diff options
| -rw-r--r-- | arch/i386/xen/enlighten.c | 152 | ||||
| -rw-r--r-- | arch/i386/xen/setup.c | 8 | ||||
| -rw-r--r-- | arch/i386/xen/smp.c | 5 | ||||
| -rw-r--r-- | arch/i386/xen/xen-ops.h | 2 | ||||
| -rw-r--r-- | include/xen/interface/vcpu.h | 13 |
5 files changed, 164 insertions, 16 deletions
diff --git a/arch/i386/xen/enlighten.c b/arch/i386/xen/enlighten.c index 142e748..e33fa09 100644 --- a/arch/i386/xen/enlighten.c +++ b/arch/i386/xen/enlighten.c @@ -61,9 +61,63 @@ DEFINE_PER_CPU(unsigned long, xen_cr3); struct start_info *xen_start_info; EXPORT_SYMBOL_GPL(xen_start_info); -void xen_vcpu_setup(int cpu) +static /* __initdata */ struct shared_info dummy_shared_info; + +/* + * Point at some empty memory to start with. We map the real shared_info + * page as soon as fixmap is up and running. + */ +struct shared_info *HYPERVISOR_shared_info = (void *)&dummy_shared_info; + +/* + * Flag to determine whether vcpu info placement is available on all + * VCPUs. We assume it is to start with, and then set it to zero on + * the first failure. This is because it can succeed on some VCPUs + * and not others, since it can involve hypervisor memory allocation, + * or because the guest failed to guarantee all the appropriate + * constraints on all VCPUs (ie buffer can't cross a page boundary). + * + * Note that any particular CPU may be using a placed vcpu structure, + * but we can only optimise if the all are. + * + * 0: not available, 1: available + */ +static int have_vcpu_info_placement = 1; + +static void __init xen_vcpu_setup(int cpu) { + struct vcpu_register_vcpu_info info; + int err; + struct vcpu_info *vcpup; + per_cpu(xen_vcpu, cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu]; + + if (!have_vcpu_info_placement) + return; /* already tested, not available */ + + vcpup = &per_cpu(xen_vcpu_info, cpu); + + info.mfn = virt_to_mfn(vcpup); + info.offset = offset_in_page(vcpup); + + printk(KERN_DEBUG "trying to map vcpu_info %d at %p, mfn %x, offset %d\n", + cpu, vcpup, info.mfn, info.offset); + + /* Check to see if the hypervisor will put the vcpu_info + structure where we want it, which allows direct access via + a percpu-variable. */ + err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, cpu, &info); + + if (err) { + printk(KERN_DEBUG "register_vcpu_info failed: err=%d\n", err); + have_vcpu_info_placement = 0; + } else { + /* This cpu is using the registered vcpu info, even if + later ones fail to. */ + per_cpu(xen_vcpu, cpu) = vcpup; + printk(KERN_DEBUG "cpu %d using vcpu_info at %p\n", + cpu, vcpup); + } } static void __init xen_banner(void) @@ -123,6 +177,20 @@ static unsigned long xen_save_fl(void) return (-flags) & X86_EFLAGS_IF; } +static unsigned long xen_save_fl_direct(void) +{ + unsigned long flags; + + /* flag has opposite sense of mask */ + flags = !x86_read_percpu(xen_vcpu_info.evtchn_upcall_mask); + + /* convert to IF type flag + -0 -> 0x00000000 + -1 -> 0xffffffff + */ + return (-flags) & X86_EFLAGS_IF; +} + static void xen_restore_fl(unsigned long flags) { struct vcpu_info *vcpu; @@ -149,6 +217,25 @@ static void xen_restore_fl(unsigned long flags) } } +static void xen_restore_fl_direct(unsigned long flags) +{ + /* convert from IF type flag */ + flags = !