[libre-riscv-dev] TLB Initial Proposal

[Luke Kenneth Casson Leighton]

On Mon, Jan 21, 2019 at 4:30 PM Luke Kenneth Casson Leighton
<lkcl at lkcl.net> wrote:

> Search "usenix sec18-gras". Describes TLB side channel attacks. Investigating.

https://www.usenix.org/system/files/conference/usenixsecurity18/sec18-gras.pdf

 so this is telling me that we would be taking a huge risk to design a
hardware TLB.  the attacks on TLBs are so new, it's not guaranteed
that there will not be more.

 if it's a software TLB, at least we stand a chance of changing the
algorithm.  or, giving the user a choice: domain-specific application,
you get great performance, just don't run arbitrary untrusted code as
it *will* be Game Over; or a slower TLB algorithm that has mitigation
for TLB attacks.

we can't possibly offer that kind of choice in hardware.

l.