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Rusty Russell

2007-Apr-18 13:02 UTC

[PATCH 2/4] x86 paravirt_ops: paravirt_desc.h for native descriptor ops.

Unfortunately, due to include cycles, we can't put these in
paravirt.h: we use a separate header for these.

The implementation comes from Zach's [RFC, PATCH 10/24] i386 Vmi descriptor
changes:

  Descriptor and trap table cleanups.  Add cleanly written accessors for
  IDT and GDT gates so the subarch may override them.  Note that this
  allows the hypervisor to transparently tweak the DPL of the descriptors
  as well as the RPL of segments in those descriptors, with no unnecessary
  kernel code modification.  It also allows the hypervisor implementation
  of the VMI to tweak the gates, allowing for custom exception frames or
  extra layers of indirection above the guest fault / IRQ handlers.

  Signed-off-by: Zachary Amsden <zach@vmware.com>

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
==================================================================---
working-2.6.18-rc2-hg-paravirt.orig/arch/i386/kernel/traps.c
+++ working-2.6.18-rc2-hg-paravirt/arch/i386/kernel/traps.c
@@ -1107,20 +1107,6 @@ void __init trap_init_f00f_bug(void)
 }
 #endif
 
-#define _set_gate(gate_addr,type,dpl,addr,seg) \
-do { \
-  int __d0, __d1; \
-  __asm__ __volatile__ ("movw %%dx,%%ax\n\t" \
-	"movw %4,%%dx\n\t" \
-	"movl %%eax,%0\n\t" \
-	"movl %%edx,%1" \
-	:"=m" (*((long *) (gate_addr))), \
-	 "=m" (*(1+(long *) (gate_addr))), "=&a" (__d0),
"=&d" (__d1) \
-	:"i" ((short) (0x8000+(dpl<<13)+(type<<8))), \
-	 "3" ((char *) (addr)),"2" ((seg) << 16)); \
-} while (0)
-
-
 /*
  * This needs to use 'idt_table' rather than 'idt', and
  * thus use the _nonmapped_ version of the IDT, as the
@@ -1129,7 +1115,7 @@ do { \
  */
 void set_intr_gate(unsigned int n, void *addr)
 {
-	_set_gate(idt_table+n,14,0,addr,__KERNEL_CS);
+	_set_gate(n, DESCTYPE_INT, addr, __KERNEL_CS);
 }
 
 /*
@@ -1137,22 +1123,22 @@ void set_intr_gate(unsigned int n, void 
  */
 static inline void set_system_intr_gate(unsigned int n, void *addr)
 {
-	_set_gate(idt_table+n, 14, 3, addr, __KERNEL_CS);
+	_set_gate(n, DESCTYPE_INT | DESCTYPE_DPL3, addr, __KERNEL_CS);
 }
 
 static void __init set_trap_gate(unsigned int n, void *addr)
 {
-	_set_gate(idt_table+n,15,0,addr,__KERNEL_CS);
+	_set_gate(n, DESCTYPE_TRAP, addr, __KERNEL_CS);
 }
 
 static void __init set_system_gate(unsigned int n, void *addr)
 {
-	_set_gate(idt_table+n,15,3,addr,__KERNEL_CS);
+	_set_gate(n, DESCTYPE_TRAP | DESCTYPE_DPL3, addr, __KERNEL_CS);
 }
 
 static void __init set_task_gate(unsigned int n, unsigned int gdt_entry)
 {
-	_set_gate(idt_table+n,5,0,0,(gdt_entry<<3));
+	_set_gate(n, DESCTYPE_TASK, (void *)0, (gdt_entry<<3));
 }
 
 
==================================================================---
working-2.6.18-rc2-hg-paravirt.orig/include/asm-i386/desc.h
+++ working-2.6.18-rc2-hg-paravirt/include/asm-i386/desc.h
@@ -33,50 +33,66 @@ static inline struct desc_struct *get_cp
 	return (struct desc_struct *)per_cpu(cpu_gdt_descr, cpu).address;
 }
 
