On 18.06.2021 12:14, Andrew Cooper wrote: > On 18/06/2021 00:39, Daniel P. Smith wrote: >> Based on feedback from 2021 Xen Developers Summit the xsm-roles RFC >> patch set is being split into two separate patch sets. This is the first >> patch set and is focused purely on the clean up and refactoring of the >> XSM hooks. >> >> This patch set refactors the xsm_ops wrapper hooks to use the >> alternative_call >> infrastructure. Then proceeds to move and realign the headers to remove the >> psuedo is/is not enable implementation. The remainder of the changes are >> clean up >> and removing no longer necessary abstractions. >> >> <snip> >> 51 files changed, 1309 insertions(+), 1413 deletions(-) > > The diffstat is great, but sadly CI says no. > https://gitlab.com/xen-project/patchew/xen/-/pipelines/323044913 > > The problem is that ARM doesn't have alternative_vcall(). Given how > much of an improvement this ought to be for hypercalls, I don't want to > lose the vcalls. > > One option is to implement vcall() support on ARM, but that will leave > new architectures (RISC-V on the way) with a heavy lift to get XSM to > compile. > > Instead, what we want to do is make vcall() a common interface, falling > back to a plain function pointer call for architectures which don't > implement the optimisation. So something like: > > 1) Introduce CONFIG_HAS_VCALL, which is selected by X86 only right now > 2) Introduce xen/vcall.h which uses CONFIG_HAS_VCALL to either include > asm/vcall.h or provide the fallback implementation
A word on the suggested names: The 'v' in alternative_vcall() stands for "returning void", as opposed to alternative_call(). It's unclear to me what you see it stand for in the names you propose. Jan
