On Fri, Dec 22, 2023 at 08:24:52AM +0000, Li, Xin3 wrote: > Date: Fri, 22 Dec 2023 08:24:52 +0000 > From: "Li, Xin3" <xin3.li@xxxxxxxxx> > Subject: RE: [PATCH v3A 1/6] target/i386: add support for FRED in CPUID > enumeration > > > > > > NULL, NULL, NULL, NULL, @@ -1552,6 +1552,14 @@ static > > > > FeatureDep feature_dependencies[] = { > > > > .from = { FEAT_VMX_SECONDARY_CTLS, > > VMX_SECONDARY_EXEC_ENABLE_USER_WAIT_PAUSE }, > > > > .to = { FEAT_7_0_ECX, CPUID_7_0_ECX_WAITPKG }, > > > > }, > > > > + { > > > > + .from = { FEAT_7_1_EAX, CPUID_7_1_EAX_LKGS }, > > > > + .to = { FEAT_7_1_EAX, CPUID_7_1_EAX_FRED }, > > > > + }, > > > > + { > > > > + .from = { FEAT_7_1_EAX, CPUID_7_1_EAX_WRMSRNS }, > > > > + .to = { FEAT_7_1_EAX, CPUID_7_1_EAX_FRED }, > > > > + }, > > > > Oh, sorry, one thing that comes to mind, is this dependency required? > > Since the FRED spec (v3.0) is all about WRMSR as the example, without > > mentioning WRMSRNS, could there be other implementations that depend on > > WRMSR instead of WRMSRNS? > > This is a community ask from tglx: > https://lkml.kernel.org/kvm/87y1h81ht4.ffs@tglx/ > > Boris had the same question: > https://lore.kernel.org/lkml/20231114050201.GAZVL%2FSd%2FyLIdON9la@fat_crate.local/ > > But it needs to go through a formal approach, which takes time, to reach > the FRED public spec. > Thanks Xin! You can add a simple note in the commit message, such as FRED's dependency on WRMSRNS will be documented, to avoid confusion for later reviewers interested in FRED. Regards, Zhao