| Message ID | ecd345619fdddfe48f375160c90322754cec9096.1702974319.git.isaku.yamahata@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: X86: Make bus clock frequency for vapic timer configurable | expand |
On 12/19/2023 4:34 PM, Isaku Yamahata wrote: > Remove APIC_BUS_FREUQNCY and calculate it based on APIC bus cycles per NS. > APIC_BUS_FREUQNCY is used only for HV_X64_MSR_APIC_FREQUENCY. The MSR is > not frequently read, calculate it every time. > > In order to make APIC bus frequency configurable, we need to make make two two 'make', please drop one. > related constants into variables. APIC_BUS_FREUQNCY and APIC_BUS_CYCLE_NS. > One can be calculated from the other. > APIC_BUS_CYCLES_NS = 1000 * 1000 * 1000 / APIC_BUS_FREQUENCY. > By removing APIC_BUS_FREQUENCY, we need to track only single variable > instead of two. > > Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> > --- > Changes v3: > - Newly added according to Maxim Levistsky suggestion. > --- > arch/x86/kvm/hyperv.c | 2 +- > arch/x86/kvm/lapic.h | 1 - > 2 files changed, 1 insertion(+), 2 deletions(-) > > diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c > index 238afd7335e4..a40ca2fef58c 100644 > --- a/arch/x86/kvm/hyperv.c > +++ b/arch/x86/kvm/hyperv.c > @@ -1687,7 +1687,7 @@ static int kvm_hv_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata, > data = (u64)vcpu->arch.virtual_tsc_khz * 1000; > break; > case HV_X64_MSR_APIC_FREQUENCY: > - data = APIC_BUS_FREQUENCY; > + data = div64_u64(1000000000ULL, APIC_BUS_CYCLE_NS); > break; > default: > kvm_pr_unimpl_rdmsr(vcpu, msr); > diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h > index 0a0ea4b5dd8c..a20cb006b6c8 100644 > --- a/arch/x86/kvm/lapic.h > +++ b/arch/x86/kvm/lapic.h > @@ -17,7 +17,6 @@ > #define APIC_DEST_MASK 0x800 > > #define APIC_BUS_CYCLE_NS 1 > -#define APIC_BUS_FREQUENCY (1000000000ULL / APIC_BUS_CYCLE_NS) > > #define APIC_BROADCAST 0xFF > #define X2APIC_BROADCAST 0xFFFFFFFFul
On Tue, 2023-12-19 at 00:34 -0800, Isaku Yamahata wrote: > Remove APIC_BUS_FREUQNCY > and calculate it based on APIC bus cycles per NS. > APIC_BUS_FREUQNCY is used only for HV_X64_MSR_APIC_FREQUENCY. The MSR is > not frequently read, calculate it every time. > > In order to make APIC bus frequency configurable, we need to make make two > related constants into variables. APIC_BUS_FREUQNCY and APIC_BUS_CYCLE_NS. > One can be calculated from the other. APIC_BUS_FREUQNCY is a typo. > APIC_BUS_CYCLES_NS = 1000 * 1000 * 1000 / APIC_BUS_FREQUENCY. > By removing APIC_BUS_FREQUENCY, we need to track only single variable > instead of two. > > Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> > --- > Changes v3: > - Newly added according to Maxim Levistsky suggestion. Typo: Maxim Levitsky > --- > arch/x86/kvm/hyperv.c | 2 +- > arch/x86/kvm/lapic.h | 1 - > 2 files changed, 1 insertion(+), 2 deletions(-) > > diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c > index 238afd7335e4..a40ca2fef58c 100644 > --- a/arch/x86/kvm/hyperv.c > +++ b/arch/x86/kvm/hyperv.c > @@ -1687,7 +1687,7 @@ static int kvm_hv_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata, > data = (u64)vcpu->arch.virtual_tsc_khz * 1000; > break; > case HV_X64_MSR_APIC_FREQUENCY: > - data = APIC_BUS_FREQUENCY; > + data = div64_u64(1000000000ULL, APIC_BUS_CYCLE_NS); > break; > default: > kvm_pr_unimpl_rdmsr(vcpu, msr); > diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h > index 0a0ea4b5dd8c..a20cb006b6c8 100644 > --- a/arch/x86/kvm/lapic.h > +++ b/arch/x86/kvm/lapic.h > @@ -17,7 +17,6 @@ > #define APIC_DEST_MASK 0x800 > > #define APIC_BUS_CYCLE_NS 1 > -#define APIC_BUS_FREQUENCY (1000000000ULL / APIC_BUS_CYCLE_NS) > > #define APIC_BROADCAST 0xFF > #define X2APIC_BROADCAST 0xFFFFFFFFul Other than typos: Reviewed-by: Maxim Levitsky <maximlevitsky@gmail.com> Best regards, Maxim Levitsky
