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Konrad Rzeszutek Wilk30edc142009-10-13 17:22:20 -04001/*
2 * PCI Backend Operations - respond to PCI requests from Frontend
3 *
4 * Author: Ryan Wilson <hap9@epoch.ncsc.mil>
5 */
6#include <linux/module.h>
7#include <linux/wait.h>
8#include <linux/bitops.h>
9#include <xen/events.h>
10#include <linux/sched.h>
11#include "pciback.h"
12
13int verbose_request;
14module_param(verbose_request, int, 0644);
15
Konrad Rzeszutek Wilk0513fe92011-07-19 18:56:39 -040016/* Ensure a device is has the fake IRQ handler "turned on/off" and is
17 * ready to be exported. This MUST be run after pciback_reset_device
18 * which does the actual PCI device enable/disable.
19 */
20void pciback_control_isr(struct pci_dev *dev, int reset)
21{
22 struct pciback_dev_data *dev_data;
23 int rc;
24 int enable = 0;
25
26 dev_data = pci_get_drvdata(dev);
27 if (!dev_data)
28 return;
29
30 /* We don't deal with bridges */
31 if (dev->hdr_type != PCI_HEADER_TYPE_NORMAL)
32 return;
33
34 if (reset) {
35 dev_data->enable_intx = 0;
36 dev_data->ack_intr = 0;
37 }
38 enable = dev_data->enable_intx;
39
40 /* Asked to disable, but ISR isn't runnig */
41 if (!enable && !dev_data->isr_on)
42 return;
43
44 /* Squirrel away the IRQs in the dev_data. We need this
45 * b/c when device transitions to MSI, the dev->irq is
46 * overwritten with the MSI vector.
47 */
48 if (enable)
49 dev_data->irq = dev->irq;
50
51 dev_dbg(&dev->dev, "%s: #%d %s %s%s %s-> %s\n",
52 dev_data->irq_name,
53 dev_data->irq,
54 pci_is_enabled(dev) ? "on" : "off",
55 dev->msi_enabled ? "MSI" : "",
56 dev->msix_enabled ? "MSI/X" : "",
57 dev_data->isr_on ? "enable" : "disable",
58 enable ? "enable" : "disable");
59
60 if (enable) {
61 rc = request_irq(dev_data->irq,
62 pciback_guest_interrupt, IRQF_SHARED,
63 dev_data->irq_name, dev);
64 if (rc) {
65 dev_err(&dev->dev, "%s: failed to install fake IRQ " \
66 "handler for IRQ %d! (rc:%d)\n",
67 dev_data->irq_name, dev_data->irq, rc);
68 goto out;
69 }
70 } else {
71 free_irq(dev_data->irq, dev);
72 dev_data->irq = 0;
73 }
74 dev_data->isr_on = enable;
75 dev_data->ack_intr = enable;
76out:
77 dev_dbg(&dev->dev, "%s: #%d %s %s%s %s\n",
78 dev_data->irq_name,
79 dev_data->irq,
80 pci_is_enabled(dev) ? "on" : "off",
81 dev->msi_enabled ? "MSI" : "",
82 dev->msix_enabled ? "MSI/X" : "",
83 enable ? (dev_data->isr_on ? "enabled" : "failed to enable") :
84 (dev_data->isr_on ? "failed to disable" : "disabled"));
85}
86
Konrad Rzeszutek Wilk30edc142009-10-13 17:22:20 -040087/* Ensure a device is "turned off" and ready to be exported.
88 * (Also see pciback_config_reset to ensure virtual configuration space is
89 * ready to be re-exported)
90 */
91void pciback_reset_device(struct pci_dev *dev)
92{
93 u16 cmd;
94
Konrad Rzeszutek Wilk0513fe92011-07-19 18:56:39 -040095 pciback_control_isr(dev, 1 /* reset device */);
96
Konrad Rzeszutek Wilk30edc142009-10-13 17:22:20 -040097 /* Disable devices (but not bridges) */
98 if (dev->hdr_type == PCI_HEADER_TYPE_NORMAL) {
Konrad Rzeszutek Wilka2be65fd2010-03-03 13:38:43 -050099#ifdef CONFIG_PCI_MSI
100 /* The guest could have been abruptly killed without
101 * disabling MSI/MSI-X interrupts.*/
102 if (dev->msix_enabled)
103 pci_disable_msix(dev);
104 if (dev->msi_enabled)
105 pci_disable_msi(dev);
106#endif
Konrad Rzeszutek Wilk30edc142009-10-13 17:22:20 -0400107 pci_disable_device(dev);
108
109 pci_write_config_word(dev, PCI_COMMAND, 0);
110
111 dev->is_busmaster = 0;
112 } else {
113 pci_read_config_word(dev, PCI_COMMAND, &cmd);
114 if (cmd & (PCI_COMMAND_INVALIDATE)) {
115 cmd &= ~(PCI_COMMAND_INVALIDATE);
116 pci_write_config_word(dev, PCI_COMMAND, cmd);
117
118 dev->is_busmaster = 0;
119 }
120 }
121}
122/*
123* Now the same evtchn is used for both pcifront conf_read_write request
124* as well as pcie aer front end ack. We use a new work_queue to schedule
125* pciback conf_read_write service for avoiding confict with aer_core
126* do_recovery job which also use the system default work_queue
127*/
128void test_and_schedule_op(struct pciback_device *pdev)
129{
130 /* Check that frontend is requesting an operation and that we are not
