    Intel said 90% of last five years, not 90% of vulnerable.

    This isn't to shit on intel, the 5ish percent slow down on COUs that support PCID isn't so bad, just a clarification of how I've understood the news.

    --
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  48. Re:Idiotic Moderation by Anonymous Coward · · Score: 0

    Because it doesn't make sense: Intel has a KNOWN UNFIXABLE FLAW in Meltdown. It cannot be fixed. You are saying "don't switch to AMD because they might have a major flaw too at some point". Meltdown is a much larger problem than Spectre is.

    A security problem that is significantly worse on Intel is a valid reason to buy AMD, but do you really need that? Seriously, AMD apparently has comparable processors again. As long as they aren't worse security wise, I'd encourage people to consider buying them, if for no other reason to try to encourage some competition.

    I should probably read up on these bugs, but I assume Linux Mint should have a patch out soon. I just installed some, but I doubt it is that one. Sure maybe the early patches will slow some things down, but articles like this one suggest that things will improve and they will likely get close to addressing the issues. Of course if in two or three weeks my computer is running like crap, I may consider an AMD update. It has been a couple years and AMD has improved.

    It should be interesting to see what this does to prices. It might be a good time to wait a bit.

  49. Re: Or just Buy AMD & get no slow down with mo by Anonymous Coward · · Score: 0

    There was no competition to Intel for high end , data centre CPU, AMD did leave the high end market for like five years and only recently came back with the Ryzen, Arm64 is raw and not even close in performance, and multicore architecture like PEZY lacks software (just like intel KNL). Intel was pretty much the only choice if you cared for performance.

  50. Just installed the Win 10 patch on my i5 7500 by rsilvergun · · Score: 1

    little or no hit to passmark performance. I haven't got any games installed to test at the moment but passmark's GPU/CPU usually give me a good idea where I'd wind up. My VMs are running fine too.

    --
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    1. Re:Just installed the Win 10 patch on my i5 7500 by Anonymous Coward · · Score: 0

      The impact happens ONLY in syscall intensive code. A benchmark is usually totally CPU bound and uses almost no context switches. It makes sense that you see no degradation.

    2. Re:Just installed the Win 10 patch on my i5 7500 by Anonymous Coward · · Score: 0

      Run a network database application benchmark. Something that uses a lot of kernel calls and file IO.

    3. Re:Just installed the Win 10 patch on my i5 7500 by bad-badtz-maru · · Score: 1

      SSD IO seem to get hit the hardest. check there and see where you're at. On an ancient dual Xeon system I took a 30% hit.

  51. Re: Idiotic Moderation by MakerDusk · · Score: 1

    Relax. With all the bad press, is it really surprising that Intel has resorted to the sponsorship of defamatory posts? They have no other recourse for spinning this in a favorable light. Another bad decision on their part, but seemingly par for the course.

  52. How about compressed/encrypted code? by mnemotronic · · Score: 1

    How does the RETPOLINE mitigation applied to binaries deal with dynamically (JIT) de-compressed or unencrypted code? The ability for speculative pre-fetching to gather data that's normally off-limits to a process seems like a huge can of worms for code that can be pre-processed by the mitigation.

    /unrelated/ I'm not up-to-speed on webasm, but I can see how a vuln might be crafted from an instruction stream since the assembly generator is (presumably) following a recipe.

    --
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  53. Re: amd needs desktop level server chips / ipmi bo by Anonymous Coward · · Score: 0

    It also applies to ARM.

    No it fucking doesn't. Spectre, the lesser, affects AMD, Intel, and ARM, but Meltdown is *intel specific*.

  54. Re: amd needs desktop level server chips / ipmi bo by Anonymous Coward · · Score: 2, Informative

    Sorry, but ARM says it does apply to some of the ARM models. Variant 3: rogue data cache load (CVE-2017-5754) is Meltdown.
    https://developer.arm.com/support/security-update

    For AMD's sake, I hope their assessment about Ryzen's different architecture is 100% correct. If someone should come up with a POC working on these, AMD would be completely screwed.