(flags & X86_EFLAGS_IF); + + /* This is an atomic update, so no need to worry about + preemption. */ + x86_write_percpu(xen_vcpu_info.evtchn_upcall_mask, flags); + + /* If we get preempted here, then any pending event will be + handled anyway. */ + + if (flags == 0) { + barrier(); /* unmask then check (avoid races) */ + if (unlikely(x86_read_percpu(xen_vcpu_info.evtchn_upcall_pending))) + force_evtchn_callback(); + } +} + static void xen_irq_disable(void) { /* There's a one instruction preempt window here. We need to @@ -159,6 +246,12 @@ static void xen_irq_disable(void) preempt_enable_no_resched(); } +static void xen_irq_disable_direct(void) +{ + /* Atomic update, so preemption not a concern. */ + x86_write_percpu(xen_vcpu_info.evtchn_upcall_mask, 1); +} + static void xen_irq_enable(void) { struct vcpu_info *vcpu; @@ -179,6 +272,19 @@ static void xen_irq_enable(void) force_evtchn_callback(); } +static void xen_irq_enable_direct(void) +{ + /* Atomic update, so preemption not a concern. */ + x86_write_percpu(xen_vcpu_info.evtchn_upcall_mask, 0); + + /* Doesn't matter if we get preempted here, because any + pending event will get dealt with anyway. */ + + barrier(); /* unmask then check (avoid races) */ + if (unlikely(x86_read_percpu(xen_vcpu_info.evtchn_upcall_pending))) + force_evtchn_callback(); +} + static void xen_safe_halt(void) { /* Blocking includes an implicit local_irq_enable(). */ @@ -551,11 +657,21 @@ static void xen_flush_tlb_others(const cpumask_t *cpus, struct mm_struct *mm, xen_mc_issue(PARAVIRT_LAZY_MMU); } +static void xen_write_cr2(unsigned long cr2) +{ + x86_read_percpu(xen_vcpu)->arch.cr2 = cr2; +} + static unsigned long xen_read_cr2(void) { return x86_read_percpu(xen_vcpu)->arch.cr2; } +static unsigned long xen_read_cr2_direct(void) +{ + return x86_read_percpu(xen_vcpu_info.arch.cr2); +} + static void xen_write_cr4(unsigned long cr4) { /* never allow TSC to be disabled */ @@ -753,8 +869,27 @@ static __init void xen_pagetable_setup_done(pgd_t *base) if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF)) BUG(); } +} - xen_vcpu_setup(smp_processor_id()); +/* This is called once we have the cpu_possible_map */ +void __init xen_setup_vcpu_info_placement(void) +{ + int cpu; + + for_each_possible_cpu(cpu) + xen_vcpu_setup(cpu); + + /* xen_vcpu_setup managed to place the vcpu_info within the + percpu area for all cpus, so make use of it */ + if (have_vcpu_info_placement) { + printk(KERN_INFO "Xen: using vcpu_info placement\n"); + + paravirt_ops.save_fl = xen_save_fl_direct; + paravirt_ops.restore_fl = xen_restore_fl_direct; + paravirt_ops.irq_disable = xen_irq_disable_direct; + paravirt_ops.irq_enable = xen_irq_enable_direct; + paravirt_ops.read_cr2 = xen_read_cr2_direct; + } } static const struct paravirt_ops xen_paravirt_ops __initdata = { @@ -788,7 +923,7 @@ static const struct paravirt_ops xen_paravirt_ops __initdata = { .write_cr0 = native_write_cr0, .read_cr2 = xen_read_cr2, - .write_cr2 = native_write_cr2, + .write_cr2 = xen_write_cr2, .read_cr3 = xen_read_cr3, .write_cr3 = xen_write_cr3, @@ -974,7 +1109,16 @@ asmlinkage void __init xen_start_kernel(void) /* keep using Xen gdt for now; no