-#define load_TR_desc() __asm__ __volatile__("ltr %w0"::"q"
(GDT_ENTRY_TSS*8))
-#define load_LDT_desc() __asm__ __volatile__("lldt
%w0"::"q" (GDT_ENTRY_LDT*8))
-
-#define load_gdt(dtr) __asm__ __volatile("lgdt %0"::"m"
(*dtr))
-#define load_idt(dtr) __asm__ __volatile("lidt %0"::"m"
(*dtr))
-#define load_tr(tr) __asm__ __volatile("ltr %0"::"mr" (tr))
-#define load_ldt(ldt) __asm__ __volatile("lldt %0"::"mr"
(ldt))
-
-#define store_gdt(dtr) __asm__ ("sgdt %0":"=m" (*dtr))
-#define store_idt(dtr) __asm__ ("sidt %0":"=m" (*dtr))
-#define store_tr(tr) __asm__ ("str %0":"=mr" (tr))
-#define store_ldt(ldt) __asm__ ("sldt %0":"=mr" (ldt))
-
 /*
  * This is the ldt that every process will get unless we need
  * something other than this.
  */
 extern struct desc_struct default_ldt[];
+extern struct desc_struct idt_table[];
 extern void set_intr_gate(unsigned int irq, void * addr);
 
-#define _set_tssldt_desc(n,addr,limit,type) \
-__asm__ __volatile__ ("movw %w3,0(%2)\n\t" \
-	"movw %w1,2(%2)\n\t" \
-	"rorl $16,%1\n\t" \
-	"movb %b1,4(%2)\n\t" \
-	"movb %4,5(%2)\n\t" \
-	"movb $0,6(%2)\n\t" \
-	"movb %h1,7(%2)\n\t" \
-	"rorl $16,%1" \
-	: "=m"(*(n)) : "q" (addr), "r"(n),
"ir"(limit), "i"(type))
+static inline void pack_descriptor(__u32 *a, __u32 *b,
+	unsigned long base, unsigned long limit, unsigned char type, unsigned char
flags)
+{
+	*a = ((base & 0xffff) << 16) | (limit & 0xffff);
+	*b = (base & 0xff000000) | ((base & 0xff0000) >> 16) |
+	     ((type & 0xff) << 8) | ((flags & 0xf) << 12);
+}
 
-static inline void __set_tss_desc(unsigned int cpu, unsigned int entry, void
*addr)
+static inline void pack_gate(__u32 *a, __u32 *b,
+	unsigned long base, unsigned short seg, unsigned char type, unsigned char
flags)
 {
-	_set_tssldt_desc(&get_cpu_gdt_table(cpu)[entry], (int)addr,
-		offsetof(struct tss_struct, __cacheline_filler) - 1, 0x89);
+	*a = (seg << 16) | (base & 0xffff);
+	*b = (base & 0xffff0000) | ((type & 0xff) << 8) | (flags &
0xff);
 }
 
-#define set_tss_desc(cpu,addr) __set_tss_desc(cpu, GDT_ENTRY_TSS, addr)
+#define DESCTYPE_LDT 	0x82	/* present, system, DPL-0, LDT */
+#define DESCTYPE_TSS 	0x89	/* present, system, DPL-0, 32-bit TSS */
+#define DESCTYPE_TASK	0x85	/* present, system, DPL-0, task gate */
+#define DESCTYPE_INT	0x8e	/* present, system, DPL-0, interrupt gate */
+#define DESCTYPE_TRAP	0x8f	/* present, system, DPL-0, trap gate */
+#define DESCTYPE_DPL3	0x60	/* DPL-3 */
+#define DESCTYPE_S	0x10	/* !system */
+
+#include <asm/paravirt_desc.h>
+
+static inline void _set_gate(int gate, unsigned int type, void *addr, unsigned
short seg)
+{
+	__u32 a, b;
+	pack_gate(&a, &b, (unsigned long)addr, seg, type, 0);
+	write_idt_entry(idt_table, gate, a, b);
+}
+
+static inline void __set_tss_desc(unsigned int cpu, unsigned int entry, const
void *addr)
+{
+	__u32 a, b;
+	pack_descriptor(&a, &b, (unsigned long)addr,
+			offsetof(struct tss_struct, __cacheline_filler) - 1,
+			DESCTYPE_TSS, 0);
+	write_gdt_entry(get_cpu_gdt_table(cpu), entry, a, b);
+}
 
