enlighten.c

linux 内核源代码

}

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)
{
	/* Just ignore cr4 changes; Xen doesn't allow us to do
	   anything anyway. */
}

static unsigned long xen_read_cr3(void)
{
	return x86_read_percpu(xen_cr3);
}

static void set_current_cr3(void *v)
{
	x86_write_percpu(xen_current_cr3, (unsigned long)v);
}

static void xen_write_cr3(unsigned long cr3)
{
	struct mmuext_op *op;
	struct multicall_space mcs;
	unsigned long mfn = pfn_to_mfn(PFN_DOWN(cr3));

	BUG_ON(preemptible());

	mcs = xen_mc_entry(sizeof(*op));  /* disables interrupts */

	/* Update while interrupts are disabled, so its atomic with
	   respect to ipis */
	x86_write_percpu(xen_cr3, cr3);

	op = mcs.args;
	op->cmd = MMUEXT_NEW_BASEPTR;
	op->arg1.mfn = mfn;

	MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);

	/* Update xen_update_cr3 once the batch has actually
	   been submitted. */
	xen_mc_callback(set_current_cr3, (void *)cr3);

	xen_mc_issue(PARAVIRT_LAZY_CPU);  /* interrupts restored */
}

/* Early in boot, while setting up the initial pagetable, assume
   everything is pinned. */
static __init void xen_alloc_pt_init(struct mm_struct *mm, u32 pfn)
{
	BUG_ON(mem_map);	/* should only be used early */
	make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
}

static void pin_pagetable_pfn(unsigned level, unsigned long pfn)
{
	struct mmuext_op op;
	op.cmd = level;
	op.arg1.mfn = pfn_to_mfn(pfn);
	if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
		BUG();
}

/* This needs to make sure the new pte page is pinned iff its being
   attached to a pinned pagetable. */
static void xen_alloc_pt(struct mm_struct *mm, u32 pfn)
{
	struct page *page = pfn_to_page(pfn);

	if (PagePinned(virt_to_page(mm->pgd))) {
		SetPagePinned(page);

		if (!PageHighMem(page)) {
			make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
			pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
		} else
			/* make sure there are no stray mappings of
			   this page */
			kmap_flush_unused();
	}
}

/* This should never happen until we're OK to use struct page */
static void xen_release_pt(u32 pfn)
{
	struct page *page = pfn_to_page(pfn);

	if (PagePinned(page)) {
		if (!PageHighMem(page)) {
			pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
			make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
		}
	}
}

#ifdef CONFIG_HIGHPTE
static void *xen_kmap_atomic_pte(struct page *page, enum km_type type)
{
	pgprot_t prot = PAGE_KERNEL;

	if (PagePinned(page))
		prot = PAGE_KERNEL_RO;

	if (0 && PageHighMem(page))
		printk("mapping highpte %lx type %d prot %s\n",
		       page_to_pfn(page), type,
		       (unsigned long)pgprot_val(prot) & _PAGE_RW ? "WRITE" : "READ");

	return kmap_atomic_prot(page, type, prot);
}
#endif

static __init pte_t mask_rw_pte(pte_t *ptep, pte_t pte)
{
	/* If there's an existing pte, then don't allow _PAGE_RW to be set */
	if (pte_val_ma(*ptep) & _PAGE_PRESENT)
		pte = __pte_ma(((pte_val_ma(*ptep) & _PAGE_RW) | ~_PAGE_RW) &
			       pte_val_ma(pte));

	return pte;
}

/* Init-time set_pte while constructing initial pagetables, which
   doesn't allow RO pagetable pages to be remapped RW */
static __init void xen_set_pte_init(pte_t *ptep, pte_t pte)
{
	pte = mask_rw_pte(ptep, pte);

	xen_set_pte(ptep, pte);
}

static __init void xen_pagetable_setup_start(pgd_t *base)
{
	pgd_t *xen_pgd = (pgd_t *)xen_start_info->pt_base;

	/* special set_pte for pagetable initialization */
	pv_mmu_ops.set_pte = xen_set_pte_init;

	init_mm.pgd = base;
	/*
	 * copy top-level of Xen-supplied pagetable into place.	 For
	 * !PAE we can use this as-is, but for PAE it is a stand-in
	 * while we copy the pmd pages.
	 */
	memcpy(base, xen_pgd, PTRS_PER_PGD * sizeof(pgd_t));

	if (PTRS_PER_PMD > 1) {
		int i;
		/*
		 * For PAE, need to allocate new pmds, rather than
		 * share Xen's, since Xen doesn't like pmd's being
		 * shared between address spaces.
		 */
		for (i = 0; i < PTRS_PER_PGD; i++) {
			if (pgd_val_ma(xen_pgd[i]) & _PAGE_PRESENT) {
				pmd_t *pmd = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE);

				memcpy(pmd, (void *)pgd_page_vaddr(xen_pgd[i]),
				       PAGE_SIZE);

				make_lowmem_page_readonly(pmd);

				set_pgd(&base[i], __pgd(1 + __pa(pmd)));
			} else
				pgd_clear(&base[i]);
		}
	}

