[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen-unstable] x86: TSC handling cleanups
# HG changeset patch # User Keir Fraser <keir.fraser@xxxxxxxxxx> # Date 1273563298 -3600 # Node ID 804304d4e05d98289de9a107c6b26c5a1db09cd8 # Parent a915a11908e3ab970887a313279650bc1d50c539 x86: TSC handling cleanups "I am removing the tsc_scaled variable that is never actually used because when tsc needs to be scaled vtsc is 1. I am also making this more explicit in tsc_set_info. I am also removing hvm_domain.gtsc_khz that is a duplicate of d->arch.tsc_khz. I am using scale_delta(delta, &d->arch.ns_to_vtsc) to scale the tsc value before returning it to the guest like in the pv case. I added a feature flag to specify that the pvclock algorithm is safe to be used in an HVM guest so that the guest can now use it without hanging." Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx> --- xen/arch/x86/hvm/hvm.c | 30 ++---------------------------- xen/arch/x86/hvm/save.c | 6 +++--- xen/arch/x86/hvm/vpt.c | 3 --- xen/arch/x86/time.c | 31 +++++++++++++++++++++++-------- xen/common/kernel.c | 2 ++ xen/include/asm-x86/hvm/domain.h | 2 -- xen/include/asm-x86/hvm/hvm.h | 1 - xen/include/asm-x86/time.h | 1 + xen/include/public/features.h | 3 +++ 9 files changed, 34 insertions(+), 45 deletions(-) diff -r a915a11908e3 -r 804304d4e05d xen/arch/x86/hvm/hvm.c --- a/xen/arch/x86/hvm/hvm.c Tue May 11 08:31:16 2010 +0100 +++ b/xen/arch/x86/hvm/hvm.c Tue May 11 08:34:58 2010 +0100 @@ -153,32 +153,6 @@ void hvm_set_rdtsc_exiting(struct domain hvm_funcs.set_rdtsc_exiting(v, enable); } -int hvm_gtsc_need_scale(struct domain *d) -{ - uint32_t gtsc_mhz, htsc_mhz; - - if ( d->arch.vtsc ) - return 0; - - gtsc_mhz = d->arch.hvm_domain.gtsc_khz / 1000; - htsc_mhz = (uint32_t)cpu_khz / 1000; - - d->arch.hvm_domain.tsc_scaled = (gtsc_mhz && (gtsc_mhz != htsc_mhz)); - return d->arch.hvm_domain.tsc_scaled; -} - -static u64 hvm_h2g_scale_tsc(struct vcpu *v, u64 host_tsc) -{ - uint32_t gtsc_khz, htsc_khz; - - if ( !v->domain->arch.hvm_domain.tsc_scaled ) - return host_tsc; - - htsc_khz = cpu_khz; - gtsc_khz = v->domain->arch.hvm_domain.gtsc_khz; - return muldiv64(host_tsc, gtsc_khz, htsc_khz); -} - void hvm_set_guest_tsc(struct vcpu *v, u64 guest_tsc) { uint64_t tsc; @@ -186,11 +160,11 @@ void hvm_set_guest_tsc(struct vcpu *v, u if ( v->domain->arch.vtsc ) { tsc = hvm_get_guest_time(v); + tsc = gtime_to_gtsc(v->domain, tsc); } else { rdtscll(tsc); - tsc = hvm_h2g_scale_tsc(v, tsc); } v->arch.hvm_vcpu.cache_tsc_offset = guest_tsc - tsc; @@ -204,12 +178,12 @@ u64 hvm_get_guest_tsc(struct vcpu *v) if ( v->domain->arch.vtsc ) { tsc = hvm_get_guest_time(v); + tsc = gtime_to_gtsc(v->domain, tsc); v->domain->arch.vtsc_kerncount++; } else { rdtscll(tsc); - tsc = hvm_h2g_scale_tsc(v, tsc); } return tsc + v->arch.hvm_vcpu.cache_tsc_offset; diff -r a915a11908e3 -r 804304d4e05d xen/arch/x86/hvm/save.c --- a/xen/arch/x86/hvm/save.c Tue May 11 08:31:16 2010 +0100 +++ b/xen/arch/x86/hvm/save.c Tue May 11 08:34:58 2010 +0100 @@ -33,7 +33,7 @@ void arch_hvm_save(struct domain *d, str