    "Lesser" is subjective. It appears that Meltdown can be mitigated if not negated by the KAISER patches to operating systems but Spectre needs to have software (and not only kernels) recompiled or partially rewritten.

    CAPTCHA: surgeons

  55. Re: amd needs desktop level server chips / ipmi b by Anonymous Coward · · Score: 0

    Intel folks are out in force. It's so obvious, it's pointless... obfuscate, comflate and try and muddy the waters.

    Read the actual papers, marketing spin is just marketing spin.

  56. Re: Idiotic Moderation by Anonymous Coward · · Score: 0

    Beware: the Intel marketing dept was here

  57. Compiler support? by Chrisq · · Score: 1

    It would be good to have speculative execution protection as a compiler option rather than as a patch to binaries. This could tune the protection to what is necessary for each specific processor.

  58. Re:Idiotic Moderation by Anonymous Coward · · Score: 5, Informative

    Correction, they speculated that they were able to get AMD chips to do that. Their toy attack (within process) succeeded showing AMD chips will do speculative ordering. No actual security risk there, beause processes can read their own memory.

    BUT, they didn't know for a fact why they didn't succeed in attacking the kernel.

    We've now had statements from AMD (after the paper was released) - namely, that permission bits are checked BEFORE issuing instructions so kernel memory isn't readable, even speculatively.

    So.. .yeah, remember the paper is only what they think could be happening.

  59. Re:Idiotic Moderation by Anonymous Coward · · Score: 3, Interesting

    AMD pushed a patch [1] to disable the workaround for Meltdown on AMD CPUs. That means they are 100% sure that their CPUs are immune.

    [1] https://lkml.org/lkml/2017/12/27/2

  60. Re:Idiotic Moderation by Ash-Fox · · Score: 1

    As long as they aren't worse security wise, I'd encourage people to consider buying them, if for no other reason to try to encourage some competition.

    There are more eyes on Intel processors than AMD at the moment. I don't know what is worse on the security spectrum.

    --
    Change is certain; progress is not obligatory.
  61. Re:Or just Buy AMD & get no slow down with mor by swb · · Score: 1

    I think this would make sense if you had the vendors at rough sales parity and the virtualization vendors had healthy experience on both platforms so all the gotchas of moving live workloads between CPU vendors were understood and mitigated.

    It might actually not work well or require heterogeneous vendor-specific clusters to avoid CPU feature masking that dumbed both vendor platforms to some lowest common denominator.

  62. Re: Idiotic Moderation by Anonymous Coward · · Score: 0

    "Is there a compelling reason to believe that AMD processors are less likely to be vulnerable in the future than Intel processors? "

    Yes. It's called their track record. Reputation. Intel has repeatedly had chip bugs and security issues over the years, Their early Pentium bug that shouod have been detected during development and especially testing, their various chipset flaws like Sandy bridge, their cable mode chip flaws that allow easy denial of service attacks, their hypervisor that let processors get wholly owned, and now Meltdown.

    Look at how they've also handled these issues. They,by far, largely did not replace chips or devices. They PR'd their way to understating the effects or to conflate their msjor security issues Their workarounds were also piss poor, oike they dkn't understand the security issues they faced, or only care abiut the economic fallout to them. Are all your devices under 5 years old?

    Intel knew of these flaws for months and kept releasing flawed chips. They didn;t even seem to have on die fixes put in place even knowing these, hence their chips for likely over a year will remain defective. They had months to prepare a fix, and left us with crap--better fixes are being released by their customer.

    Finally, and I say this with repidation given the discussion that may ensue, but when a company gets involved in the political sphere like Intel has repeatedly recently, to me, it points to their lack of ability to compete. When your are the biggest supplier of chips, missed the smartphone and tablet boats, and whine you need tsx breaks others aren;t getting, it indicates to me there are flaws underneath where you cannot maintain your edge without help, meaning you will release shit or can't handle the shit you've released.

