[PULL 036/115] i386/cpu: Store LAPIC bus frequency in CPU structure

[Paolo Bonzini]

From: Liran Alon <liran.alon@oracle.com>

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

Reviewed-by: Nikita Leshenko <nikita.leshchenko@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Message-Id: <20200312165431.82118-15-liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 target/i386/cpu.h |  1 +
 target/i386/kvm.c | 10 +++++++---
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index 408392dbf6..00d1f4f013 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -1584,6 +1584,7 @@ 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 34f838728d..95bbeb424b 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -59,6 +59,10 @@
     do { } while (0)
 #endif
 
+/* From arch/x86/kvm/lapic.h */
+#define KVM_APIC_BUS_CYCLE_NS       1
+#define KVM_APIC_BUS_FREQUENCY      (1000000000ULL / KVM_APIC_BUS_CYCLE_NS)
+
 #define MSR_KVM_WALL_CLOCK  0x11
 #define MSR_KVM_SYSTEM_TIME 0x12
 
@@ -1469,6 +1473,8 @@ 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) {
@@ -1773,9 +1779,7 @@ 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);
-- 
2.26.2