[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v4 06/10] x86/hvm: Setup TSC scaling ratio
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. Before applying the TSC scaling ratio to CPU, we check its validity in tsc_set_info(). If an invalid ratio is given, we will leave the default value in tsc_scaling_ratio (i.e. ratio = 1) and setup guest TSC as if no TSC scaling is used: * For TSC_MODE_FAULT, - if a user-specified TSC frequency is given, we will set the guest TSC frequency to it; otherwise, we set it to the host TSC frequency. - if guest TSC frequency does not equal to host TSC frequency, we will emulate guest TSC (i.e. d->arch.vtsc is set to 1). In both cases, guest TSC runs in the guest TSC frequency. * For TSC_MODE_PVRDTSCP, - we set the guest TSC frequency to the host TSC frequency. - guest rdtsc is executed natively in the host TSC frequency as before. - if rdtscp is not available to guest, it will be emulated; otherwise, it will be executed natively. In both cases, guest rdtscp gets TSC in the host TSC frequency as before. Signed-off-by: Haozhong Zhang <haozhong.zhang@xxxxxxxxx> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx> --- Changes in v4: (addressing Boris Ostrovsky's comments) * Factor out common code in hvm_validate_tsc_scaling_ratio() and hvm_setup_tsc_scaling() - replace bool_t hvm_validate_tsc_scaling_ratio(u32 gtsc_khz) with u64 hvm_get_tsc_scaling_ratio(u32 gtsc_khz) which returns 0 if TSC scaling is not available or gtsc_khz is bogus. (addressing Jan Beulich's comments) * Move adding setup_tsc_scaling in hvm_funcs to patch 9 where it is first used. xen/arch/x86/hvm/hvm.c | 35 +++++++++++++++++++++++++++++++++++ xen/arch/x86/hvm/svm/svm.c | 6 ++++-- xen/arch/x86/time.c | 19 ++++++++++++++++--- xen/include/asm-x86/hvm/hvm.h | 3 +++ xen/include/asm-x86/hvm/svm/svm.h | 3 --- xen/include/asm-x86/hvm/vcpu.h | 2 ++ 6 files changed, 60 insertions(+), 8 deletions(-) diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c index 6d30d8b..64a7760 100644 --- a/xen/arch/x86/hvm/hvm.c +++ b/xen/arch/x86/hvm/hvm.c @@ -65,6 +65,7 @@ #include <asm/mtrr.h> #include <asm/apic.h> #include <asm/vm_event.h> +#include <asm/math64.h> #include <public/sched.h> #include <public/hvm/ioreq.h> #include <public/version.h> @@ -301,6 +302,34 @@ int hvm_set_guest_pat(struct vcpu *v, u64 guest_pat) return 1; } +/* + * Get the ratio to scale host TSC frequency to gtsc_khz. zero will be + * returned if TSC scaling is unavailable or ratio cannot be handled + * by host CPU. Otherwise, a non-zero ratio will be returned. + */ +u64 hvm_get_tsc_scaling_ratio(u32 gtsc_khz) +{ + u64 ratio; + + if ( !hvm_tsc_scaling_supported ) + return 0; + + /* + * 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, + gtsc_khz, cpu_khz); + + return ratio > hvm_funcs.max_tsc_scaling_ratio ? 0 : ratio; +} + +void hvm_setup_tsc_scaling(struct vcpu *v) +{ + v->arch.hvm_vcpu.tsc_scaling_ratio = + hvm_get_tsc_scaling_ratio(v->domain->arch.tsc_khz); +} + void hvm_set_guest_tsc_fixed(struct vcpu *v, u64 guest_tsc, u64 at_tsc) { uint64_t tsc; @@ -2026,6 +2055,9 @@ 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_tsc_scaling_supported && !d->arch.vtsc ) + hvm_setup_tsc_scaling(v); + v->arch.hvm_vcpu.msr_tsc_aux = ctxt.msr_tsc_aux; seg.limit = ctxt.idtr_limit; @@ -5504,6 +5536,9 @@ 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_tsc_scaling_supported && !d->arch.vtsc ) + 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 8b316a0..17bce5c 100644 --- a/xen/arch/x86/hvm/svm/svm.c +++ b/xen/arch/x86/hvm/svm/svm.c @@ -808,7 +808,7 @@ static uint64_t svm_scale_tsc(const struct vcpu *v, uint64_t tsc) { ASSERT(cpu_has_tsc_ratio && !v->domain->arch.vtsc); - 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, @@ -985,7 +985,7 @@ 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) @@ -1192,6 +1192,8 @@ 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 a243bc3..2ce6447 100644 --- a/xen/arch/x86/time.c +++ b/xen/arch/x86/time.c @@ -1864,7 +1864,8 @@ void tsc_set_info(struct domain *d, */ if ( tsc_mode == TSC_MODE_DEFAULT && host_tsc_is_safe() && (has_hvm_container_domain(d) ? - d->arch.tsc_khz == cpu_khz || hvm_tsc_scaling_supported : + (d->arch.tsc_khz == cpu_khz || + hvm_get_tsc_scaling_ratio(d->arch.tsc_khz)) : incarnation == 0) ) { case TSC_MODE_NEVER_EMULATE: @@ -1878,7 +1879,8 @@ void tsc_set_info(struct domain *d, d->arch.vtsc = !boot_cpu_has(X86_FEATURE_RDTSCP) || !host_tsc_is_safe(); enable_tsc_scaling = has_hvm_container_domain(d) && - hvm_tsc_scaling_supported && !d->arch.vtsc; + !d->arch.vtsc && + hvm_get_tsc_scaling_ratio(gtsc_khz ?: cpu_khz); d->arch.tsc_khz = (enable_tsc_scaling && gtsc_khz) ? gtsc_khz : cpu_khz; set_time_scale(&d->arch.vtsc_to_ns, d->arch.tsc_khz * 1000 ); d->arch.ns_to_vtsc = scale_reciprocal(d->arch.vtsc_to_ns); @@ -1897,9 +1899,20 @@ 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 domain + * creation, while the same TSC scaling ratio on APs will + * be set in hvm_vcpu_reset_state(). + */ + if ( hvm_tsc_scaling_supported && !d->arch.vtsc ) + 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 * offset. diff --git a/xen/include/asm-x86/hvm/hvm.h b/xen/include/asm-x86/hvm/hvm.h index 79ea59e..f2d1419 100644 --- a/xen/include/asm-x86/hvm/hvm.h +++ b/xen/include/asm-x86/hvm/hvm.h @@ -263,6 +263,9 @@ u64 hvm_get_guest_tsc_fixed(struct vcpu *v, u64 at_tsc); #define hvm_tsc_scaling_supported (!!hvm_funcs.default_tsc_scaling_ratio) +u64 hvm_get_tsc_scaling_ratio(u32 gtsc_khz); +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; -- 2.7.0 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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