[Qemu-devel] [PATCH v3 2/3] target-i386: calculate vcpu's TSC rate to be migrated

[Haozhong Zhang <haozhong.zhang@intel.com>]

The value of the migrated vcpu's TSC rate is determined as below.
 1. If a TSC rate is specified by the cpu option 'tsc-freq', then this
    user-specified value will be used.
 2. If neither a user-specified TSC rate nor a migrated TSC rate is
    present, we will use the TSC rate from KVM (returned by
    KVM_GET_TSC_KHZ).
 3. Otherwise, we will use the migrated TSC rate.

Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
---
 include/sysemu/kvm.h |  2 ++
 kvm-all.c            |  1 +
 target-arm/kvm.c     |  5 +++++
 target-i386/kvm.c    | 33 +++++++++++++++++++++++++++++++++
 target-mips/kvm.c    |  5 +++++
 target-ppc/kvm.c     |  5 +++++
 target-s390x/kvm.c   |  5 +++++
 7 files changed, 56 insertions(+)

diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
index 461ef65..0ec8b98 100644
--- a/include/sysemu/kvm.h
+++ b/include/sysemu/kvm.h
@@ -328,6 +328,8 @@ int kvm_arch_fixup_msi_route(struct kvm_irq_routing_entry *route,
 
 int kvm_arch_msi_data_to_gsi(uint32_t data);
 
+int kvm_arch_setup_tsc_khz(CPUState *cpu);
+
 int kvm_set_irq(KVMState *s, int irq, int level);
 int kvm_irqchip_send_msi(KVMState *s, MSIMessage msg);
 
diff --git a/kvm-all.c b/kvm-all.c
index c442838..1ecaf04 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -1757,6 +1757,7 @@ static void do_kvm_cpu_synchronize_post_init(void *arg)
 {
     CPUState *cpu = arg;
 
+    kvm_arch_setup_tsc_khz(cpu);
     kvm_arch_put_registers(cpu, KVM_PUT_FULL_STATE);
     cpu->kvm_vcpu_dirty = false;
 }
diff --git a/target-arm/kvm.c b/target-arm/kvm.c
index 79ef4c6..a724f6d 100644
--- a/target-arm/kvm.c
+++ b/target-arm/kvm.c
@@ -614,3 +614,8 @@ int kvm_arch_msi_data_to_gsi(uint32_t data)
 {
     return (data - 32) & 0xffff;
 }
+
+int kvm_arch_setup_tsc_khz(CPUState *cs)
+{
+    return 0;
+}
diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index 64046cb..aae5e58 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -3034,3 +3034,36 @@ int kvm_arch_msi_data_to_gsi(uint32_t data)
 {
     abort();
 }
+
+int kvm_arch_setup_tsc_khz(CPUState *cs)
+{
+    X86CPU *cpu = X86_CPU(cs);
+    CPUX86State *env = &cpu->env;
+    int r;
+
+    /*
+     * Prepare vcpu's TSC rate to be migrated.
+     *
+     * - If the user specifies the TSC rate by cpu option 'tsc-freq',
+     *   we will use the user-specified value.
+     *
+     * - If there is neither user-specified TSC rate nor migrated TSC
+     *   rate, we will ask KVM for the TSC rate by calling
+     *   KVM_GET_TSC_KHZ.
+     *
+     * - Otherwise, if there is a migrated TSC rate, we will use the
+     *   migrated value.
+     */
+    if (env->tsc_khz) {
+        env->tsc_khz_saved = env->tsc_khz;
+    } else if (!env->tsc_khz_saved) {
+        r = kvm_vcpu_ioctl(cs, KVM_GET_TSC_KHZ);
+        if (r < 0) {
+            fprintf(stderr, "KVM_GET_TSC_KHZ failed\n");
+            return r;
+        }
+        env->tsc_khz_saved = r;
+    }
+
+    return 0;
+}
diff --git a/target-mips/kvm.c b/target-mips/kvm.c
index 12d7db3..fb26d7e 100644
--- a/target-mips/kvm.c
+++ b/target-mips/kvm.c
@@ -687,3 +687,8 @@ int kvm_arch_msi_data_to_gsi(uint32_t data)
 {
     abort();
 }
+
+int kvm_arch_setup_tsc_khz(CPUState *cs)
+{
+    return 0;
+}
diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
index ac70f08..c429f0c 100644
--- a/target-ppc/kvm.c
+++ b/target-ppc/kvm.c
@@ -2510,3 +2510,8 @@ int kvmppc_enable_hwrng(void)
 
     return kvmppc_enable_hcall(kvm_state, H_RANDOM);
 }
+
+int kvm_arch_setup_tsc_khz(CPUState *cs)
+{
+    return 0;
+}
diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c
index c3be180..db5d436 100644
--- a/target-s390x/kvm.c
+++ b/target-s390x/kvm.c
@@ -2248,3 +2248,8 @@ int kvm_arch_msi_data_to_gsi(uint32_t data)
 {
     abort();
 }
+
+int kvm_arch_setup_tsc_khz(CPUState *cs)
+{
+    return 0;
+}
-- 
2.4.8