[mirror_ubuntu-jammy-kernel.git] / drivers / xen / xen-pciback / pciback_ops.c

/*
 * PCI Backend Operations - respond to PCI requests from Frontend
 *
 *   Author: Ryan Wilson <hap9@epoch.ncsc.mil>
 */
#include <linux/module.h>
#include <linux/wait.h>
#include <linux/bitops.h>
#include <xen/events.h>
#include <linux/sched.h>
#include "pciback.h"

int verbose_request;
module_param(verbose_request, int, 0644);

/* Ensure a device is "turned off" and ready to be exported.
 * (Also see pciback_config_reset to ensure virtual configuration space is
 * ready to be re-exported)
 */
void pciback_reset_device(struct pci_dev *dev)
{
	u16 cmd;

	/* Disable devices (but not bridges) */
	if (dev->hdr_type == PCI_HEADER_TYPE_NORMAL) {
#ifdef CONFIG_PCI_MSI
		/* The guest could have been abruptly killed without
		 * disabling MSI/MSI-X interrupts.*/
		if (dev->msix_enabled)
			pci_disable_msix(dev);
		if (dev->msi_enabled)
			pci_disable_msi(dev);
#endif
		pci_disable_device(dev);

		pci_write_config_word(dev, PCI_COMMAND, 0);

		dev->is_busmaster = 0;
	} else {
		pci_read_config_word(dev, PCI_COMMAND, &cmd);
		if (cmd & (PCI_COMMAND_INVALIDATE)) {
			cmd &= ~(PCI_COMMAND_INVALIDATE);
			pci_write_config_word(dev, PCI_COMMAND, cmd);

			dev->is_busmaster = 0;
		}
	}
}
/*
* Now the same evtchn is used for both pcifront conf_read_write request
* as well as pcie aer front end ack. We use a new work_queue to schedule
* pciback conf_read_write service for avoiding confict with aer_core
* do_recovery job which also use the system default work_queue
*/
void test_and_schedule_op(struct pciback_device *pdev)
{
	/* Check that frontend is requesting an operation and that we are not
	 * already processing a request */
	if (test_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags)
	    && !test_and_set_bit(_PDEVF_op_active, &pdev->flags)) {
		queue_work(pciback_wq, &pdev->op_work);
	}
	/*_XEN_PCIB_active should have been cleared by pcifront. And also make
	sure pciback is waiting for ack by checking _PCIB_op_pending*/
	if (!test_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags)
	    && test_bit(_PCIB_op_pending, &pdev->flags)) {
		wake_up(&aer_wait_queue);
	}
}

/* Performing the configuration space reads/writes must not be done in atomic
 * context because some of the pci_* functions can sleep (mostly due to ACPI
 * use of semaphores). This function is intended to be called from a work
 * queue in process context taking a struct pciback_device as a parameter */

void pciback_do_op(struct work_struct *data)
{
	struct pciback_device *pdev =
		container_of(data, struct pciback_device, op_work);
	struct pci_dev *dev;
	struct xen_pci_op *op = &pdev->sh_info->op;

	dev = pciback_get_pci_dev(pdev, op->domain, op->bus, op->devfn);

	if (dev == NULL)
		op->err = XEN_PCI_ERR_dev_not_found;
	else {
		switch (op->cmd) {
		case XEN_PCI_OP_conf_read:
			op->err = pciback_config_read(dev,
				  op->offset, op->size, &op->value);
			break;
		case XEN_PCI_OP_conf_write:
			op->err = pciback_config_write(dev,
				  op->offset, op->size,	op->value);
			break;
#ifdef CONFIG_PCI_MSI
		case XEN_PCI_OP_enable_msi:
			op->err = pciback_enable_msi(pdev, dev, op);
			break;
		case XEN_PCI_OP_disable_msi:
			op->err = pciback_disable_msi(pdev, dev, op);
			break;
		case XEN_PCI_OP_enable_msix:
			op->err = pciback_enable_msix(pdev, dev, op);
			break;
		case XEN_PCI_OP_disable_msix:
			op->err = pciback_disable_msix(pdev, dev, op);
			break;
#endif
		default:
			op->err = XEN_PCI_ERR_not_implemented;
			break;
		}
	}
	/* Tell the driver domain that we're done. */
	wmb();
	clear_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags);
	notify_remote_via_irq(pdev->evtchn_irq);

	/* Mark that we're done. */
	smp_mb__before_clear_bit(); /* /after/ clearing PCIF_active */
	clear_bit(_PDEVF_op_active, &pdev->flags);
	smp_mb__after_clear_bit(); /* /before/ final check for work */