hdr->cpuid = eax; /* Save guest's preferred TSC. */ - hdr->gtsc_khz = d->arch.hvm_domain.gtsc_khz; + hdr->gtsc_khz = d->arch.tsc_khz; } int arch_hvm_load(struct domain *d, struct hvm_save_header *hdr) @@ -62,8 +62,8 @@ int arch_hvm_load(struct domain *d, stru /* Restore guest's preferred TSC frequency. */ if ( hdr->gtsc_khz ) - d->arch.hvm_domain.gtsc_khz = hdr->gtsc_khz; - if ( hvm_gtsc_need_scale(d) ) + d->arch.tsc_khz = hdr->gtsc_khz; + if ( d->arch.vtsc ) { hvm_set_rdtsc_exiting(d, 1); gdprintk(XENLOG_WARNING, "Domain %d expects freq %uMHz " diff -r a915a11908e3 -r 804304d4e05d xen/arch/x86/hvm/vpt.c --- a/xen/arch/x86/hvm/vpt.c Tue May 11 08:31:16 2010 +0100 +++ b/xen/arch/x86/hvm/vpt.c Tue May 11 08:34:58 2010 +0100 @@ -32,9 +32,6 @@ void hvm_init_guest_time(struct domain * spin_lock_init(&pl->pl_time_lock); pl->stime_offset = -(u64)get_s_time(); pl->last_guest_time = 0; - - d->arch.hvm_domain.gtsc_khz = cpu_khz; - d->arch.hvm_domain.tsc_scaled = 0; } u64 hvm_get_guest_time(struct vcpu *v) diff -r a915a11908e3 -r 804304d4e05d xen/arch/x86/time.c --- a/xen/arch/x86/time.c Tue May 11 08:31:16 2010 +0100 +++ b/xen/arch/x86/time.c Tue May 11 08:34:58 2010 +0100 @@ -828,8 +828,13 @@ static void __update_vcpu_system_time(st if ( d->arch.vtsc ) { - u64 delta = max_t(s64, t->stime_local_stamp - d->arch.vtsc_offset, 0); - tsc_stamp = scale_delta(delta, &d->arch.ns_to_vtsc); + u64 stime = t->stime_local_stamp; + if ( is_hvm_domain(d) ) + { + struct pl_time *pl = &v->domain->arch.hvm_domain.pl_time; + stime += pl->stime_offset + v->arch.hvm_vcpu.stime_offset; + } + tsc_stamp = gtime_to_gtsc(d, stime); } else { @@ -852,6 +857,8 @@ static void __update_vcpu_system_time(st _u.tsc_to_system_mul = t->tsc_scale.mul_frac; _u.tsc_shift = (s8)t->tsc_scale.shift; } + if ( is_hvm_domain(d) ) + _u.tsc_timestamp += v->arch.hvm_vcpu.cache_tsc_offset; /* Don't bother unless timestamp record has changed or we are forced. */ _u.version = u->version; /* make versions match for memcmp test */ @@ -1618,11 +1625,18 @@ struct tm wallclock_time(void) * PV SoftTSC Emulation. */ +u64 gtime_to_gtsc(struct domain *d, u64 tsc) +{ + if ( !is_hvm_domain(d) ) + tsc = max_t(s64, tsc - d->arch.vtsc_offset, 0); + return scale_delta(tsc, &d->arch.ns_to_vtsc); +} + void pv_soft_rdtsc(struct vcpu *v, struct cpu_user_regs *regs, int rdtscp) { s_time_t now = get_s_time(); struct domain *d = v->domain; - u64 delta; + u64 tsc; spin_lock(&d->arch.vtsc_lock); @@ -1638,8 +1652,7 @@ void pv_soft_rdtsc(struct vcpu *v, struc spin_unlock(&d->arch.vtsc_lock); - delta = max_t(s64, now - d->arch.vtsc_offset, 0); - now = scale_delta(delta, &d->arch.ns_to_vtsc); + tsc = gtime_to_gtsc(d, now); regs->eax = (uint32_t)now; regs->edx = (uint32_t)(now >> 32); @@ -1780,8 +1793,10 @@ void tsc_set_info(struct domain *d, d->arch.vtsc_offset = get_s_time() - elapsed_nsec; d->arch.tsc_khz = gtsc_khz ? gtsc_khz : cpu_khz; set_time_scale(&d->arch.vtsc_to_ns, d->arch.tsc_khz * 1000 ); - /* use native TSC if initial host has safe TSC and not migrated yet */ - if ( host_tsc_is_safe() && incarnation == 