| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* Paravirtualization interfaces |
| Copyright (C) 2006 Rusty Russell IBM Corporation |
| |
| |
| 2007 - x86_64 support added by Glauber de Oliveira Costa, Red Hat Inc |
| */ |
| |
| #include <linux/errno.h> |
| #include <linux/init.h> |
| #include <linux/export.h> |
| #include <linux/efi.h> |
| #include <linux/bcd.h> |
| #include <linux/highmem.h> |
| #include <linux/kprobes.h> |
| |
| #include <asm/bug.h> |
| #include <asm/paravirt.h> |
| #include <asm/debugreg.h> |
| #include <asm/desc.h> |
| #include <asm/setup.h> |
| #include <asm/pgtable.h> |
| #include <asm/time.h> |
| #include <asm/pgalloc.h> |
| #include <asm/irq.h> |
| #include <asm/delay.h> |
| #include <asm/fixmap.h> |
| #include <asm/apic.h> |
| #include <asm/tlbflush.h> |
| #include <asm/timer.h> |
| #include <asm/special_insns.h> |
| #include <asm/tlb.h> |
| |
| /* |
| * nop stub, which must not clobber anything *including the stack* to |
| * avoid confusing the entry prologues. |
| */ |
| extern void _paravirt_nop(void); |
| asm (".pushsection .entry.text, \"ax\"\n" |
| ".global _paravirt_nop\n" |
| "_paravirt_nop:\n\t" |
| "ret\n\t" |
| ".size _paravirt_nop, . - _paravirt_nop\n\t" |
| ".type _paravirt_nop, @function\n\t" |
| ".popsection"); |
| |
| void __init default_banner(void) |
| { |
| printk(KERN_INFO "Booting paravirtualized kernel on %s\n", |
| pv_info.name); |
| } |
| |
| /* Undefined instruction for dealing with missing ops pointers. */ |
| static const unsigned char ud2a[] = { 0x0f, 0x0b }; |
| |
| struct branch { |
| unsigned char opcode; |
| u32 delta; |
| } __attribute__((packed)); |
| |
| static unsigned paravirt_patch_call(void *insn_buff, const void *target, |
| unsigned long addr, unsigned len) |
| { |
| const int call_len = 5; |
| struct branch *b = insn_buff; |
| unsigned long delta = (unsigned long)target - (addr+call_len); |
| |
| if (len < call_len) { |
| pr_warn("paravirt: Failed to patch indirect CALL at %ps\n", (void *)addr); |
| /* Kernel might not be viable if patching fails, bail out: */ |
| BUG_ON(1); |
| } |
| |
| b->opcode = 0xe8; /* call */ |
| b->delta = delta; |
| BUILD_BUG_ON(sizeof(*b) != call_len); |
| |
| return call_len; |
| } |
| |
| #ifdef CONFIG_PARAVIRT_XXL |
| /* identity function, which can be inlined */ |
| u64 notrace _paravirt_ident_64(u64 x) |
| { |
| return x; |
| } |
| |
| static unsigned paravirt_patch_jmp(void *insn_buff, const void *target, |
| unsigned long addr, unsigned len) |
| { |
| struct branch *b = insn_buff; |
| unsigned long delta = (unsigned long)target - (addr+5); |
| |
| if (len < 5) { |
| #ifdef CONFIG_RETPOLINE |
| WARN_ONCE(1, "Failing to patch indirect JMP in %ps\n", (void *)addr); |
| #endif |
| return len; /* call too long for patch site */ |
| } |
| |
| b->opcode = 0xe9; /* jmp */ |
| b->delta = delta; |
| |
| return 5; |
| } |
| #endif |
| |
| DEFINE_STATIC_KEY_TRUE(virt_spin_lock_key); |
| |
| void __init native_pv_lock_init(void) |
| { |
| if (!boot_cpu_has(X86_FEATURE_HYPERVISOR)) |
| static_branch_disable(&virt_spin_lock_key); |
| } |
| |
| unsigned paravirt_patch_default(u8 type, void *insn_buff, |
| unsigned long addr, unsigned len) |
| { |
| /* |
| * Neat trick to map patch type back to the call within the |