-static inline void set_ldt_desc(unsigned int cpu, void *addr, unsigned int
size)
+static inline void set_ldt_desc(unsigned int cpu, void *addr, unsigned int
entries)
 {
-	_set_tssldt_desc(&get_cpu_gdt_table(cpu)[GDT_ENTRY_LDT], (int)addr, ((size
<< 3)-1), 0x82);
+	__u32 a, b;
+	pack_descriptor(&a, &b, (unsigned long)addr,
+			entries * sizeof(struct desc_struct) - 1,
+			DESCTYPE_LDT, 0);
+	write_gdt_entry(get_cpu_gdt_table(cpu), GDT_ENTRY_LDT, a, b);
 }
 
+#define set_tss_desc(cpu,addr) __set_tss_desc(cpu, GDT_ENTRY_TSS, addr)
+
 #define LDT_entry_a(info) \
 	((((info)->base_addr & 0x0000ffff) << 16) | ((info)->limit
& 0x0ffff))
 
@@ -102,24 +118,6 @@ static inline void set_ldt_desc(unsigned
 	(info)->seg_not_present	== 1	&& \
 	(info)->useable		== 0	)
 
-static inline void write_ldt_entry(void *ldt, int entry, __u32 entry_a, __u32
entry_b)
-{
-	__u32 *lp = (__u32 *)((char *)ldt + entry*8);
-	*lp = entry_a;
-	*(lp+1) = entry_b;
-}
-
-#if TLS_SIZE != 24
-# error update this code.
-#endif
-
-static inline void load_TLS(struct thread_struct *t, unsigned int cpu)
-{
-#define C(i) get_cpu_gdt_table(cpu)[GDT_ENTRY_TLS_MIN + i] = t->tls_array[i]
-	C(0); C(1); C(2);
-#undef C
-}
-
 static inline void clear_LDT(void)
 {
 	int cpu = get_cpu();
==================================================================--- /dev/null
+++ working-2.6.18-rc2-hg-paravirt/include/asm-i386/no_paravirt_desc.h
@@ -0,0 +1,41 @@
+#ifndef __ASM_NO_PARAVIRT_DESC_H
+#define __ASM_NO_PARAVIRT_DESC_H
+/* The GDT instructions are here, not in paravirt.h because they need
+ * processor.h, which needs paravirt.h... */
+
+#define load_TR_desc() __asm__ __volatile__("ltr %w0"::"q"
(GDT_ENTRY_TSS*8))
+#define load_LDT_desc() __asm__ __volatile__("lldt
%w0"::"q" (GDT_ENTRY_LDT*8))
+
+#define load_gdt(dtr) __asm__ __volatile("lgdt %0"::"m"
(*dtr))
+#define load_idt(dtr) __asm__ __volatile("lidt %0"::"m"
(*dtr))
+#define load_tr(tr) __asm__ __volatile("ltr %0"::"m" (tr))
+#define load_ldt(ldt) __asm__ __volatile("lldt %0"::"m"
(ldt))
+
+#define store_gdt(dtr) __asm__ ("sgdt %0":"=m" (*dtr))
+#define store_idt(dtr) __asm__ ("sidt %0":"=m" (*dtr))
+#define store_tr(tr) __asm__ ("str %0":"=m" (tr))
+#define store_ldt(ldt) __asm__ ("sldt %0":"=m" (ldt))
+
+#if TLS_SIZE != 24
+# error update this code.
+#endif
+
+static inline void load_TLS(struct thread_struct *t, unsigned int cpu)
+{
+#define C(i) get_cpu_gdt_table(cpu)[GDT_ENTRY_TLS_MIN + i] = t->tls_array[i]
+	C(0); C(1); C(2);
+#undef C
+}
+
+static inline void write_dt_entry(void *dt, int entry, __u32 entry_a, __u32
entry_b)
+{
+	__u32 *lp = (__u32 *)((char *)dt + entry*8);
+	*lp = entry_a;
+	*(lp+1) = entry_b;
+}
+
+#define write_ldt_entry(dt, entry, a, b) write_dt_entry(dt, entry, a, b)
+#define write_gdt_entry(dt, entry, a, b) write_dt_entry(dt, entry, a, b)
+#define write_idt_entry(dt, entry, a, b) write_dt_entry(dt, entry, a, b)
+
+#endif	/* __ASM_NO_PARAVIRT_DESC_H */
==================================================================--- /dev/null
+++ working-2.6.18-rc2-hg-paravirt/include/asm-i386/paravirt_desc.h
@@ -0,0 +1,6 @@
+#ifndef __ASM_PARAVIRT_DESC_H
+#define __ASM_PARAVIRT_DESC_H
+/* A separate header because they need processor.h, which needs paravirt.h */
+#include <asm/no_paravirt_desc.h>
+
+#endif	/* __ASM_PARAVIRT_DESC_H */

