[PATCH] vmi: apic ops

Use para_fill instead of directly setting the APIC ops to the result of the
vmi_get_function call - this allows one to implement a VMI ROM without
implementing APIC functions, just using the native APIC functions.

While doing this, I realized that there is a lot more cleanup that should have
been done.  Basically, we should never assume that the ROM implements a
specific set of functions, and always allow fallback to the native
implementation.

This is critical for future compatibility.

Signed-off-by: Anthony Liguori <anthony@codemonkey.ws>
Signed-off-by: Zachary Amsden <zach@vmware.com>

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 92 insertions, 73 deletions

diff --git a/arch/i386/kernel/vmi.c b/arch/i386/kernel/vmi.c
index 30e8253e6eef..af8c54245f9a 100644
--- a/arch/i386/kernel/vmi.c
+++ b/arch/i386/kernel/vmi.c
@@ -54,6 +54,7 @@ static int disable_sep;
 static int disable_tsc;
 static int disable_mtrr;
 static int disable_noidle;
+static int disable_vmi_timer;
 
 /* Cached VMI operations */
 struct {
@@ -661,12 +662,12 @@ static inline int __init probe_vmi_rom(void)
 void vmi_bringup(void)
 {
         /* We must establish the lowmem mapping for MMU ops to work */
-        if (vmi_rom)
+        if (vmi_ops.set_linear_mapping)
                 vmi_ops.set_linear_mapping(0, __PAGE_OFFSET, max_low_pfn, 0);
 }
 
 /*
- * Return a pointer to the VMI function or a NOP stub
+ * Return a pointer to a VMI function or NULL if unimplemented
  */
 static void *vmi_get_function(int vmicall)
 {
@@ -677,12 +678,13 @@ static void *vmi_get_function(int vmicall)
         if (rel->type == VMI_RELOCATION_CALL_REL)
                 return (void *)rel->eip;
         else
-                return (void *)vmi_nop;
+                return NULL;
 }
 
 /*
  * Helper macro for making the VMI paravirt-ops fill code readable.
- * For unimplemented operations, fall back to default.
+ * For unimplemented operations, fall back to default, unless nop
+ * is returned by the ROM.
  */
 #define para_fill(opname, vmicall)                              \
 do {                                                            \
@@ -691,9 +693,29 @@ do {								\
         if (rel->type != VMI_RELOCATION_NONE) {                 \
                 BUG_ON(rel->type != VMI_RELOCATION_CALL_REL);   \
                 paravirt_ops.opname = (void *)rel->eip;         \
+        } else if (rel->type == VMI_RELOCATION_NOP)             \
+                paravirt_ops.opname = (void *)vmi_nop;          \
+} while (0)
+
+/*
+ * Helper macro for making the VMI paravirt-ops fill code readable.
+ * For cached operations which do not match the VMI ROM ABI and must
+ * go through a tranlation stub.  Ignore NOPs, since it is not clear
+ * a NOP * VMI function corresponds to a NOP paravirt-op when the
+ * functions are not in 1-1 correspondence.
+ */
+#define para_wrap(opname, wrapper, cache, vmicall)              \
+do {                                                            \
+        reloc = call_vrom_long_func(vmi_rom, get_reloc,         \
+                                    VMI_CALL_##vmicall);        \
+        BUG_ON(rel->type == VMI_RELOCATION_JUMP_REL);           \
+        if (rel->type == VMI_RELOCATION_CALL_REL) {             \
+                paravirt_ops.opname = wrapper;                  \
+                vmi_ops.cache = (void *)rel->eip;               \
         }                                                       \
 } while (0)
 
+
 /*
  * Activate the VMI interface and switch into paravirtualized mode
  */
@@ -730,13 +752,8 @@ static inline int __init activate_vmi(void)
          *  rdpmc is not yet used in Linux
          */
 
