Re: [PATCH 01/12] KVM: x86: Collect information for setting TSC scaling ratio

2015-09-28 Thread Eric Northup 
On Sun, Sep 27, 2015 at 10:38 PM, Haozhong Zhang
 wrote:
>
> The number of bits of the fractional part of the 64-bit TSC scaling
> ratio in VMX and SVM is different. This patch makes the architecture
> code to collect the number of fractional bits and other related
> information into variables that can be accessed in the common code.
>
> Signed-off-by: Haozhong Zhang 
> ---
>  arch/x86/include/asm/kvm_host.h | 8 
>  arch/x86/kvm/svm.c  | 5 +
>  arch/x86/kvm/x86.c  | 8 
>  3 files changed, 21 insertions(+)
>
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 2beee03..5b9b86e 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -965,6 +965,14 @@ extern bool kvm_has_tsc_control;
>  extern u32  kvm_min_guest_tsc_khz;
>  /* maximum supported tsc_khz for guests */
>  extern u32  kvm_max_guest_tsc_khz;
> +/* number of bits of the fractional part of the TSC scaling ratio */
> +extern u8   kvm_tsc_scaling_ratio_frac_bits;
> +/* reserved bits of TSC scaling ratio (SBZ) */
> +extern u64  kvm_tsc_scaling_ratio_rsvd;
> +/* default TSC scaling ratio (= 1.0) */
> +extern u64  kvm_default_tsc_scaling_ratio;
> +/* maximum allowed value of TSC scaling ratio */
> +extern u64  kvm_max_tsc_scaling_ratio;

Do we need all 3 of kvm_max_guest_tsc_khz, kvm_max_tsc_scaling_ratio,
and kvm_tsc_scaling_ratio_rsvd (since only SVM has reserved bits - and
just for complaining if the high bits are set, which can already be
expressed by max_tsc_scaling ratio)

kvm_max_tsc_scaling_ratio seems to be write-only.

>
>  enum emulation_result {
> EMULATE_DONE, /* no further processing */
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index 94b7d15..eff7db7 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -963,7 +963,12 @@ static __init int svm_hardware_setup(void)
> max = min(0x7fffULL, __scale_tsc(tsc_khz, TSC_RATIO_MAX));
>
> kvm_max_guest_tsc_khz = max;
> +
> +   kvm_max_tsc_scaling_ratio = TSC_RATIO_MAX;
> +   kvm_tsc_scaling_ratio_frac_bits = 32;
> +   kvm_tsc_scaling_ratio_rsvd = TSC_RATIO_RSVD;
> }
> +   kvm_default_tsc_scaling_ratio = TSC_RATIO_DEFAULT;
>
> if (nested) {
> printk(KERN_INFO "kvm: Nested Virtualization enabled\n");
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 991466b..f888225 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -106,6 +106,14 @@ bool kvm_has_tsc_control;
>  EXPORT_SYMBOL_GPL(kvm_has_tsc_control);
>  u32  kvm_max_guest_tsc_khz;
>  EXPORT_SYMBOL_GPL(kvm_max_guest_tsc_khz);
> +u8   kvm_tsc_scaling_ratio_frac_bits;
> +EXPORT_SYMBOL_GPL(kvm_tsc_scaling_ratio_frac_bits);
> +u64  kvm_tsc_scaling_ratio_rsvd;
> +EXPORT_SYMBOL_GPL(kvm_tsc_scaling_ratio_rsvd);
> +u64  kvm_default_tsc_scaling_ratio;
> +EXPORT_SYMBOL_GPL(kvm_default_tsc_scaling_ratio);
> +u64  kvm_max_tsc_scaling_ratio;
> +EXPORT_SYMBOL_GPL(kvm_max_tsc_scaling_ratio);
>
>  /* tsc tolerance in parts per million - default to 1/2 of the NTP threshold 
> */
>  static u32 tsc_tolerance_ppm = 250;
> --
> 2.4.8
>
> --
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Re: [PATCH 01/12] KVM: x86: Collect information for setting TSC scaling ratio