| * corresponding structure. |
| */ |
| void *opfunc = *((void **)&pv_ops + type); |
| unsigned ret; |
| |
| if (opfunc == NULL) |
| /* If there's no function, patch it with a ud2a (BUG) */ |
| ret = paravirt_patch_insns(insn_buff, len, ud2a, ud2a+sizeof(ud2a)); |
| else if (opfunc == _paravirt_nop) |
| ret = 0; |
| |
| #ifdef CONFIG_PARAVIRT_XXL |
| /* identity functions just return their single argument */ |
| else if (opfunc == _paravirt_ident_64) |
| ret = paravirt_patch_ident_64(insn_buff, len); |
| |
| else if (type == PARAVIRT_PATCH(cpu.iret) || |
| type == PARAVIRT_PATCH(cpu.usergs_sysret64)) |
| /* If operation requires a jmp, then jmp */ |
| ret = paravirt_patch_jmp(insn_buff, opfunc, addr, len); |
| #endif |
| else |
| /* Otherwise call the function. */ |
| ret = paravirt_patch_call(insn_buff, opfunc, addr, len); |
| |
| return ret; |
| } |
| |
| unsigned paravirt_patch_insns(void *insn_buff, unsigned len, |
| const char *start, const char *end) |
| { |
| unsigned insn_len = end - start; |
| |
| /* Alternative instruction is too large for the patch site and we cannot continue: */ |
| BUG_ON(insn_len > len || start == NULL); |
| |
| memcpy(insn_buff, start, insn_len); |
| |
| return insn_len; |
| } |
| |
| static void native_flush_tlb(void) |
| { |
| __native_flush_tlb(); |
| } |
| |
| /* |
| * Global pages have to be flushed a bit differently. Not a real |
| * performance problem because this does not happen often. |
| */ |
| static void native_flush_tlb_global(void) |
| { |
| __native_flush_tlb_global(); |
| } |
| |
| static void native_flush_tlb_one_user(unsigned long addr) |
| { |
| __native_flush_tlb_one_user(addr); |
| } |
| |
| struct static_key paravirt_steal_enabled; |
| struct static_key paravirt_steal_rq_enabled; |
| |
| static u64 native_steal_clock(int cpu) |
| { |
| return 0; |
| } |
| |
| /* These are in entry.S */ |
| extern void native_iret(void); |
| extern void native_usergs_sysret64(void); |
| |
| static struct resource reserve_ioports = { |
| .start = 0, |
| .end = IO_SPACE_LIMIT, |
| .name = "paravirt-ioport", |
| .flags = IORESOURCE_IO | IORESOURCE_BUSY, |
| }; |
| |
| /* |
| * Reserve the whole legacy IO space to prevent any legacy drivers |
| * from wasting time probing for their hardware. This is a fairly |
| * brute-force approach to disabling all non-virtual drivers. |
| * |
| * Note that this must be called very early to have any effect. |
| */ |
| int paravirt_disable_iospace(void) |
| { |
| return request_resource(&ioport_resource, &reserve_ioports); |
| } |
| |
| static DEFINE_PER_CPU(enum paravirt_lazy_mode, paravirt_lazy_mode) = PARAVIRT_LAZY_NONE; |
| |
| static inline void enter_lazy(enum paravirt_lazy_mode mode) |
| { |
| BUG_ON(this_cpu_read(paravirt_lazy_mode) != PARAVIRT_LAZY_NONE); |
| |
| this_cpu_write(paravirt_lazy_mode, mode); |
| } |
| |
| static void leave_lazy(enum paravirt_lazy_mode mode) |
| { |
| BUG_ON(this_cpu_read(paravirt_lazy_mode) != mode); |
| |
| this_cpu_write(paravirt_lazy_mode, PARAVIRT_LAZY_NONE); |
| } |
| |
| void paravirt_enter_lazy_mmu(void) |
| { |
| enter_lazy(PARAVIRT_LAZY_MMU); |
| } |
| |
| void paravirt_leave_lazy_mmu(void) |
| { |
| leave_lazy(PARAVIRT_LAZY_MMU); |
| } |
| |
| void paravirt_flush_lazy_mmu(void) |
| { |