-        /* CPUID is special, so very special */
-        reloc = call_vrom_long_func(vmi_rom, get_reloc, VMI_CALL_CPUID);
-        if (rel->type != VMI_RELOCATION_NONE) {
-                BUG_ON(rel->type != VMI_RELOCATION_CALL_REL);
-                vmi_ops.cpuid = (void *)rel->eip;
-                paravirt_ops.cpuid = vmi_cpuid;
-        }
+        /* CPUID is special, so very special it gets wrapped like a present */
+        para_wrap(cpuid, vmi_cpuid, cpuid, CPUID);
 
         para_fill(clts, CLTS);
         para_fill(get_debugreg, GetDR);
@@ -753,6 +770,7 @@ static inline int __init activate_vmi(void)
         para_fill(restore_fl, SetInterruptMask);
         para_fill(irq_disable, DisableInterrupts);
         para_fill(irq_enable, EnableInterrupts);
+
         /* irq_save_disable !!! sheer pain */
         patch_offset(&irq_save_disable_callout[IRQ_PATCH_INT_MASK],
                      (char *)paravirt_ops.save_fl);
@@ -760,26 +778,18 @@ static inline int __init activate_vmi(void)
                      (char *)paravirt_ops.irq_disable);
 
         para_fill(wbinvd, WBINVD);
+        para_fill(read_tsc, RDTSC);
+
+        /* The following we emulate with trap and emulate for now */
         /* paravirt_ops.read_msr = vmi_rdmsr */
         /* paravirt_ops.write_msr = vmi_wrmsr */
-        para_fill(read_tsc, RDTSC);
         /* paravirt_ops.rdpmc = vmi_rdpmc */
 
-        /* TR interface doesn't pass TR value */
-        reloc = call_vrom_long_func(vmi_rom, get_reloc, VMI_CALL_SetTR);
-        if (rel->type != VMI_RELOCATION_NONE) {
-                BUG_ON(rel->type != VMI_RELOCATION_CALL_REL);
-                vmi_ops.set_tr = (void *)rel->eip;
-                paravirt_ops.load_tr_desc = vmi_set_tr;
-        }
+        /* TR interface doesn't pass TR value, wrap */
+        para_wrap(load_tr_desc, vmi_set_tr, set_tr, SetTR);
 
         /* LDT is special, too */
-        reloc = call_vrom_long_func(vmi_rom, get_reloc, VMI_CALL_SetLDT);
-        if (rel->type != VMI_RELOCATION_NONE) {
-                BUG_ON(rel->type != VMI_RELOCATION_CALL_REL);
-                vmi_ops._set_ldt = (void *)rel->eip;
-                paravirt_ops.set_ldt = vmi_set_ldt;
-        }
+        para_wrap(set_ldt, vmi_set_ldt, _set_ldt, SetLDT);
 
         para_fill(load_gdt, SetGDT);
         para_fill(load_idt, SetIDT);
@@ -790,25 +800,14 @@ static inline int __init activate_vmi(void)
         para_fill(write_ldt_entry, WriteLDTEntry);
         para_fill(write_gdt_entry, WriteGDTEntry);
         para_fill(write_idt_entry, WriteIDTEntry);
-        reloc = call_vrom_long_func(vmi_rom, get_reloc,
-                                    VMI_CALL_UpdateKernelStack);
-        if (rel->type != VMI_RELOCATION_NONE) {
-                BUG_ON(rel->type != VMI_RELOCATION_CALL_REL);
-                vmi_ops.set_kernel_stack = (void *)rel->eip;
-                paravirt_ops.load_esp0 = vmi_load_esp0;
-        }
-
+        para_wrap(load_esp0, vmi_load_esp0, set_kernel_stack, UpdateKernelStack);
         para_fill(set_iopl_mask, SetIOPLMask);
-        paravirt_ops.io_delay = (void *)vmi_nop;
-
+        para_fill(io_delay, IODelay);
         para_fill(set_lazy_mode, SetLazyMode);
 
