1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
|
/* SPDX-License-Identifier: GPL-2.0-only */
/*
* pv/mm.c
*
* Memory managment code for PV guests
*
* Copyright (c) 2002-2005 K A Fraser
* Copyright (c) 2004 Christian Limpach
*/
#include <xen/guest_access.h>
#include <asm/current.h>
#include <asm/p2m.h>
#include "mm.h"
/*
* Get a mapping of a PV guest's l1e for this linear address. The return
* pointer should be unmapped using unmap_domain_page().
*/
l1_pgentry_t *map_guest_l1e(unsigned long linear, mfn_t *gl1mfn)
{
l2_pgentry_t l2e;
ASSERT(!paging_mode_translate(current->domain));
ASSERT(!paging_mode_external(current->domain));
if ( unlikely(!__addr_ok(linear)) )
return NULL;
/* Find this l1e and its enclosing l1mfn in the linear map. */
if ( get_unsafe(l2e, &__linear_l2_table[l2_linear_offset(linear)]) )
return NULL;
/* Check flags that it will be safe to read the l1e. */
if ( (l2e_get_flags(l2e) & (_PAGE_PRESENT | _PAGE_PSE)) != _PAGE_PRESENT )
return NULL;
*gl1mfn = l2e_get_mfn(l2e);
return (l1_pgentry_t *)map_domain_page(*gl1mfn) + l1_table_offset(linear);
}
/*
* Map a guest's LDT page (covering the byte at @offset from start of the LDT)
* into Xen's virtual range. Returns true if the mapping changed, false
* otherwise.
*/
bool pv_map_ldt_shadow_page(unsigned int offset)
{
struct vcpu *curr = current;
struct domain *currd = curr->domain;
struct page_info *page;
l1_pgentry_t gl1e, *pl1e;
unsigned long linear = curr->arch.pv.ldt_base + offset;
BUG_ON(unlikely(in_irq()));
/*
* Prior limit checking should guarantee this property. NB. This is
* safe as updates to the LDT can only be made by MMUEXT_SET_LDT to the
* current vcpu, and vcpu_reset() will block until this vcpu has been
* descheduled before continuing.
*/
if ( unlikely((offset >> 3) >= curr->arch.pv.ldt_ents) )
{
ASSERT_UNREACHABLE();
return false;
}
if ( is_pv_32bit_domain(currd) )
linear = (uint32_t)linear;
gl1e = guest_get_eff_kern_l1e(linear);
if ( unlikely(!(l1e_get_flags(gl1e) & _PAGE_PRESENT)) )
return false;
page = get_page_from_gfn(currd, l1e_get_pfn(gl1e), NULL, P2M_ALLOC);
if ( unlikely(!page) )
return false;
if ( unlikely(!get_page_type(page, PGT_seg_desc_page)) )
{
put_page(page);
return false;
}
pl1e = &pv_ldt_ptes(curr)[offset >> PAGE_SHIFT];
l1e_add_flags(gl1e, _PAGE_RW);
l1e_write(pl1e, gl1e);
return true;
}
#ifdef CONFIG_PV32
void init_xen_pae_l2_slots(l2_pgentry_t *l2t, const struct domain *d)
{
memcpy(&l2t[COMPAT_L2_PAGETABLE_FIRST_XEN_SLOT(d)],
compat_idle_pg_table_l2,
COMPAT_L2_PAGETABLE_XEN_SLOTS(d) * sizeof(*l2t));
}
#endif
/*
* Local variables:
* mode: C
* c-file-style: "BSD"
* c-basic-offset: 4
* tab-width: 4
* indent-tabs-mode: nil
* End:
*/
|
