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@xxxxxxxxx>
---
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