-        reloc = call_vrom_long_func(vmi_rom, get_reloc, VMI_CALL_FlushTLB);
-        if (rel->type != VMI_RELOCATION_NONE) {
-                vmi_ops.flush_tlb = (void *)rel->eip;
-                paravirt_ops.flush_tlb_user = vmi_flush_tlb_user;
-                paravirt_ops.flush_tlb_kernel = vmi_flush_tlb_kernel;
-        }
+        /* user and kernel flush are just handled with different flags to FlushTLB */
+        para_wrap(flush_tlb_user, vmi_flush_tlb_user, flush_tlb, FlushTLB);
+        para_wrap(flush_tlb_kernel, vmi_flush_tlb_kernel, flush_tlb, FlushTLB);
         para_fill(flush_tlb_single, InvalPage);
 
         /*
@@ -823,28 +822,40 @@ static inline int __init activate_vmi(void)
         vmi_ops.set_pte = vmi_get_function(VMI_CALL_SetPxE);
         vmi_ops.update_pte = vmi_get_function(VMI_CALL_UpdatePxE);
 #endif
-        vmi_ops.set_linear_mapping = vmi_get_function(VMI_CALL_SetLinearMapping);
-        vmi_ops.allocate_page = vmi_get_function(VMI_CALL_AllocatePage);
-        vmi_ops.release_page = vmi_get_function(VMI_CALL_ReleasePage);
 
-        paravirt_ops.map_pt_hook = vmi_map_pt_hook;
-        paravirt_ops.alloc_pt = vmi_allocate_pt;
-        paravirt_ops.alloc_pd = vmi_allocate_pd;
-        paravirt_ops.alloc_pd_clone = vmi_allocate_pd_clone;
-        paravirt_ops.release_pt = vmi_release_pt;
-        paravirt_ops.release_pd = vmi_release_pd;
-        paravirt_ops.set_pte = vmi_set_pte;
-        paravirt_ops.set_pte_at = vmi_set_pte_at;
-        paravirt_ops.set_pmd = vmi_set_pmd;
-        paravirt_ops.pte_update = vmi_update_pte;
-        paravirt_ops.pte_update_defer = vmi_update_pte_defer;
+        if (vmi_ops.set_pte) {
+                paravirt_ops.set_pte = vmi_set_pte;
+                paravirt_ops.set_pte_at = vmi_set_pte_at;
+                paravirt_ops.set_pmd = vmi_set_pmd;
 #ifdef CONFIG_X86_PAE
-        paravirt_ops.set_pte_atomic = vmi_set_pte_atomic;
-        paravirt_ops.set_pte_present = vmi_set_pte_present;
-        paravirt_ops.set_pud = vmi_set_pud;
-        paravirt_ops.pte_clear = vmi_pte_clear;
-        paravirt_ops.pmd_clear = vmi_pmd_clear;
+                paravirt_ops.set_pte_atomic = vmi_set_pte_atomic;
+                paravirt_ops.set_pte_present = vmi_set_pte_present;
+                paravirt_ops.set_pud = vmi_set_pud;
+                paravirt_ops.pte_clear = vmi_pte_clear;
+                paravirt_ops.pmd_clear = vmi_pmd_clear;
 #endif
+        }
+
+        if (vmi_ops.update_pte) {
+                paravirt_ops.pte_update = vmi_update_pte;
+                paravirt_ops.pte_update_defer = vmi_update_pte_defer;
+        }
+
+        vmi_ops.allocate_page = vmi_get_function(VMI_CALL_AllocatePage);
+        if (vmi_ops.allocate_page) {
+                paravirt_ops.alloc_pt = vmi_allocate_pt;
+                paravirt_ops.alloc_pd = vmi_allocate_pd;
+                paravirt_ops.alloc_pd_clone = vmi_allocate_pd_clone;
+        }
+
+        vmi_ops.release_page = vmi_get_function(VMI_CALL_ReleasePage);
+        if (vmi_ops.release_page) {
+                paravirt_ops.release_pt = vmi_release_pt;
+                paravirt_ops.release_pd = vmi_release_pd;
+        }
+        para_wrap(map_pt_hook, vmi_map_pt_hook, set_linear_mapping,
+                  SetLinearMapping);
+
         /*
          * These MUST always be patched.  Don't support indirect jumps
          * through these operations, as the VMI interface may use either
@@ -856,21 +867,20 @@ static inline int __init activate_vmi(void)
         paravirt_ops.iret = (void *)0xbadbab0;
 