131 * already processing a request */
132 if (test_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags)
133 && !test_and_set_bit(_PDEVF_op_active, &pdev->flags)) {
134 queue_work(pciback_wq, &pdev->op_work);
135 }
136 /*_XEN_PCIB_active should have been cleared by pcifront. And also make
137 sure pciback is waiting for ack by checking _PCIB_op_pending*/
138 if (!test_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags)
139 && test_bit(_PCIB_op_pending, &pdev->flags)) {
140 wake_up(&aer_wait_queue);
141 }
142}
143
144/* Performing the configuration space reads/writes must not be done in atomic
145 * context because some of the pci_* functions can sleep (mostly due to ACPI
146 * use of semaphores). This function is intended to be called from a work
147 * queue in process context taking a struct pciback_device as a parameter */
148
149void pciback_do_op(struct work_struct *data)
150{
151 struct pciback_device *pdev =
152 container_of(data, struct pciback_device, op_work);
153 struct pci_dev *dev;
Konrad Rzeszutek Wilk0513fe92011-07-19 18:56:39 -0400154 struct pciback_dev_data *dev_data = NULL;
Konrad Rzeszutek Wilk30edc142009-10-13 17:22:20 -0400155 struct xen_pci_op *op = &pdev->sh_info->op;
Konrad Rzeszutek Wilk0513fe92011-07-19 18:56:39 -0400156 int test_intx = 0;
Konrad Rzeszutek Wilk30edc142009-10-13 17:22:20 -0400157
158 dev = pciback_get_pci_dev(pdev, op->domain, op->bus, op->devfn);
159
160 if (dev == NULL)
161 op->err = XEN_PCI_ERR_dev_not_found;
162 else {
Konrad Rzeszutek Wilk0513fe92011-07-19 18:56:39 -0400163 dev_data = pci_get_drvdata(dev);
164 if (dev_data)
165 test_intx = dev_data->enable_intx;
Konrad Rzeszutek Wilk30edc142009-10-13 17:22:20 -0400166 switch (op->cmd) {
167 case XEN_PCI_OP_conf_read:
168 op->err = pciback_config_read(dev,
169 op->offset, op->size, &op->value);
170 break;
171 case XEN_PCI_OP_conf_write:
172 op->err = pciback_config_write(dev,
173 op->offset, op->size, op->value);
174 break;
175#ifdef CONFIG_PCI_MSI
176 case XEN_PCI_OP_enable_msi:
177 op->err = pciback_enable_msi(pdev, dev, op);
178 break;
179 case XEN_PCI_OP_disable_msi:
180 op->err = pciback_disable_msi(pdev, dev, op);
181 break;
182 case XEN_PCI_OP_enable_msix:
183 op->err = pciback_enable_msix(pdev, dev, op);
184 break;
185 case XEN_PCI_OP_disable_msix:
186 op->err = pciback_disable_msix(pdev, dev, op);
187 break;
188#endif
189 default:
190 op->err = XEN_PCI_ERR_not_implemented;
191 break;
192 }
193 }
Konrad Rzeszutek Wilk0513fe92011-07-19 18:56:39 -0400194 if (!op->err && dev && dev_data) {
195 /* Transition detected */
196 if ((dev_data->enable_intx != test_intx))
197 pciback_control_isr(dev, 0 /* no reset */);
198 }
Konrad Rzeszutek Wilk30edc142009-10-13 17:22:20 -0400199 /* Tell the driver domain that we're done. */
200 wmb();
201 clear_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags);
202 notify_remote_via_irq(pdev->evtchn_irq);
203
204 /* Mark that we're done. */
205 smp_mb__before_clear_bit(); /* /after/ clearing PCIF_active */
206 clear_bit(_PDEVF_op_active, &pdev->flags);
207 smp_mb__after_clear_bit(); /* /before/ final check for work */
208
209 /* Check to see if the driver domain tried to start another request in
210 * between clearing _XEN_PCIF_active and clearing _PDEVF_op_active.
211 */
212 test_and_schedule_op(pdev);
213}
214
215irqreturn_t pciback_handle_event(int irq, void *dev_id)
216{
217 struct pciback_device *pdev = dev_id;
218
219 test_and_schedule_op(pdev);
220
221 return IRQ_HANDLED;
222}
Konrad Rzeszutek Wilk0513fe92011-07-19 18:56:39 -0400223irqreturn_t pciback_guest_interrupt(int irq, void *dev_id)
224{
225 struct pci_dev *dev = (struct pci_dev *)dev_id;
226 struct pciback_dev_data *dev_data = pci_get_drvdata(dev);
227
228 if (dev_data->isr_on && dev_data->ack_intr) {
229 dev_data->handled++;
230 if ((dev_data->handled % 1000) == 0) {
231 if (xen_test_irq_shared(irq)) {
232 printk(KERN_INFO "%s IRQ line is not shared "
233 "with other domains. Turning ISR off\n",
234 dev_data->irq_name);
235 dev_data->ack_intr = 0;
236 }
237 }
238 return IRQ_HANDLED;
239 }
240 return IRQ_NONE;
241}