| Message ID | 1443418711-24106-3-git-send-email-haozhong.zhang@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Sep 28, 2015 at 01:38:30PM +0800, Haozhong Zhang wrote: > When creating a vcpu, we initialize its TSC rate to the value from > KVM (through ioctl KVM_GET_TSC_KHZ). > > Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com> > --- > target-i386/kvm.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/target-i386/kvm.c b/target-i386/kvm.c > index 7b0ba17..c2b161a 100644 > --- a/target-i386/kvm.c > +++ b/target-i386/kvm.c > @@ -751,6 +751,13 @@ int kvm_arch_init_vcpu(CPUState *cs) > } > } > > + 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 = r; You are silently overwriting the tsc_khz value set by the user, why?
On Mon, Sep 28, 2015 at 01:17:44PM -0300, Eduardo Habkost wrote: > On Mon, Sep 28, 2015 at 01:38:30PM +0800, Haozhong Zhang wrote: > > When creating a vcpu, we initialize its TSC rate to the value from > > KVM (through ioctl KVM_GET_TSC_KHZ). > > > > Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com> > > --- > > target-i386/kvm.c | 7 +++++++ > > 1 file changed, 7 insertions(+) > > > > diff --git a/target-i386/kvm.c b/target-i386/kvm.c > > index 7b0ba17..c2b161a 100644 > > --- a/target-i386/kvm.c > > +++ b/target-i386/kvm.c > > @@ -751,6 +751,13 @@ int kvm_arch_init_vcpu(CPUState *cs) > > } > > } > > > > + 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 = r; > > You are silently overwriting the tsc_khz value set by the user, why? > Oh, I need to check if user has provided tsc_khz, and if so then just use the user-provided value. So I'll replace it with code like if (env->tsc_khz) { kvm_vcpu_ioctl(cs, KVM_SET_TSC_KHZ, env->tsc_khz); } else { 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 = r; } - Haozhong > -- > Eduardo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Sep 29, 2015 at 09:23:39AM +0800, Haozhong Zhang wrote: > On Mon, Sep 28, 2015 at 01:17:44PM -0300, Eduardo Habkost wrote: > > On Mon, Sep 28, 2015 at 01:38:30PM +0800, Haozhong Zhang wrote: > > > When creating a vcpu, we initialize its TSC rate to the value from > > > KVM (through ioctl KVM_GET_TSC_KHZ). > > > > > > Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com> > > > --- > > > target-i386/kvm.c | 7 +++++++ > > > 1 file changed, 7 insertions(+) > > > > > > diff --git a/target-i386/kvm.c b/target-i386/kvm.c > > > index 7b0ba17..c2b161a 100644 > > > --- a/target-i386/kvm.c > > > +++ b/target-i386/kvm.c > > > @@ -751,6 +751,13 @@ int kvm_arch_init_vcpu(CPUState *cs) > > > } > > > } > > > > > > + 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 = r; > > > > You are silently overwriting the tsc_khz value set by the user, why? > > > > Oh, I need to check if user has provided tsc_khz, and if so then just > use the user-provided value. So I'll replace it with code like > > if (env->tsc_khz) { > kvm_vcpu_ioctl(cs, KVM_SET_TSC_KHZ, env->tsc_khz); Just notice this line duplicates code several lines above. Only the else branch is needed. > } else { > 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 = r; > } > > - Haozhong > > > -- > > Eduardo > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html - Haozhong Zhang -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/target-i386/kvm.c b/target-i386/kvm.c index 7b0ba17..c2b161a 100644 --- a/target-i386/kvm.c +++ b/target-i386/kvm.c @@ -751,6 +751,13 @@ int kvm_arch_init_vcpu(CPUState *cs) } } + 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 = r; + if (kvm_has_xsave()) { env->kvm_xsave_buf = qemu_memalign(4096, sizeof(struct kvm_xsave)); }
When creating a vcpu, we initialize its TSC rate to the value from KVM (through ioctl KVM_GET_TSC_KHZ). Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com> --- target-i386/kvm.c | 7 +++++++ 1 file changed, 7 insertions(+)