paravirt: refactor struct paravirt_ops into smaller pv_*_ops

This patch refactors the paravirt_ops structure into groups of
functionally related ops:

pv_info - random info, rather than function entrypoints
pv_init_ops - functions used at boot time (some for module_init too)
pv_misc_ops - lazy mode, which didn't fit well anywhere else
pv_time_ops - time-related functions
pv_cpu_ops - various privileged instruction ops
pv_irq_ops - operations for managing interrupt state
pv_apic_ops - APIC operations
pv_mmu_ops - operations for managing pagetables

There are several motivations for this:

1. Some of these ops will be general to all x86, and some will be
   i386/x86-64 specific.  This makes it easier to share common stuff
   while allowing separate implementations where needed.

2. At the moment we must export all of paravirt_ops, but modules only
   need selected parts of it.  This allows us to export on a case by case
   basis (and also choose which export license we want to apply).

3. Functional groupings make things a bit more readable.

Struct paravirt_ops is now only used as a template to generate
patch-site identifiers, and to extract function pointers for inserting
into jmp/calls when patching.  It is only instantiated when needed.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Andi Kleen <ak@suse.de>
Cc: Zach Amsden <zach@vmware.com>
Cc: Avi Kivity <avi@qumranet.com>
Cc: Anthony Liguory <aliguori@us.ibm.com>
Cc: "Glauber de Oliveira Costa" <glommer@gmail.com>
Cc: Jun Nakajima <jun.nakajima@intel.com>

1 files changed, 103 insertions, 71 deletions

diff --git a/arch/x86/kernel/paravirt_32.c b/arch/x86/kernel/paravirt_32.c
index 739cfb207dd7..fa412515af79 100644
--- a/arch/x86/kernel/paravirt_32.c
+++ b/arch/x86/kernel/paravirt_32.c
@@ -42,32 +42,33 @@ void _paravirt_nop(void)
 static void __init default_banner(void)
 {
         printk(KERN_INFO "Booting paravirtualized kernel on %s\n",
-               paravirt_ops.name);
+               pv_info.name);
 }
 
 char *memory_setup(void)
 {
-        return paravirt_ops.memory_setup();
+        return pv_init_ops.memory_setup();
 }
 
 /* Simple instruction patching code. */
-#define DEF_NATIVE(name, code)                                  \
-        extern const char start_##name[], end_##name[];         \
-        asm("start_" #name ": " code "; end_" #name ":")
-
-DEF_NATIVE(irq_disable, "cli");
-DEF_NATIVE(irq_enable, "sti");
-DEF_NATIVE(restore_fl, "push %eax; popf");
-DEF_NATIVE(save_fl, "pushf; pop %eax");
-DEF_NATIVE(iret, "iret");
-DEF_NATIVE(irq_enable_sysexit, "sti; sysexit");
-DEF_NATIVE(read_cr2, "mov %cr2, %eax");
-DEF_NATIVE(write_cr3, "mov %eax, %cr3");
-DEF_NATIVE(read_cr3, "mov %cr3, %eax");
-DEF_NATIVE(clts, "clts");
-DEF_NATIVE(read_tsc, "rdtsc");
-
-DEF_NATIVE(ud2a, "ud2a");
+#define DEF_NATIVE(ops, name, code)                                     \
+        extern const char start_##ops##_##name[], end_##ops##_##name[]; \
+        asm("start_" #ops "_" #name ": " code "; end_" #ops "_" #name ":")
+
+DEF_NATIVE(pv_irq_ops, irq_disable, "cli");
+DEF_NATIVE(pv_irq_ops, irq_enable, "sti");
+DEF_NATIVE(pv_irq_ops, restore_fl, "push %eax; popf");
+DEF_NATIVE(pv_irq_ops, save_fl, "pushf; pop %eax");
+DEF_NATIVE(pv_cpu_ops, iret, "iret");
+DEF_NATIVE(pv_cpu_ops, irq_enable_sysexit, "sti; sysexit");
+DEF_NATIVE(pv_mmu_ops, read_cr2, "mov %cr2, %eax");
+DEF_NATIVE(pv_mmu_ops, write_cr3, "mov %eax, %cr3");
+DEF_NATIVE(pv_mmu_ops, read_cr3, "mov %cr3, %eax");
+DEF_NATIVE(pv_cpu_ops, clts, "clts");
+DEF_NATIVE(pv_cpu_ops, read_tsc, "rdtsc");
+
+/* Undefined instruction for dealing with missing ops pointers. */
+static const unsigned char ud2a[] = { 0x0f, 0x0b };
 
 static unsigned native_patch(u8 type, u16 clobbers, void *ibuf,
                              unsigned long addr, unsigned len)
@@ -76,37 +77,29 @@ static unsigned native_patch(u8 type, u16 clobbers, void *ibuf,
         unsigned ret;
 
         switch(type) {
-#define SITE(x) case PARAVIRT_PATCH(x): start = start_##x; end = end_##x; goto patch_site
-                SITE(irq_disable);
-                SITE(irq_enable);
-                SITE(restore_fl);
-                SITE(save_fl);
-                SITE(iret);
-                SITE(irq_enable_sysexit);
-                SITE(read_cr2);
-                SITE(read_cr3);
-                SITE(write_cr3);
-                SITE(clts);
-                SITE(read_tsc);
+#define SITE(ops, x)                                            \
+        case PARAVIRT_PATCH(ops.x):                             \
+                start = start_##ops##_##x;                      \
+                end = end_##ops##_##x;                          \
+                goto patch_site
+
+        SITE(pv_irq_ops, irq_disable);
+        SITE(pv_irq_ops, irq_enable);
+        SITE(pv_irq_ops, restore_fl);
+        SITE(pv_irq_ops, save_fl);
+        SITE(pv_cpu_ops, iret);
+        SITE(pv_cpu_ops, irq_enable_sysexit);
+        SITE(pv_mmu_ops, read_cr2);
+        SITE(pv_mmu_ops, read_cr3);
+        SITE(pv_mmu_ops, write_cr3);
+        SITE(pv_cpu_ops, clts);
+        SITE(pv_cpu_ops, read_tsc);
 #undef SITE
 
         patch_site:
                 ret = paravirt_patch_insns(ibuf, len, start, end);
                 break;
 
-        case PARAVIRT_PATCH(make_pgd):
-        case PARAVIRT_PATCH(make_pte):
-        case PARAVIRT_PATCH(pgd_val):
-        case PARAVIRT_PATCH(pte_val):
-#ifdef CONFIG_X86_PAE
-        case PARAVIRT_PATCH(make_pmd):
-        case PARAVIRT_PATCH(pmd_val):
-#endif
-                /* These functions end up returning exactly what
-                   they're passed, in the same registers. */
-                ret = paravirt_patch_nop();
-                break;
-
         default:
                 ret = paravirt_patch_default(type, clobbers, ibuf, addr, len);
                 break;
@@ -150,7 +143,7 @@ unsigned paravirt_patch_call(void *insnbuf,
         return 5;
 }
 
-unsigned paravirt_patch_jmp(const void *target, void *insnbuf,
+unsigned paravirt_patch_jmp(void *insnbuf, const void *target,
                             unsigned long addr, unsigned len)
 {
         struct branch *b = insnbuf;
@@ -165,22 +158,38 @@ unsigned paravirt_patch_jmp(const void *target, void *insnbuf,
         return 5;
 }
 
+/* Neat trick to map patch type back to the call within the
+ * corresponding structure. */
+static void *get_call_destination(u8 type)
+{
+        struct paravirt_patch_template tmpl = {
+                .pv_init_ops = pv_init_ops,
+                .pv_misc_ops = pv_misc_ops,
+                .pv_time_ops = pv_time_ops,
+                .pv_cpu_ops = pv_cpu_ops,
+                .pv_irq_ops = pv_irq_ops,
+                .pv_apic_ops = pv_apic_ops,
+                .pv_mmu_ops = pv_mmu_ops,
+        };
+        return *((void **)&tmpl + type);
+}
+
 unsigned paravirt_patch_default(u8 type, u16 clobbers, void *insnbuf,
                                 unsigned long addr, unsigned len)
 {
-        void *opfunc = *((void **)&paravirt_ops + type);
+        void *opfunc = get_call_destination(type);
         unsigned ret;
 
         if (opfunc == NULL)
                 /* If there's no function, patch it with a ud2a (BUG) */
-                ret = paravirt_patch_insns(insnbuf, len, start_ud2a, end_ud2a);
+                ret = paravirt_patch_insns(insnbuf, len, ud2a, ud2a+sizeof(ud2a));
         else if (opfunc == paravirt_nop)
                 /* If the operation is a nop, then nop the callsite */
                 ret = paravirt_patch_nop();
-        else if (type == PARAVIRT_PATCH(iret) ||
-                 type == PARAVIRT_PATCH(irq_enable_sysexit))
+        else if (type == PARAVIRT_PATCH(pv_cpu_ops.iret) ||
+                 type == PARAVIRT_PATCH(pv_cpu_ops.irq_enable_sysexit))
                 /* If operation requires a jmp, then jmp */
-                ret = paravirt_patch_jmp(opfunc, insnbuf, addr, len);
+                ret = paravirt_patch_jmp(insnbuf, opfunc, addr, len);
         else
                 /* Otherwise call the function; assume target could
                    clobber any caller-save reg */
@@ -205,7 +214,7 @@ unsigned paravirt_patch_insns(void *insnbuf, unsigned len,
 
 void init_IRQ(void)
 {
-        paravirt_ops.init_IRQ();
+        pv_irq_ops.init_IRQ();
 }
 
 static void native_flush_tlb(void)
@@ -233,7 +242,7 @@ extern void native_irq_enable_sysexit(void);
 
 static int __init print_banner(void)
 {
-        paravirt_ops.banner();
+        pv_init_ops.banner();
         return 0;
 }
 core_initcall(print_banner);
@@ -273,47 +282,53 @@ int paravirt_disable_iospace(void)
         return ret;
 }
 
