1 files changed, 424 insertions, 0 deletions
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
new file mode 100644
index 000000000..e21937680
--- /dev/null
+++ b/arch/x86/kernel/paravirt.c
@@ -0,0 +1,424 @@
+// 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 <linux/pgtable.h>
+
+#include <asm/bug.h>
+#include <asm/paravirt.h>
+#include <asm/debugreg.h>
+#include <asm/desc.h>
+#include <asm/setup.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>
+#include <asm/io_bitmap.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"
+     ASM_RET
+     ".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;
+}
+
+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
+	.extra_user_64bit_cs = __USER_CS,
+#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,
+	.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,
+	.cpu.load_gs_index	= native_load_gs_index,
+	.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,
+
+	.cpu.usergs_sysret64	= native_usergs_sysret64,
+	.cpu.iret		= native_iret,
+
+#ifdef CONFIG_X86_IOPL_IOPERM
+	.cpu.invalidate_io_bitmap	= native_tss_invalidate_io_bitmap,
+	.cpu.update_io_bitmap		= native_tss_update_io_bitmap,
+#endif
+
+	.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_local,
+	.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_pmd		= native_set_pmd,
+
+	.mmu.ptep_modify_prot_start	= __ptep_modify_prot_start,
+	.mmu.ptep_modify_prot_commit	= __ptep_modify_prot_commit,
+
+	.mmu.set_pud		= native_set_pud,
+
+	.mmu.pmd_val		= PTE_IDENT,
+	.mmu.make_pmd		= PTE_IDENT,
+
+	.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 */
+
+	.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);