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 "xen-ops.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 */
18 static 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 }
31 static struct vmcore_cb xen_vmcore_cb = {
32 .pfn_is_ram = xen_vmcore_pfn_is_ram,
33 };
34 #endif
35
36 static 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
47 static 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
62 void __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 }
70
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