	/* make sure zero_page is mapped RO so we can use it in pagetables */
	make_lowmem_page_readonly(empty_zero_page);
	make_lowmem_page_readonly(base);
	/*
	 * Switch to new pagetable.  This is done before
	 * pagetable_init has done anything so that the new pages
	 * added to the table can be prepared properly for Xen.
	 */
	xen_write_cr3(__pa(base));
}

static __init void xen_pagetable_setup_done(pgd_t *base)
{
	/* This will work as long as patching hasn't happened yet
	   (which it hasn't) */
	pv_mmu_ops.alloc_pt = xen_alloc_pt;
	pv_mmu_ops.set_pte = xen_set_pte;

	if (!xen_feature(XENFEAT_auto_translated_physmap)) {
		/*
		 * Create a mapping for the shared info page.
		 * Should be set_fixmap(), but shared_info is a machine
		 * address with no corresponding pseudo-phys address.
		 */
		set_pte_mfn(fix_to_virt(FIX_PARAVIRT_BOOTMAP),
			    PFN_DOWN(xen_start_info->shared_info),
			    PAGE_KERNEL);

		HYPERVISOR_shared_info =
			(struct shared_info *)fix_to_virt(FIX_PARAVIRT_BOOTMAP);

	} else
		HYPERVISOR_shared_info =
			(struct shared_info *)__va(xen_start_info->shared_info);

	/* Actually pin the pagetable down, but we can't set PG_pinned
	   yet because the page structures don't exist yet. */
	{
		unsigned level;

#ifdef CONFIG_X86_PAE
		level = MMUEXT_PIN_L3_TABLE;
#else
		level = MMUEXT_PIN_L2_TABLE;
#endif

		pin_pagetable_pfn(level, PFN_DOWN(__pa(base)));
	}
}

/* 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");

		pv_irq_ops.save_fl = xen_save_fl_direct;
		pv_irq_ops.restore_fl = xen_restore_fl_direct;
		pv_irq_ops.irq_disable = xen_irq_disable_direct;
		pv_irq_ops.irq_enable = xen_irq_enable_direct;
		pv_mmu_ops.read_cr2 = xen_read_cr2_direct;
		pv_cpu_ops.iret = xen_iret_direct;
	}
}

static unsigned xen_patch(u8 type, u16 clobbers, void *insnbuf,
			  unsigned long addr, unsigned len)
{
	char *start, *end, *reloc;
	unsigned ret;

	start = end = reloc = NULL;

#define SITE(op, x)							\
	case PARAVIRT_PATCH(op.x):					\
	if (have_vcpu_info_placement) {					\
		start = (char *)xen_##x##_direct;			\
		end = xen_##x##_direct_end;				\
		reloc = xen_##x##_direct_reloc;				\
	}								\
	goto patch_site

	switch (type) {
		SITE(pv_irq_ops, irq_enable);
		SITE(pv_irq_ops, irq_disable);
		SITE(pv_irq_ops, save_fl);
		SITE(pv_irq_ops, restore_fl);
#undef SITE

	patch_site:
		if (start == NULL || (end-start) > len)
			goto default_patch;

		ret = paravirt_patch_insns(insnbuf, len, start, end);

		/* Note: because reloc is assigned from something that
		   appears to be an array, gcc assumes it's non-null,
		   but doesn't know its relationship with start and
		   end. */
		if (reloc > start && reloc < end) {
			int reloc_off = reloc - start;
			long *relocp = (long *)(insnbuf + reloc_off);
			long delta = start - (char *)addr;

			*relocp += delta;
		}
		break;

	default_patch:
	default:
		ret = paravirt_patch_default(type, clobbers, insnbuf,
					     addr, len);
		break;
	}

	return ret;
}

static const struct pv_info xen_info __initdata = {
	.paravirt_enabled = 1,
	.shared_kernel_pmd = 0,