2015-09-28 Thread Haozhong Zhang 
On Mon, Sep 28, 2015 at 08:28:57PM -0700, Eric Northup wrote:
> On Sun, Sep 27, 2015 at 10:38 PM, Haozhong Zhang
>  wrote:
> >
> > The number of bits of the fractional part of the 64-bit TSC scaling
> > ratio in VMX and SVM is different. This patch makes the architecture
> > code to collect the number of fractional bits and other related
> > information into variables that can be accessed in the common code.
> >
> > Signed-off-by: Haozhong Zhang 
> > ---
> >  arch/x86/include/asm/kvm_host.h | 8 
> >  arch/x86/kvm/svm.c  | 5 +
> >  arch/x86/kvm/x86.c  | 8 
> >  3 files changed, 21 insertions(+)
> >
> > diff --git a/arch/x86/include/asm/kvm_host.h 
> > b/arch/x86/include/asm/kvm_host.h
> > index 2beee03..5b9b86e 100644
> > --- a/arch/x86/include/asm/kvm_host.h
> > +++ b/arch/x86/include/asm/kvm_host.h
> > @@ -965,6 +965,14 @@ extern bool kvm_has_tsc_control;
> >  extern u32  kvm_min_guest_tsc_khz;
> >  /* maximum supported tsc_khz for guests */
> >  extern u32  kvm_max_guest_tsc_khz;
> > +/* number of bits of the fractional part of the TSC scaling ratio */
> > +extern u8   kvm_tsc_scaling_ratio_frac_bits;
> > +/* reserved bits of TSC scaling ratio (SBZ) */
> > +extern u64  kvm_tsc_scaling_ratio_rsvd;
> > +/* default TSC scaling ratio (= 1.0) */
> > +extern u64  kvm_default_tsc_scaling_ratio;
> > +/* maximum allowed value of TSC scaling ratio */
> > +extern u64  kvm_max_tsc_scaling_ratio;
> 
> Do we need all 3 of kvm_max_guest_tsc_khz, kvm_max_tsc_scaling_ratio,
> and kvm_tsc_scaling_ratio_rsvd (since only SVM has reserved bits - and
> just for complaining if the high bits are set, which can already be
> expressed by max_tsc_scaling ratio)
> 
> kvm_max_tsc_scaling_ratio seems to be write-only.
>

You are right. I'll remove kvm_tsc_scaling_ratio_rsvd and just use
kvm_max_tsc_scaling_ratio to verify TSC scaling ratio in
set_tsc_khz().

> >
> >  enum emulation_result {
> > EMULATE_DONE, /* no further processing */
> > diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> > index 94b7d15..eff7db7 100644
> > --- a/arch/x86/kvm/svm.c
> > +++ b/arch/x86/kvm/svm.c
> > @@ -963,7 +963,12 @@ static __init int svm_hardware_setup(void)
> > max = min(0x7fffULL, __scale_tsc(tsc_khz, 
> > TSC_RATIO_MAX));
> >
> > kvm_max_guest_tsc_khz = max;
> > +
> > +   kvm_max_tsc_scaling_ratio = TSC_RATIO_MAX;
> > +   kvm_tsc_scaling_ratio_frac_bits = 32;
> > +   kvm_tsc_scaling_ratio_rsvd = TSC_RATIO_RSVD;
> > }
> > +   kvm_default_tsc_scaling_ratio = TSC_RATIO_DEFAULT;
> >
> > if (nested) {
> > printk(KERN_INFO "kvm: Nested Virtualization enabled\n");
> > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> > index 991466b..f888225 100644
> > --- a/arch/x86/kvm/x86.c
> > +++ b/arch/x86/kvm/x86.c
> > @@ -106,6 +106,14 @@ bool kvm_has_tsc_control;
> >  EXPORT_SYMBOL_GPL(kvm_has_tsc_control);
> >  u32  kvm_max_guest_tsc_khz;
> >  EXPORT_SYMBOL_GPL(kvm_max_guest_tsc_khz);
> > +u8   kvm_tsc_scaling_ratio_frac_bits;
> > +EXPORT_SYMBOL_GPL(kvm_tsc_scaling_ratio_frac_bits);
> > +u64  kvm_tsc_scaling_ratio_rsvd;
> > +EXPORT_SYMBOL_GPL(kvm_tsc_scaling_ratio_rsvd);
> > +u64  kvm_default_tsc_scaling_ratio;
> > +EXPORT_SYMBOL_GPL(kvm_default_tsc_scaling_ratio);
> > +u64  kvm_max_tsc_scaling_ratio;
> > +EXPORT_SYMBOL_GPL(kvm_max_tsc_scaling_ratio);
> >
> >  /* tsc tolerance in parts per million - default to 1/2 of the NTP 
> > threshold */
> >  static u32 tsc_tolerance_ppm = 250;
> > --
> > 2.4.8
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe kvm" in
> > the body of a message to majord...@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
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[PATCH 01/12] KVM: x86: Collect information for setting TSC scaling ratio

