On Tue, Jun 20, 2023 at 6:23 PM Richard Henderson <richard.hender...@linaro.org> wrote: > > On 6/20/23 17:16, Paolo Bonzini wrote: > > TCG reports the SEP feature (SYSENTER/SYSEXIT) in user mode emulation, > > but does not plumb it into the linux-user run loop. Split the helper into > > system emulation and user-mode emulation cases and implement the latter. > > I'm not keen on this. > > This belongs with the rest of the vdso (see patches posted years ago; > committing binary > blobs rejected, still waiting on a decent way to invoke cross-compilers to > build them).
As we discussed in Dublin, that should be doable by reusing the tests/tcg logic in configure (though we would likely commit the binary blobs as well). You could do it in your sleep. ;) > Further, this shouldn't ever be reachable, because AT_SYSINFO won't be > present to give the > guest libc the location of the vdso routine to call. Even without AT_SYSINFO the program should be able to do SYSENTER and 'trust" the kernel not to change the epilog of the routine. To be honest I don't like it particularly either; but I also didn't like that SEP is reported but doesn't work (and the purpose of these patches is to allow using named CPU models in linux-user)... I can certainly drop the patch since it's been like this for ages. Paolo
