Meltdown, aka “Dear Intel, you suck” • Hacker News Board

Re: Meltdown, aka “Dear Intel, you suck”

#31

Post by maxerickson » Sat, Jan 06, 2018, 2:05 PM UTC

amelius wrote: post #27

jrimbault wrote: post #23

Earlier quoted context omitted.

Arguably , the most important phase of hardware design is actual production of said design.

I somewhat doubt that is still the case, with modern EDA tools.

I think they were maybe making a joke about whether you want to use the chip or not.

Re: Meltdown, aka “Dear Intel, you suck”

#32

Post by IronBacon » Sat, Jan 06, 2018, 2:06 PM UTC

mnw21cam wrote: post #26

sverige wrote: post #22

Earlier quoted context omitted.

Which widely available and affordable CPUs aren't affected by Spectre?

Most of the ARM CPUs are not affected. For instance, the Raspberry Pi beards are not affected.

And Atom circa 2012(?). Well, OK not really easily available, but I suppose what you can find on eBay should be affordable...

Re: Meltdown, aka “Dear Intel, you suck”

#33

Post by mnw21cam » Sat, Jan 06, 2018, 2:07 PM UTC

K0nserv wrote: post #15

roblabla wrote: post #12

Earlier quoted context omitted.

Everyone is affected by Spectre, but my understanding is that Meltdown is a particularly powerful "version" of Spectre that only affects Intel CPUs ?

Having just read the Meltdown paper, but not the Spectre paper. My understanding is that yes Meltdown is much easier to exploit and more powerful. I believe Spectre requires the attacker to consistently fool the branch predictor while Meltdown enables reading kernel memory mapped into user space process via access in speculatively executed code and observing the affects on the CPU cache.

Spectre involves finding some code in the kernel that has access to the data, and getting it to access it speculatively before the conditional that tells it not to is evaluated.

Meltdown involves crafting some code yourself that speculatively accesses data it does not have access to before the CPU rejects the access due to permissions.

In other words, Meltdown involves your code accessing the data, but Spectre involves getting the kernel to do it for you. Spectre is a neat clever side-channel attack that is hard to protect against, while Meltdown is a blundering error in the way the CPU works.

Re: Meltdown, aka “Dear Intel, you suck”

#34

Post by cleeus » Sat, Jan 06, 2018, 2:09 PM UTC

google cache: https://webcache.googleusercontent.com/search?q=cache:jqSuv7...

Re: Meltdown, aka “Dear Intel, you suck”

#35

Post by hanniabu » Sat, Jan 06, 2018, 2:10 PM UTC

sverige wrote: post #21

ksec wrote: post #4

May be time for OpenBSD people ( if they have the resources ) to build a CPU from ground up with RISC-V?

OpenBSD has struggled at times to pay their power bills. They don't have the resources to branch off into building new hardware from first principles.

Hopefully there are some tech savvy new crypto millionaires that are willing to help contribute to worthy projects such as this.

Re: Meltdown, aka “Dear Intel, you suck”

#36

Post by raverbashing » Sat, Jan 06, 2018, 2:15 PM UTC

ksec wrote: post #4

May be time for OpenBSD people ( if they have the resources ) to build a CPU from ground up with RISC-V?

Given the dismissiveness and tone of "hw designers are morons, we're the only smart people around here" from some people at OpenBSD, I don't think they know what it actually entails or how hard it is

Re: Meltdown, aka “Dear Intel, you suck”

#37

Post by betterunix2 » Sat, Jan 06, 2018, 2:15 PM UTC

K0nserv wrote: post #28

Fnoord wrote: post #18

Earlier quoted context omitted.

My ELI5 attempt: There are 3 vulnerabilities. Meltdown is 1 of the 3. Meltdown is pretty much Intel only. Some ARM SoCs are also affected, but these are relatively rare. AMD64 is unaffected by Meltdown. Spectre are the other 2 vulnerabilities. Spectre affects pretty much everyone. Meltdown is more severe, and more of a blunder. For a technical explanation, see [1]. Was recently referred to at HN as well. [1] https://…

Do you have any source on why AMD64 is unaffected? The paper only mentions that they couldn't make their current approach work on AMD, but it doesn't rule out that it could be improved and made work

AMD's microarchitecture does not perform speculative loads that would cause a segfault, according to this AMD engineer:

https://lkml.org/lkml/2017/12/27/2

Re: Meltdown, aka “Dear Intel, you suck”

#38

Post by [deleted] » Sat, Jan 06, 2018, 2:18 PM UTC

K0nserv wrote: post #28

Fnoord wrote: post #18

Earlier quoted context omitted.

My ELI5 attempt: There are 3 vulnerabilities. Meltdown is 1 of the 3. Meltdown is pretty much Intel only. Some ARM SoCs are also affected, but these are relatively rare. AMD64 is unaffected by Meltdown. Spectre are the other 2 vulnerabilities. Spectre affects pretty much everyone. Meltdown is more severe, and more of a blunder. For a technical explanation, see [1]. Was recently referred to at HN as well. [1] https://…

Do you have any source on why AMD64 is unaffected? The paper only mentions that they couldn't make their current approach work on AMD, but it doesn't rule out that it could be improved and made work

[deleted]

Re: Meltdown, aka “Dear Intel, you suck”

#39

Post by mnw21cam » Sat, Jan 06, 2018, 2:19 PM UTC

alsadi wrote: post #11

Why you single intel on this, ARM and POWER also affected https://www.ibm.com/blogs/psirt/potential-impact-processors-...

In terms of ARM, only some of the ARM CPUs are affected. The CPUs used in the Raspberry Pi range don't have out of order execution, so aren't affected.

Re: Meltdown, aka “Dear Intel, you suck”

#40

Post by DougN7 » Sat, Jan 06, 2018, 2:21 PM UTC

I don’t understand the Intel hate. It’s not like their engineers are dumb or lazy. This exploit is very hard to imagine before now. And it’s there because chip makers were trying to wring out more performance. It’s unfortunate if anythig.