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1// SPDX-License-Identifier: GPL-2.0-only
2#include "kvm_util.h"
3#include "linux/types.h"
4#include "linux/bitmap.h"
5#include "linux/atomic.h"
6
7#define GUEST_UCALL_FAILED -1
8
9struct ucall_header {
10 DECLARE_BITMAP(in_use, KVM_MAX_VCPUS);
11 struct ucall ucalls[KVM_MAX_VCPUS];
12};
13
14/*
15 * ucall_pool holds per-VM values (global data is duplicated by each VM), it
16 * must not be accessed from host code.
17 */
18static struct ucall_header *ucall_pool;
19
20void ucall_init(struct kvm_vm *vm, vm_paddr_t mmio_gpa)
21{
22 struct ucall_header *hdr;
23 struct ucall *uc;
24 vm_vaddr_t vaddr;
25 int i;
26
27 vaddr = __vm_vaddr_alloc(vm, sizeof(*hdr), KVM_UTIL_MIN_VADDR, MEM_REGION_DATA);
28 hdr = (struct ucall_header *)addr_gva2hva(vm, vaddr);
29 memset(hdr, 0, sizeof(*hdr));
30
31 for (i = 0; i < KVM_MAX_VCPUS; ++i) {
32 uc = &hdr->ucalls[i];
33 uc->hva = uc;
34 }
35
36 write_guest_global(vm, ucall_pool, (struct ucall_header *)vaddr);
37
38 ucall_arch_init(vm, mmio_gpa);
39}
40
41static struct ucall *ucall_alloc(void)
42{
43 struct ucall *uc;
44 int i;
45
46 if (!ucall_pool)
47 goto ucall_failed;
48
49 for (i = 0; i < KVM_MAX_VCPUS; ++i) {
50 if (!test_and_set_bit(i, ucall_pool->in_use)) {
51 uc = &ucall_pool->ucalls[i];
52 memset(uc->args, 0, sizeof(uc->args));
53 return uc;
54 }
55 }
56
57ucall_failed:
58 /*
59 * If the vCPU cannot grab a ucall structure, make a bare ucall with a
60 * magic value to signal to get_ucall() that things went sideways.
61 * GUEST_ASSERT() depends on ucall_alloc() and so cannot be used here.
62 */
63 ucall_arch_do_ucall(GUEST_UCALL_FAILED);
64 return NULL;
65}
66
67static void ucall_free(struct ucall *uc)
68{
69 /* Beware, here be pointer arithmetic. */
70 clear_bit(uc - ucall_pool->ucalls, ucall_pool->in_use);
71}
72
73void ucall(uint64_t cmd, int nargs, ...)
74{
75 struct ucall *uc;
76 va_list va;
77 int i;
78
79 uc = ucall_alloc();
80
81 WRITE_ONCE(uc->cmd, cmd);
82
83 nargs = min(nargs, UCALL_MAX_ARGS);
84
85 va_start(va, nargs);
86 for (i = 0; i < nargs; ++i)
87 WRITE_ONCE(uc->args[i], va_arg(va, uint64_t));
88 va_end(va);
89
90 ucall_arch_do_ucall((vm_vaddr_t)uc->hva);
91
92 ucall_free(uc);
93}
94
95uint64_t get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc)
96{
97 struct ucall ucall;
98 void *addr;
99
100 if (!uc)
101 uc = &ucall;
102
103 addr = ucall_arch_get_ucall(vcpu);
104 if (addr) {
105 TEST_ASSERT(addr != (void *)GUEST_UCALL_FAILED,
106 "Guest failed to allocate ucall struct");
107
108 memcpy(uc, addr, sizeof(*uc));
109 vcpu_run_complete_io(vcpu);
110 } else {
111 memset(uc, 0, sizeof(*uc));
112 }
113
114 return uc->cmd;
115}
1// SPDX-License-Identifier: GPL-2.0-only
2#include "kvm_util.h"
3#include "linux/types.h"
4#include "linux/bitmap.h"
5#include "linux/atomic.h"
6
7#define GUEST_UCALL_FAILED -1
8
9struct ucall_header {
10 DECLARE_BITMAP(in_use, KVM_MAX_VCPUS);
11 struct ucall ucalls[KVM_MAX_VCPUS];
12};
13
14int ucall_nr_pages_required(uint64_t page_size)
15{
16 return align_up(sizeof(struct ucall_header), page_size) / page_size;
17}
18
19/*
20 * ucall_pool holds per-VM values (global data is duplicated by each VM), it
21 * must not be accessed from host code.
