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linux/arch/x86/xen/xen-ops.h
Jeremy Fitzhardinge 9f79991d41 xen: deal with stale cr3 values when unpinning pagetables
When a pagetable is no longer in use, it must be unpinned so that its
pages can be freed.  However, this is only possible if there are no
stray uses of the pagetable.  The code currently deals with all the
usual cases, but there's a rare case where a vcpu is changing cr3, but
is doing so lazily, and the change hasn't actually happened by the time
the pagetable is unpinned, even though it appears to have been completed.

This change adds a second per-cpu cr3 variable - xen_current_cr3 -
which tracks the actual state of the vcpu cr3.  It is only updated once
the actual hypercall to set cr3 has been completed.  Other processors
wishing to unpin a pagetable can check other vcpu's xen_current_cr3
values to see if any cross-cpu IPIs are needed to clean things up.

[ Stable folks: 2.6.23 bugfix ]

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Stable Kernel <stable@kernel.org>
2007-10-16 11:51:30 -07:00

68 lines
2.0 KiB
C

#ifndef XEN_OPS_H
#define XEN_OPS_H
#include <linux/init.h>
/* These are code, but not functions. Defined in entry.S */
extern const char xen_hypervisor_callback[];
extern const char xen_failsafe_callback[];
void xen_copy_trap_info(struct trap_info *traps);
DECLARE_PER_CPU(struct vcpu_info *, xen_vcpu);
DECLARE_PER_CPU(unsigned long, xen_cr3);
DECLARE_PER_CPU(unsigned long, xen_current_cr3);
extern struct start_info *xen_start_info;
extern struct shared_info *HYPERVISOR_shared_info;
char * __init xen_memory_setup(void);
void __init xen_arch_setup(void);
void __init xen_init_IRQ(void);
void xen_setup_timer(int cpu);
void xen_setup_cpu_clockevents(void);
unsigned long xen_cpu_khz(void);
void __init xen_time_init(void);
unsigned long xen_get_wallclock(void);
int xen_set_wallclock(unsigned long time);
unsigned long long xen_sched_clock(void);
bool xen_vcpu_stolen(int vcpu);
void xen_mark_init_mm_pinned(void);
void __init xen_fill_possible_map(void);
void __init xen_setup_vcpu_info_placement(void);
void xen_smp_prepare_boot_cpu(void);
void xen_smp_prepare_cpus(unsigned int max_cpus);
int xen_cpu_up(unsigned int cpu);
void xen_smp_cpus_done(unsigned int max_cpus);
void xen_smp_send_stop(void);
void xen_smp_send_reschedule(int cpu);
int xen_smp_call_function (void (*func) (void *info), void *info, int nonatomic,
int wait);
int xen_smp_call_function_single(int cpu, void (*func) (void *info), void *info,
int nonatomic, int wait);
int xen_smp_call_function_mask(cpumask_t mask, void (*func)(void *),
void *info, int wait);
/* Declare an asm function, along with symbols needed to make it
inlineable */
#define DECL_ASM(ret, name, ...) \
ret name(__VA_ARGS__); \
extern char name##_end[]; \
extern char name##_reloc[] \
DECL_ASM(void, xen_irq_enable_direct, void);
DECL_ASM(void, xen_irq_disable_direct, void);
DECL_ASM(unsigned long, xen_save_fl_direct, void);
DECL_ASM(void, xen_restore_fl_direct, unsigned long);
void xen_iret_direct(void);
#endif /* XEN_OPS_H */