On Wed, Apr 17, 2024, Wei Wang wrote: > Introduces two new macros, KVM_X86_SC() and KVM_X86_SCC(), to streamline > the usage of KVM_X86_OPS static calls. The current implementation of these > calls is verbose and can lead to alignment challenges due to the two pairs > of parentheses. This makes the code susceptible to exceeding the "80 > columns per single line of code" limit as defined in the coding-style > document. The two macros are added to improve code readability and > maintainability, while adhering to the coding style guidelines. Heh, I've considered something similar on multiple occasionsi. Not because the verbosity bothers me, but because I often search for exact "word" matches when looking for function usage and the kvm_x86_ prefix trips me up. > Please note that this RFC only updated a few callsites for demonstration > purposes. If the approach looks good, all callsites will be updated in > the next version. > > Signed-off-by: Wei Wang <wei.w.wang@xxxxxxxxx> > --- > arch/x86/include/asm/kvm_host.h | 3 +++ > arch/x86/kvm/lapic.c | 15 ++++++++------- > arch/x86/kvm/trace.h | 3 ++- > arch/x86/kvm/x86.c | 8 ++++---- > 4 files changed, 17 insertions(+), 12 deletions(-) > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index 6efd1497b026..42f6450c10ec 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -1856,6 +1856,9 @@ extern struct kvm_x86_ops kvm_x86_ops; > DECLARE_STATIC_CALL(kvm_x86_##func, *(((struct kvm_x86_ops *)0)->func)); > #define KVM_X86_OP_OPTIONAL KVM_X86_OP > #define KVM_X86_OP_OPTIONAL_RET0 KVM_X86_OP > + > +#define KVM_X86_SC(func, ...) static_call(kvm_x86_##func)(__VA_ARGS__) > +#define KVM_X86_SCC(func, ...) static_call_cond(kvm_x86_##func)(__VA_ARGS__) IIRC, static_call_cond() is essentially dead code, i.e. it's the exact same as static_call(). I believe there's details buried in a proposed series to remove it[*]. And to not lead things astray, I verified that invoking a NULL kvm_x86_op with static_call() does no harm (well, doesn't explode at least). So if we add wrapper macros, I would be in favor in removing all static_call_cond() as a prep patch so that we can have a single macro. kvm_ops_update() already WARNs if a mandatory hook isn't defined, so doing more checks at runtime wouldn't provide any value. As for the name, what about KVM_X86_CALL() instead of KVM_X86_SC()? Two extra characters, but should make it much more obvious what's going on for readers that aren't familiar with the infrastructure. And I bet we can get away with KVM_PMU_CALL() for the PMU hooks. [*] https://lore.kernel.org/all/cover.1679456900.git.jpoimboe@xxxxxxxxxx
