linux/drivers/xen/platform-pci.c
David Woodhouse 3e8cd711c3 xen: Allow platform PCI interrupt to be shared
When we don't use the per-CPU vector callback, we ask Xen to deliver event
channel interrupts as INTx on the PCI platform device. As such, it can be
shared with INTx on other PCI devices.

Set IRQF_SHARED, and make it return IRQ_HANDLED or IRQ_NONE according to
whether the evtchn_upcall_pending flag was actually set. Now I can share
the interrupt:

 11:         82          0   IO-APIC  11-fasteoi   xen-platform-pci, ens4

Drop the IRQF_TRIGGER_RISING. It has no effect when the IRQ is shared,
and besides, the only effect it was having even beforehand was to trigger
a debug message in both I/OAPIC and legacy PIC cases:

[    0.915441] genirq: No set_type function for IRQ 11 (IO-APIC)
[    0.951939] genirq: No set_type function for IRQ 11 (XT-PIC)

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/f9a29a68d05668a3636dd09acd94d970269eaec6.camel@infradead.org
Signed-off-by: Juergen Gross <jgross@suse.com>
2023-02-13 06:53:20 +01:00

194 lines
4.2 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/******************************************************************************
* platform-pci.c
*
* Xen platform PCI device driver
*
* Authors: ssmith@xensource.com and stefano.stabellini@eu.citrix.com
*
* Copyright (c) 2005, Intel Corporation.
* Copyright (c) 2007, XenSource Inc.
* Copyright (c) 2010, Citrix
*/
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <xen/platform_pci.h>
#include <xen/grant_table.h>
#include <xen/xenbus.h>
#include <xen/events.h>
#include <xen/hvm.h>
#include <xen/xen-ops.h>
#define DRV_NAME "xen-platform-pci"
static unsigned long platform_mmio;
static unsigned long platform_mmio_alloc;
static unsigned long platform_mmiolen;
static uint64_t callback_via;
static unsigned long alloc_xen_mmio(unsigned long len)
{
unsigned long addr;
addr = platform_mmio + platform_mmio_alloc;
platform_mmio_alloc += len;
BUG_ON(platform_mmio_alloc > platform_mmiolen);
return addr;
}
static uint64_t get_callback_via(struct pci_dev *pdev)
{
u8 pin;
int irq;
irq = pdev->irq;
if (irq < 16)
return irq; /* ISA IRQ */
pin = pdev->pin;
/* We don't know the GSI. Specify the PCI INTx line instead. */
return ((uint64_t)HVM_PARAM_CALLBACK_TYPE_PCI_INTX <<
HVM_CALLBACK_VIA_TYPE_SHIFT) |
((uint64_t)pci_domain_nr(pdev->bus) << 32) |
((uint64_t)pdev->bus->number << 16) |
((uint64_t)(pdev->devfn & 0xff) << 8) |
((uint64_t)(pin - 1) & 3);
}
static irqreturn_t do_hvm_evtchn_intr(int irq, void *dev_id)
{
return xen_hvm_evtchn_do_upcall();
}
static int xen_allocate_irq(struct pci_dev *pdev)
{
return request_irq(pdev->irq, do_hvm_evtchn_intr,
IRQF_NOBALANCING | IRQF_SHARED,
"xen-platform-pci", pdev);
}
static int platform_pci_resume(struct device *dev)
{
int err;
if (xen_have_vector_callback)
return 0;
err = xen_set_callback_via(callback_via);
if (err) {
dev_err(dev, "platform_pci_resume failure!\n");
return err;
}
return 0;
}
static int platform_pci_probe(struct pci_dev *pdev,
const struct pci_device_id *ent)
{
int i, ret;
long ioaddr;
long mmio_addr, mmio_len;
unsigned int max_nr_gframes;
unsigned long grant_frames;
if (!xen_domain())
return -ENODEV;
i = pci_enable_device(pdev);
if (i)
return i;
ioaddr = pci_resource_start(pdev, 0);
mmio_addr = pci_resource_start(pdev, 1);
mmio_len = pci_resource_len(pdev, 1);
if (mmio_addr == 0 || ioaddr == 0) {
dev_err(&pdev->dev, "no resources found\n");
ret = -ENOENT;
goto pci_out;
}
ret = pci_request_region(pdev, 1, DRV_NAME);
if (ret < 0)
goto pci_out;
ret = pci_request_region(pdev, 0, DRV_NAME);
if (ret < 0)
goto mem_out;
platform_mmio = mmio_addr;
platform_mmiolen = mmio_len;
if (!xen_have_vector_callback) {
ret = xen_allocate_irq(pdev);
if (ret) {
dev_warn(&pdev->dev, "request_irq failed err=%d\n", ret);
goto out;
}
/*
* It doesn't strictly *have* to run on CPU0 but it sure
* as hell better process the event channel ports delivered
* to CPU0.
*/
irq_set_affinity(pdev->irq, cpumask_of(0));
callback_via = get_callback_via(pdev);
ret = xen_set_callback_via(callback_via);
if (ret) {
dev_warn(&pdev->dev, "Unable to set the evtchn callback "
"err=%d\n", ret);
goto irq_out;
}
}
max_nr_gframes = gnttab_max_grant_frames();
grant_frames = alloc_xen_mmio(PAGE_SIZE * max_nr_gframes);
ret = gnttab_setup_auto_xlat_frames(grant_frames);
if (ret)
goto irq_out;
ret = gnttab_init();
if (ret)
goto grant_out;
return 0;
grant_out:
gnttab_free_auto_xlat_frames();
irq_out:
if (!xen_have_vector_callback)
free_irq(pdev->irq, pdev);
out:
pci_release_region(pdev, 0);
mem_out:
pci_release_region(pdev, 1);
pci_out:
pci_disable_device(pdev);
return ret;
}
static const struct pci_device_id platform_pci_tbl[] = {
{PCI_VENDOR_ID_XEN, PCI_DEVICE_ID_XEN_PLATFORM,
PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0},
{0,}
};
static const struct dev_pm_ops platform_pm_ops = {
.resume_noirq = platform_pci_resume,
};
static struct pci_driver platform_driver = {
.name = DRV_NAME,
.probe = platform_pci_probe,
.id_table = platform_pci_tbl,
.driver = {
.pm = &platform_pm_ops,
},
};
builtin_pci_driver(platform_driver);