1// SPDX-License-Identifier: GPL-2.0
 2#include <linux/types.h>
 3#include <linux/crash_dump.h>
 4
 5#include <xen/interface/xen.h>
 6#include <xen/hvm.h>
 7
 8#include "mmu.h"
 9
10#ifdef CONFIG_PROC_VMCORE
11/*
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 * Returns "false" if the pfn is not backed by a RAM page, the caller may
 
 
 
16 * handle the pfn special in this case.
17 */
18static bool xen_vmcore_pfn_is_ram(struct vmcore_cb *cb, unsigned long pfn)
19{
20	struct xen_hvm_get_mem_type a = {
21		.domid = DOMID_SELF,
22		.pfn = pfn,
23	};
 
24
25	if (HYPERVISOR_hvm_op(HVMOP_get_mem_type, &a)) {
26		pr_warn_once("Unexpected HVMOP_get_mem_type failure\n");
27		return true;
 
 
 
 
 
 
 
 
 
28	}
29	return a.mem_type != HVMMEM_mmio_dm;
 
30}
31static struct vmcore_cb xen_vmcore_cb = {
32	.pfn_is_ram = xen_vmcore_pfn_is_ram,
33};
34#endif
35
36static void xen_hvm_exit_mmap(struct mm_struct *mm)
37{
38	struct xen_hvm_pagetable_dying a;
39	int rc;
40
41	a.domid = DOMID_SELF;
42	a.gpa = __pa(mm->pgd);
43	rc = HYPERVISOR_hvm_op(HVMOP_pagetable_dying, &a);
44	WARN_ON_ONCE(rc < 0);
45}
46
47static int is_pagetable_dying_supported(void)
48{
49	struct xen_hvm_pagetable_dying a;
50	int rc = 0;
51
52	a.domid = DOMID_SELF;
53	a.gpa = 0x00;
54	rc = HYPERVISOR_hvm_op(HVMOP_pagetable_dying, &a);
55	if (rc < 0) {
56		printk(KERN_DEBUG "HVMOP_pagetable_dying not supported\n");
57		return 0;
58	}
59	return 1;
60}
61
62void __init xen_hvm_init_mmu_ops(void)
63{
64	if (is_pagetable_dying_supported())
65		pv_ops.mmu.exit_mmap = xen_hvm_exit_mmap;
66#ifdef CONFIG_PROC_VMCORE
67	register_vmcore_cb(&xen_vmcore_cb);
68#endif
69}

 1// SPDX-License-Identifier: GPL-2.0
 2#include <linux/types.h>
 3#include <linux/crash_dump.h>
 4
 5#include <xen/interface/xen.h>
 6#include <xen/hvm.h>
 7
 8#include "mmu.h"
 9
10#ifdef CONFIG_PROC_VMCORE
11/*
12 * This function is used in two contexts:
13 * - the kdump kernel has to check whether a pfn of the crashed kernel
14 *   was a ballooned page. vmcore is using this function to decide
15 *   whether to access a pfn of the crashed kernel.
16 * - the kexec kernel has to check whether a pfn was ballooned by the
17 *   previous kernel. If the pfn is ballooned, handle it properly.
18 * Returns 0 if the pfn is not backed by a RAM page, the caller may
19 * handle the pfn special in this case.
20 */
21static int xen_oldmem_pfn_is_ram(unsigned long pfn)
22{
23	struct xen_hvm_get_mem_type a = {
24		.domid = DOMID_SELF,
25		.pfn = pfn,
26	};
27	int ram;
28
29	if (HYPERVISOR_hvm_op(HVMOP_get_mem_type, &a))
30		return -ENXIO;
31
32	switch (a.mem_type) {
33	case HVMMEM_mmio_dm:
34		ram = 0;
35		break;
36	case HVMMEM_ram_rw:
37	case HVMMEM_ram_ro:
38	default:
39		ram = 1;
40		break;
41	}
42
43	return ram;
44}
 
 
 
45#endif
46
47static void xen_hvm_exit_mmap(struct mm_struct *mm)
48{
49	struct xen_hvm_pagetable_dying a;
50	int rc;
51
52	a.domid = DOMID_SELF;
53	a.gpa = __pa(mm->pgd);
54	rc = HYPERVISOR_hvm_op(HVMOP_pagetable_dying, &a);
55	WARN_ON_ONCE(rc < 0);
56}
57
58static int is_pagetable_dying_supported(void)
59{
60	struct xen_hvm_pagetable_dying a;
61	int rc = 0;
62
63	a.domid = DOMID_SELF;
64	a.gpa = 0x00;
65	rc = HYPERVISOR_hvm_op(HVMOP_pagetable_dying, &a);
66	if (rc < 0) {
67		printk(KERN_DEBUG "HVMOP_pagetable_dying not supported\n");
68		return 0;
69	}
70	return 1;
71}
72
73void __init xen_hvm_init_mmu_ops(void)
74{
75	if (is_pagetable_dying_supported())
76		pv_ops.mmu.exit_mmap = xen_hvm_exit_mmap;
77#ifdef CONFIG_PROC_VMCORE
78	WARN_ON(register_oldmem_pfn_is_ram(&xen_oldmem_pfn_is_ram));
79#endif
80}