It might also depend on how AMD clears this temporal register across contexts, and the method it's updated.
The first I could think of (in the 5 minutes I've read this) is that it could be potentially ASLR breaking. As Agner says, it's highly useful for stack operations, but that also can help an adversary derive where the stack is.
Second, I could see an attack where the CPU predicts a sequence will use this register (since the address in the register could be speculative) and prefetch (since it kind of looks like it's prefetching) but it ends up being wrong and not killing/clearing the register, or not preventing its usage speculatively.
But it all depends heavily on lots of things. I feel like it's pretty similar to spec v4 in that exploitation would depend on the memory disambiguator, but we'll see.
Agner Fog mentions that the CPU assumes different registers have different values and the calculation has to be rerun if it turns out a write with one register invalidated a cached read with another register.
That means you can measure this penalty and infer that the registers had the same or overlapping addresses.
This is no different than the existing memory aliasing predictor that has existed for a long time already though, so it doesn't add any new speculation opportunity as far as I can tell.
A thread in the same process could observe the timing change and infer certain things about the memory address. This is mitigated by the fact that intra-thread and host-guest communication is already a side channel nightmare and everyone now only considers process boundaries to be defensible. It's sort of like worrying about someone being able to cut keys from a picture you posted on Facebook when all your house locks can be raked open with a $5 tool from Amazon.
Yup, during college I even created electrical schematics in MS Paint during one course, nobody believed it was done using it :) Although I must admit creating schematics in CAD software is more sane ;)
Well, he didn't take full advantage of the hardware - he changed significant part of it (raising total final price by 1/3).
Nevertheless I agree - it is very impressing ! :)
> he changed significant part of it (raising total final price by 1/3)
Have to say the coolest thing about the recent collaboration projects from Ikea is you get work from well regarded product designers at prices everyone can afford.
That is Ikea's usual modus operandi. Their merchandise is well designed and engineered for the most part. The cheap furniture is good - but only for the price. Some of the less cheap stuff is pretty good quality, like kitchens.
IKEA needs to Apple it up a bit. Increase the hardware specs, , add 1/3 to the manufacturing cost, double the price, build an app store for people to download new effects to their box, charge 30% of the revenue from these effects.
Something like 2-3 years ago I've read similar thing with master foo but about git. Does anyone happen to know where I can find it? I've searched for it but failed to find :(
