[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>
diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig
index 1f0f7b6..bb1fa06 100644
--- a/arch/i386/Kconfig
+++ b/arch/i386/Kconfig
@@ -182,6 +182,17 @@
endchoice
+config PARAVIRT
+ bool "Paravirtualization support (EXPERIMENTAL)"
+ depends on EXPERIMENTAL
+ help
+ Paravirtualization is a way of running multiple instances of
+ Linux on the same machine, under a hypervisor. This option
+ changes the kernel so it can modify itself when it is run
+ under a hypervisor, improving performance significantly.
+ However, when run without a hypervisor the kernel is
+ theoretically slower. If in doubt, say N.
+
config ACPI_SRAT
bool
default y
diff --git a/arch/i386/boot/compressed/misc.c b/arch/i386/boot/compressed/misc.c
index dc15389..c6798c75 100644
--- a/arch/i386/boot/compressed/misc.c
+++ b/arch/i386/boot/compressed/misc.c
@@ -9,6 +9,7 @@
* High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996
*/
+#undef CONFIG_PARAVIRT
#include <linux/linkage.h>
#include <linux/vmalloc.h>
#include <linux/screen_info.h>
diff --git a/arch/i386/kernel/Makefile b/arch/i386/kernel/Makefile
index f614854..4066121 100644
--- a/arch/i386/kernel/Makefile
+++ b/arch/i386/kernel/Makefile
@@ -39,6 +39,7 @@
obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
obj-$(CONFIG_HPET_TIMER) += hpet.o
obj-$(CONFIG_K8_NB) += k8.o
+obj-$(CONFIG_PARAVIRT) += paravirt.o
EXTRA_AFLAGS := -traditional
diff --git a/arch/i386/kernel/asm-offsets.c b/arch/i386/kernel/asm-offsets.c
index 0666eb0e..1b2f3cd 100644
--- a/arch/i386/kernel/asm-offsets.c
+++ b/arch/i386/kernel/asm-offsets.c
@@ -101,4 +101,14 @@
BLANK();
OFFSET(PDA_cpu, i386_pda, cpu_number);
OFFSET(PDA_pcurrent, i386_pda, pcurrent);
+
+#ifdef CONFIG_PARAVIRT
+ BLANK();
+ OFFSET(PARAVIRT_enabled, paravirt_ops, paravirt_enabled);
+ OFFSET(PARAVIRT_irq_disable, paravirt_ops, irq_disable);
+ OFFSET(PARAVIRT_irq_enable, paravirt_ops, irq_enable);
+ OFFSET(PARAVIRT_irq_enable_sysexit, paravirt_ops, irq_enable_sysexit);
+ OFFSET(PARAVIRT_iret, paravirt_ops, iret);
+ OFFSET(PARAVIRT_read_cr0, paravirt_ops, read_cr0);
+#endif
}
diff --git a/arch/i386/kernel/entry.S b/arch/i386/kernel/entry.S
index 0220bc8..d274612 100644
--- a/arch/i386/kernel/entry.S
+++ b/arch/i386/kernel/entry.S
@@ -62,13 +62,6 @@
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
#else
@@ -416,6 +409,20 @@
jnz restore_nocheck
testl $0x00400000, %eax # returning to 32bit stack?
jnz restore_nocheck # allright, normal return
+
+#ifdef CONFIG_PARAVIRT
+ /*
+ * The kernel can't run on a non-flat stack if paravirt mode
+ * is active. Rather than try to fixup the high bits of
+ * ESP, bypass this code entirely. This may break DOSemu
+ * and/or Wine support in a paravirt VM, although the option
+ * is still available to implement the setting of the high
+ * 16-bits in the INTERRUPT_RETURN paravirt-op.
+ */
+ cmpl $0, paravirt_ops+PARAVIRT_enabled
+ jne restore_nocheck
+#endif
+
/* If returning to userspace with 16bit stack,
* try to fix the higher word of ESP, as the CPU
* won't restore it.
