[PATCH] paravirt: header and stubs for paravirtualisation

Create a paravirt.h header for all the critical operations which need to be
replaced with hypervisor calls, and include that instead of defining native
operations, when CONFIG_PARAVIRT.

This patch does the dumbest possible replacement of paravirtualized
instructions: calls through a "paravirt_ops" structure.  Currently these are
function implementations of native hardware: hypervisors will override the ops
structure with their own variants.

All the pv-ops functions are declared "fastcall" so that a specific
register-based ABI is used, to make inlining assember easier.

And:

+From: Andy Whitcroft <apw@shadowen.org>

The paravirt ops introduce a 'weak' attribute onto memory_setup().
Code ordering leads to the following warnings on x86:

    arch/i386/kernel/setup.c:651: warning: weak declaration of
                `memory_setup' after first use results in unspecified behavior

Move memory_setup() to avoid this.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Zachary Amsden <zach@vmware.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Andy Whitcroft <apw@shadowen.org>

1 files changed, 281 insertions, 0 deletions

diff --git a/include/asm-i386/paravirt.h b/include/asm-i386/paravirt.h
new file mode 100644
index 000000000000..a7551a44686f
--- /dev/null
+++ b/include/asm-i386/paravirt.h
@@ -0,0 +1,281 @@
+#ifndef __ASM_PARAVIRT_H
+#define __ASM_PARAVIRT_H
+/* Various instructions on x86 need to be replaced for
+ * para-virtualization: those hooks are defined here. */
+#include <linux/linkage.h>
+
+#ifdef CONFIG_PARAVIRT
+#ifndef __ASSEMBLY__
+struct thread_struct;
+struct Xgt_desc_struct;
+struct tss_struct;
+struct paravirt_ops
+{
+        unsigned int kernel_rpl;
+        int paravirt_enabled;
+        const char *name;
+
+        void (*arch_setup)(void);
+        char *(*memory_setup)(void);
+        void (*init_IRQ)(void);
+
+        void (*banner)(void);
+
+        unsigned long (*get_wallclock)(void);
+        int (*set_wallclock)(unsigned long);
+        void (*time_init)(void);
+
+        /* All the function pointers here are declared as "fastcall"
+           so that we get a specific register-based calling
+           convention.  This makes it easier to implement inline
+           assembler replacements. */
+
+        void (fastcall *cpuid)(unsigned int *eax, unsigned int *ebx,
+                      unsigned int *ecx, unsigned int *edx);
+
+        unsigned long (fastcall *get_debugreg)(int regno);
+        void (fastcall *set_debugreg)(int regno, unsigned long value);
+
+        void (fastcall *clts)(void);
+
+        unsigned long (fastcall *read_cr0)(void);
+        void (fastcall *write_cr0)(unsigned long);
+
+        unsigned long (fastcall *read_cr2)(void);
+        void (fastcall *write_cr2)(unsigned long);
+
+        unsigned long (fastcall *read_cr3)(void);
+        void (fastcall *write_cr3)(unsigned long);
+
+        unsigned long (fastcall *read_cr4_safe)(void);
+        unsigned long (fastcall *read_cr4)(void);
+        void (fastcall *write_cr4)(unsigned long);
+
+        unsigned long (fastcall *save_fl)(void);
+        void (fastcall *restore_fl)(unsigned long);
+        void (fastcall *irq_disable)(void);
+        void (fastcall *irq_enable)(void);
+        void (fastcall *safe_halt)(void);
+        void (fastcall *halt)(void);
+        void (fastcall *wbinvd)(void);
+
+        /* err = 0/-EFAULT.  wrmsr returns 0/-EFAULT. */
+        u64 (fastcall *read_msr)(unsigned int msr, int *err);
+        int (fastcall *write_msr)(unsigned int msr, u64 val);
+
+        u64 (fastcall *read_tsc)(void);
+        u64 (fastcall *read_pmc)(void);
+
+        void (fastcall *load_tr_desc)(void);
+        void (fastcall *load_gdt)(const struct Xgt_desc_struct *);
+        void (fastcall *load_idt)(const struct Xgt_desc_struct *);
+        void (fastcall *store_gdt)(struct Xgt_desc_struct *);