-struct paravirt_ops paravirt_ops = {
+struct pv_info pv_info = {
         .name = "bare hardware",
         .paravirt_enabled = 0,
         .kernel_rpl = 0,
         .shared_kernel_pmd = 1, /* Only used when CONFIG_X86_PAE is set */
+};
 
-        .patch = native_patch,
+struct pv_init_ops pv_init_ops = {
+        .patch = native_patch,
         .banner = default_banner,
         .arch_setup = paravirt_nop,
         .memory_setup = machine_specific_memory_setup,
+};
+
+struct pv_time_ops pv_time_ops = {
+        .time_init = hpet_time_init,
         .get_wallclock = native_get_wallclock,
         .set_wallclock = native_set_wallclock,
-        .time_init = hpet_time_init,
+        .sched_clock = native_sched_clock,
+        .get_cpu_khz = native_calculate_cpu_khz,
+};
+
+struct pv_irq_ops pv_irq_ops = {
         .init_IRQ = native_init_IRQ,
+        .save_fl = native_save_fl,
+        .restore_fl = native_restore_fl,
+        .irq_disable = native_irq_disable,
+        .irq_enable = native_irq_enable,
+        .safe_halt = native_safe_halt,
+        .halt = native_halt,
+};
 
+struct pv_cpu_ops pv_cpu_ops = {
         .cpuid = native_cpuid,
         .get_debugreg = native_get_debugreg,
         .set_debugreg = native_set_debugreg,
         .clts = native_clts,
         .read_cr0 = native_read_cr0,
         .write_cr0 = native_write_cr0,
-        .read_cr2 = native_read_cr2,
-        .write_cr2 = native_write_cr2,
-        .read_cr3 = native_read_cr3,
-        .write_cr3 = native_write_cr3,
         .read_cr4 = native_read_cr4,
         .read_cr4_safe = native_read_cr4_safe,
         .write_cr4 = native_write_cr4,
-        .save_fl = native_save_fl,
-        .restore_fl = native_restore_fl,
-        .irq_disable = native_irq_disable,
-        .irq_enable = native_irq_enable,
-        .safe_halt = native_safe_halt,
-        .halt = native_halt,
         .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,
-        .sched_clock = native_sched_clock,
-        .get_cpu_khz = native_calculate_cpu_khz,
         .load_tr_desc = native_load_tr_desc,
         .set_ldt = native_set_ldt,
         .load_gdt = native_load_gdt,
@@ -327,9 +342,14 @@ struct paravirt_ops paravirt_ops = {
         .write_idt_entry = write_dt_entry,
         .load_esp0 = native_load_esp0,
 
+        .irq_enable_sysexit = native_irq_enable_sysexit,
+        .iret = native_iret,
+
         .set_iopl_mask = native_set_iopl_mask,
         .io_delay = native_io_delay,
+};
 
+struct pv_apic_ops pv_apic_ops = {
 #ifdef CONFIG_X86_LOCAL_APIC
         .apic_write = native_apic_write,
         .apic_write_atomic = native_apic_write_atomic,
@@ -338,11 +358,21 @@ struct paravirt_ops paravirt_ops = {
         .setup_secondary_clock = setup_secondary_APIC_clock,
         .startup_ipi_hook = paravirt_nop,
 #endif
+};
+
+struct pv_misc_ops pv_misc_ops = {
         .set_lazy_mode = paravirt_nop,
+};
 
+struct pv_mmu_ops pv_mmu_ops = {
         .pagetable_setup_start = native_pagetable_setup_start,
         .pagetable_setup_done = native_pagetable_setup_done,
 
+        .read_cr2 = native_read_cr2,
+        .write_cr2 = native_write_cr2,
+        .read_cr3 = native_read_cr3,
+        .write_cr3 = native_write_cr3,
+
         .flush_tlb_user = native_flush_tlb,
         .flush_tlb_kernel = native_flush_tlb_global,
         .flush_tlb_single = native_flush_tlb_single,
@@ -381,12 +411,14 @@ struct paravirt_ops paravirt_ops = {
         .make_pte = native_make_pte,
         .make_pgd = native_make_pgd,
 
-        .irq_enable_sysexit = native_irq_enable_sysexit,
-        .iret = native_iret,
-
         .dup_mmap = paravirt_nop,
         .exit_mmap = paravirt_nop,
         .activate_mm = paravirt_nop,
 };
 
-EXPORT_SYMBOL(paravirt_ops);
+EXPORT_SYMBOL_GPL(pv_time_ops);
+EXPORT_SYMBOL_GPL(pv_cpu_ops);
+EXPORT_SYMBOL_GPL(pv_mmu_ops);
+EXPORT_SYMBOL_GPL(pv_apic_ops);
+EXPORT_SYMBOL_GPL(pv_info);
+EXPORT_SYMBOL    (pv_irq_ops);