[PATCH 12/14] i386/cpu: Store LAPIC bus frequency in CPU structure

[Liran Alon]

No functional change.
This information will be used by following patches.

Reviewed-by: Nikita Leshenko <address@hidden>
Signed-off-by: Liran Alon <address@hidden>
---
 linux-headers/asm-x86/kvm.h | 4 ++++
 target/i386/cpu.h           | 1 +
 target/i386/kvm.c           | 6 +++---
 3 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/linux-headers/asm-x86/kvm.h b/linux-headers/asm-x86/kvm.h
index 503d3f42da16..99eeaaf2f0b4 100644
--- a/linux-headers/asm-x86/kvm.h
+++ b/linux-headers/asm-x86/kvm.h
@@ -446,4 +446,8 @@ struct kvm_pmu_event_filter {
 #define KVM_PMU_EVENT_ALLOW 0
 #define KVM_PMU_EVENT_DENY 1
 
+/* From arch/x86/kvm/lapic.h */
+#define KVM_APIC_BUS_CYCLE_NS       1
+#define KVM_APIC_BUS_FREQUENCY      (1000000000ULL / KVM_APIC_BUS_CYCLE_NS)
+
 #endif /* _ASM_X86_KVM_H */
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index 576f309bbfc8..9c7cd7cde107 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -1580,6 +1580,7 @@ typedef struct CPUX86State {
     bool tsc_valid;
     int64_t tsc_khz;
     int64_t user_tsc_khz; /* for sanity check only */
+    uint64_t apic_bus_freq;
 #if defined(CONFIG_KVM) || defined(CONFIG_HVF)
     void *xsave_buf;
 #endif
diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index 69eb43d796e6..00917196dffb 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -1496,6 +1496,8 @@ int kvm_arch_init_vcpu(CPUState *cs)
         }
     }
 
+    env->apic_bus_freq = KVM_APIC_BUS_FREQUENCY;
+
     /* Paravirtualization CPUIDs */
     r = hyperv_handle_properties(cs, cpuid_data.entries);
     if (r < 0) {
@@ -1800,9 +1802,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
         c = &cpuid_data.entries[cpuid_i++];
         c->function = KVM_CPUID_SIGNATURE | 0x10;
         c->eax = env->tsc_khz;
-        /* LAPIC resolution of 1ns (freq: 1GHz) is hardcoded in KVM's
-         * APIC_BUS_CYCLE_NS */
-        c->ebx = 1000000;
+        c->ebx = env->apic_bus_freq / 1000; /* Hz to KHz */
         c->ecx = c->edx = 0;
 
         c = cpuid_find_entry(&cpuid_data.cpuid, kvm_base, 0);
-- 
2.20.1