+        void (fastcall *store_idt)(struct Xgt_desc_struct *);
+        void (fastcall *set_ldt)(const void *desc, unsigned entries);
+        unsigned long (fastcall *store_tr)(void);
+        void (fastcall *load_tls)(struct thread_struct *t, unsigned int cpu);
+        void (fastcall *write_ldt_entry)(void *dt, int entrynum,
+                                         u32 low, u32 high);
+        void (fastcall *write_gdt_entry)(void *dt, int entrynum,
+                                         u32 low, u32 high);
+        void (fastcall *write_idt_entry)(void *dt, int entrynum,
+                                         u32 low, u32 high);
+        void (fastcall *load_esp0)(struct tss_struct *tss,
+                                   struct thread_struct *thread);
+
+        void (fastcall *set_iopl_mask)(unsigned mask);
+
+        void (fastcall *io_delay)(void);
+        void (*const_udelay)(unsigned long loops);
+
+        /* These two are jmp to, not actually called. */
+        void (fastcall *irq_enable_sysexit)(void);
+        void (fastcall *iret)(void);
+};
+
+extern struct paravirt_ops paravirt_ops;
+
+#define paravirt_enabled() (paravirt_ops.paravirt_enabled)
+
+static inline void load_esp0(struct tss_struct *tss,
+                             struct thread_struct *thread)
+{
+        paravirt_ops.load_esp0(tss, thread);
+}
+
+#define ARCH_SETUP                      paravirt_ops.arch_setup();
+static inline unsigned long get_wallclock(void)
+{
+        return paravirt_ops.get_wallclock();
+}
+
+static inline int set_wallclock(unsigned long nowtime)
+{
+        return paravirt_ops.set_wallclock(nowtime);
+}
+
+static inline void do_time_init(void)
+{
+        return paravirt_ops.time_init();
+}
+
+/* The paravirtualized CPUID instruction. */
+static inline void __cpuid(unsigned int *eax, unsigned int *ebx,
+                           unsigned int *ecx, unsigned int *edx)
+{
+        paravirt_ops.cpuid(eax, ebx, ecx, edx);
+}
+
+/*
+ * These special macros can be used to get or set a debugging register
+ */
+#define get_debugreg(var, reg) var = paravirt_ops.get_debugreg(reg)
+#define set_debugreg(val, reg) paravirt_ops.set_debugreg(reg, val)
+
+#define clts() paravirt_ops.clts()
+
+#define read_cr0() paravirt_ops.read_cr0()
+#define write_cr0(x) paravirt_ops.write_cr0(x)
+
+#define read_cr2() paravirt_ops.read_cr2()
+#define write_cr2(x) paravirt_ops.write_cr2(x)
+
+#define read_cr3() paravirt_ops.read_cr3()
+#define write_cr3(x) paravirt_ops.write_cr3(x)
+
+#define read_cr4() paravirt_ops.read_cr4()
+#define read_cr4_safe(x) paravirt_ops.read_cr4_safe()
+#define write_cr4(x) paravirt_ops.write_cr4(x)
+
+static inline unsigned long __raw_local_save_flags(void)
+{
+        return paravirt_ops.save_fl();
+}
+
+static inline void raw_local_irq_restore(unsigned long flags)
+{
+        return paravirt_ops.restore_fl(flags);
+}
+
+static inline void raw_local_irq_disable(void)
+{
+        paravirt_ops.irq_disable();
+}
+
+static inline void raw_local_irq_enable(void)
+{
+        paravirt_ops.irq_enable();
+}
+
+static inline unsigned long __raw_local_irq_save(void)
+{
+        unsigned long flags = paravirt_ops.save_fl();
+
+        paravirt_ops.irq_disable();
+
+        return flags;
+}
+
+static inline void raw_safe_halt(void)
+{
+        paravirt_ops.safe_halt();
+}
+
+static inline void halt(void)
+{
+        paravirt_ops.safe_halt();
+}
+#define wbinvd() paravirt_ops.wbinvd()
+
+#define get_kernel_rpl()  (paravirt_ops.kernel_rpl)
+
+#define rdmsr(msr,val1,val2) do {                               \
+        int _err;                                               \
+        u64 _l = paravirt_ops.read_msr(msr,&_err);              \
+        val1 = (u32)_l;                                         \
+        val2 = _l >> 32;                                        \
+} while(0)
+
+#define wrmsr(msr,val1,val2) do {                               \
+        u64 _l = ((u64)(val2) << 32) | (val1);                  \