	.name = "Xen",
};

static const struct pv_init_ops xen_init_ops __initdata = {
	.patch = xen_patch,

	.banner = xen_banner,
	.memory_setup = xen_memory_setup,
	.arch_setup = xen_arch_setup,
	.post_allocator_init = xen_mark_init_mm_pinned,
};

static const struct pv_time_ops xen_time_ops __initdata = {
	.time_init = xen_time_init,

	.set_wallclock = xen_set_wallclock,
	.get_wallclock = xen_get_wallclock,
	.get_cpu_khz = xen_cpu_khz,
	.sched_clock = xen_sched_clock,
};

static const struct pv_cpu_ops xen_cpu_ops __initdata = {
	.cpuid = xen_cpuid,

	.set_debugreg = xen_set_debugreg,
	.get_debugreg = xen_get_debugreg,

	.clts = native_clts,

	.read_cr0 = native_read_cr0,
	.write_cr0 = native_write_cr0,

	.read_cr4 = native_read_cr4,
	.read_cr4_safe = native_read_cr4_safe,
	.write_cr4 = xen_write_cr4,

	.wbinvd = native_wbinvd,

	.read_msr = native_read_msr_safe,
	.write_msr = native_write_msr_safe,
	.read_tsc = native_read_tsc,
	.read_pmc = native_read_pmc,

	.iret = (void *)&hypercall_page[__HYPERVISOR_iret],
	.irq_enable_sysexit = NULL,  /* never called */

	.load_tr_desc = paravirt_nop,
	.set_ldt = xen_set_ldt,
	.load_gdt = xen_load_gdt,
	.load_idt = xen_load_idt,
	.load_tls = xen_load_tls,

	.store_gdt = native_store_gdt,
	.store_idt = native_store_idt,
	.store_tr = xen_store_tr,

	.write_ldt_entry = xen_write_ldt_entry,
	.write_gdt_entry = xen_write_gdt_entry,
	.write_idt_entry = xen_write_idt_entry,
	.load_esp0 = xen_load_esp0,

	.set_iopl_mask = xen_set_iopl_mask,
	.io_delay = xen_io_delay,

	.lazy_mode = {
		.enter = paravirt_enter_lazy_cpu,
		.leave = xen_leave_lazy,
	},
};

static const struct pv_irq_ops xen_irq_ops __initdata = {
	.init_IRQ = xen_init_IRQ,
	.save_fl = xen_save_fl,
	.restore_fl = xen_restore_fl,
	.irq_disable = xen_irq_disable,
	.irq_enable = xen_irq_enable,
	.safe_halt = xen_safe_halt,
	.halt = xen_halt,
};

static const struct pv_apic_ops xen_apic_ops __initdata = {
#ifdef CONFIG_X86_LOCAL_APIC
	.apic_write = xen_apic_write,
	.apic_write_atomic = xen_apic_write,
	.apic_read = xen_apic_read,
	.setup_boot_clock = paravirt_nop,
	.setup_secondary_clock = paravirt_nop,
	.startup_ipi_hook = paravirt_nop,
#endif
};

static const struct pv_mmu_ops xen_mmu_ops __initdata = {
	.pagetable_setup_start = xen_pagetable_setup_start,
	.pagetable_setup_done = xen_pagetable_setup_done,

	.read_cr2 = xen_read_cr2,
	.write_cr2 = xen_write_cr2,

	.read_cr3 = xen_read_cr3,
	.write_cr3 = xen_write_cr3,

	.flush_tlb_user = xen_flush_tlb,
	.flush_tlb_kernel = xen_flush_tlb,
	.flush_tlb_single = xen_flush_tlb_single,
	.flush_tlb_others = xen_flush_tlb_others,

	.pte_update = paravirt_nop,
	.pte_update_defer = paravirt_nop,

	.alloc_pt = xen_alloc_pt_init,
	.release_pt = xen_release_pt,
	.alloc_pd = paravirt_nop,
	.alloc_pd_clone = paravirt_nop,
	.release_pd = paravirt_nop,

#ifdef CONFIG_HIGHPTE
	.kmap_atomic_pte = xen_kmap_atomic_pte,
#endif

	.set_pte = NULL,	/* see xen_pagetable_setup_* */
	.set_pte_at = xen_set_pte_at,
	.set_pmd = xen_set_pmd,

	.pte_val = xen_pte_val,
	.pgd_val = xen_pgd_val,

	.make_pte = xen_make_pte,
	.make_pgd = xen_make_pgd,

#ifdef CONFIG_X86_PAE
	.set_pte_atomic = xen_set_pte_atomic,
	.set_pte_present = xen_set_pte_at,
	.set_pud = xen_set_pud,
	.pte_clear = xen_pte_clear,
	.pmd_clear = xen_pmd_clear,