@@ -833,6 +840,19 @@
.previous
KPROBE_END(nmi)
+#ifdef CONFIG_PARAVIRT
+ENTRY(native_iret)
+1: iret
+.section __ex_table,"a"
+ .align 4
+ .long 1b,iret_exc
+.previous
+
+ENTRY(native_irq_enable_sysexit)
+ sti
+ sysexit
+#endif
+
KPROBE_ENTRY(int3)
RING0_INT_FRAME
pushl $-1 # mark this as an int
diff --git a/arch/i386/kernel/i8259.c b/arch/i386/kernel/i8259.c
index 62996cd..c8d4582 100644
--- a/arch/i386/kernel/i8259.c
+++ b/arch/i386/kernel/i8259.c
@@ -381,7 +381,10 @@
}
}
-void __init init_IRQ(void)
+/* Overridden in paravirt.c */
+void init_IRQ(void) __attribute__((weak, alias("native_init_IRQ")));
+
+void __init native_init_IRQ(void)
{
int i;
diff --git a/arch/i386/kernel/paravirt.c b/arch/i386/kernel/paravirt.c
new file mode 100644
index 0000000..478192c
--- /dev/null
+++ b/arch/i386/kernel/paravirt.c
@@ -0,0 +1,404 @@
+/* Paravirtualization interfaces
+ Copyright (C) 2006 Rusty Russell IBM Corporation
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+*/
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/efi.h>
+#include <linux/bcd.h>
+
+#include <asm/bug.h>
+#include <asm/paravirt.h>
+#include <asm/desc.h>
+#include <asm/setup.h>
+#include <asm/arch_hooks.h>
+#include <asm/time.h>
+#include <asm/irq.h>
+#include <asm/delay.h>
+
+/* nop stub */
+static void native_nop(void)
+{
+}
+
+static void __init default_banner(void)
+{
+ printk(KERN_INFO "Booting paravirtualized kernel on %s\n",
+ paravirt_ops.name);
+}
+
+char *memory_setup(void)
+{
+ return paravirt_ops.memory_setup();
+}
+
+static fastcall unsigned long native_get_debugreg(int regno)
+{
+ unsigned long val = 0; /* Damn you, gcc! */
+
+ switch (regno) {
+ case 0:
+ asm("movl %%db0, %0" :"=r" (val)); break;
+ case 1:
+ asm("movl %%db1, %0" :"=r" (val)); break;
+ case 2:
+ asm("movl %%db2, %0" :"=r" (val)); break;
+ case 3:
+ asm("movl %%db3, %0" :"=r" (val)); break;
+ case 6:
+ asm("movl %%db6, %0" :"=r" (val)); break;
+ case 7:
+ asm("movl %%db7, %0" :"=r" (val)); break;
+ default:
+ BUG();
+ }
+ return val;
+}
+
+static fastcall void native_set_debugreg(int regno, unsigned long value)
+{
+ switch (regno) {
+ case 0:
+ asm("movl %0,%%db0" : /* no output */ :"r" (value));
+ break;
+ case 1:
+ asm("movl %0,%%db1" : /* no output */ :"r" (value));
+ break;
+ case 2:
+ asm("movl %0,%%db2" : /* no output */ :"r" (value));
+ break;
+ case 3:
+ asm("movl %0,%%db3" : /* no output */ :"r" (value));
+ break;
+ case 6:
+ asm("movl %0,%%db6" : /* no output */ :"r" (value));
+ break;
+ case 7:
+ asm("movl %0,%%db7" : /* no output */ :"r" (value));
+ break;
+ default:
+ BUG();
+ }
+}
+
+void init_IRQ(void)
+{
+ paravirt_ops.init_IRQ();
+}
+
+static fastcall void native_clts(void)
+{
+ asm volatile ("clts");
+}
+
+static fastcall unsigned long native_read_cr0(void)
+{
+ unsigned long val;
+ asm volatile("movl %%cr0,%0\n\t" :"=r" (val));
+ return val;
+}
+
+static fastcall void native_write_cr0(unsigned long val)
+{
+ asm volatile("movl %0,%%cr0": :"r" (val));