22 */
23static struct ucall_header *ucall_pool;
24
25void ucall_init(struct kvm_vm *vm, vm_paddr_t mmio_gpa)
26{
27 struct ucall_header *hdr;
28 struct ucall *uc;
29 vm_vaddr_t vaddr;
30 int i;
31
32 vaddr = __vm_vaddr_alloc(vm, sizeof(*hdr), KVM_UTIL_MIN_VADDR, MEM_REGION_DATA);
33 hdr = (struct ucall_header *)addr_gva2hva(vm, vaddr);
34 memset(hdr, 0, sizeof(*hdr));
35
36 for (i = 0; i < KVM_MAX_VCPUS; ++i) {
37 uc = &hdr->ucalls[i];
38 uc->hva = uc;
39 }
40
41 write_guest_global(vm, ucall_pool, (struct ucall_header *)vaddr);
42
43 ucall_arch_init(vm, mmio_gpa);
44}
45
46static struct ucall *ucall_alloc(void)
47{
48 struct ucall *uc;
49 int i;
50
51 if (!ucall_pool)
52 goto ucall_failed;
53
54 for (i = 0; i < KVM_MAX_VCPUS; ++i) {
55 if (!test_and_set_bit(i, ucall_pool->in_use)) {
56 uc = &ucall_pool->ucalls[i];
57 memset(uc->args, 0, sizeof(uc->args));
58 return uc;
59 }
60 }
61
62ucall_failed:
63 /*
64 * If the vCPU cannot grab a ucall structure, make a bare ucall with a
65 * magic value to signal to get_ucall() that things went sideways.
66 * GUEST_ASSERT() depends on ucall_alloc() and so cannot be used here.
67 */
68 ucall_arch_do_ucall(GUEST_UCALL_FAILED);
69 return NULL;
70}
71
72static void ucall_free(struct ucall *uc)
73{
74 /* Beware, here be pointer arithmetic. */
75 clear_bit(uc - ucall_pool->ucalls, ucall_pool->in_use);
76}
77
78void ucall_assert(uint64_t cmd, const char *exp, const char *file,
79 unsigned int line, const char *fmt, ...)
80{
81 struct ucall *uc;
82 va_list va;
83
84 uc = ucall_alloc();
85 uc->cmd = cmd;
86
87 WRITE_ONCE(uc->args[GUEST_ERROR_STRING], (uint64_t)(exp));
88 WRITE_ONCE(uc->args[GUEST_FILE], (uint64_t)(file));
89 WRITE_ONCE(uc->args[GUEST_LINE], line);
90
91 va_start(va, fmt);
92 guest_vsnprintf(uc->buffer, UCALL_BUFFER_LEN, fmt, va);
93 va_end(va);
94
95 ucall_arch_do_ucall((vm_vaddr_t)uc->hva);
96
97 ucall_free(uc);
98}
99
100void ucall_fmt(uint64_t cmd, const char *fmt, ...)
101{
102 struct ucall *uc;
103 va_list va;
104
105 uc = ucall_alloc();
106 uc->cmd = cmd;
107
108 va_start(va, fmt);
109 guest_vsnprintf(uc->buffer, UCALL_BUFFER_LEN, fmt, va);
110 va_end(va);
111
112 ucall_arch_do_ucall((vm_vaddr_t)uc->hva);
113
114 ucall_free(uc);
115}
116
117void ucall(uint64_t cmd, int nargs, ...)
118{
119 struct ucall *uc;
120 va_list va;
121 int i;
122
123 uc = ucall_alloc();
124
125 WRITE_ONCE(uc->cmd, cmd);
126
127 nargs = min(nargs, UCALL_MAX_ARGS);
128
129 va_start(va, nargs);
130 for (i = 0; i < nargs; ++i)
131 WRITE_ONCE(uc->args[i], va_arg(va, uint64_t));
132 va_end(va);
133
134 ucall_arch_do_ucall((vm_vaddr_t)uc->hva);
135
136 ucall_free(uc);
137}
138
139uint64_t get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc)
140{
141 struct ucall ucall;
142 void *addr;
143
144 if (!uc)
145 uc = &ucall;
146
147 addr = ucall_arch_get_ucall(vcpu);
148 if (addr) {
149 TEST_ASSERT(addr != (void *)GUEST_UCALL_FAILED,
150 "Guest failed to allocate ucall struct");
151
152 memcpy(uc, addr, sizeof(*uc));
153 vcpu_run_complete_io(vcpu);
154 } else {
155 memset(uc, 0, sizeof(*uc));
156 }
157
158 return uc->cmd;
159}