-- 
Help! Save Australia from the worst of the DMCA: http://linux.org.au/law

Andi Kleen

2007-Apr-18 13:02 UTC

head link

[PATCH 1/4] x86 paravirt_ops: create no_paravirt.h for native ops

> ==================================================================> ---
/dev/null
> +++ b/include/asm-i386/no_paravirt.h
I can't say I like the name. After all that should be the normal
case for a long time now ... native? normal? bareiron?

Also I would prefer if you split this file up a bit - the old
processor/system/irqflags split wasn't too bad.


> +
> +/*
> + * Set IOPL bits in EFLAGS from given mask
> + */
> +static inline void set_iopl_mask(unsigned mask)
This function can be completely written in C using
local_save_flags()/local_restore_flags()
Please do that. I guess it's still a good idea to keep it separated
though because it might allow other optimizations.

e.g. i've been thinking about special casing IF changes in save/restore
flags
to optimize CPUs which have slow pushf/popf. If you already make sure
all non IF manipulations of flags are separated that would help.


> +/* Stop speculative execution */
> +static inline void sync_core(void)
> +{
> +	unsigned int eax = 1, ebx, ecx, edx;
> +	__cpuid(&eax, &ebx, &ecx, &edx);
> +}
Actually I don't think this one should be para virtualized at all.
I don't see any reason at all why a hypervisor should trap it and it
is very time critical. I would recommend you move it back into the 
normal files without hooks.
> +
> +/*
> + * Clear and set 'TS' bit respectively
> + */
The comment seems out of date (no set TS)

> +#define clts() __asm__ __volatile__ ("clts")
> +#define read_cr0() ({ \
> +	unsigned int __dummy; \
> +	__asm__ __volatile__( \
Maybe it's just me, but can't you just drop all these __s around
asm and volatile? They are completely useless as far I know. 

Also the assembly will be easier readable if you just keep it on a single 
line for the simple ones.

-Andi

Rusty Russell

2007-Apr-18 13:02 UTC

head link

[PATCH 1/4] x86 paravirt_ops: create no_paravirt.h for native ops

(Andrew, please sit these in the -mm tree for cooking)

Create a paravirt.h header for (almost) all the critical operations
which need to be replaced with hypervisor calls.

For the moment, this simply includes no_paravirt.h, where all the
native implementations now live.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Zachary Amsden <zach@vmware.com>

==================================================================---
a/arch/i386/kernel/entry.S
+++ b/arch/i386/kernel/entry.S
@@ -49,6 +49,7 @@
 #include <asm/page.h>
 #include <asm/desc.h>
 #include <asm/dwarf2.h>
+#include <asm/paravirt.h>
 #include "irq_vectors.h"
 
 #define nr_syscalls ((syscall_table_size)/4)
@@ -75,13 +76,6 @@ DF_MASK		= 0x00000400
 DF_MASK		= 0x00000400 
 NT_MASK		= 0x00004000
 VM_MASK		= 0x00020000
-
-/* These are replaces for paravirtualization */
-#define DISABLE_INTERRUPTS		cli
-#define ENABLE_INTERRUPTS		sti
-#define ENABLE_INTERRUPTS_SYSEXIT	sti; sysexit
-#define INTERRUPT_RETURN		iret
-#define GET_CR0_INTO_EAX		movl %cr0, %eax
 