On 12/21/2023 1:26 PM, Xiaoyao Li wrote: > On 12/19/2023 4:34 PM, Isaku Yamahata wrote: >> Remove APIC_BUS_FREUQNCY and calculate it based on APIC bus cycles per >> NS. >> APIC_BUS_FREUQNCY is used only for HV_X64_MSR_APIC_FREQUENCY. The MSR is >> not frequently read, calculate it every time. >> >> In order to make APIC bus frequency configurable, we need to make make >> two > > two 'make', please drop one. With this and other typos pointed by Maxim fixed. Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com> >> related constants into variables. APIC_BUS_FREUQNCY and >> APIC_BUS_CYCLE_NS. >> One can be calculated from the other. >> APIC_BUS_CYCLES_NS = 1000 * 1000 * 1000 / APIC_BUS_FREQUENCY. >> By removing APIC_BUS_FREQUENCY, we need to track only single variable >> instead of two. >> >> Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> >> --- >> Changes v3: >> - Newly added according to Maxim Levistsky suggestion. >> --- >> arch/x86/kvm/hyperv.c | 2 +- >> arch/x86/kvm/lapic.h | 1 - >> 2 files changed, 1 insertion(+), 2 deletions(-) >> >> diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c >> index 238afd7335e4..a40ca2fef58c 100644 >> --- a/arch/x86/kvm/hyperv.c >> +++ b/arch/x86/kvm/hyperv.c >> @@ -1687,7 +1687,7 @@ static int kvm_hv_get_msr(struct kvm_vcpu *vcpu, >> u32 msr, u64 *pdata, >> data = (u64)vcpu->arch.virtual_tsc_khz * 1000; >> break; >> case HV_X64_MSR_APIC_FREQUENCY: >> - data = APIC_BUS_FREQUENCY; >> + data = div64_u64(1000000000ULL, APIC_BUS_CYCLE_NS); >> break; >> default: >> kvm_pr_unimpl_rdmsr(vcpu, msr); >> diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h >> index 0a0ea4b5dd8c..a20cb006b6c8 100644 >> --- a/arch/x86/kvm/lapic.h >> +++ b/arch/x86/kvm/lapic.h >> @@ -17,7 +17,6 @@ >> #define APIC_DEST_MASK 0x800 >> #define APIC_BUS_CYCLE_NS 1 >> -#define APIC_BUS_FREQUENCY (1000000000ULL / APIC_BUS_CYCLE_NS) >> #define APIC_BROADCAST 0xFF >> #define X2APIC_BROADCAST 0xFFFFFFFFul > >
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index 238afd7335e4..a40ca2fef58c 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -1687,7 +1687,7 @@ static int kvm_hv_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata, data = (u64)vcpu->arch.virtual_tsc_khz * 1000; break; case HV_X64_MSR_APIC_FREQUENCY: - data = APIC_BUS_FREQUENCY; + data = div64_u64(1000000000ULL, APIC_BUS_CYCLE_NS); break; default: kvm_pr_unimpl_rdmsr(vcpu, msr); diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h index 0a0ea4b5dd8c..a20cb006b6c8 100644 --- a/arch/x86/kvm/lapic.h +++ b/arch/x86/kvm/lapic.h @@ -17,7 +17,6 @@ #define APIC_DEST_MASK 0x800 #define APIC_BUS_CYCLE_NS 1 -#define APIC_BUS_FREQUENCY (1000000000ULL / APIC_BUS_CYCLE_NS) #define APIC_BROADCAST 0xFF #define X2APIC_BROADCAST 0xFFFFFFFFul
Remove APIC_BUS_FREUQNCY and calculate it based on APIC bus cycles per NS. APIC_BUS_FREUQNCY is used only for HV_X64_MSR_APIC_FREQUENCY. The MSR is not frequently read, calculate it every time. In order to make APIC bus frequency configurable, we need to make make two related constants into variables. APIC_BUS_FREUQNCY and APIC_BUS_CYCLE_NS. One can be calculated from the other. APIC_BUS_CYCLES_NS = 1000 * 1000 * 1000 / APIC_BUS_FREQUENCY. By removing APIC_BUS_FREQUENCY, we need to track only single variable instead of two. Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> --- Changes v3: - Newly added according to Maxim Levistsky suggestion. --- arch/x86/kvm/hyperv.c | 2 +- arch/x86/kvm/lapic.h | 1 - 2 files changed, 1 insertion(+), 2 deletions(-)