	.make_pmd = xen_make_pmd,
	.pmd_val = xen_pmd_val,
#endif	/* PAE */

	.activate_mm = xen_activate_mm,
	.dup_mmap = xen_dup_mmap,
	.exit_mmap = xen_exit_mmap,

	.lazy_mode = {
		.enter = paravirt_enter_lazy_mmu,
		.leave = xen_leave_lazy,
	},
};

#ifdef CONFIG_SMP
static const struct smp_ops xen_smp_ops __initdata = {
	.smp_prepare_boot_cpu = xen_smp_prepare_boot_cpu,
	.smp_prepare_cpus = xen_smp_prepare_cpus,
	.cpu_up = xen_cpu_up,
	.smp_cpus_done = xen_smp_cpus_done,

	.smp_send_stop = xen_smp_send_stop,
	.smp_send_reschedule = xen_smp_send_reschedule,
	.smp_call_function_mask = xen_smp_call_function_mask,
};
#endif	/* CONFIG_SMP */

static void xen_reboot(int reason)
{
#ifdef CONFIG_SMP
	smp_send_stop();
#endif

	if (HYPERVISOR_sched_op(SCHEDOP_shutdown, reason))
		BUG();
}

static void xen_restart(char *msg)
{
	xen_reboot(SHUTDOWN_reboot);
}

static void xen_emergency_restart(void)
{
	xen_reboot(SHUTDOWN_reboot);
}

static void xen_machine_halt(void)
{
	xen_reboot(SHUTDOWN_poweroff);
}

static void xen_crash_shutdown(struct pt_regs *regs)
{
	xen_reboot(SHUTDOWN_crash);
}

static const struct machine_ops __initdata xen_machine_ops = {
	.restart = xen_restart,
	.halt = xen_machine_halt,
	.power_off = xen_machine_halt,
	.shutdown = xen_machine_halt,
	.crash_shutdown = xen_crash_shutdown,
	.emergency_restart = xen_emergency_restart,
};


static void __init xen_reserve_top(void)
{
	unsigned long top = HYPERVISOR_VIRT_START;
	struct xen_platform_parameters pp;

	if (HYPERVISOR_xen_version(XENVER_platform_parameters, &pp) == 0)
		top = pp.virt_start;

	reserve_top_address(-top + 2 * PAGE_SIZE);
}

/* First C function to be called on Xen boot */
asmlinkage void __init xen_start_kernel(void)
{
	pgd_t *pgd;

	if (!xen_start_info)
		return;

	BUG_ON(memcmp(xen_start_info->magic, "xen-3", 5) != 0);

	/* Install Xen paravirt ops */
	pv_info = xen_info;
	pv_init_ops = xen_init_ops;
	pv_time_ops = xen_time_ops;
	pv_cpu_ops = xen_cpu_ops;
	pv_irq_ops = xen_irq_ops;
	pv_apic_ops = xen_apic_ops;
	pv_mmu_ops = xen_mmu_ops;

	machine_ops = xen_machine_ops;

#ifdef CONFIG_SMP
	smp_ops = xen_smp_ops;
#endif

	xen_setup_features();

	/* Get mfn list */
	if (!xen_feature(XENFEAT_auto_translated_physmap))
		phys_to_machine_mapping = (unsigned long *)xen_start_info->mfn_list;

	pgd = (pgd_t *)xen_start_info->pt_base;

	init_pg_tables_end = __pa(pgd) + xen_start_info->nr_pt_frames*PAGE_SIZE;

	init_mm.pgd = pgd; /* use the Xen pagetables to start */

	/* keep using Xen gdt for now; no urgent need to change it */

	x86_write_percpu(xen_cr3, __pa(pgd));
	x86_write_percpu(xen_current_cr3, __pa(pgd));

#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

	pv_info.kernel_rpl = 1;
	if (xen_feature(XENFEAT_supervisor_mode_kernel))
		pv_info.kernel_rpl = 0;

	/* set the limit of our address space */
	xen_reserve_top();

	/* set up basic CPUID stuff */
	cpu_detect(&new_cpu_data);
	new_cpu_data.hard_math = 1;
	new_cpu_data.x86_capability[0] = cpuid_edx(1);

	/* Poke various useful things into boot_params */
	boot_params.hdr.type_of_loader = (9 << 4) | 0;
	boot_params.hdr.ramdisk_image = xen_start_info->mod_start
		? __pa(xen_start_info->mod_start) : 0;
	boot_params.hdr.ramdisk_size = xen_start_info->mod_len;

	/* Start the world */
	start_kernel();
}