 #ifdef CONFIG_PREEMPT
 #define preempt_stop		DISABLE_INTERRUPTS; TRACE_IRQS_OFF
==================================================================---
a/include/asm-i386/irqflags.h
+++ b/include/asm-i386/irqflags.h
@@ -9,62 +9,12 @@
  */
 #ifndef _ASM_IRQFLAGS_H
 #define _ASM_IRQFLAGS_H
+#include <asm/paravirt.h>
 
 #ifndef __ASSEMBLY__
 
-static inline unsigned long __raw_local_save_flags(void)
-{
-	unsigned long flags;
-
-	__asm__ __volatile__(
-		"pushfl ; popl %0"
-		: "=g" (flags)
-		: /* no input */
-	);
-
-	return flags;
-}
-
 #define raw_local_save_flags(flags) \
 		do { (flags) = __raw_local_save_flags(); } while (0)
-
-static inline void raw_local_irq_restore(unsigned long flags)
-{
-	__asm__ __volatile__(
-		"pushl %0 ; popfl"
-		: /* no output */
-		:"g" (flags)
-		:"memory", "cc"
-	);
-}
-
-static inline void raw_local_irq_disable(void)
-{
-	__asm__ __volatile__("cli" : : : "memory");
-}
-
-static inline void raw_local_irq_enable(void)
-{
-	__asm__ __volatile__("sti" : : : "memory");
-}
-
-/*
- * Used in the idle loop; sti takes one instruction cycle
- * to complete:
- */
-static inline void raw_safe_halt(void)
-{
-	__asm__ __volatile__("sti; hlt" : : : "memory");
-}
-
-/*
- * Used when interrupts are already enabled or to
- * shutdown the processor:
- */
-static inline void halt(void)
-{
-	__asm__ __volatile__("hlt": : :"memory");
-}
 
 static inline int raw_irqs_disabled_flags(unsigned long flags)
 {
@@ -76,18 +26,6 @@ static inline int raw_irqs_disabled(void
 	unsigned long flags = __raw_local_save_flags();
 
 	return raw_irqs_disabled_flags(flags);
-}
-
-/*
- * For spinlocks, etc:
- */
-static inline unsigned long __raw_local_irq_save(void)
-{
-	unsigned long flags = __raw_local_save_flags();
-
-	raw_local_irq_disable();
-
-	return flags;
 }
 
 #define raw_local_irq_save(flags) \
==================================================================---
a/include/asm-i386/processor.h
+++ b/include/asm-i386/processor.h
@@ -20,6 +20,7 @@
 #include <linux/threads.h>
 #include <asm/percpu.h>
 #include <linux/cpumask.h>
+#include <asm/paravirt.h>
 
 /* flag for disabling the tsc */
 extern int tsc_disable;
@@ -143,18 +144,6 @@ static inline void detect_ht(struct cpui
 #define X86_EFLAGS_VIP	0x00100000 /* Virtual Interrupt Pending */
 #define X86_EFLAGS_ID	0x00200000 /* CPUID detection flag */
 
-static inline void __cpuid(unsigned int *eax, unsigned int *ebx,
-			   unsigned int *ecx, unsigned int *edx)
-{
-	/* ecx is often an input as well as an output. */
-	__asm__("cpuid"
-		: "=a" (*eax),
-		  "=b" (*ebx),
-		  "=c" (*ecx),
-		  "=d" (*edx)
-		: "0" (*eax), "2" (*ecx));
-}
-
 /*
  * Generic CPUID function
  * clear %ecx since some cpus (Cyrix MII) do not set or clear %ecx
@@ -281,13 +270,6 @@ static inline void clear_in_cr4 (unsigne
 	outb((reg), 0x22); \
 	outb((data), 0x23); \
 } while (0)
-
-/* Stop speculative execution */
-static inline void sync_core(void)
-{
-	int tmp;
-	asm volatile("cpuid" : "=a" (tmp) : "0" (1) :
"ebx","ecx","edx","memory");
-}
 
 static inline void __monitor(const void *eax, unsigned long ecx,
 		unsigned long edx)
@@ -508,33 +490,6 @@ static inline void load_esp0(struct tss_
 	regs->esp = new_esp;					\
 } while (0)
 