    Meltdown seems to be evidence enough. How Intel has handled -this- isue,mMeltdown, their spin on it, should be warning enough and evidence plenty. Track record. Reputation.

    btw, most of my processors are ARM.

  63. Re:Idiotic Moderation by admin7087 · · Score: 1

    Security assessments need to be based on evidence, not speculation. In that respect GP's advice was perfectly sound. However, this may be a case where waiting a bit might help to get a better picture.

  64. Re: Idiotic Moderation by atrex · · Score: 1

    I can understand the potential severity of the reported issue, but, iirc doesn't it also rely on the attacker having penetrated the system far enough to have permission to execute malicious code? I don't think it's something that they could manage with javascript in a rogue ad on facebook.

  65. Re: Idiotic Moderation by epine · · Score: 1

    Intel seems to be the one cutting corners - for decades. You do remember the FDIV and FOOF bugs in early Pentiums?

    I recall the FDIV bug quite well, and it had nothing to do with cutting corners. The design of the circuit was correct. In the transfer to manufacturing, some relatively insignificant bits in a hardware lookup table were truncated erroneously. The rarity of the failures allowed the mishap to escape detection in the validation phase.

    Intel's test probably should have been stronger in this area, but that's an awfully easy thing to say in hindsight concerning the validation of extraordinarily complex designs.

    Nostradamus: "There's a horrible bug in this design, and if you double your test coverage from stem to stern, you'll probably find it."

    Intel: "Gee, thanks, Nostradamus. Invest another $10 million and wind up a year late. I think we'll pass on the engineering, and expand our PR team by one full-time professional bullshitter."

    Nostradamus: "So be it. For what it's worth, I also wrote this nice quatrain on the horrors of speculation."

    Intel: "We'll pass."

    Nostradamus: "No, you won't."

    Intel has been many things over the years (with a weird, clockwork heel-turn), but skimping on validation is pretty much the last thing on my list of Intel malfeasance.

    i860
    RDRAM
    Caminogate
    Itanium
    general crisis-management ethos

    Oral History of John H. Crawford 2014 Computer History Museum Fellow — 2014

    I recall that as a great read. From my own notes:

    Big numeric coprocessor redesign as part of the Pentium. This lead to the world-famous Pentium FDIV bug. He claims that transcendentals were easy to test on existing software, but most software took extraordinary efforts to avoid division, so that coverage was extremely thin at this testing layer by comparison.

    I think that discussion also covers the i860, a litany of terror.

    Intel i860

    The Intel i860 (also known as 80860) was a RISC microprocessor design introduced by Intel in 1989.

    It was one of Intel's first attempts at an entirely new, high-end instruction set architecture since the failed Intel i432 from the 1980s. It was released with considerable fanfare, slightly obscuring the earlier Intel i960, which was successful in some niches of embedded systems, and which many considered to be a better design. The i860 never achieved commercial success and the project was terminated in the mid-1990s....

    On paper, performance was impressive for a single-chip solution; however, real-world performance was anything but.

    One problem, perhaps unrecognized at the time, was that runtime code paths are difficult to predict, meaning that it becomes exceedingly difficult to order instructions properly at compile time. For instance, an instruction to add two numbers will take considerably longer if the data are not in the cache, yet there is no way for the programmer to know if they are or not. If an incorrect guess is made, the entire pipeline will stall, waiting for the data.

    The entire i860 design was based on the compiler efficiently handling this task, which proved almost impossible in practice. While theoretically capable of peaking at about 60-80 MFLOPS for both single precision and double precision for the XP versions, hand-coded assemblers managed to get only about up to 40 MFLOPS, and most compilers had difficulty getting even 10 MFLOPs.

    The later Itanium architecture, also a VLIW design, suffered again from the problem of compilers incapable of delivering optimized (enough) code.

    Another serious problem was the lack of any solution to handle context switching quickly. The i860 had several pipelines (for the ALU and FPU parts) and an interrupt could spill them and require them all to be

  66. Re: amd needs desktop level server chips / ipmi bo by Anonymous Coward · · Score: 0

    No. Meltdown affects Intel & ARM. AMD is not affected.