+}
+
+static fastcall unsigned long native_read_cr2(void)
+{
+ unsigned long val;
+ asm volatile("movl %%cr2,%0\n\t" :"=r" (val));
+ return val;
+}
+
+static fastcall void native_write_cr2(unsigned long val)
+{
+ asm volatile("movl %0,%%cr2": :"r" (val));
+}
+
+static fastcall unsigned long native_read_cr3(void)
+{
+ unsigned long val;
+ asm volatile("movl %%cr3,%0\n\t" :"=r" (val));
+ return val;
+}
+
+static fastcall void native_write_cr3(unsigned long val)
+{
+ asm volatile("movl %0,%%cr3": :"r" (val));
+}
+
+static fastcall unsigned long native_read_cr4(void)
+{
+ unsigned long val;
+ asm volatile("movl %%cr4,%0\n\t" :"=r" (val));
+ return val;
+}
+
+static fastcall unsigned long native_read_cr4_safe(void)
+{
+ unsigned long val;
+ /* 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" (val): "0" (0));
+ return val;
+}
+
+static fastcall void native_write_cr4(unsigned long val)
+{
+ asm volatile("movl %0,%%cr4": :"r" (val));
+}
+
+static fastcall unsigned long native_save_fl(void)
+{
+ unsigned long f;
+ asm volatile("pushfl ; popl %0":"=g" (f): /* no input */);
+ return f;
+}
+
+static fastcall void native_restore_fl(unsigned long f)
+{
+ asm volatile("pushl %0 ; popfl": /* no output */
+ :"g" (f)
+ :"memory", "cc");
+}
+
+static fastcall void native_irq_disable(void)
+{
+ asm volatile("cli": : :"memory");
+}
+
+static fastcall void native_irq_enable(void)
+{
+ asm volatile("sti": : :"memory");
+}
+
+static fastcall void native_safe_halt(void)
+{
+ asm volatile("sti; hlt": : :"memory");
+}
+
+static fastcall void native_halt(void)
+{
+ asm volatile("hlt": : :"memory");
+}
+
+static fastcall void native_wbinvd(void)
+{
+ asm volatile("wbinvd": : :"memory");
+}
+
+static fastcall unsigned long long native_read_msr(unsigned int msr, int *err)
+{
+ unsigned long long val;
+
+ asm volatile("2: rdmsr ; xorl %0,%0\n"
+ "1:\n\t"
+ ".section .fixup,\"ax\"\n\t"
+ "3: movl %3,%0 ; jmp 1b\n\t"
+ ".previous\n\t"
+ ".section __ex_table,\"a\"\n"
+ " .align 4\n\t"
+ " .long 2b,3b\n\t"
+ ".previous"
+ : "=r" (*err), "=A" (val)
+ : "c" (msr), "i" (-EFAULT));
+
+ return val;
+}
+
+static fastcall int native_write_msr(unsigned int msr, unsigned long long val)
+{
+ int err;
+ asm volatile("2: wrmsr ; xorl %0,%0\n"
+ "1:\n\t"
+ ".section .fixup,\"ax\"\n\t"
+ "3: movl %4,%0 ; jmp 1b\n\t"
+ ".previous\n\t"
+ ".section __ex_table,\"a\"\n"
+ " .align 4\n\t"
+ " .long 2b,3b\n\t"
+ ".previous"
+ : "=a" (err)
+ : "c" (msr), "0" ((u32)val), "d" ((u32)(val>>32)),
+ "i" (-EFAULT));
+ return err;
+}
+
+static fastcall unsigned long long native_read_tsc(void)
+{
+ unsigned long long val;
+ asm volatile("rdtsc" : "=A" (val));
+ return val;
+}
+
+static fastcall unsigned long long native_read_pmc(void)
+{
+ unsigned long long val;
+ asm volatile("rdpmc" : "=A" (val));
+ return val;
+}
+
+static fastcall void native_load_tr_desc(void)
+{
+ asm volatile("ltr %w0"::"q" (GDT_ENTRY_TSS*8));
+}
+
+static fastcall void native_load_gdt(const struct Xgt_desc_struct *dtr)