	/* Check to see if the driver domain tried to start another request in
	 * between clearing _XEN_PCIF_active and clearing _PDEVF_op_active.
	*/
	test_and_schedule_op(pdev);
}

irqreturn_t pciback_handle_event(int irq, void *dev_id)
{
	struct pciback_device *pdev = dev_id;

	test_and_schedule_op(pdev);

	return IRQ_HANDLED;
}
Commit	Line	Data
30edc14b KRW	1	/*
	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
	13	int verbose_request;
	14	module_param(verbose_request, int, 0644);
	15
	16	/* Ensure a device is "turned off" and ready to be exported.
	17	* (Also see pciback_config_reset to ensure virtual configuration space is
	18	* ready to be re-exported)
	19	*/
	20	void pciback_reset_device(struct pci_dev *dev)
	21	{
	22	u16 cmd;
	23
	24	/* Disable devices (but not bridges) */
	25	if (dev->hdr_type == PCI_HEADER_TYPE_NORMAL) {
a2be65fd KRW	26	#ifdef CONFIG_PCI_MSI
	27	/* The guest could have been abruptly killed without
	28	* disabling MSI/MSI-X interrupts.*/
	29	if (dev->msix_enabled)
	30	pci_disable_msix(dev);
	31	if (dev->msi_enabled)
	32	pci_disable_msi(dev);
	33	#endif
30edc14b KRW	34	pci_disable_device(dev);
	35
	36	pci_write_config_word(dev, PCI_COMMAND, 0);
	37
	38	dev->is_busmaster = 0;
	39	} else {
	40	pci_read_config_word(dev, PCI_COMMAND, &cmd);
	41	if (cmd & (PCI_COMMAND_INVALIDATE)) {
	42	cmd &= ~(PCI_COMMAND_INVALIDATE);
	43	pci_write_config_word(dev, PCI_COMMAND, cmd);
	44
	45	dev->is_busmaster = 0;
	46	}
	47	}
	48	}
	49	/*
	50	* Now the same evtchn is used for both pcifront conf_read_write request
	51	* as well as pcie aer front end ack. We use a new work_queue to schedule
	52	* pciback conf_read_write service for avoiding confict with aer_core
	53	* do_recovery job which also use the system default work_queue
	54	*/
	55	void test_and_schedule_op(struct pciback_device *pdev)
	56	{
	57	/* Check that frontend is requesting an operation and that we are not
	58	* already processing a request */
	59	if (test_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags)
	60	&& !test_and_set_bit(_PDEVF_op_active, &pdev->flags)) {
	61	queue_work(pciback_wq, &pdev->op_work);
	62	}
	63	/*_XEN_PCIB_active should have been cleared by pcifront. And also make
	64	sure pciback is waiting for ack by checking _PCIB_op_pending*/
	65	if (!test_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags)
	66	&& test_bit(_PCIB_op_pending, &pdev->flags)) {
	67	wake_up(&aer_wait_queue);
	68	}
	69	}
	70
	71	/* Performing the configuration space reads/writes must not be done in atomic
	72	* context because some of the pci_* functions can sleep (mostly due to ACPI
	73	* use of semaphores). This function is intended to be called from a work
	74	* queue in process context taking a struct pciback_device as a parameter */
	75
	76	void pciback_do_op(struct work_struct *data)
	77	{
	78	struct pciback_device *pdev =
	79	container_of(data, struct pciback_device, op_work);
	80	struct pci_dev *dev;
	81	struct xen_pci_op *op = &pdev->sh_info->op;
	82
	83	dev = pciback_get_pci_dev(pdev, op->domain, op->bus, op->devfn);
	84
	85	if (dev == NULL)
	86	op->err = XEN_PCI_ERR_dev_not_found;
	87	else {
	88	switch (op->cmd) {
	89	case XEN_PCI_OP_conf_read:
	90	op->err = pciback_config_read(dev,
	91	op->offset, op->size, &op->value);
	92	break;
	93	case XEN_PCI_OP_conf_write:
	94	op->err = pciback_config_write(dev,
	95	op->offset, op->size, op->value);
	96	break;
	97	#ifdef CONFIG_PCI_MSI
98	case XEN_PCI_OP_enable_msi:
99	op->err = pciback_enable_msi(pdev, dev, op);
100	break;
101	case XEN_PCI_OP_disable_msi:
102	op->err = pciback_disable_msi(pdev, dev, op);
103	break;
104	case XEN_PCI_OP_enable_msix:
105	op->err = pciback_enable_msix(pdev, dev, op);
106	break;
107	case XEN_PCI_OP_disable_msix:
108	op->err = pciback_disable_msix(pdev, dev, op);
109	break;
110	#endif
111	default:
112	op->err = XEN_PCI_ERR_not_implemented;
113	break;
114	}
115	}
116	/* Tell the driver domain that we're done. */
117	wmb();
118	clear_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags);
119	notify_remote_via_irq(pdev->evtchn_irq);
120
121	/* Mark that we're done. */
122	smp_mb__before_clear_bit(); /* /after/ clearing PCIF_active */
123	clear_bit(_PDEVF_op_active, &pdev->flags);
124	smp_mb__after_clear_bit(); /* /before/ final check for work */
125
126	/* Check to see if the driver domain tried to start another request in
127	* between clearing _XEN_PCIF_active and clearing _PDEVF_op_active.
128	*/
129	test_and_schedule_op(pdev);
130	}
131
132	irqreturn_t pciback_handle_event(int irq, void *dev_id)
133	{
134	struct pciback_device *pdev = dev_id;
135
136	test_and_schedule_op(pdev);
137
138	return IRQ_HANDLED;
139	}