- Jul 22, 2014
- 2,525
Linus Torvalds wrote a scathing email to the Linux Kernel mailing list where he does not hold back regarding how he feels about the Spectre patches. Calling them "complete and utter garbage", Linus states that while Intel appears to be trying, or will be doing, the right thing regarding the Meltdown patches, he felt that Intel was passing the buck to the Linux team when it comes to resolving the Spectre issues.
You can read his whole email here, but some of the choice parts include:
That's part of the big problem here. The speculation control cpuid stuff shows that Intel actually seems to plan on doing the right thing for meltdown (the main question being _when_). Which is not a huge surprise, since it should be easy to fix, and it's a really honking big hole to drive through. Not doing the right thing for meltdown would be completely unacceptable.
So the IBRS garbage implies that Intel is _not_ planning on doing the right thing for the indirect branch speculation.
Honestly, that's completely unacceptable too.
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 lookbad in benchmarks".
So instead they try to push the garbage down to us. And they are doing it entirely wrong, even from a technical standpoint.
I'm sure there is some lawyer there who says "we'll have to go through motions to protect against a lawsuit". But legal reasons do not make for good technology, or good patches that I should apply.
Have you _looked_ at the patches you are talking about? You should have - several of them bear your name.
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You can read his whole email here, but some of the choice parts include:
That's part of the big problem here. The speculation control cpuid stuff shows that Intel actually seems to plan on doing the right thing for meltdown (the main question being _when_). Which is not a huge surprise, since it should be easy to fix, and it's a really honking big hole to drive through. Not doing the right thing for meltdown would be completely unacceptable.
So the IBRS garbage implies that Intel is _not_ planning on doing the right thing for the indirect branch speculation.
Honestly, that's completely unacceptable too.
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 lookbad in benchmarks".
So instead they try to push the garbage down to us. And they are doing it entirely wrong, even from a technical standpoint.
I'm sure there is some lawyer there who says "we'll have to go through motions to protect against a lawsuit". But legal reasons do not make for good technology, or good patches that I should apply.
Have you _looked_ at the patches you are talking about? You should have - several of them bear your name.
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