linux/drivers/xen/platform-pci.c
David Woodhouse 8f4fd86aa5 xen: Set platform PCI device INTX affinity to CPU0
With INTX or GSI delivery, Xen uses the event channel structures of CPU0.

If the interrupt gets handled by Linux on a different CPU, then no events
are seen as pending. Rather than introducing locking to allow other CPUs
to process CPU0's events, just ensure that the PCI interrupts happens
only on CPU0.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/20210106153958.584169-3-dwmw2@infradead.org
Signed-off-by: Juergen Gross <jgross@suse.com>
2021-01-13 16:12:03 +01:00

191 lines
4.1 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)0x01 << HVM_CALLBACK_VIA_TYPE_SHIFT) | /* PCI INTx identifier */
((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)
{
xen_hvm_evtchn_do_upcall();
return IRQ_HANDLED;
}
static int xen_allocate_irq(struct pci_dev *pdev)
{
return request_irq(pdev->irq, do_hvm_evtchn_intr,
IRQF_NOBALANCING | IRQF_TRIGGER_RISING,
"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 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 out;
ret = gnttab_init();
if (ret)
goto grant_out;
return 0;
grant_out:
gnttab_free_auto_xlat_frames();
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);