+{
+ asm volatile("lgdt %0"::"m" (*dtr));
+}
+
+static fastcall void native_load_idt(const struct Xgt_desc_struct *dtr)
+{
+ asm volatile("lidt %0"::"m" (*dtr));
+}
+
+static fastcall void native_store_gdt(struct Xgt_desc_struct *dtr)
+{
+ asm ("sgdt %0":"=m" (*dtr));
+}
+
+static fastcall void native_store_idt(struct Xgt_desc_struct *dtr)
+{
+ asm ("sidt %0":"=m" (*dtr));
+}
+
+static fastcall unsigned long native_store_tr(void)
+{
+ unsigned long tr;
+ asm ("str %0":"=r" (tr));
+ return tr;
+}
+
+static fastcall void native_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 native_write_dt_entry(void *dt, int entry, u32 entry_low, u32 entry_high)
+{
+ u32 *lp = (u32 *)((char *)dt + entry*8);
+ lp[0] = entry_low;
+ lp[1] = entry_high;
+}
+
+static fastcall void native_write_ldt_entry(void *dt, int entrynum, u32 low, u32 high)
+{
+ native_write_dt_entry(dt, entrynum, low, high);
+}
+
+static fastcall void native_write_gdt_entry(void *dt, int entrynum, u32 low, u32 high)
+{
+ native_write_dt_entry(dt, entrynum, low, high);
+}
+
+static fastcall void native_write_idt_entry(void *dt, int entrynum, u32 low, u32 high)
+{
+ native_write_dt_entry(dt, entrynum, low, high);
+}
+
+static fastcall void native_load_esp0(struct tss_struct *tss,
+ struct thread_struct *thread)
+{
+ tss->esp0 = thread->esp0;
+
+ /* This can only happen when SEP is enabled, no need to test "SEP"arately */
+ if (unlikely(tss->ss1 != thread->sysenter_cs)) {
+ tss->ss1 = thread->sysenter_cs;
+ wrmsr(MSR_IA32_SYSENTER_CS, thread->sysenter_cs, 0);
+ }
+}
+
+static fastcall void native_io_delay(void)
+{
+ asm volatile("outb %al,$0x80");
+}
+
+/* These are in entry.S */
+extern fastcall void native_iret(void);
+extern fastcall void native_irq_enable_sysexit(void);
+
+static int __init print_banner(void)
+{
+ paravirt_ops.banner();
+ return 0;
+}
+core_initcall(print_banner);
+
+struct paravirt_ops paravirt_ops = {
+ .name = "bare hardware",
+ .paravirt_enabled = 0,
+ .kernel_rpl = 0,
+
+ .banner = default_banner,
+ .arch_setup = native_nop,
+ .memory_setup = machine_specific_memory_setup,
+ .get_wallclock = native_get_wallclock,
+ .set_wallclock = native_set_wallclock,
+ .time_init = time_init_hook,
+ .init_IRQ = native_init_IRQ,
+
+ .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,
+ .write_msr = native_write_msr,
+ .read_tsc = native_read_tsc,
+ .read_pmc = native_read_pmc,
+ .load_tr_desc = native_load_tr_desc,
+ .set_ldt = native_set_ldt,
+ .load_gdt = native_load_gdt,
+ .load_idt = native_load_idt,
+ .store_gdt = native_store_gdt,
+ .store_idt = native_store_idt,
+ .store_tr = native_store_tr,
+ .load_tls = native_load_tls,
+ .write_ldt_entry = native_write_ldt_entry,
+ .write_gdt_entry = native_write_gdt_entry,
+ .write_idt_entry = native_write_idt_entry,
+ .load_esp0 = native_load_esp0,
+
+ .set_iopl_mask = native_set_iopl_mask,
+ .io_delay = native_io_delay,
+ .const_udelay = __const_udelay,
+
