Tuesday, June 11th 2019

AMD Zen 2 has Hardware Mitigation for Spectre V4

AMD in its technical brief revealed that its Zen 2 microarchitecture has hardware mitigation against the Spectre V4 speculative store bypass vulnerability. The current generation "Zen" and "Zen+" microarchitectures have OS-level mitigation. A hardware mitigation typically has less of a performance overhead than a software mitigation deployed at the OS or firmware level. In addition, just like older generations of "Zen," the new "Zen 2" microarchitecture is inherently immune to Meltdown, Foreshadow, Spectre V3a, Lazy FPU, Spoiler, and the recently discovered MDS vulnerability. In comparison, the 9th generation Core "Coffee Lake Refresh" processors still rely on software or microcode-level mitigation for Spectre V4, Spectre V3a, MDS, and RIDL.
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25 Comments on AMD Zen 2 has Hardware Mitigation for Spectre V4

#1
windwhirl
If I didn't know any better, I would think that AMD processors are vulnerable to almost everything, because the slide simply says "N/A" for many vulnerabilities.

Anyhow, nice to know that those two are now hardware-mitigated.
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#2
btarunr
Editor & Senior Moderator
windwhirl said:

If I didn't know any better, I would think that AMD processors are vulnerable to almost everything, because the slide simply says "N/A" for many vulnerabilities.

Anyhow, nice to know that those two are now hardware-mitigated.
N/A (not applicable), means immune.
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#3
windwhirl
btarunr said:

N/A (not applicable), means immune.
Ah. I normally translate it to "Not Available". My bad.
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#4
lexluthermiester
windwhirl said:

Ah. I normally translate it to "Not Available". My bad.
And it generally does have that meaning, just not in the context of the above graph.
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#5
londiste
These hardware changes are not fixes as such but features to assist in mitigation. With regards to performance, guys at Anandtech usually verify their claims and:
https://www.anandtech.com/show/14525/amd-zen-2-microarchitecture-analysis-ryzen-3000-and-epyc-rome/3
AMD doesn’t expect any performance change from these updates.
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#6
Crackong
Meanwhile at Intel .......................
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#7
PaddieMayne
lexluthermiester said:

And it generally does have that meaning, just not in the context of the above graph.
No it doesn't....NA always in the English Language means Not Applicable.
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#8
lexluthermiester
PaddieMayne said:

No it doesn't....NA always in the English Language means Not Applicable.
Incorrect. Being a native english speaker, which includes 6 dialects, I can state with complete confidence the term "N/A" and "NA" have several common meanings, one of which is "Not Available". But I digress..
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#9
Metroid
So here with zen 2 you get what you pay for, with coffee lake you get what you did not pay for hehe
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#10
PaddieMayne
lexluthermiester said:

Incorrect. Being a native english speaker, which includes 6 dialects, I can state with complete confidence the term "N/A" and "NA" have several common meanings, one of which is "Not Available". But I digress..
Being a native speaker of 47 years, living in the country where the language originated and having been taught the Queens English as it should be taught, i can quite categorically tell you that the abbreviation in the Queens English language stands for Not Applicable. But i of course understand that my rebellious tax fearing cousins from across the pond have taken the beautiful language that is English and bastardized it for their own use, which i blame mainly on American Media and Commercial Enterprises. :)

But I digress ;)
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#11
Ferrum Master
PaddieMayne said:

Being a native speaker of 47 years, living in the country where the language originated and having been taught the Queens English as it should be taught, i can quite categorically tell you that the abbreviation in the Queens English language stands for Not Applicable. But i of course understand that my rebellious tax fearing cousins from across the pond have taken the beautiful language that is English and bastardized it for their own use, which i blame mainly on American Media and Commercial Enterprises. :)

But I digress ;)
Putting under one blanket all "tax fearing cousins from across the pond" is rather infantile for a 47+ years old. There is a majority of people who can teach thing or two two anyone, no matter he is a native speaker or not, wherever he may live.

It is not only the US media. Is the cultural globalization tendencies overall, it doesn't happen only with English. It is our human nature to be lazy at everything.

It is totally fine that we ask for uncertain things here and we are not afraid to do it so, and someone helps and sincerely explains.
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#12
PaddieMayne
Ferrum Master said:

Putting under one blanket all "tax fearing cousins from across the pond" is rather infantile for a 47+ years old. There is a majority of people who can teach thing or two two anyone, no matter he is a native speaker or not, wherever he may live.

It is not only the US media. Is the cultural globalization tendencies overall, it doesn't happen only with English. It is our human nature to be lazy at everything.