    Spectre affects Intel, ARM, & AMD.

  67. Re:Idiotic Moderation by Anonymous Coward · · Score: 0

    Meltdown has already been fixed with OS updates.

    Spectre is the unfixable one.

  68. ARM Out of Order cores only. by Anonymous Coward · · Score: 0

    All in-order cores are safe from the issue, which likely also means Intel In-Order cores are as well (IE Intel Atoms before the switch to out of order processing!)

    Besides that, most of the Big Endian processors already kept seperate cache lines/page tables for kernel vs user space and are apparently not affected as a result, even if they do speculative execution on out of order processors.

  69. Re: Idiotic Moderation by Anonymous Coward · · Score: 0

    As far as it seems now, any out of order execution CPU is in principle vulnerable it's just AMD happen to be more robust to this particular exploits,. Same for ARM, same for PowerPC. So it is an industry wide problem . Bashing Intel only is not so responsible and not technically correct.

  70. Re: amd needs desktop level server chips / ipmi bo by Anonymous Coward · · Score: 0

    Well, but ARM have been able to push fixes for the KPTI themselves, without even waiting for 'Google' to save the day - or not

  71. Re:Idiotic Moderation by Anonymous Coward · · Score: 0

    I would buy a computer with AMD CPU if there was any decent laptop with Ryzen (and not the cut-down "U" versions) and a high end Nvidia GPU. Since there isn't, I'll be sticking with Intel and simply not applying the patch so I keep my performance. There is practically no security risk.

  72. Re:Or just Buy AMD & get no slow down with mor by RhettLivingston · · Score: 1

    Google, Microsoft, and Amazon dwarf Intel. They should not be waiting around for sales parity. They should be creating vendors if the vendors they need aren't there.

    In past industries, powerful industries would foster competition amongst their suppliers even if it involved significant loss. It is a necessary business expense that leads to many benefits including competition, diversity in supply (we are vulnerable to terrorists taking out foundries and countries cutting chip supplies today), and diversity in design that helps with problems like the one we just encountered.

    I'm not sure why tech operations don't concern themselves as much with this though perhaps they are starting to. It may be a maturity thing. There seem to be more cases of manufacturers using multiple suppliers cropping up lately. Apple intentionally uses both Intel and Qualcomm in phones. Samsung is using both a Qualcomm processor and one of their own design in the S9 generation.

    In the data center arena we may be at a threshold. There is renewed competition from AMD and long-shot entries like Qualcomm's 48-core ARM chip. There are also efforts such as Google's TPU to make huge efficiency gains with custom silicone. Those efforts could spread to asking themselves whether they could create a better processor or offload other computation loads onto custom silicone. They can afford to spend a lot of dough to save power or protect their business.

    Hopefully, this problem will end up being the catalyst for the big data center operators to do whatever it takes to foster competitors. Such a critical market should have at least three viable suppliers with very different designs and diverse manufacturing centers.

  73. Re: Idiotic Moderation by Anonymous Coward · · Score: 0

    AMD's problem is shitty performance and shitty, unstable drivers.

    Even with the Meltdown patch in place, I Intel CPUs still trash AMD CPUs in performance. That's how far ahead Intel is.

  74. Re:Or just Buy AMD & get no slow down with mor by swb · · Score: 1

    My guess is that the broadest explanation is that Google, Microsoft and Amazon largely want x86 compatibility because of the efficiencies associated with the network effect of a widely adopted processor, both in terms of software availability and in terms of platform stability.

    As AMD (and failed competitors) have shown, a competing platform to Intel's CPUs isn't easy to pull off. Google, et al, could pay a subsidy to AMD to produce a competing product but there's no guarantee they would get one and they would probably rather spend that money investigating a competitive product they alone would benefit from (like a custom ARM design for their own data center use).

  75. Re:Or just Buy AMD & get no slow down with mor by Anonymous Coward · · Score: 0

    No thanks, I don't need another heater operating next to my feet.