urgent need to change it */ x86_write_percpu(xen_cr3, __pa(pgd)); - xen_vcpu_setup(0); + +#ifdef CONFIG_SMP + /* Don't do the full vcpu_info placement stuff until we have a + possible map. */ + per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0]; +#else + /* May as well do it now, since there's no good time to call + it later on UP. */ + xen_setup_vcpu_info_placement(); +#endif paravirt_ops.kernel_rpl = 1; if (xen_feature(XENFEAT_supervisor_mode_kernel)) diff --git a/arch/i386/xen/setup.c b/arch/i386/xen/setup.c index 18a994d..3f8684e 100644 --- a/arch/i386/xen/setup.c +++ b/arch/i386/xen/setup.c @@ -24,14 +24,6 @@ extern const char xen_hypervisor_callback[]; extern const char xen_failsafe_callback[]; -static __initdata struct shared_info init_shared; - -/* - * Point at some empty memory to start with. We map the real shared_info - * page as soon as fixmap is up and running. - */ -struct shared_info *HYPERVISOR_shared_info = &init_shared; - unsigned long *phys_to_machine_mapping; EXPORT_SYMBOL(phys_to_machine_mapping); diff --git a/arch/i386/xen/smp.c b/arch/i386/xen/smp.c index a620918..557b8e2 100644 --- a/arch/i386/xen/smp.c +++ b/arch/i386/xen/smp.c @@ -142,8 +142,6 @@ void __init xen_smp_prepare_boot_cpu(void) BUG_ON(smp_processor_id() != 0); native_smp_prepare_boot_cpu(); - xen_vcpu_setup(0); - /* We've switched to the "real" per-cpu gdt, so make sure the old memory can be recycled */ make_lowmem_page_readwrite(&per_cpu__gdt_page); @@ -152,6 +150,8 @@ void __init xen_smp_prepare_boot_cpu(void) cpus_clear(cpu_sibling_map[cpu]); cpus_clear(cpu_core_map[cpu]); } + + xen_setup_vcpu_info_placement(); } void __init xen_smp_prepare_cpus(unsigned int max_cpus) @@ -262,7 +262,6 @@ int __cpuinit xen_cpu_up(unsigned int cpu) init_gdt(cpu); per_cpu(current_task, cpu) = idle; - xen_vcpu_setup(cpu); irq_ctx_init(cpu); xen_setup_timer(cpu); diff --git a/arch/i386/xen/xen-ops.h b/arch/i386/xen/xen-ops.h index 4069be8..5b56f7f 100644 --- a/arch/i386/xen/xen-ops.h +++ b/arch/i386/xen/xen-ops.h @@ -38,7 +38,7 @@ static inline unsigned xen_get_lazy_mode(void) void __init xen_fill_possible_map(void); -void xen_vcpu_setup(int cpu); +void __init xen_setup_vcpu_info_placement(void); void xen_smp_prepare_boot_cpu(void); void xen_smp_prepare_cpus(unsigned int max_cpus); int xen_cpu_up(unsigned int cpu); diff --git a/include/xen/interface/vcpu.h b/include/xen/interface/vcpu.h index c6218f1..ff61ea3 100644 --- a/include/xen/interface/vcpu.h +++ b/include/xen/interface/vcpu.h @@ -151,4 +151,17 @@ struct vcpu_set_singleshot_timer { #define _VCPU_SSHOTTMR_future (0) #define VCPU_SSHOTTMR_future (1U << _VCPU_SSHOTTMR_future) +/* + * Register a memory location in the guest address space for the + * vcpu_info structure. This allows the guest to place the vcpu_info + * structure in a convenient place, such as in a per-cpu data area. + * The pointer need not be page aligned, but the structure must not + * cross a page boundary. + */ +#define VCPUOP_register_vcpu_info 10 /* arg == struct vcpu_info */ +struct vcpu_register_vcpu_info { + uint32_t mfn; /* mfn of page to place vcpu_info */ + uint32_t offset; /* offset within page */ +}; + #endif /* __XEN_PUBLIC_VCPU_H__ */ |