It is totally fine that we ask for uncertain things here and we are not afraid to do it so, and someone helps and sincerely explains.
Infantile, no. I was merely excising my right as a Brit to be sarcastic, its a particular form of humor that us Brits are famous for. But i forgive you.
Please do not take what i say too seriously or literally.
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#13
Thefumigator
I'm not a native english speaker and all I can say is that when I see N/A it means Not Applicable to me.
Note: I learned english in the American Alliance of Montevideo, Uruguay.

Back to the topic, I can't seems to figure out why a giant like intel has these vulnerabilities in their CPUs, and AMD doesn't....
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#14
windwhirl
Thefumigator said:

Back to the topic, I can't seems to figure out why a giant like intel has these vulnerabilities in their CPUs, and AMD doesn't....
Likely, their specific implementation of speculative execution and SMT, which seems to have changed very little since Sandy Bridge or even Nehalem, according to some. I imagine that changing such implementation completely, or at least enough to neutralize all the vulnerabilities encountered so far, while not losing more performance, or recovering what was lost, will require a lot of research, and time. Time is what they need most, I think.

AMD had their own share of vulnerabilities, but Intel is still the bigger target because of their larger market share.
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#15
juiseman
https://en.wikipedia.org/wiki/N/a

Everybody is correct!!!



[LEFT]Acronym[/LEFT][LEFT]Definition[/LEFT]
N/ANot Available
N/ANot Applicable
N/ANorth America
N/ANo Answer
N/ANever Again
N/ANot Acceptable
N/ANon Alcoholic
N/ANaturally Aspirated (non-turbocharged/non-supercharged engine)
N/ANon Action
N/ANon-Aspirated (engine)

My
Not Available,
Not Applicable,
Non Alcoholic Beer was
Not Acceptable in
North America.
Never Again will I try a
Non Alcoholic
Naturally Aspirated Beer. When I called the company there was
No Answer. Drinking that beer resulted in
Non Action from myself on a Saturday night get together......
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#16
R-T-B
londiste said:

These hardware changes are not fixes as such but features to assist in mitigation. With regards to performance, guys at Anandtech usually verify their claims and:
Performance change from what? It's a new unreleased microarchitecture. What could it possibly "lose performance" compared to? :laugh:
Posted on Reply
#17
lexluthermiester
Thefumigator said:

I can't seems to figure out why a giant like intel has these vulnerabilities in their CPUs, and AMD doesn't....
It's as simple as the way they designed the architecture. None of it was intentional as many of these type of vulnerabilities affect most of the CPU's made since the 1990's. These latest ones are Intel specific, but that doesn't mean that more for other CPU's won't be found.
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#19
R-T-B
GoldenX said:

My favourite.
Why does AMD need less time to mitigate Spectre V4?
Probably because they went ground up redesign first. Intel keeps patching along the core series since... blah. Too long. Don't make me think.
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#20
Athlonite
juiseman said:

Naturally Aspirated (non-turbocharged/non-supercharged engine)
Well that's just wrong on so many ways it's not funny

The real definition of Naturally Aspirated means to be non electronically fuel injected ie: Carburettored like almost all pre 1970's cars
Posted on Reply
#21
lexluthermiester
Athlonite said:

Well that's just wrong on so many ways it's not funny
What are you talking about?!? That was very funny because it was wrong but also because it made a valid point while being wrong. Tell us you don't see the humor there..
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#22
Makaveli
lexluthermiester said:

It's as simple as the way they designed the architecture. None of it was intentional as many of these type of vulnerabilities affect most of the CPU's made since the 1990's. These latest ones are Intel specific, but that doesn't mean that more for other CPU's won't be found.
I also think this shows how important it is that more than one company is making x86 cpu's.

You get a variety in designs, and a choice as a consumer when they find vulnerabilities like this.

Competition is necessary in this market.
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#23
Vycyous
Athlonite said:

The real definition of Naturally Aspirated means to be non electronically fuel injected ie: Carburettored like almost all pre 1970's cars
What?! That is entirely wrong. In regards to internal combustion engines, aspiration is the process of drawing air into the engine. Therefore, naturally aspirated means there is no forced induction (turbo or blower/supercharger, like it says). It has nothing to do with fuel delivery.
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#24
lexluthermiester
Makaveli said:

I also think this shows how important it is that more than one company is making x86 cpu's.

You get a variety in designs, and a choice as a consumer when they find vulnerabilities like this.

Competition is necessary in this market.
Can not agree more with this! :clap: Well spoken good sir!:toast:
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