diff mbox

[v6,1/3] target-i386: fallback vcpu's TSC rate to value returned by KVM

Message ID 1448336037-6035-2-git-send-email-haozhong.zhang@intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Haozhong Zhang Nov. 24, 2015, 3:33 a.m. UTC
If no user-specified TSC rate is present, we will try to set
env->tsc_khz to the value returned by KVM_GET_TSC_KHZ. This patch does
not change the current functionality of QEMU and just prepares for later
patches to enable migrating vcpu's TSC rate.

Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
---
 target-i386/kvm.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

Comments

Eduardo Habkost Nov. 25, 2015, 5:53 p.m. UTC | #1
On Tue, Nov 24, 2015 at 11:33:55AM +0800, Haozhong Zhang wrote:
> If no user-specified TSC rate is present, we will try to set
> env->tsc_khz to the value returned by KVM_GET_TSC_KHZ. This patch does
> not change the current functionality of QEMU and just prepares for later
> patches to enable migrating vcpu's TSC rate.
> 
> Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>

Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>

> ---
>  target-i386/kvm.c | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/target-i386/kvm.c b/target-i386/kvm.c
> index 2a9953b..a0fe9d4 100644
> --- a/target-i386/kvm.c
> +++ b/target-i386/kvm.c
> @@ -832,6 +832,20 @@ int kvm_arch_init_vcpu(CPUState *cs)
>          }
>      }
>  
> +    /* vcpu's TSC frequency is either specified by user, or following
> +     * the value used by KVM if the former is not present. In the
> +     * latter case, we query it from KVM and record in env->tsc_khz,
> +     * so that vcpu's TSC frequency can be migrated later via this field.
> +     */
> +    if (!env->tsc_khz) {
> +        r = kvm_check_extension(cs->kvm_state, KVM_CAP_GET_TSC_KHZ) ?
> +            kvm_vcpu_ioctl(cs, KVM_GET_TSC_KHZ) :
> +            -ENOTSUP;
> +        if (r > 0) {
> +            env->tsc_khz = r;
> +        }
> +    }
> +
>      if (has_xsave) {
>          env->kvm_xsave_buf = qemu_memalign(4096, sizeof(struct kvm_xsave));
>      }
> -- 
> 2.4.8
>
Eduardo Habkost Nov. 26, 2015, 2 p.m. UTC | #2
On Tue, Nov 24, 2015 at 11:33:55AM +0800, Haozhong Zhang wrote:
> If no user-specified TSC rate is present, we will try to set
> env->tsc_khz to the value returned by KVM_GET_TSC_KHZ. This patch does
> not change the current functionality of QEMU and just prepares for later
> patches to enable migrating vcpu's TSC rate.
> 
> Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>

Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>

> ---
>  target-i386/kvm.c | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/target-i386/kvm.c b/target-i386/kvm.c
> index 2a9953b..a0fe9d4 100644
> --- a/target-i386/kvm.c
> +++ b/target-i386/kvm.c
> @@ -832,6 +832,20 @@ int kvm_arch_init_vcpu(CPUState *cs)
>          }
>      }
>  
> +    /* vcpu's TSC frequency is either specified by user, or following
> +     * the value used by KVM if the former is not present. In the
> +     * latter case, we query it from KVM and record in env->tsc_khz,
> +     * so that vcpu's TSC frequency can be migrated later via this field.
> +     */
> +    if (!env->tsc_khz) {
> +        r = kvm_check_extension(cs->kvm_state, KVM_CAP_GET_TSC_KHZ) ?
> +            kvm_vcpu_ioctl(cs, KVM_GET_TSC_KHZ) :
> +            -ENOTSUP;
> +        if (r > 0) {
> +            env->tsc_khz = r;
> +        }
> +    }
> +
>      if (has_xsave) {
>          env->kvm_xsave_buf = qemu_memalign(4096, sizeof(struct kvm_xsave));
>      }
> -- 
> 2.4.8
>
diff mbox

Patch

diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index 2a9953b..a0fe9d4 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -832,6 +832,20 @@  int kvm_arch_init_vcpu(CPUState *cs)
         }
     }
 
+    /* vcpu's TSC frequency is either specified by user, or following
+     * the value used by KVM if the former is not present. In the
+     * latter case, we query it from KVM and record in env->tsc_khz,
+     * so that vcpu's TSC frequency can be migrated later via this field.
+     */
+    if (!env->tsc_khz) {
+        r = kvm_check_extension(cs->kvm_state, KVM_CAP_GET_TSC_KHZ) ?
+            kvm_vcpu_ioctl(cs, KVM_GET_TSC_KHZ) :
+            -ENOTSUP;
+        if (r > 0) {
+            env->tsc_khz = r;
+        }
+    }
+
     if (has_xsave) {
         env->kvm_xsave_buf = qemu_memalign(4096, sizeof(struct kvm_xsave));
     }