[linux-2.6-block.git] / arch / x86 / xen / mmu_hvm.c

#include <linux/types.h>
#include <linux/crash_dump.h>

#include <xen/interface/xen.h>
#include <xen/hvm.h>

#include "mmu.h"

#ifdef CONFIG_PROC_VMCORE
/*
 * This function is used in two contexts:
 * - the kdump kernel has to check whether a pfn of the crashed kernel
 *   was a ballooned page. vmcore is using this function to decide
 *   whether to access a pfn of the crashed kernel.
 * - the kexec kernel has to check whether a pfn was ballooned by the
 *   previous kernel. If the pfn is ballooned, handle it properly.
 * Returns 0 if the pfn is not backed by a RAM page, the caller may
 * handle the pfn special in this case.
 */
static int xen_oldmem_pfn_is_ram(unsigned long pfn)
{
	struct xen_hvm_get_mem_type a = {
		.domid = DOMID_SELF,
		.pfn = pfn,
	};
	int ram;

	if (HYPERVISOR_hvm_op(HVMOP_get_mem_type, &a))
		return -ENXIO;

	switch (a.mem_type) {
	case HVMMEM_mmio_dm:
		ram = 0;
		break;
	case HVMMEM_ram_rw:
	case HVMMEM_ram_ro:
	default:
		ram = 1;
		break;
	}

	return ram;
}
#endif

static void xen_hvm_exit_mmap(struct mm_struct *mm)
{
	struct xen_hvm_pagetable_dying a;
	int rc;

	a.domid = DOMID_SELF;
	a.gpa = __pa(mm->pgd);
	rc = HYPERVISOR_hvm_op(HVMOP_pagetable_dying, &a);
	WARN_ON_ONCE(rc < 0);
}

static int is_pagetable_dying_supported(void)
{
	struct xen_hvm_pagetable_dying a;
	int rc = 0;

	a.domid = DOMID_SELF;
	a.gpa = 0x00;
	rc = HYPERVISOR_hvm_op(HVMOP_pagetable_dying, &a);
	if (rc < 0) {
		printk(KERN_DEBUG "HVMOP_pagetable_dying not supported\n");
		return 0;
	}
	return 1;
}

void __init xen_hvm_init_mmu_ops(void)
{
	if (is_pagetable_dying_supported())
		pv_mmu_ops.exit_mmap = xen_hvm_exit_mmap;
#ifdef CONFIG_PROC_VMCORE
	register_oldmem_pfn_is_ram(&xen_oldmem_pfn_is_ram);
#endif
}
Commit	Line	Data
feef87eb VK	1	#include <linux/types.h>
	2	#include <linux/crash_dump.h>
	3
	4	#include <xen/interface/xen.h>
	5	#include <xen/hvm.h>
	6
	7	#include "mmu.h"
	8
	9	#ifdef CONFIG_PROC_VMCORE
	10	/*
	11	* This function is used in two contexts:
	12	* - the kdump kernel has to check whether a pfn of the crashed kernel
	13	* was a ballooned page. vmcore is using this function to decide
	14	* whether to access a pfn of the crashed kernel.
	15	* - the kexec kernel has to check whether a pfn was ballooned by the
	16	* previous kernel. If the pfn is ballooned, handle it properly.
	17	* Returns 0 if the pfn is not backed by a RAM page, the caller may
	18	* handle the pfn special in this case.
	19	*/
	20	static int xen_oldmem_pfn_is_ram(unsigned long pfn)
	21	{
	22	struct xen_hvm_get_mem_type a = {
	23	.domid = DOMID_SELF,
	24	.pfn = pfn,
	25	};
	26	int ram;
	27
	28	if (HYPERVISOR_hvm_op(HVMOP_get_mem_type, &a))
	29	return -ENXIO;
	30
	31	switch (a.mem_type) {
	32	case HVMMEM_mmio_dm:
	33	ram = 0;
	34	break;
	35	case HVMMEM_ram_rw:
	36	case HVMMEM_ram_ro:
	37	default:
	38	ram = 1;
	39	break;
	40	}
	41
	42	return ram;
	43	}
	44	#endif
	45
	46	static void xen_hvm_exit_mmap(struct mm_struct *mm)
	47	{
	48	struct xen_hvm_pagetable_dying a;
	49	int rc;
	50
	51	a.domid = DOMID_SELF;
	52	a.gpa = __pa(mm->pgd);
	53	rc = HYPERVISOR_hvm_op(HVMOP_pagetable_dying, &a);
	54	WARN_ON_ONCE(rc < 0);
	55	}
	56
	57	static int is_pagetable_dying_supported(void)
	58	{
	59	struct xen_hvm_pagetable_dying a;
	60	int rc = 0;
	61
	62	a.domid = DOMID_SELF;
	63	a.gpa = 0x00;
	64	rc = HYPERVISOR_hvm_op(HVMOP_pagetable_dying, &a);
65	if (rc < 0) {
66	printk(KERN_DEBUG "HVMOP_pagetable_dying not supported\n");
67	return 0;
68	}
69	return 1;
70	}
71
72	void __init xen_hvm_init_mmu_ops(void)
73	{
74	if (is_pagetable_dying_supported())
75	pv_mmu_ops.exit_mmap = xen_hvm_exit_mmap;
76	#ifdef CONFIG_PROC_VMCORE
77	register_oldmem_pfn_is_ram(&xen_oldmem_pfn_is_ram);
78	#endif
79	}