Switching RMID from previous vcpu to next vcpu only needs to write MSR_IA32_PSR_ASSOC once. Write it with the value of next vcpu is enough, no need to write '0' first. Idle domain has RMID set to 0 and because MSR is already updated lazily, so just switch it as it does.
Also move the initialization of per-CPU variable which used for lazy update from context switch to CPU starting. Signed-off-by: Chao Peng <chao.p.p...@linux.intel.com> Reviewed-by: Andrew Cooper <andrew.coop...@citrix.com> Reviewed-by: Dario Faggioli <dario.faggi...@citrix.com> --- Cahnges in v6: * blankline fix. Changes in v5: * use this_cpu() rather than per_cpu(). Changes in v4: * Move psr_assoc_reg_read/psr_assoc_reg_write into psr_ctxt_switch_to. * Use 0 instead of smp_processor_id() for boot cpu. * add cpu parameter to psr_assoc_init. Changes in v2: * Move initialization for psr_assoc from context switch to CPU_STARTING. --- xen/arch/x86/domain.c | 7 ++--- xen/arch/x86/psr.c | 71 +++++++++++++++++++++++++++++++++-------------- xen/include/asm-x86/psr.h | 2 +- 3 files changed, 53 insertions(+), 27 deletions(-) diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c index fcea94b..c26c732 100644 --- a/xen/arch/x86/domain.c +++ b/xen/arch/x86/domain.c @@ -1444,8 +1444,6 @@ static void __context_switch(void) { memcpy(&p->arch.user_regs, stack_regs, CTXT_SWITCH_STACK_BYTES); vcpu_save_fpu(p); - if ( psr_cmt_enabled() ) - psr_assoc_rmid(0); p->arch.ctxt_switch_from(p); } @@ -1470,11 +1468,10 @@ static void __context_switch(void) } vcpu_restore_fpu_eager(n); n->arch.ctxt_switch_to(n); - - if ( psr_cmt_enabled() && n->domain->arch.psr_rmid > 0 ) - psr_assoc_rmid(n->domain->arch.psr_rmid); } + psr_ctxt_switch_to(n->domain); + gdt = !is_pv_32on64_vcpu(n) ? per_cpu(gdt_table, cpu) : per_cpu(compat_gdt_table, cpu); if ( need_full_gdt(n) ) diff --git a/xen/arch/x86/psr.c b/xen/arch/x86/psr.c index 344de3c..2490d22 100644 --- a/xen/arch/x86/psr.c +++ b/xen/arch/x86/psr.c @@ -22,7 +22,6 @@ struct psr_assoc { uint64_t val; - bool_t initialized; }; struct psr_cmt *__read_mostly psr_cmt; @@ -122,14 +121,6 @@ static void __init init_psr_cmt(unsigned int rmid_max) printk(XENLOG_INFO "Cache Monitoring Technology enabled\n"); } -static int __init init_psr(void) -{ - if ( (opt_psr & PSR_CMT) && opt_rmid_max ) - init_psr_cmt(opt_rmid_max); - return 0; -} -__initcall(init_psr); - /* Called with domain lock held, no psr specific lock needed */ int psr_alloc_rmid(struct domain *d) { @@ -175,27 +166,65 @@ void psr_free_rmid(struct domain *d) d->arch.psr_rmid = 0; } -void psr_assoc_rmid(unsigned int rmid) +static inline void psr_assoc_init(void) { - uint64_t val; - uint64_t new_val; struct psr_assoc *psra = &this_cpu(psr_assoc); - if ( !psra->initialized ) - { + if ( psr_cmt_enabled() ) rdmsrl(MSR_IA32_PSR_ASSOC, psra->val); - psra->initialized = 1; - } - val = psra->val; +} + +static inline void psr_assoc_rmid(uint64_t *reg, unsigned int rmid) +{ + *reg = (*reg & ~rmid_mask) | (rmid & rmid_mask); +} + +void psr_ctxt_switch_to(struct domain *d) +{ + struct psr_assoc *psra = &this_cpu(psr_assoc); + uint64_t reg = psra->val; + + if ( psr_cmt_enabled() ) + psr_assoc_rmid(®, d->arch.psr_rmid); - new_val = (val & ~rmid_mask) | (rmid & rmid_mask); - if ( val != new_val ) + if ( reg != psra->val ) { - wrmsrl(MSR_IA32_PSR_ASSOC, new_val); - psra->val = new_val; + wrmsrl(MSR_IA32_PSR_ASSOC, reg); + psra->val = reg; } } +static void psr_cpu_init(void) +{ + psr_assoc_init(); +} + +static int cpu_callback( + struct notifier_block *nfb, unsigned long action, void *hcpu) +{ + if ( action == CPU_STARTING ) + psr_cpu_init(); + + return NOTIFY_DONE; +} + +static struct notifier_block cpu_nfb = { + .notifier_call = cpu_callback +}; + +static int __init psr_presmp_init(void) +{ + if ( (opt_psr & PSR_CMT) && opt_rmid_max ) + init_psr_cmt(opt_rmid_max); + + psr_cpu_init(); + if ( psr_cmt_enabled() ) + register_cpu_notifier(&cpu_nfb); + + return 0; +} +presmp_initcall(psr_presmp_init); + /* * Local variables: * mode: C diff --git a/xen/include/asm-x86/psr.h b/xen/include/asm-x86/psr.h index c6076e9..12d593b 100644 --- a/xen/include/asm-x86/psr.h +++ b/xen/include/asm-x86/psr.h @@ -46,7 +46,7 @@ static inline bool_t psr_cmt_enabled(void) int psr_alloc_rmid(struct domain *d); void psr_free_rmid(struct domain *d); -void psr_assoc_rmid(unsigned int rmid); +void psr_ctxt_switch_to(struct domain *d); #endif /* __ASM_PSR_H__ */ -- 1.9.1 _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel