GNU Linux-libre 5.19-rc6-gnu
[releases.git] / drivers / iommu / hyperv-iommu.c
1 // SPDX-License-Identifier: GPL-2.0
2
3 /*
4  * Hyper-V stub IOMMU driver.
5  *
6  * Copyright (C) 2019, Microsoft, Inc.
7  *
8  * Author : Lan Tianyu <Tianyu.Lan@microsoft.com>
9  */
10
11 #include <linux/types.h>
12 #include <linux/interrupt.h>
13 #include <linux/irq.h>
14 #include <linux/iommu.h>
15 #include <linux/module.h>
16
17 #include <asm/apic.h>
18 #include <asm/cpu.h>
19 #include <asm/hw_irq.h>
20 #include <asm/io_apic.h>
21 #include <asm/irq_remapping.h>
22 #include <asm/hypervisor.h>
23 #include <asm/mshyperv.h>
24
25 #include "irq_remapping.h"
26
27 #ifdef CONFIG_IRQ_REMAP
28
29 /*
30  * According 82093AA IO-APIC spec , IO APIC has a 24-entry Interrupt
31  * Redirection Table. Hyper-V exposes one single IO-APIC and so define
32  * 24 IO APIC remmapping entries.
33  */
34 #define IOAPIC_REMAPPING_ENTRY 24
35
36 static cpumask_t ioapic_max_cpumask = { CPU_BITS_NONE };
37 static struct irq_domain *ioapic_ir_domain;
38
39 static int hyperv_ir_set_affinity(struct irq_data *data,
40                 const struct cpumask *mask, bool force)
41 {
42         struct irq_data *parent = data->parent_data;
43         struct irq_cfg *cfg = irqd_cfg(data);
44         int ret;
45
46         /* Return error If new irq affinity is out of ioapic_max_cpumask. */
47         if (!cpumask_subset(mask, &ioapic_max_cpumask))
48                 return -EINVAL;
49
50         ret = parent->chip->irq_set_affinity(parent, mask, force);
51         if (ret < 0 || ret == IRQ_SET_MASK_OK_DONE)
52                 return ret;
53
54         send_cleanup_vector(cfg);
55
56         return 0;
57 }
58
59 static struct irq_chip hyperv_ir_chip = {
60         .name                   = "HYPERV-IR",
61         .irq_ack                = apic_ack_irq,
62         .irq_set_affinity       = hyperv_ir_set_affinity,
63 };
64
65 static int hyperv_irq_remapping_alloc(struct irq_domain *domain,
66                                      unsigned int virq, unsigned int nr_irqs,
67                                      void *arg)
68 {
69         struct irq_alloc_info *info = arg;
70         struct irq_data *irq_data;
71         struct irq_desc *desc;
72         int ret = 0;
73
74         if (!info || info->type != X86_IRQ_ALLOC_TYPE_IOAPIC || nr_irqs > 1)
75                 return -EINVAL;
76
77         ret = irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, arg);
78         if (ret < 0)
79                 return ret;
80
81         irq_data = irq_domain_get_irq_data(domain, virq);
82         if (!irq_data) {
83                 irq_domain_free_irqs_common(domain, virq, nr_irqs);
84                 return -EINVAL;
85         }
86
87         irq_data->chip = &hyperv_ir_chip;
88
89         /*
90          * Hypver-V IO APIC irq affinity should be in the scope of
91          * ioapic_max_cpumask because no irq remapping support.
92          */
93         desc = irq_data_to_desc(irq_data);
94         cpumask_copy(desc->irq_common_data.affinity, &ioapic_max_cpumask);
95
96         return 0;
97 }
98
99 static void hyperv_irq_remapping_free(struct irq_domain *domain,
100                                  unsigned int virq, unsigned int nr_irqs)
101 {
102         irq_domain_free_irqs_common(domain, virq, nr_irqs);
103 }
104
105 static int hyperv_irq_remapping_select(struct irq_domain *d,
106                                        struct irq_fwspec *fwspec,
107                                        enum irq_domain_bus_token bus_token)
108 {
109         /* Claim the only I/O APIC emulated by Hyper-V */
110         return x86_fwspec_is_ioapic(fwspec);
111 }
112
113 static const struct irq_domain_ops hyperv_ir_domain_ops = {
114         .select = hyperv_irq_remapping_select,
115         .alloc = hyperv_irq_remapping_alloc,
116         .free = hyperv_irq_remapping_free,
117 };
118
119 static const struct irq_domain_ops hyperv_root_ir_domain_ops;
120 static int __init hyperv_prepare_irq_remapping(void)
121 {
122         struct fwnode_handle *fn;
123         int i;
124         const char *name;
125         const struct irq_domain_ops *ops;
126
127         if (!hypervisor_is_type(X86_HYPER_MS_HYPERV) ||
128             x86_init.hyper.msi_ext_dest_id() ||
129             !x2apic_supported())
130                 return -ENODEV;
131
132         if (hv_root_partition) {
133                 name = "HYPERV-ROOT-IR";
134                 ops = &hyperv_root_ir_domain_ops;
135         } else {
136                 name = "HYPERV-IR";
137                 ops = &hyperv_ir_domain_ops;
138         }
139
140         fn = irq_domain_alloc_named_id_fwnode(name, 0);
141         if (!fn)
142                 return -ENOMEM;
143
144         ioapic_ir_domain =
145                 irq_domain_create_hierarchy(arch_get_ir_parent_domain(),
146                                 0, IOAPIC_REMAPPING_ENTRY, fn, ops, NULL);
147
148         if (!ioapic_ir_domain) {
149                 irq_domain_free_fwnode(fn);
150                 return -ENOMEM;
151         }
152
153         if (hv_root_partition)
154                 return 0; /* The rest is only relevant to guests */
155
156         /*
157          * Hyper-V doesn't provide irq remapping function for
158          * IO-APIC and so IO-APIC only accepts 8-bit APIC ID.
159          * Cpu's APIC ID is read from ACPI MADT table and APIC IDs
160          * in the MADT table on Hyper-v are sorted monotonic increasingly.
161          * APIC ID reflects cpu topology. There maybe some APIC ID
162          * gaps when cpu number in a socket is not power of two. Prepare
163          * max cpu affinity for IOAPIC irqs. Scan cpu 0-255 and set cpu
164          * into ioapic_max_cpumask if its APIC ID is less than 256.
165          */
166         for (i = min_t(unsigned int, num_possible_cpus() - 1, 255); i >= 0; i--)
167                 if (cpu_physical_id(i) < 256)
168                         cpumask_set_cpu(i, &ioapic_max_cpumask);
169
170         return 0;
171 }
172
173 static int __init hyperv_enable_irq_remapping(void)
174 {
175         return IRQ_REMAP_X2APIC_MODE;
176 }
177
178 struct irq_remap_ops hyperv_irq_remap_ops = {
179         .prepare                = hyperv_prepare_irq_remapping,
180         .enable                 = hyperv_enable_irq_remapping,
181 };
182
183 /* IRQ remapping domain when Linux runs as the root partition */
184 struct hyperv_root_ir_data {
185         u8 ioapic_id;
186         bool is_level;
187         struct hv_interrupt_entry entry;
188 };
189
190 static void
191 hyperv_root_ir_compose_msi_msg(struct irq_data *irq_data, struct msi_msg *msg)
192 {
193         u64 status;
194         u32 vector;
195         struct irq_cfg *cfg;
196         int ioapic_id;
197         struct cpumask *affinity;
198         int cpu;
199         struct hv_interrupt_entry entry;
200         struct hyperv_root_ir_data *data = irq_data->chip_data;
201         struct IO_APIC_route_entry e;
202
203         cfg = irqd_cfg(irq_data);
204         affinity = irq_data_get_effective_affinity_mask(irq_data);
205         cpu = cpumask_first_and(affinity, cpu_online_mask);
206
207         vector = cfg->vector;
208         ioapic_id = data->ioapic_id;
209
210         if (data->entry.source == HV_DEVICE_TYPE_IOAPIC
211             && data->entry.ioapic_rte.as_uint64) {
212                 entry = data->entry;
213
214                 status = hv_unmap_ioapic_interrupt(ioapic_id, &entry);
215
216                 if (status != HV_STATUS_SUCCESS)
