linux-kernel-test/arch/x86/xen/xen-ops.h
Olaf Hering 9d02b43dee xen PVonHVM: use E820_Reserved area for shared_info
This is a respin of 00e37bdb01
("xen PVonHVM: move shared_info to MMIO before kexec").

Currently kexec in a PVonHVM guest fails with a triple fault because the
new kernel overwrites the shared info page. The exact failure depends on
the size of the kernel image. This patch moves the pfn from RAM into an
E820 reserved memory area.

The pfn containing the shared_info is located somewhere in RAM. This will
cause trouble if the current kernel is doing a kexec boot into a new
kernel. The new kernel (and its startup code) can not know where the pfn
is, so it can not reserve the page. The hypervisor will continue to update
the pfn, and as a result memory corruption occours in the new kernel.

The toolstack marks the memory area FC000000-FFFFFFFF as reserved in the
E820 map. Within that range newer toolstacks (4.3+) will keep 1MB
starting from FE700000 as reserved for guest use. Older Xen4 toolstacks
will usually not allocate areas up to FE700000, so FE700000 is expected
to work also with older toolstacks.

In Xen3 there is no reserved area at a fixed location. If the guest is
started on such old hosts the shared_info page will be placed in RAM. As
a result kexec can not be used.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-11-02 11:04:01 -04:00

127 lines
3.2 KiB
C

#ifndef XEN_OPS_H
#define XEN_OPS_H
#include <linux/init.h>
#include <linux/clocksource.h>
#include <linux/irqreturn.h>
#include <xen/xen-ops.h>
/* These are code, but not functions. Defined in entry.S */
extern const char xen_hypervisor_callback[];
extern const char xen_failsafe_callback[];
extern void *xen_initial_gdt;
struct trap_info;
void xen_copy_trap_info(struct trap_info *traps);
DECLARE_PER_CPU(struct vcpu_info, xen_vcpu_info);
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 xen_dummy_shared_info;
extern struct shared_info *HYPERVISOR_shared_info;
void xen_setup_mfn_list_list(void);
void xen_setup_shared_info(void);
void xen_build_mfn_list_list(void);
void xen_setup_machphys_mapping(void);
void xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn);
void xen_reserve_top(void);
extern unsigned long xen_max_p2m_pfn;
void xen_set_pat(u64);
char * __init xen_memory_setup(void);
void __init xen_arch_setup(void);
void xen_enable_sysenter(void);
void xen_enable_syscall(void);
void xen_vcpu_restore(void);
void xen_callback_vector(void);
void xen_hvm_resume_shared_info(void);
void xen_unplug_emulated_devices(void);
void __init xen_build_dynamic_phys_to_machine(void);
unsigned long __init xen_revector_p2m_tree(void);
void xen_init_irq_ops(void);
void xen_setup_timer(int cpu);
void xen_setup_runstate_info(int cpu);
void xen_teardown_timer(int cpu);
cycle_t xen_clocksource_read(void);
void xen_setup_cpu_clockevents(void);
void __init xen_init_time_ops(void);
void __init xen_hvm_init_time_ops(void);
irqreturn_t xen_debug_interrupt(int irq, void *dev_id);
bool xen_vcpu_stolen(int vcpu);
void xen_setup_vcpu_info_placement(void);
#ifdef CONFIG_SMP
void xen_smp_init(void);
void __init xen_hvm_smp_init(void);
extern cpumask_var_t xen_cpu_initialized_map;
#else
static inline void xen_smp_init(void) {}
static inline void xen_hvm_smp_init(void) {}
#endif
#ifdef CONFIG_PARAVIRT_SPINLOCKS
void __init xen_init_spinlocks(void);
void __cpuinit xen_init_lock_cpu(int cpu);
void xen_uninit_lock_cpu(int cpu);
#else
static inline void xen_init_spinlocks(void)
{
}
static inline void xen_init_lock_cpu(int cpu)
{
}
static inline void xen_uninit_lock_cpu(int cpu)
{
}
#endif
struct dom0_vga_console_info;
#ifdef CONFIG_XEN_DOM0
void __init xen_init_vga(const struct dom0_vga_console_info *, size_t size);
void __init xen_init_apic(void);
#else
static inline void __init xen_init_vga(const struct dom0_vga_console_info *info,
size_t size)
{
}
static inline void __init xen_init_apic(void)
{
}
#endif
/* 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);
/* These are not functions, and cannot be called normally */
void xen_iret(void);
void xen_sysexit(void);
void xen_sysret32(void);
void xen_sysret64(void);
void xen_adjust_exception_frame(void);
extern int xen_panic_handler_init(void);
#endif /* XEN_OPS_H */