0 ) + /* use native TSC if initial host has safe TSC, has not migrated + * yet and tsc_khz == cpu_khz */ + if ( host_tsc_is_safe() && incarnation == 0 && + d->arch.tsc_khz == cpu_khz ) d->arch.vtsc = 0; else d->arch.ns_to_vtsc = scale_reciprocal(d->arch.vtsc_to_ns); @@ -1806,7 +1821,7 @@ void tsc_set_info(struct domain *d, } d->arch.incarnation = incarnation + 1; if ( is_hvm_domain(d) ) - hvm_set_rdtsc_exiting(d, d->arch.vtsc || hvm_gtsc_need_scale(d)); + hvm_set_rdtsc_exiting(d, d->arch.vtsc); } /* vtsc may incur measurable performance degradation, diagnose with this */ diff -r a915a11908e3 -r 804304d4e05d xen/common/kernel.c --- a/xen/common/kernel.c Tue May 11 08:31:16 2010 +0100 +++ b/xen/common/kernel.c Tue May 11 08:34:58 2010 +0100 @@ -243,6 +243,8 @@ DO(xen_version)(int cmd, XEN_GUEST_HANDL fi.submap |= (1U << XENFEAT_mmu_pt_update_preserve_ad) | (1U << XENFEAT_highmem_assist) | (1U << XENFEAT_gnttab_map_avail_bits); + else + fi.submap |= (1U << XENFEAT_hvm_safe_pvclock); #endif break; default: diff -r a915a11908e3 -r 804304d4e05d xen/include/asm-x86/hvm/domain.h --- a/xen/include/asm-x86/hvm/domain.h Tue May 11 08:31:16 2010 +0100 +++ b/xen/include/asm-x86/hvm/domain.h Tue May 11 08:34:58 2010 +0100 @@ -45,8 +45,6 @@ struct hvm_domain { struct hvm_ioreq_page ioreq; struct hvm_ioreq_page buf_ioreq; - uint32_t gtsc_khz; /* kHz */ - bool_t tsc_scaled; struct pl_time pl_time; struct hvm_io_handler io_handler; diff -r a915a11908e3 -r 804304d4e05d xen/include/asm-x86/hvm/hvm.h --- a/xen/include/asm-x86/hvm/hvm.h Tue May 11 08:31:16 2010 +0100 +++ b/xen/include/asm-x86/hvm/hvm.h Tue May 11 08:34:58 2010 +0100 @@ -294,7 +294,6 @@ uint8_t hvm_combine_hw_exceptions(uint8_ uint8_t hvm_combine_hw_exceptions(uint8_t vec1, uint8_t vec2); void hvm_set_rdtsc_exiting(struct domain *d, bool_t enable); -int hvm_gtsc_need_scale(struct domain *d); static inline int hvm_cpu_prepare(unsigned int cpu) diff -r a915a11908e3 -r 804304d4e05d xen/include/asm-x86/time.h --- a/xen/include/asm-x86/time.h Tue May 11 08:31:16 2010 +0100 +++ b/xen/include/asm-x86/time.h Tue May 11 08:34:58 2010 +0100 @@ -60,6 +60,7 @@ uint64_t ns_to_acpi_pm_tick(uint64_t ns) uint64_t ns_to_acpi_pm_tick(uint64_t ns); void pv_soft_rdtsc(struct vcpu *v, struct cpu_user_regs *regs, int rdtscp); +u64 gtime_to_gtsc(struct domain *d, u64 tsc); void tsc_set_info(struct domain *d, uint32_t tsc_mode, uint64_t elapsed_nsec, uint32_t gtsc_khz, uint32_t incarnation); diff -r a915a11908e3 -r 804304d4e05d xen/include/public/features.h --- a/xen/include/public/features.h Tue May 11 08:31:16 2010 +0100 +++ b/xen/include/public/features.h Tue May 11 08:34:58 2010 +0100 @@ -68,6 +68,9 @@ */ #define XENFEAT_gnttab_map_avail_bits 7 +/* x86: pvclock algorithm is safe to use on HVM */ +#define XENFEAT_hvm_safe_pvclock 9 + #define XENFEAT_NR_SUBMAPS 1 #endif /* __XEN_PUBLIC_FEATURES_H__ */ _______________________________________________ Xen-changelog mailing list Xen-changelog@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-changelog
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