217                         pr_debug("%s: unexpected unmap status %lld\n", __func__, status);
218
219                 data->entry.ioapic_rte.as_uint64 = 0;
220                 data->entry.source = 0; /* Invalid source */
221         }
222
223
224         status = hv_map_ioapic_interrupt(ioapic_id, data->is_level, cpu,
225                                         vector, &entry);
226
227         if (status != HV_STATUS_SUCCESS) {
228                 pr_err("%s: map hypercall failed, status %lld\n", __func__, status);
229                 return;
230         }
231
232         data->entry = entry;
233
234         /* Turn it into an IO_APIC_route_entry, and generate MSI MSG. */
235         e.w1 = entry.ioapic_rte.low_uint32;
236         e.w2 = entry.ioapic_rte.high_uint32;
237
238         memset(msg, 0, sizeof(*msg));
239         msg->arch_data.vector = e.vector;
240         msg->arch_data.delivery_mode = e.delivery_mode;
241         msg->arch_addr_lo.dest_mode_logical = e.dest_mode_logical;
242         msg->arch_addr_lo.dmar_format = e.ir_format;
243         msg->arch_addr_lo.dmar_index_0_14 = e.ir_index_0_14;
244 }
245
246 static int hyperv_root_ir_set_affinity(struct irq_data *data,
247                 const struct cpumask *mask, bool force)
248 {
249         struct irq_data *parent = data->parent_data;
250         struct irq_cfg *cfg = irqd_cfg(data);
251         int ret;
252
253         ret = parent->chip->irq_set_affinity(parent, mask, force);
254         if (ret < 0 || ret == IRQ_SET_MASK_OK_DONE)
255                 return ret;
256
257         send_cleanup_vector(cfg);
258
259         return 0;
260 }
261
262 static struct irq_chip hyperv_root_ir_chip = {
263         .name                   = "HYPERV-ROOT-IR",
264         .irq_ack                = apic_ack_irq,
265         .irq_set_affinity       = hyperv_root_ir_set_affinity,
266         .irq_compose_msi_msg    = hyperv_root_ir_compose_msi_msg,
267 };
268
269 static int hyperv_root_irq_remapping_alloc(struct irq_domain *domain,
270                                      unsigned int virq, unsigned int nr_irqs,
271                                      void *arg)
272 {
273         struct irq_alloc_info *info = arg;
274         struct irq_data *irq_data;
275         struct hyperv_root_ir_data *data;
276         int ret = 0;
277
278         if (!info || info->type != X86_IRQ_ALLOC_TYPE_IOAPIC || nr_irqs > 1)
279                 return -EINVAL;
280
281         ret = irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, arg);
282         if (ret < 0)
283                 return ret;
284
285         data = kzalloc(sizeof(*data), GFP_KERNEL);
286         if (!data) {
287                 irq_domain_free_irqs_common(domain, virq, nr_irqs);
288                 return -ENOMEM;
289         }
290
291         irq_data = irq_domain_get_irq_data(domain, virq);
292         if (!irq_data) {
293                 kfree(data);
294                 irq_domain_free_irqs_common(domain, virq, nr_irqs);
295                 return -EINVAL;
296         }
297
298         data->ioapic_id = info->devid;
299         data->is_level = info->ioapic.is_level;
300
301         irq_data->chip = &hyperv_root_ir_chip;
302         irq_data->chip_data = data;
303
304         return 0;
305 }
306
307 static void hyperv_root_irq_remapping_free(struct irq_domain *domain,
308                                  unsigned int virq, unsigned int nr_irqs)
309 {
310         struct irq_data *irq_data;
311         struct hyperv_root_ir_data *data;
312         struct hv_interrupt_entry *e;
313         int i;
314
315         for (i = 0; i < nr_irqs; i++) {
316                 irq_data = irq_domain_get_irq_data(domain, virq + i);
317
318                 if (irq_data && irq_data->chip_data) {
319                         data = irq_data->chip_data;
320                         e = &data->entry;
321
322                         if (e->source == HV_DEVICE_TYPE_IOAPIC
323                               && e->ioapic_rte.as_uint64)
324                                 hv_unmap_ioapic_interrupt(data->ioapic_id,
325                                                         &data->entry);
326
327                         kfree(data);
328                 }
329         }
330
331         irq_domain_free_irqs_common(domain, virq, nr_irqs);
332 }
333
334 static const struct irq_domain_ops hyperv_root_ir_domain_ops = {
335         .select = hyperv_irq_remapping_select,
336         .alloc = hyperv_root_irq_remapping_alloc,
337         .free = hyperv_root_irq_remapping_free,
338 };
339
340 #endif