-/*
- * These special macros can be used to get or set a debugging register
- */
-#define get_debugreg(var, register)				\
-		__asm__("movl %%db" #register ", %0"		\
-			:"=r" (var))
-#define set_debugreg(value, register)			\
-		__asm__("movl %0,%%db" #register		\
-			: /* no output */			\
-			:"r" (value))
-
-/*
- * Set IOPL bits in EFLAGS from given mask
- */
-static inline void set_iopl_mask(unsigned mask)
-{
-	unsigned int reg;
-	__asm__ __volatile__ ("pushfl;"
-			      "popl %0;"
-			      "andl %1, %0;"
-			      "orl %2, %0;"
-			      "pushl %0;"
-			      "popfl"
-				: "=&r" (reg)
-				: "i" (~X86_EFLAGS_IOPL), "r" (mask));
-}
-
 /* Forward declaration, a strange C thing */
 struct task_struct;
 struct mm_struct;
==================================================================---
a/include/asm-i386/segment.h
+++ b/include/asm-i386/segment.h
@@ -121,5 +121,4 @@
 /* Bottom three bits of xcs give the ring privilege level */
 #define SEGMENT_RPL_MASK 0x3
 
-#define get_kernel_rpl()  0
 #endif
==================================================================---
a/include/asm-i386/spinlock.h
+++ b/include/asm-i386/spinlock.h
@@ -5,6 +5,7 @@
 #include <asm/rwlock.h>
 #include <asm/page.h>
 #include <linux/compiler.h>
+#include <asm/paravirt.h>
 
 /*
  * Your basic SMP spinlocks, allowing only a single CPU anywhere
@@ -16,9 +17,6 @@
  *
  * (the type definitions are in asm/spinlock_types.h)
  */
-
-#define CLI_STRING	"cli"
-#define STI_STRING	"sti"
 
 #define __raw_spin_is_locked(x) \
 		(*(volatile signed char *)(&(x)->slock) <= 0)
==================================================================---
a/include/asm-i386/system.h
+++ b/include/asm-i386/system.h
@@ -5,6 +5,7 @@
 #include <asm/segment.h>
 #include <asm/cpufeature.h>
 #include <linux/bitops.h> /* for LOCK_PREFIX */
+#include <asm/paravirt.h>
 
 #ifdef __KERNEL__
 
@@ -82,67 +83,10 @@ __asm__ __volatile__ ("movw %%dx,%1\n\t"
 #define savesegment(seg, value) \
 	asm volatile("mov %%" #seg ",%0":"=rm" (value))
 
-#define read_cr0() ({ \
-	unsigned int __dummy; \
-	__asm__ __volatile__( \
-		"movl %%cr0,%0\n\t" \
-		:"=r" (__dummy)); \
-	__dummy; \
-})
-#define write_cr0(x) \
-	__asm__ __volatile__("movl %0,%%cr0": :"r" (x))
-
-#define read_cr2() ({ \
-	unsigned int __dummy; \
-	__asm__ __volatile__( \
-		"movl %%cr2,%0\n\t" \
-		:"=r" (__dummy)); \
-	__dummy; \
-})
-#define write_cr2(x) \
-	__asm__ __volatile__("movl %0,%%cr2": :"r" (x))
-
-#define read_cr3() ({ \
-	unsigned int __dummy; \
-	__asm__ ( \
-		"movl %%cr3,%0\n\t" \
-		:"=r" (__dummy)); \
-	__dummy; \
-})
-#define write_cr3(x) \
-	__asm__ __volatile__("movl %0,%%cr3": :"r" (x))
-
-#define read_cr4() ({ \
-	unsigned int __dummy; \
-	__asm__( \
-		"movl %%cr4,%0\n\t" \
-		:"=r" (__dummy)); \
-	__dummy; \
-})
-#define read_cr4_safe() ({			      \
-	unsigned int __dummy;			      \
-	/* This could fault if %cr4 does not exist */ \
-	__asm__("1: movl %%cr4, %0		\n"   \
-		"2:				\n"   \
-		".section __ex_table,\"a\"	\n"   \
-		".long 1b,2b			\n"   \
-		".previous			\n"   \
-		: "=r" (__dummy): "0" (0));	      \
-	__dummy;				      \
-})
-#define write_cr4(x) \
-	__asm__ __volatile__("movl %0,%%cr4": :"r" (x))
-
-/*
- * Clear and set 'TS' bit respectively
- */
-#define clts() __asm__ __volatile__ ("clts")
+/* Set 'TS' bit */
 #define stts() write_cr0(8 | read_cr0())
 
