![]() ![]() ![]() Then along came Paul with the cunning plan of … retpoline. And a vile hack, but for a while it was the only option we had. The third feature (IBRS) is more complicated. Or different VM guests running on HT siblings. You *might* want this when running unrelated processes in userspace, for example. The second (STIBP) protects a hyperthread sibling from following branch predictions which were learned on another sibling. … It's kind of expensive (order of magnitude ~4000 cycles). One new feature (IBPB) is a complete barrier for branch prediction. I bet the Linux kernel team really love it when the media quotes one of Linus’s infamous curse-o-grams, amirite? David Woodhouse tries to pacify things: Since the peanut gallery is paying lots of attention it's probably worth explaining it a little more. Nobody sane will use them, since the cost is too damn high. Since we already know that the IBRS overhead is huge on existing hardware, all those hardware capability bits are just complete and utter garbage. The whole IBRS_ALL feature to me very clearly says "Intel is not serious about this, we'll have a ugly hack that will be so expensive that we don't want to enable it by default, because that would look bad in benchmarks." … Honestly, that's completely unacceptable. … Intel is not planning on doing the right thing. At least, according to Linus Benedict Torvalds: Is Intel really planning on making this **** architectural? Has anybody talked to them and told them? Oh, wait, it could actually be worse that that. Intel's performance so far seems best described as "clown show." Especially for major, industry-wide patches that they should be sure will fix the problem without introducing crippling problems that are just as bad (or worse) than the original problem. In agreement, here’s ThisIsNotAName: Considering how poorly Intel has handled this, I'm looking forward to seeing the legal consequences. … Spectre mitigation requires … sweeping, conceptual changes in how processors manage data flows. developing stable patches for every processor, every firmware stack, and every operating system a tall order. … It doesn't help that downplayed the challenges at first. can inadvertently cause serious problems beyond processing slowdowns, including random restarts, and even the blue screen of death. Lily Hay Newman calls it A Total Train Wreck: The bigger issue so far … is that some patches have done more harm than good.Īll of modern chips are impacted, and the company's attempts to patch the vulnerabilities have seen mixed results. … It pays to hold off on firmware patches, too. The bright, new firmware versions - which Intel has had six months to patch - have a nasty habit of causing “higher system reboots.” … The breadth of the recall is breathtaking - second-, third-, fourth-, fifth-, sixth-, seventh- and eighth-generation Core processors, Xeon, Atom, and lesser Core i3, i5 and i7 processors.īy implication, that means the … firmware updates you’ve installed from Lenovo or HP or Dell are officially trash. What’s the craic, Woody Leonhard? Intel says you should NOT install its … firmware fixes: You know how you’re supposed to flash the BIOS or update the UEFI on all of your Intel machines, to guard against … Spectre? Well, belay that order, private! Your humble blogwatcher curated these bloggy bits for your entertainment. In this week’s Security Blogwatch, we take out the trash. Meanwhile, Linus Torvalds unleashes a stream of foul language at Intel and some Linux kernel devs. Apparently, they’re causing unexplained reboots. This week, the big CPU kahuna offers (ahem) “updated guidance,” telling us not to use its BIOS, EFI or other microcode updates. Intel’s Spectre bug mitigation doesn’t work quite right. ![]()
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