On 03/12/2024 8:11 am, Penny Zheng wrote: > Add Collaborative Processor Performance Control feature flag for > AMD processors. > > amd-pstate is the AMD CPU performance scaling driver that > introduces a new CPU frequency control mechanism on modern AMD > APU and CPU series. > There are two types of hardware implementations: "Full MSR Support" > and "Shared Memory Support". > > Right now, xen will only implement "Full MSR Support", and this new > feature flag indicates whether processor has this feature or not.
Do you have a reference to where this is documented? > > Signed-off-by: Penny Zheng <penny.zh...@amd.com> > --- > xen/arch/x86/include/asm/cpufeature.h | 1 + > xen/include/public/arch-x86/cpufeatureset.h | 1 + > 2 files changed, 2 insertions(+) > > diff --git a/xen/arch/x86/include/asm/cpufeature.h > b/xen/arch/x86/include/asm/cpufeature.h > index 3a06b6f297..6935703e71 100644 > --- a/xen/arch/x86/include/asm/cpufeature.h > +++ b/xen/arch/x86/include/asm/cpufeature.h > @@ -170,6 +170,7 @@ static inline bool boot_cpu_has(unsigned int feat) > #define cpu_has_amd_ssbd boot_cpu_has(X86_FEATURE_AMD_SSBD) > #define cpu_has_virt_ssbd boot_cpu_has(X86_FEATURE_VIRT_SSBD) > #define cpu_has_ssb_no boot_cpu_has(X86_FEATURE_SSB_NO) > +#define cpu_has_cppc boot_cpu_has(X86_FEATURE_CPPC) > #define cpu_has_auto_ibrs boot_cpu_has(X86_FEATURE_AUTO_IBRS) > > /* CPUID level 0x00000007:0.edx */ > diff --git a/xen/include/public/arch-x86/cpufeatureset.h > b/xen/include/public/arch-x86/cpufeatureset.h > index 8fa3fb711a..15f707639b 100644 > --- a/xen/include/public/arch-x86/cpufeatureset.h > +++ b/xen/include/public/arch-x86/cpufeatureset.h > @@ -265,6 +265,7 @@ XEN_CPUFEATURE(AMD_PPIN, 8*32+23) /* Protected > Processor Inventory Number > XEN_CPUFEATURE(AMD_SSBD, 8*32+24) /*S MSR_SPEC_CTRL.SSBD available */ > XEN_CPUFEATURE(VIRT_SSBD, 8*32+25) /*! MSR_VIRT_SPEC_CTRL.SSBD */ > XEN_CPUFEATURE(SSB_NO, 8*32+26) /*A Hardware not vulnerable to SSB */ > +XEN_CPUFEATURE(CPPC, 8*32+27) /*A Collaborative Processor > Performance Control */ There needs to be no "A" in this patch, because it's certainly not ready to advertise to guests yet. If you're intending it for eventual use by guests, then the "A" only goes back in at the end of the series when the support to correctly virtualise it appears, but it looks like it will be Xen-only. ~Andrew