 #endif	/* __KERNEL__ */
-
-#define wbinvd() \
-	__asm__ __volatile__ ("wbinvd": : :"memory")
 
 static inline unsigned long get_limit(unsigned long segment)
 {
==================================================================--- /dev/null
+++ b/include/asm-i386/no_paravirt.h
@@ -0,0 +1,189 @@
+#ifndef __ASM_NO_PARAVIRT_H
+#define __ASM_NO_PARAVIRT_H
+/* This is the native implementation of the paravirtualized
+ * instruction wrappers. */
+
+#ifndef __ASSEMBLY__
+/* The non-paravirtualized CPUID instruction. */
+static inline void __cpuid(unsigned int *eax, unsigned int *ebx,
+			   unsigned int *ecx, unsigned int *edx)
+{
+	/* ecx is often an input as well: see processor.h. */
+	__asm__("cpuid"
+		: "=a" (*eax),
+		  "=b" (*ebx),
+		  "=c" (*ecx),
+		  "=d" (*edx)
+		: "0" (*eax), "2" (*ecx));
+}
+
+/*
+ * These special macros can be used to get or set a debugging register
+ */
+#define get_debugreg(var, register)				\
+		__asm__("movl %%db" #register ", %0"		\
+			:"=r" (var))
+#define set_debugreg(value, register)			\
+		__asm__("movl %0,%%db" #register		\
+			: /* no output */			\
+			:"r" (value))
+
+/*
+ * Set IOPL bits in EFLAGS from given mask
+ */
+static inline void set_iopl_mask(unsigned mask)
+{
+	unsigned int reg;
+	__asm__ __volatile__ ("pushfl;"
+			      "popl %0;"
+			      "andl %1, %0;"
+			      "orl %2, %0;"
+			      "pushl %0;"
+			      "popfl"
+				: "=&r" (reg)
+				: "i" (~0x3000 /*X86_EFLAGS_IOPL*/), "r" (mask));
+}
+
+/* Stop speculative execution */
+static inline void sync_core(void)
+{
+	unsigned int eax = 1, ebx, ecx, edx;
+	__cpuid(&eax, &ebx, &ecx, &edx);
+}
+
+/*
+ * Clear and set 'TS' bit respectively
+ */
+#define clts() __asm__ __volatile__ ("clts")
+#define read_cr0() ({ \
+	unsigned int __dummy; \
+	__asm__ __volatile__( \
+		"movl %%cr0,%0\n\t" \
+		:"=r" (__dummy)); \
+	__dummy; \
+})
+#define write_cr0(x) \
+	__asm__ __volatile__("movl %0,%%cr0": :"r" (x));
+
+#define read_cr2() ({ \
+	unsigned int __dummy; \
+	__asm__ __volatile__( \
+		"movl %%cr2,%0\n\t" \
+		:"=r" (__dummy)); \
+	__dummy; \
+})
+#define write_cr2(x) \
+	__asm__ __volatile__("movl %0,%%cr2": :"r" (x));
+
+#define read_cr3() ({ \
+	unsigned int __dummy; \
+	__asm__ ( \
+		"movl %%cr3,%0\n\t" \
+		:"=r" (__dummy)); \
+	__dummy; \
+})
+#define write_cr3(x) \
+	__asm__ __volatile__("movl %0,%%cr3": :"r" (x));
+
+#define read_cr4() ({ \
+	unsigned int __dummy; \
+	__asm__( \
+		"movl %%cr4,%0\n\t" \
+		:"=r" (__dummy)); \
+	__dummy; \
+})
+
+#define read_cr4_safe() ({			      \
+	unsigned int __dummy;			      \
+	/* This could fault if %cr4 does not exist */ \
+	__asm__("1: movl %%cr4, %0		\n"   \
+		"2:				\n"   \
+		".section __ex_table,\"a\"	\n"   \
+		".long 1b,2b			\n"   \
+		".previous			\n"   \
+		: "=r" (__dummy): "0" (0));	      \
+	__dummy;				      \
+})
+