+        paravirt_ops.write_msr((msr), _l);                      \
+} while(0)
+
+#define rdmsrl(msr,val) do {                                    \
+        int _err;                                               \
+        val = paravirt_ops.read_msr((msr),&_err);               \
+} while(0)
+
+#define wrmsrl(msr,val) (paravirt_ops.write_msr((msr),(val)))
+#define wrmsr_safe(msr,a,b) ({                                  \
+        u64 _l = ((u64)(b) << 32) | (a);                        \
+        paravirt_ops.write_msr((msr),_l);                       \
+})
+
+/* rdmsr with exception handling */
+#define rdmsr_safe(msr,a,b) ({                                  \
+        int _err;                                               \
+        u64 _l = paravirt_ops.read_msr(msr,&_err);              \
+        (*a) = (u32)_l;                                         \
+        (*b) = _l >> 32;                                        \
+        _err; })
+
+#define rdtsc(low,high) do {                                    \
+        u64 _l = paravirt_ops.read_tsc();                       \
+        low = (u32)_l;                                          \
+        high = _l >> 32;                                        \
+} while(0)
+
+#define rdtscl(low) do {                                        \
+        u64 _l = paravirt_ops.read_tsc();                       \
+        low = (int)_l;                                          \
+} while(0)
+
+#define rdtscll(val) (val = paravirt_ops.read_tsc())
+
+#define write_tsc(val1,val2) wrmsr(0x10, val1, val2)
+
+#define rdpmc(counter,low,high) do {                            \
+        u64 _l = paravirt_ops.read_pmc();                       \
+        low = (u32)_l;                                          \
+        high = _l >> 32;                                        \
+} while(0)
+
+#define load_TR_desc() (paravirt_ops.load_tr_desc())
+#define load_gdt(dtr) (paravirt_ops.load_gdt(dtr))
+#define load_idt(dtr) (paravirt_ops.load_idt(dtr))
+#define set_ldt(addr, entries) (paravirt_ops.set_ldt((addr), (entries)))
+#define store_gdt(dtr) (paravirt_ops.store_gdt(dtr))
+#define store_idt(dtr) (paravirt_ops.store_idt(dtr))
+#define store_tr(tr) ((tr) = paravirt_ops.store_tr())
+#define load_TLS(t,cpu) (paravirt_ops.load_tls((t),(cpu)))
+#define write_ldt_entry(dt, entry, low, high)                           \
+        (paravirt_ops.write_ldt_entry((dt), (entry), (low), (high)))
+#define write_gdt_entry(dt, entry, low, high)                           \
+        (paravirt_ops.write_gdt_entry((dt), (entry), (low), (high)))
+#define write_idt_entry(dt, entry, low, high)                           \
+        (paravirt_ops.write_idt_entry((dt), (entry), (low), (high)))
+#define set_iopl_mask(mask) (paravirt_ops.set_iopl_mask(mask))
+
+/* The paravirtualized I/O functions */
+static inline void slow_down_io(void) {
+        paravirt_ops.io_delay();
+#ifdef REALLY_SLOW_IO
+        paravirt_ops.io_delay();
+        paravirt_ops.io_delay();
+        paravirt_ops.io_delay();
+#endif
+}
+
+#define CLI_STRING      "pushl %eax; pushl %ecx; pushl %edx; call *paravirt_ops+PARAVIRT_irq_disable; popl %edx; popl %ecx; popl %eax"
+#define STI_STRING      "pushl %eax; pushl %ecx; pushl %edx; call *paravirt_ops+PARAVIRT_irq_enable; popl %edx; popl %ecx; popl %eax"
+#else  /* __ASSEMBLY__ */
+
+#define INTERRUPT_RETURN        jmp *%cs:paravirt_ops+PARAVIRT_iret
+#define DISABLE_INTERRUPTS      pushl %eax; pushl %ecx; pushl %edx; call *paravirt_ops+PARAVIRT_irq_disable; popl %edx; popl %ecx; popl %eax
+#define ENABLE_INTERRUPTS       pushl %eax; pushl %ecx; pushl %edx; call *%cs:paravirt_ops+PARAVIRT_irq_enable; popl %edx; popl %ecx; popl %eax
+#define ENABLE_INTERRUPTS_SYSEXIT       jmp *%cs:paravirt_ops+PARAVIRT_irq_enable_sysexit
+#define GET_CR0_INTO_EAX        call *paravirt_ops+PARAVIRT_read_cr0
+#endif /* __ASSEMBLY__ */
+#endif /* CONFIG_PARAVIRT */
+#endif  /* __ASM_PARAVIRT_H */