On 10/23/23 11:22, Josh Poimboeuf wrote: > On Fri, Oct 20, 2023 at 01:45:03PM -0700, Pawan Gupta wrote: >> + /* Mitigate CPU data sampling attacks .e.g. MDS */ >> + USER_CLEAR_CPU_BUFFERS >> + >> jmp .Lnative_iret >> >> >> @@ -774,6 +780,9 @@ native_irq_return_ldt: >> */ >> popq %rax /* Restore user RAX */ >> >> + /* Mitigate CPU data sampling attacks .e.g. MDS */ >> + USER_CLEAR_CPU_BUFFERS >> + > > I'm thinking the comments add unnecessary noise here. The macro name is > self-documenting enough. > > The detail about what mitigations are being done can go above the macro > definition itself, which the reader can refer to if they want more > detail about what the macro is doing and why. > > Speaking of the macro name, I think just "CLEAR_CPU_BUFFERS" is > sufficient. The "USER_" prefix makes it harder to read IMO. Yes, please. The "USER_" prefix should be reserved for things that are uniquely for the unambiguous return-to-userspace paths.