+#define write_cr4(x) \
+	__asm__ __volatile__("movl %0,%%cr4": :"r" (x));
+
+static inline unsigned long __raw_local_save_flags(void)
+{
+	unsigned long flags;
+
+	__asm__ __volatile__(
+		"pushfl ; popl %0"
+		: "=g" (flags)
+		: /* no input */
+	);
+
+	return flags;
+}
+
+static inline void raw_local_irq_restore(unsigned long flags)
+{
+	__asm__ __volatile__(
+		"pushl %0 ; popfl"
+		: /* no output */
+		:"g" (flags)
+		:"memory", "cc"
+	);
+}
+
+static inline void raw_local_irq_disable(void)
+{
+	__asm__ __volatile__("cli" : : : "memory");
+}
+
+static inline unsigned long __raw_local_irq_save(void)
+{
+	unsigned long flags = __raw_local_save_flags();
+
+	raw_local_irq_disable();
+
+	return flags;
+}
+
+static inline void raw_local_irq_enable(void)
+{
+	__asm__ __volatile__("sti" : : : "memory");
+}
+
+/*
+ * Used in the idle loop; sti takes one instruction cycle
+ * to complete:
+ */
+static inline void raw_safe_halt(void)
+{
+	__asm__ __volatile__("sti; hlt" : : : "memory");
+}
+
+/*
+ * Used when interrupts are already enabled or to
+ * shutdown the processor:
+ */
+static inline void halt(void)
+{
+	__asm__ __volatile__("hlt": : :"memory");
+}
+
+static inline void wbinvd(void)
+{
+	__asm__ __volatile__("wbinvd": : :"memory");
+}
+
+#define get_kernel_rpl()  0
+
+#define CLI_STRING	"cli"
+#define STI_STRING	"sti"
+
+#else  /* ... __ASSEMBLY__ */
+#define INTERRUPT_RETURN		iret
+#define DISABLE_INTERRUPTS		cli
+#define ENABLE_INTERRUPTS		sti
+#define ENABLE_INTERRUPTS_SYSEXIT	sti; sysexit
+#define GET_CR0_INTO_EAX		mov %cr0, %eax
+#endif /* __ASSEMBLY__ */
+
+#endif /* __ASM_NO_PARAVIRT_H */
==================================================================--- /dev/null
+++ b/include/asm-i386/paravirt.h
@@ -0,0 +1,7 @@
+#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 <asm/no_paravirt.h>
+
+#endif	/* __ASM_PARAVIRT_H */

-- 
Help! Save Australia from the worst of the DMCA: http://linux.org.au/law

Jeremy Fitzhardinge

2007-Apr-18 13:02 UTC

head link

[PATCH 1/4] x86 paravirt_ops: create no_paravirt.h for native ops

Rusty Russell wrote:> (Andrew, please sit these in the -mm tree for cooking)
>
> Create a paravirt.h header for (almost) all the critical operations
> which need to be replaced with hypervisor calls.
>
> For the moment, this simply includes no_paravirt.h, where all the
> native implementations now live.
>   
Sorry, but I have to say these are not yet ready for -mm.  While they're 
better than before (I can successfully boot), the machine locks up when 
I start X, and I wouldn't have any confidence in running with this stuff 
enabled.  I'd prefer these weren't in -mm until we somewhat confident 
one could run with CONFIG_PARAVIRT on all the time (ie, think it could 
be default on, even if it isn't).

    J

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