| preempt_disable(); |
| |
| if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) { |
| arch_leave_lazy_mmu_mode(); |
| arch_enter_lazy_mmu_mode(); |
| } |
| |
| preempt_enable(); |
| } |
| |
| #ifdef CONFIG_PARAVIRT_XXL |
| void paravirt_start_context_switch(struct task_struct *prev) |
| { |
| BUG_ON(preemptible()); |
| |
| if (this_cpu_read(paravirt_lazy_mode) == PARAVIRT_LAZY_MMU) { |
| arch_leave_lazy_mmu_mode(); |
| set_ti_thread_flag(task_thread_info(prev), TIF_LAZY_MMU_UPDATES); |
| } |
| enter_lazy(PARAVIRT_LAZY_CPU); |
| } |
| |
| void paravirt_end_context_switch(struct task_struct *next) |
| { |
| BUG_ON(preemptible()); |
| |
| leave_lazy(PARAVIRT_LAZY_CPU); |
| |
| if (test_and_clear_ti_thread_flag(task_thread_info(next), TIF_LAZY_MMU_UPDATES)) |
| arch_enter_lazy_mmu_mode(); |
| } |
| #endif |
| |
| enum paravirt_lazy_mode paravirt_get_lazy_mode(void) |
| { |
| if (in_interrupt()) |
| return PARAVIRT_LAZY_NONE; |
| |
| return this_cpu_read(paravirt_lazy_mode); |
| } |
| |
| struct pv_info pv_info = { |
| .name = "bare hardware", |
| #ifdef CONFIG_PARAVIRT_XXL |
| .kernel_rpl = 0, |
| .shared_kernel_pmd = 1, /* Only used when CONFIG_X86_PAE is set */ |
| |
| #ifdef CONFIG_X86_64 |
| .extra_user_64bit_cs = __USER_CS, |
| #endif |
| #endif |
| }; |
| |
| /* 64-bit pagetable entries */ |
| #define PTE_IDENT __PV_IS_CALLEE_SAVE(_paravirt_ident_64) |
| |
| struct paravirt_patch_template pv_ops = { |
| /* Init ops. */ |
| .init.patch = native_patch, |
| |
| /* Time ops. */ |
| .time.sched_clock = native_sched_clock, |
| .time.steal_clock = native_steal_clock, |
| |
| /* Cpu ops. */ |
| .cpu.io_delay = native_io_delay, |
| |
| #ifdef CONFIG_PARAVIRT_XXL |
| .cpu.cpuid = native_cpuid, |
| .cpu.get_debugreg = native_get_debugreg, |
| .cpu.set_debugreg = native_set_debugreg, |
| .cpu.read_cr0 = native_read_cr0, |
| .cpu.write_cr0 = native_write_cr0, |
| .cpu.write_cr4 = native_write_cr4, |
| #ifdef CONFIG_X86_64 |
| .cpu.read_cr8 = native_read_cr8, |
| .cpu.write_cr8 = native_write_cr8, |
| #endif |
| .cpu.wbinvd = native_wbinvd, |
| .cpu.read_msr = native_read_msr, |
| .cpu.write_msr = native_write_msr, |
| .cpu.read_msr_safe = native_read_msr_safe, |
| .cpu.write_msr_safe = native_write_msr_safe, |
| .cpu.read_pmc = native_read_pmc, |
| .cpu.load_tr_desc = native_load_tr_desc, |
| .cpu.set_ldt = native_set_ldt, |
| .cpu.load_gdt = native_load_gdt, |
| .cpu.load_idt = native_load_idt, |
| .cpu.store_tr = native_store_tr, |
| .cpu.load_tls = native_load_tls, |
| #ifdef CONFIG_X86_64 |
| .cpu.load_gs_index = native_load_gs_index, |
| #endif |
| .cpu.write_ldt_entry = native_write_ldt_entry, |
| .cpu.write_gdt_entry = native_write_gdt_entry, |
| .cpu.write_idt_entry = native_write_idt_entry, |
| |
| .cpu.alloc_ldt = paravirt_nop, |
| .cpu.free_ldt = paravirt_nop, |
| |
| .cpu.load_sp0 = native_load_sp0, |
| |
| #ifdef CONFIG_X86_64 |
| .cpu.usergs_sysret64 = native_usergs_sysret64, |
| #endif |
| .cpu.iret = native_iret, |
| .cpu.swapgs = native_swapgs, |
| |
| .cpu.set_iopl_mask = native_set_iopl_mask, |
| |
| .cpu.start_context_switch = paravirt_nop, |
| .cpu.end_context_switch = paravirt_nop, |
| |
| /* Irq ops. */ |
| .irq.save_fl = __PV_IS_CALLEE_SAVE(native_save_fl), |
| .irq.restore_fl = __PV_IS_CALLEE_SAVE(native_restore_fl), |