+ .irq_enable_sysexit = native_irq_enable_sysexit,
+ .iret = native_iret,
+};
+EXPORT_SYMBOL(paravirt_ops);
diff --git a/arch/i386/kernel/setup.c b/arch/i386/kernel/setup.c
index e5bb87a..695d53f 100644
--- a/arch/i386/kernel/setup.c
+++ b/arch/i386/kernel/setup.c
@@ -495,6 +495,12 @@
static void set_mca_bus(int x) { }
#endif
+/* Overridden in paravirt.c if CONFIG_PARAVIRT */
+char * __attribute__((weak)) memory_setup(void)
+{
+ return machine_specific_memory_setup();
+}
+
/*
* Determine if we were loaded by an EFI loader. If so, then we have also been
* passed the efi memmap, systab, etc., so we should use these data structures
@@ -547,7 +553,7 @@
efi_init();
else {
printk(KERN_INFO "BIOS-provided physical RAM map:\n");
- print_memory_map(machine_specific_memory_setup());
+ print_memory_map(memory_setup());
}
copy_edd();
diff --git a/arch/i386/kernel/smpboot.c b/arch/i386/kernel/smpboot.c
index 0956366..cd7de9c 100644
--- a/arch/i386/kernel/smpboot.c
+++ b/arch/i386/kernel/smpboot.c
@@ -33,6 +33,11 @@
* Dave Jones : Report invalid combinations of Athlon CPUs.
* Rusty Russell : Hacked into shape for new "hotplug" boot process. */
+
+/* SMP boot always wants to use real time delay to allow sufficient time for
+ * the APs to come online */
+#define USE_REAL_TIME_DELAY
+
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
diff --git a/arch/i386/kernel/time.c b/arch/i386/kernel/time.c
index 78af572..c505b16 100644
--- a/arch/i386/kernel/time.c
+++ b/arch/i386/kernel/time.c
@@ -56,6 +56,7 @@
#include <asm/uaccess.h>
#include <asm/processor.h>
#include <asm/timer.h>
+#include <asm/time.h>
#include "mach_time.h"
@@ -116,10 +117,7 @@
/* gets recalled with irq locally disabled */
/* XXX - does irqsave resolve this? -johnstul */
spin_lock_irqsave(&rtc_lock, flags);
- if (efi_enabled)
- retval = efi_set_rtc_mmss(nowtime);
- else
- retval = mach_set_rtc_mmss(nowtime);
+ retval = set_wallclock(nowtime);
spin_unlock_irqrestore(&rtc_lock, flags);
return retval;
@@ -223,10 +221,7 @@
spin_lock_irqsave(&rtc_lock, flags);
- if (efi_enabled)
- retval = efi_get_time();
- else
- retval = mach_get_cmos_time();
+ retval = get_wallclock();
spin_unlock_irqrestore(&rtc_lock, flags);
@@ -370,7 +365,7 @@
printk("Using HPET for base-timer\n");
}
- time_init_hook();
+ do_time_init();
}
#endif
@@ -392,5 +387,5 @@
do_settimeofday(&ts);
- time_init_hook();
+ do_time_init();
}
diff --git a/arch/i386/power/cpu.c b/arch/i386/power/cpu.c
index 5a1abef..2c15500 100644
--- a/arch/i386/power/cpu.c
+++ b/arch/i386/power/cpu.c
@@ -26,8 +26,8 @@
/*
* descriptor tables
*/
- store_gdt(&ctxt->gdt_limit);
- store_idt(&ctxt->idt_limit);
+ store_gdt(&ctxt->gdt);
+ store_idt(&ctxt->idt);
store_tr(ctxt->tr);
/*
@@ -99,8 +99,8 @@
* now restore the descriptor tables to their proper values
* ltr is done i fix_processor_context().
*/
- load_gdt(&ctxt->gdt_limit);
- load_idt(&ctxt->idt_limit);
+ load_gdt(&ctxt->gdt);
+ load_idt(&ctxt->idt);
/*
* segment registers