2015-09-27 Thread Haozhong Zhang 
The number of bits of the fractional part of the 64-bit TSC scaling
ratio in VMX and SVM is different. This patch makes the architecture
code to collect the number of fractional bits and other related
information into variables that can be accessed in the common code.

Signed-off-by: Haozhong Zhang 
---
 arch/x86/include/asm/kvm_host.h | 8 
 arch/x86/kvm/svm.c  | 5 +
 arch/x86/kvm/x86.c  | 8 
 3 files changed, 21 insertions(+)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 2beee03..5b9b86e 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -965,6 +965,14 @@ extern bool kvm_has_tsc_control;
 extern u32  kvm_min_guest_tsc_khz;
 /* maximum supported tsc_khz for guests */
 extern u32  kvm_max_guest_tsc_khz;
+/* number of bits of the fractional part of the TSC scaling ratio */
+extern u8   kvm_tsc_scaling_ratio_frac_bits;
+/* reserved bits of TSC scaling ratio (SBZ) */
+extern u64  kvm_tsc_scaling_ratio_rsvd;
+/* default TSC scaling ratio (= 1.0) */
+extern u64  kvm_default_tsc_scaling_ratio;
+/* maximum allowed value of TSC scaling ratio */
+extern u64  kvm_max_tsc_scaling_ratio;
 
 enum emulation_result {
EMULATE_DONE, /* no further processing */
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 94b7d15..eff7db7 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -963,7 +963,12 @@ static __init int svm_hardware_setup(void)
max = min(0x7fffULL, __scale_tsc(tsc_khz, TSC_RATIO_MAX));
 
kvm_max_guest_tsc_khz = max;
+
+   kvm_max_tsc_scaling_ratio = TSC_RATIO_MAX;
+   kvm_tsc_scaling_ratio_frac_bits = 32;
+   kvm_tsc_scaling_ratio_rsvd = TSC_RATIO_RSVD;
}
+   kvm_default_tsc_scaling_ratio = TSC_RATIO_DEFAULT;
 
if (nested) {
printk(KERN_INFO "kvm: Nested Virtualization enabled\n");
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 991466b..f888225 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -106,6 +106,14 @@ bool kvm_has_tsc_control;
 EXPORT_SYMBOL_GPL(kvm_has_tsc_control);
 u32  kvm_max_guest_tsc_khz;
 EXPORT_SYMBOL_GPL(kvm_max_guest_tsc_khz);
+u8   kvm_tsc_scaling_ratio_frac_bits;
+EXPORT_SYMBOL_GPL(kvm_tsc_scaling_ratio_frac_bits);
+u64  kvm_tsc_scaling_ratio_rsvd;
+EXPORT_SYMBOL_GPL(kvm_tsc_scaling_ratio_rsvd);
+u64  kvm_default_tsc_scaling_ratio;
+EXPORT_SYMBOL_GPL(kvm_default_tsc_scaling_ratio);
+u64  kvm_max_tsc_scaling_ratio;
+EXPORT_SYMBOL_GPL(kvm_max_tsc_scaling_ratio);
 
 /* tsc tolerance in parts per million - default to 1/2 of the NTP threshold */
 static u32 tsc_tolerance_ppm = 250;
-- 
2.4.8

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