| .irq.irq_disable = __PV_IS_CALLEE_SAVE(native_irq_disable), |
| .irq.irq_enable = __PV_IS_CALLEE_SAVE(native_irq_enable), |
| .irq.safe_halt = native_safe_halt, |
| .irq.halt = native_halt, |
| #endif /* CONFIG_PARAVIRT_XXL */ |
| |
| /* Mmu ops. */ |
| .mmu.flush_tlb_user = native_flush_tlb, |
| .mmu.flush_tlb_kernel = native_flush_tlb_global, |
| .mmu.flush_tlb_one_user = native_flush_tlb_one_user, |
| .mmu.flush_tlb_others = native_flush_tlb_others, |
| .mmu.tlb_remove_table = |
| (void (*)(struct mmu_gather *, void *))tlb_remove_page, |
| |
| .mmu.exit_mmap = paravirt_nop, |
| |
| #ifdef CONFIG_PARAVIRT_XXL |
| .mmu.read_cr2 = __PV_IS_CALLEE_SAVE(native_read_cr2), |
| .mmu.write_cr2 = native_write_cr2, |
| .mmu.read_cr3 = __native_read_cr3, |
| .mmu.write_cr3 = native_write_cr3, |
| |
| .mmu.pgd_alloc = __paravirt_pgd_alloc, |
| .mmu.pgd_free = paravirt_nop, |
| |
| .mmu.alloc_pte = paravirt_nop, |
| .mmu.alloc_pmd = paravirt_nop, |
| .mmu.alloc_pud = paravirt_nop, |
| .mmu.alloc_p4d = paravirt_nop, |
| .mmu.release_pte = paravirt_nop, |
| .mmu.release_pmd = paravirt_nop, |
| .mmu.release_pud = paravirt_nop, |
| .mmu.release_p4d = paravirt_nop, |
| |
| .mmu.set_pte = native_set_pte, |
| .mmu.set_pte_at = native_set_pte_at, |
| .mmu.set_pmd = native_set_pmd, |
| |
| .mmu.ptep_modify_prot_start = __ptep_modify_prot_start, |
| .mmu.ptep_modify_prot_commit = __ptep_modify_prot_commit, |
| |
| #if CONFIG_PGTABLE_LEVELS >= 3 |
| #ifdef CONFIG_X86_PAE |
| .mmu.set_pte_atomic = native_set_pte_atomic, |
| .mmu.pte_clear = native_pte_clear, |
| .mmu.pmd_clear = native_pmd_clear, |
| #endif |
| .mmu.set_pud = native_set_pud, |
| |
| .mmu.pmd_val = PTE_IDENT, |
| .mmu.make_pmd = PTE_IDENT, |
| |
| #if CONFIG_PGTABLE_LEVELS >= 4 |
| .mmu.pud_val = PTE_IDENT, |
| .mmu.make_pud = PTE_IDENT, |
| |
| .mmu.set_p4d = native_set_p4d, |
| |
| #if CONFIG_PGTABLE_LEVELS >= 5 |
| .mmu.p4d_val = PTE_IDENT, |
| .mmu.make_p4d = PTE_IDENT, |
| |
| .mmu.set_pgd = native_set_pgd, |
| #endif /* CONFIG_PGTABLE_LEVELS >= 5 */ |
| #endif /* CONFIG_PGTABLE_LEVELS >= 4 */ |
| #endif /* CONFIG_PGTABLE_LEVELS >= 3 */ |
| |
| .mmu.pte_val = PTE_IDENT, |
| .mmu.pgd_val = PTE_IDENT, |
| |
| .mmu.make_pte = PTE_IDENT, |
| .mmu.make_pgd = PTE_IDENT, |
| |
| .mmu.dup_mmap = paravirt_nop, |
| .mmu.activate_mm = paravirt_nop, |
| |
| .mmu.lazy_mode = { |
| .enter = paravirt_nop, |
| .leave = paravirt_nop, |
| .flush = paravirt_nop, |
| }, |
| |
| .mmu.set_fixmap = native_set_fixmap, |
| #endif /* CONFIG_PARAVIRT_XXL */ |
| |
| #if defined(CONFIG_PARAVIRT_SPINLOCKS) |
| /* Lock ops. */ |
| #ifdef CONFIG_SMP |
| .lock.queued_spin_lock_slowpath = native_queued_spin_lock_slowpath, |
| .lock.queued_spin_unlock = |
| PV_CALLEE_SAVE(__native_queued_spin_unlock), |
| .lock.wait = paravirt_nop, |
| .lock.kick = paravirt_nop, |
| .lock.vcpu_is_preempted = |
| PV_CALLEE_SAVE(__native_vcpu_is_preempted), |
| #endif /* SMP */ |
| #endif |
| }; |
| |
| #ifdef CONFIG_PARAVIRT_XXL |
| /* At this point, native_get/set_debugreg has real function entries */ |
| NOKPROBE_SYMBOL(native_get_debugreg); |
| NOKPROBE_SYMBOL(native_set_debugreg); |
| NOKPROBE_SYMBOL(native_load_idt); |
| #endif |
| |
| EXPORT_SYMBOL(pv_ops); |
| EXPORT_SYMBOL_GPL(pv_info); |