From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boris Ostrovsky Subject: Re: [PATCH v2 09/14] x86/hvm: Setup TSC scaling ratio Date: Mon, 7 Dec 2015 13:42:59 -0500 Message-ID: <5665D333.9040001@oracle.com> References: <1449435529-12989-1-git-send-email-haozhong.zhang@intel.com> <1449435529-12989-10-git-send-email-haozhong.zhang@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1449435529-12989-10-git-send-email-haozhong.zhang@intel.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Haozhong Zhang , xen-devel@lists.xen.org Cc: Kevin Tian , Keir Fraser , Jan Beulich , Jun Nakajima , Andrew Cooper , Aravind Gopalakrishnan , Suravee Suthikulpanit List-Id: xen-devel@lists.xenproject.org On 12/06/2015 03:58 PM, Haozhong Zhang wrote: > This patch adds a field tsc_scaling_ratio in struct hvm_vcpu to > record the TSC scaling ratio, and sets it up when tsc_set_info() is > called for a vcpu or when a vcpu is restored or reset. > > Signed-off-by: Haozhong Zhang Reviewed-by: Boris Ostrovsky with a few nits below. > --- > xen/arch/x86/hvm/hvm.c | 30 ++++++++++++++++++++++++++++++ > xen/arch/x86/hvm/svm/svm.c | 6 ++++-- > xen/arch/x86/time.c | 13 ++++++++++++- > xen/include/asm-x86/hvm/hvm.h | 5 +++++ > xen/include/asm-x86/hvm/svm/svm.h | 3 --- > xen/include/asm-x86/hvm/vcpu.h | 2 ++ > xen/include/asm-x86/math64.h | 30 ++++++++++++++++++++++++++++++ > 7 files changed, 83 insertions(+), 6 deletions(-) > create mode 100644 xen/include/asm-x86/math64.h > > diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c > index 0e63c33..52a0ef8 100644 > --- a/xen/arch/x86/hvm/hvm.c > +++ b/xen/arch/x86/hvm/hvm.c > @@ -65,6 +65,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -301,6 +302,29 @@ int hvm_set_guest_pat(struct vcpu *v, u64 guest_pat) > return 1; > } > > +void hvm_setup_tsc_scaling(struct vcpu *v) > +{ > + u64 ratio; > + > + if ( !hvm_funcs.tsc_scaling_supported ) > + return; > + > + /* > + * The multiplication of the first two terms may overflow a 64-bit > + * integer, so use mul_u64_u32_div() instead to keep precision. > + */ > + ratio = mul_u64_u32_div(1ULL << hvm_funcs.tsc_scaling_ratio_frac_bits, > + v->domain->arch.tsc_khz, cpu_khz); > + > + if ( ratio == 0 || ratio > hvm_funcs.max_tsc_scaling_ratio ) > + return; > + > + v->arch.hvm_vcpu.tsc_scaling_ratio = ratio; > + > + if ( hvm_funcs.setup_tsc_scaling ) > + hvm_funcs.setup_tsc_scaling(v); > +} > + > void hvm_set_guest_tsc_fixed(struct vcpu *v, u64 guest_tsc, u64 at_tsc) > { > uint64_t tsc; > @@ -2024,6 +2048,9 @@ static int hvm_load_cpu_ctxt(struct domain *d, hvm_domain_context_t *h) > if ( hvm_funcs.load_cpu_ctxt(v, &ctxt) < 0 ) > return -EINVAL; > > + if ( hvm_funcs.tsc_scaling_supported ) > + hvm_setup_tsc_scaling(v); > + I think you can drop the test here (and below) since you do the same check inside hvm_setup_tsc_scaling() > v->arch.hvm_vcpu.msr_tsc_aux = ctxt.msr_tsc_aux; > > seg.limit = ctxt.idtr_limit; > @@ -5584,6 +5611,9 @@ void hvm_vcpu_reset_state(struct vcpu *v, uint16_t cs, uint16_t ip) > hvm_set_segment_register(v, x86_seg_gdtr, ®); > hvm_set_segment_register(v, x86_seg_idtr, ®); > > + if ( hvm_funcs.tsc_scaling_supported ) > + hvm_setup_tsc_scaling(v); > + > /* Sync AP's TSC with BSP's. */ > v->arch.hvm_vcpu.cache_tsc_offset = > v->domain->vcpu[0]->arch.hvm_vcpu.cache_tsc_offset; > diff --git a/xen/arch/x86/hvm/svm/svm.c b/xen/arch/x86/hvm/svm/svm.c > index 9f741d0..d291327 100644 > --- a/xen/arch/x86/hvm/svm/svm.c > +++ b/xen/arch/x86/hvm/svm/svm.c > @@ -811,7 +811,7 @@ static uint64_t svm_scale_tsc(struct vcpu *v, uint64_t tsc) > if ( !cpu_has_tsc_ratio || d->arch.vtsc ) > return tsc; > > - return scale_tsc(tsc, vcpu_tsc_ratio(v)); > + return scale_tsc(tsc, v->arch.hvm_vcpu.tsc_scaling_ratio); > } > > static uint64_t svm_get_tsc_offset(uint64_t host_tsc, uint64_t guest_tsc, > @@ -987,7 +987,7 @@ static inline void svm_tsc_ratio_save(struct vcpu *v) > static inline void svm_tsc_ratio_load(struct vcpu *v) > { > if ( cpu_has_tsc_ratio && !v->domain->arch.vtsc ) > - wrmsrl(MSR_AMD64_TSC_RATIO, vcpu_tsc_ratio(v)); > + wrmsrl(MSR_AMD64_TSC_RATIO, v->arch.hvm_vcpu.tsc_scaling_ratio); > } > > static void svm_ctxt_switch_from(struct vcpu *v) > @@ -1193,6 +1193,8 @@ static int svm_vcpu_initialise(struct vcpu *v) > > svm_guest_osvw_init(v); > > + v->arch.hvm_vcpu.tsc_scaling_ratio = DEFAULT_TSC_RATIO; > + > return 0; > } > > diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c > index 732d1e9..d4a94eb 100644 > --- a/xen/arch/x86/time.c > +++ b/xen/arch/x86/time.c > @@ -1902,8 +1902,19 @@ void tsc_set_info(struct domain *d, > if ( has_hvm_container_domain(d) ) > { > hvm_set_rdtsc_exiting(d, d->arch.vtsc); > - if ( d->vcpu && d->vcpu[0] && incarnation == 0 ) > + if ( d->vcpu && d->vcpu[0] ) > { > + /* > + * TSC scaling ratio on BSP is set here during initial boot, while During domain creation rather then during boot. > + * the same TSC scaling ratio on APs will be set in > + * hvm_vcpu_reset_state(). > + */ > + if ( !d->arch.vtsc && hvm_funcs.tsc_scaling_supported ) > + hvm_setup_tsc_scaling(d->vcpu[0]); > + > + if ( incarnation ) > + return; > + > /* > * set_tsc_offset() is called from hvm_vcpu_initialise() before > * tsc_set_info(). New vtsc mode may require recomputing TSC > diff --git a/xen/include/asm-x86/hvm/hvm.h b/xen/include/asm-x86/hvm/hvm.h > index 8b10a67..e74524e 100644 > --- a/xen/include/asm-x86/hvm/hvm.h > +++ b/xen/include/asm-x86/hvm/hvm.h > @@ -226,6 +226,9 @@ struct hvm_function_table { > int (*altp2m_vcpu_emulate_vmfunc)(struct cpu_user_regs *regs); > > uint64_t (*scale_tsc)(struct vcpu *v, uint64_t tsc); > + > + /* Architecture function to setup TSC scaling ratio */ > + void (*setup_tsc_scaling)(struct vcpu *v); > }; > > extern struct hvm_function_table hvm_funcs; > @@ -261,6 +264,8 @@ void hvm_set_guest_tsc_fixed(struct vcpu *v, u64 guest_tsc, u64 at_tsc); > u64 hvm_get_guest_tsc_fixed(struct vcpu *v, u64 at_tsc); > #define hvm_get_guest_tsc(v) hvm_get_guest_tsc_fixed(v, 0) > > +void hvm_setup_tsc_scaling(struct vcpu *v); > + > int hvm_set_mode(struct vcpu *v, int mode); > void hvm_init_guest_time(struct domain *d); > void hvm_set_guest_time(struct vcpu *v, u64 guest_time); > diff --git a/xen/include/asm-x86/hvm/svm/svm.h b/xen/include/asm-x86/hvm/svm/svm.h > index d60ec23..c954b7e 100644 > --- a/xen/include/asm-x86/hvm/svm/svm.h > +++ b/xen/include/asm-x86/hvm/svm/svm.h > @@ -97,9 +97,6 @@ extern u32 svm_feature_flags; > /* TSC rate */ > #define DEFAULT_TSC_RATIO 0x0000000100000000ULL > #define TSC_RATIO_RSVD_BITS 0xffffff0000000000ULL > -#define TSC_RATIO(g_khz, h_khz) ( (((u64)(g_khz)<<32)/(u64)(h_khz)) & \ > - ~TSC_RATIO_RSVD_BITS ) > -#define vcpu_tsc_ratio(v) TSC_RATIO((v)->domain->arch.tsc_khz, cpu_khz) > > extern void svm_host_osvw_reset(void); > extern void svm_host_osvw_init(void); > diff --git a/xen/include/asm-x86/hvm/vcpu.h b/xen/include/asm-x86/hvm/vcpu.h > index 152d9f3..901c988 100644 > --- a/xen/include/asm-x86/hvm/vcpu.h > +++ b/xen/include/asm-x86/hvm/vcpu.h > @@ -175,6 +175,8 @@ struct hvm_vcpu { > u64 msr_tsc_adjust; > u64 msr_xss; > > + u64 tsc_scaling_ratio; > + > union { > struct arch_vmx_struct vmx; > struct arch_svm_struct svm; > diff --git a/xen/include/asm-x86/math64.h b/xen/include/asm-x86/math64.h > new file mode 100644 > index 0000000..9af6aee > --- /dev/null > +++ b/xen/include/asm-x86/math64.h > @@ -0,0 +1,30 @@ > +#ifndef __X86_MATH64 > +#define __X86_MATH64 > + > +/* > + * (a * mul) / divisor > + */ > +static inline u64 mul_u64_u32_div(u64 a, u32 mul, u32 divisor) Since this is taken from Linux code I thinkit's worth mentioning so. -boris > +{ > + union { > + u64 ll; > + struct { > + u32 low, high; > + } l; > + } u, rl, rh; > + > + u.ll = a; > + rl.ll = (u64)u.l.low * mul; > + rh.ll = (u64)u.l.high * mul + rl.l.high; > + > + /* Bits 32-63 of the result will be in rh.l.low. */ > + rl.l.high = do_div(rh.ll, divisor); > + > + /* Bits 0-31 of the result will be in rl.l.low. */ > + do_div(rl.ll, divisor); > + > + rl.l.high = rh.l.low; > + return rl.ll; > +} > + > +#endif