diff options
author | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-07-18 10:18:39 -0700 |
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committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-07-18 10:18:39 -0700 |
commit | 5cc97bf2d8eaa6cab60727c3eba3e85e29062669 (patch) | |
tree | 975976f2cb37b932d65440e6fb9960be93fc0bd7 /arch/i386/xen/smp.c | |
parent | 826ea8f22cf612d534f33c492c98f7895043bfd1 (diff) | |
parent | dfdcdd42fdf63452ddd1bed6f49ae2a35dfb5d6c (diff) |
Merge branch 'xen-upstream' of ssh://master.kernel.org/pub/scm/linux/kernel/git/jeremy/xen
* 'xen-upstream' of ssh://master.kernel.org/pub/scm/linux/kernel/git/jeremy/xen: (44 commits)
xen: disable all non-virtual drivers
xen: use iret directly when possible
xen: suppress abs symbol warnings for unused reloc pointers
xen: Attempt to patch inline versions of common operations
xen: Place vcpu_info structure into per-cpu memory
xen: handle external requests for shutdown, reboot and sysrq
xen: machine operations
xen: add virtual network device driver
xen: add virtual block device driver.
xen: add the Xenbus sysfs and virtual device hotplug driver
xen: Add grant table support
xen: use the hvc console infrastructure for Xen console
xen: hack to prevent bad segment register reload
xen: lazy-mmu operations
xen: Add support for preemption
xen: SMP guest support
xen: Implement sched_clock
xen: Account for stolen time
xen: ignore RW mapping of RO pages in pagetable_init
xen: Complete pagetable pinning
...
Diffstat (limited to 'arch/i386/xen/smp.c')
-rw-r--r-- | arch/i386/xen/smp.c | 404 |
1 files changed, 404 insertions, 0 deletions
diff --git a/arch/i386/xen/smp.c b/arch/i386/xen/smp.c new file mode 100644 index 00000000000..557b8e24706 --- /dev/null +++ b/arch/i386/xen/smp.c @@ -0,0 +1,404 @@ +/* + * Xen SMP support + * + * This file implements the Xen versions of smp_ops. SMP under Xen is + * very straightforward. Bringing a CPU up is simply a matter of + * loading its initial context and setting it running. + * + * IPIs are handled through the Xen event mechanism. + * + * Because virtual CPUs can be scheduled onto any real CPU, there's no + * useful topology information for the kernel to make use of. As a + * result, all CPUs are treated as if they're single-core and + * single-threaded. + * + * This does not handle HOTPLUG_CPU yet. + */ +#include <linux/sched.h> +#include <linux/err.h> +#include <linux/smp.h> + +#include <asm/paravirt.h> +#include <asm/desc.h> +#include <asm/pgtable.h> +#include <asm/cpu.h> + +#include <xen/interface/xen.h> +#include <xen/interface/vcpu.h> + +#include <asm/xen/interface.h> +#include <asm/xen/hypercall.h> + +#include <xen/page.h> +#include <xen/events.h> + +#include "xen-ops.h" +#include "mmu.h" + +static cpumask_t cpu_initialized_map; +static DEFINE_PER_CPU(int, resched_irq); +static DEFINE_PER_CPU(int, callfunc_irq); + +/* + * Structure and data for smp_call_function(). This is designed to minimise + * static memory requirements. It also looks cleaner. + */ +static DEFINE_SPINLOCK(call_lock); + +struct call_data_struct { + void (*func) (void *info); + void *info; + atomic_t started; + atomic_t finished; + int wait; +}; + +static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id); + +static struct call_data_struct *call_data; + +/* + * Reschedule call back. Nothing to do, + * all the work is done automatically when + * we return from the interrupt. + */ +static irqreturn_t xen_reschedule_interrupt(int irq, void *dev_id) +{ + return IRQ_HANDLED; +} + +static __cpuinit void cpu_bringup_and_idle(void) +{ + int cpu = smp_processor_id(); + + cpu_init(); + + preempt_disable(); + per_cpu(cpu_state, cpu) = CPU_ONLINE; + + xen_setup_cpu_clockevents(); + + /* We can take interrupts now: we're officially "up". */ + local_irq_enable(); + + wmb(); /* make sure everything is out */ + cpu_idle(); +} + +static int xen_smp_intr_init(unsigned int cpu) +{ + int rc; + const char *resched_name, *callfunc_name; + + per_cpu(resched_irq, cpu) = per_cpu(callfunc_irq, cpu) = -1; + + resched_name = kasprintf(GFP_KERNEL, "resched%d", cpu); + rc = bind_ipi_to_irqhandler(XEN_RESCHEDULE_VECTOR, + cpu, + xen_reschedule_interrupt, + IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING, + resched_name, + NULL); + if (rc < 0) + goto fail; + per_cpu(resched_irq, cpu) = rc; + + callfunc_name = kasprintf(GFP_KERNEL, "callfunc%d", cpu); + rc = bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_VECTOR, + cpu, + xen_call_function_interrupt, + IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING, + callfunc_name, + NULL); + if (rc < 0) + goto fail; + per_cpu(callfunc_irq, cpu) = rc; + + return 0; + + fail: + if (per_cpu(resched_irq, cpu) >= 0) + unbind_from_irqhandler(per_cpu(resched_irq, cpu), NULL); + if (per_cpu(callfunc_irq, cpu) >= 0) + unbind_from_irqhandler(per_cpu(callfunc_irq, cpu), NULL); + return rc; +} + +void __init xen_fill_possible_map(void) +{ + int i, rc; + + for (i = 0; i < NR_CPUS; i++) { + rc = HYPERVISOR_vcpu_op(VCPUOP_is_up, i, NULL); + if (rc >= 0) + cpu_set(i, cpu_possible_map); + } +} + +void __init xen_smp_prepare_boot_cpu(void) +{ + int cpu; + + BUG_ON(smp_processor_id() != 0); + native_smp_prepare_boot_cpu(); + + /* 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); + + for (cpu = 0; cpu < NR_CPUS; cpu++) { + 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) +{ + unsigned cpu; + + for (cpu = 0; cpu < NR_CPUS; cpu++) { + cpus_clear(cpu_sibling_map[cpu]); + cpus_clear(cpu_core_map[cpu]); + } + + smp_store_cpu_info(0); + set_cpu_sibling_map(0); + + if (xen_smp_intr_init(0)) + BUG(); + + cpu_initialized_map = cpumask_of_cpu(0); + + /* Restrict the possible_map according to max_cpus. */ + while ((num_possible_cpus() > 1) && (num_possible_cpus() > max_cpus)) { + for (cpu = NR_CPUS-1; !cpu_isset(cpu, cpu_possible_map); cpu--) + continue; + cpu_clear(cpu, cpu_possible_map); + } + + for_each_possible_cpu (cpu) { + struct task_struct *idle; + + if (cpu == 0) + continue; + + idle = fork_idle(cpu); + if (IS_ERR(idle)) + panic("failed fork for CPU %d", cpu); + + cpu_set(cpu, cpu_present_map); + } + + //init_xenbus_allowed_cpumask(); +} + +static __cpuinit int +cpu_initialize_context(unsigned int cpu, struct task_struct *idle) +{ + struct vcpu_guest_context *ctxt; + struct gdt_page *gdt = &per_cpu(gdt_page, cpu); + + if (cpu_test_and_set(cpu, cpu_initialized_map)) + return 0; + + ctxt = kzalloc(sizeof(*ctxt), GFP_KERNEL); + if (ctxt == NULL) + return -ENOMEM; + + ctxt->flags = VGCF_IN_KERNEL; + ctxt->user_regs.ds = __USER_DS; + ctxt->user_regs.es = __USER_DS; + ctxt->user_regs.fs = __KERNEL_PERCPU; + ctxt->user_regs.gs = 0; + ctxt->user_regs.ss = __KERNEL_DS; + ctxt->user_regs.eip = (unsigned long)cpu_bringup_and_idle; + ctxt->user_regs.eflags = 0x1000; /* IOPL_RING1 */ + + memset(&ctxt->fpu_ctxt, 0, sizeof(ctxt->fpu_ctxt)); + + xen_copy_trap_info(ctxt->trap_ctxt); + + ctxt->ldt_ents = 0; + + BUG_ON((unsigned long)gdt->gdt & ~PAGE_MASK); + make_lowmem_page_readonly(gdt->gdt); + + ctxt->gdt_frames[0] = virt_to_mfn(gdt->gdt); + ctxt->gdt_ents = ARRAY_SIZE(gdt->gdt); + + ctxt->user_regs.cs = __KERNEL_CS; + ctxt->user_regs.esp = idle->thread.esp0 - sizeof(struct pt_regs); + + ctxt->kernel_ss = __KERNEL_DS; + ctxt->kernel_sp = idle->thread.esp0; + + ctxt->event_callback_cs = __KERNEL_CS; + ctxt->event_callback_eip = (unsigned long)xen_hypervisor_callback; + ctxt->failsafe_callback_cs = __KERNEL_CS; + ctxt->failsafe_callback_eip = (unsigned long)xen_failsafe_callback; + + per_cpu(xen_cr3, cpu) = __pa(swapper_pg_dir); + ctxt->ctrlreg[3] = xen_pfn_to_cr3(virt_to_mfn(swapper_pg_dir)); + + if (HYPERVISOR_vcpu_op(VCPUOP_initialise, cpu, ctxt)) + BUG(); + + kfree(ctxt); + return 0; +} + +int __cpuinit xen_cpu_up(unsigned int cpu) +{ + struct task_struct *idle = idle_task(cpu); + int rc; + +#if 0 + rc = cpu_up_check(cpu); + if (rc) + return rc; +#endif + + init_gdt(cpu); + per_cpu(current_task, cpu) = idle; + irq_ctx_init(cpu); + xen_setup_timer(cpu); + + /* make sure interrupts start blocked */ + per_cpu(xen_vcpu, cpu)->evtchn_upcall_mask = 1; + + rc = cpu_initialize_context(cpu, idle); + if (rc) + return rc; + + if (num_online_cpus() == 1) + alternatives_smp_switch(1); + + rc = xen_smp_intr_init(cpu); + if (rc) + return rc; + + smp_store_cpu_info(cpu); + set_cpu_sibling_map(cpu); + /* This must be done before setting cpu_online_map */ + wmb(); + + cpu_set(cpu, cpu_online_map); + + rc = HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL); + BUG_ON(rc); + + return 0; +} + +void xen_smp_cpus_done(unsigned int max_cpus) +{ +} + +static void stop_self(void *v) +{ + int cpu = smp_processor_id(); + + /* make sure we're not pinning something down */ + load_cr3(swapper_pg_dir); + /* should set up a minimal gdt */ + + HYPERVISOR_vcpu_op(VCPUOP_down, cpu, NULL); + BUG(); +} + +void xen_smp_send_stop(void) +{ + smp_call_function(stop_self, NULL, 0, 0); +} + +void xen_smp_send_reschedule(int cpu) +{ + xen_send_IPI_one(cpu, XEN_RESCHEDULE_VECTOR); +} + + +static void xen_send_IPI_mask(cpumask_t mask, enum ipi_vector vector) +{ + unsigned cpu; + + cpus_and(mask, mask, cpu_online_map); + + for_each_cpu_mask(cpu, mask) + xen_send_IPI_one(cpu, vector); +} + +static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id) +{ + void (*func) (void *info) = call_data->func; + void *info = call_data->info; + int wait = call_data->wait; + + /* + * Notify initiating CPU that I've grabbed the data and am + * about to execute the function + */ + mb(); + atomic_inc(&call_data->started); + /* + * At this point the info structure may be out of scope unless wait==1 + */ + irq_enter(); + (*func)(info); + irq_exit(); + + if (wait) { + mb(); /* commit everything before setting finished */ + atomic_inc(&call_data->finished); + } + + return IRQ_HANDLED; +} + +int xen_smp_call_function_mask(cpumask_t mask, void (*func)(void *), + void *info, int wait) +{ + struct call_data_struct data; + int cpus; + + /* Holding any lock stops cpus from going down. */ + spin_lock(&call_lock); + + cpu_clear(smp_processor_id(), mask); + + cpus = cpus_weight(mask); + if (!cpus) { + spin_unlock(&call_lock); + return 0; + } + + /* Can deadlock when called with interrupts disabled */ + WARN_ON(irqs_disabled()); + + data.func = func; + data.info = info; + atomic_set(&data.started, 0); + data.wait = wait; + if (wait) + atomic_set(&data.finished, 0); + + call_data = &data; + mb(); /* write everything before IPI */ + + /* Send a message to other CPUs and wait for them to respond */ + xen_send_IPI_mask(mask, XEN_CALL_FUNCTION_VECTOR); + + /* Make sure other vcpus get a chance to run. + XXX too severe? Maybe we should check the other CPU's states? */ + HYPERVISOR_sched_op(SCHEDOP_yield, 0); + + /* Wait for response */ + while (atomic_read(&data.started) != cpus || + (wait && atomic_read(&data.finished) != cpus)) + cpu_relax(); + + spin_unlock(&call_lock); + + return 0; +} |