 #ifdef CONFIG_SMP
-        paravirt_ops.startup_ipi_hook = vmi_startup_ipi_hook;
-        vmi_ops.set_initial_ap_state = vmi_get_function(VMI_CALL_SetInitialAPState);
+        para_wrap(startup_ipi_hook, vmi_startup_ipi_hook, set_initial_ap_state, SetInitialAPState);
 #endif
 
 #ifdef CONFIG_X86_LOCAL_APIC
-        paravirt_ops.apic_read = vmi_get_function(VMI_CALL_APICRead);
-        paravirt_ops.apic_write = vmi_get_function(VMI_CALL_APICWrite);
-        paravirt_ops.apic_write_atomic = vmi_get_function(VMI_CALL_APICWrite);
+        para_fill(apic_read, APICRead);
+        para_fill(apic_write, APICWrite);
+        para_fill(apic_write_atomic, APICWrite);
 #endif
 
         /*
          * Check for VMI timer functionality by probing for a cycle frequency method
          */
         reloc = call_vrom_long_func(vmi_rom, get_reloc, VMI_CALL_GetCycleFrequency);
-        if (rel->type != VMI_RELOCATION_NONE) {
+        if (!disable_vmi_timer && rel->type != VMI_RELOCATION_NONE) {
                 vmi_timer_ops.get_cycle_frequency = (void *)rel->eip;
                 vmi_timer_ops.get_cycle_counter =
                         vmi_get_function(VMI_CALL_GetCycleCounter);
@@ -890,13 +900,19 @@ static inline int __init activate_vmi(void)
 #endif
                 paravirt_ops.get_scheduled_cycles = vmi_get_sched_cycles;
                 paravirt_ops.get_cpu_khz = vmi_cpu_khz;
+
+                /* We have true wallclock functions; disable CMOS clock sync */
+                no_sync_cmos_clock = 1;
+        } else {
+                disable_noidle = 1;
+                disable_vmi_timer = 1;
         }
-        if (!disable_noidle)
+
+        /* No idle HZ mode only works if VMI timer and no idle is enabled */
+        if (disable_noidle || disable_vmi_timer)
                 para_fill(safe_halt, Halt);
-        else {
-                vmi_ops.halt = vmi_get_function(VMI_CALL_Halt);
-                paravirt_ops.safe_halt = vmi_safe_halt;
-        }
+        else
+                para_wrap(safe_halt, vmi_safe_halt, halt, Halt);
 
         /*
          * Alternative instruction rewriting doesn't happen soon enough
@@ -932,10 +948,9 @@ void __init vmi_init(void)
         activate_vmi();
 
 #ifdef CONFIG_X86_IO_APIC
+        /* This is virtual hardware; timer routing is wired correctly */
         no_timer_check = 1;
 #endif
-        no_sync_cmos_clock = 1;
-
         local_irq_restore(flags & X86_EFLAGS_IF);
 }
 
@@ -959,6 +974,9 @@ static int __init parse_vmi(char *arg)
         } else if (!strcmp(arg, "disable_mtrr")) {
                 clear_bit(X86_FEATURE_MTRR, boot_cpu_data.x86_capability);
                 disable_mtrr = 1;
+        } else if (!strcmp(arg, "disable_timer")) {
+                disable_vmi_timer = 1;
+                disable_noidle = 1;
         } else if (!strcmp(arg, "disable_noidle"))
                 disable_noidle = 1;
         return 0;
diff --git a/include/asm-i386/vmi.h b/include/asm-i386/vmi.h
index 43c89333037e..eb8bd892c01e 100644
--- a/include/asm-i386/vmi.h
+++ b/include/asm-i386/vmi.h
@@ -97,6 +97,7 @@
 #define VMI_CALL_SetInitialAPState      62
 #define VMI_CALL_APICWrite              63
 #define VMI_CALL_APICRead               64
+#define VMI_CALL_IODelay                65
 #define VMI_CALL_SetLazyMode            73
 
 /*