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linux/arch/x86/pci/xen.c
Stefano Stabellini af42b8d12f xen: fix MSI setup and teardown for PV on HVM guests 
When remapping MSIs into pirqs for PV on HVM guests, qemu is responsible
for doing the actual mapping and unmapping.
We only give qemu the desired pirq number when we ask to do the mapping
the first time, after that we should be reading back the pirq number
from qemu every time we want to re-enable the MSI.

This fixes a bug in xen_hvm_setup_msi_irqs that manifests itself when
trying to enable the same MSI for the second time: the old MSI to pirq
mapping is still valid at this point but xen_hvm_setup_msi_irqs would
try to assign a new pirq anyway.
A simple way to reproduce this bug is to assign an MSI capable network
card to a PV on HVM guest, if the user brings down the corresponding
ethernet interface and up again, Linux would fail to enable MSIs on the
device.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
2010-12-02 14:34:25 +00:00

430 lines
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/*
* Xen PCI Frontend Stub - puts some "dummy" functions in to the Linux
* x86 PCI core to support the Xen PCI Frontend
*
* Author: Ryan Wilson <hap9@epoch.ncsc.mil>
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <linux/acpi.h>
#include <linux/io.h>
#include <asm/io_apic.h>
#include <asm/pci_x86.h>
#include <asm/xen/hypervisor.h>
#include <xen/features.h>
#include <xen/events.h>
#include <asm/xen/pci.h>
#ifdef CONFIG_ACPI
static int xen_hvm_register_pirq(u32 gsi, int triggering)
{
int rc, irq;
struct physdev_map_pirq map_irq;
int shareable = 0;
char *name;
if (!xen_hvm_domain())
return -1;
map_irq.domid = DOMID_SELF;
map_irq.type = MAP_PIRQ_TYPE_GSI;
map_irq.index = gsi;
map_irq.pirq = -1;
rc = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq, &map_irq);
if (rc) {
printk(KERN_WARNING "xen map irq failed %d\n", rc);
return -1;
}
if (triggering == ACPI_EDGE_SENSITIVE) {
shareable = 0;
name = "ioapic-edge";
} else {
shareable = 1;
name = "ioapic-level";
}
irq = xen_map_pirq_gsi(map_irq.pirq, gsi, shareable, name);
printk(KERN_DEBUG "xen: --> irq=%d, pirq=%d\n", irq, map_irq.pirq);
return irq;
}
static int acpi_register_gsi_xen_hvm(struct device *dev, u32 gsi,
int trigger, int polarity)
{
return xen_hvm_register_pirq(gsi, trigger);
}
#endif
#if defined(CONFIG_PCI_MSI)
#include <linux/msi.h>
#include <asm/msidef.h>
struct xen_pci_frontend_ops *xen_pci_frontend;
EXPORT_SYMBOL_GPL(xen_pci_frontend);
#define XEN_PIRQ_MSI_DATA (MSI_DATA_TRIGGER_EDGE | \
MSI_DATA_LEVEL_ASSERT | (3 << 8) | MSI_DATA_VECTOR(0))
static void xen_msi_compose_msg(struct pci_dev *pdev, unsigned int pirq,
struct msi_msg *msg)
{
/* We set vector == 0 to tell the hypervisor we don't care about it,
* but we want a pirq setup instead.
* We use the dest_id field to pass the pirq that we want. */
msg->address_hi = MSI_ADDR_BASE_HI | MSI_ADDR_EXT_DEST_ID(pirq);
msg->address_lo =
MSI_ADDR_BASE_LO |
MSI_ADDR_DEST_MODE_PHYSICAL |
MSI_ADDR_REDIRECTION_CPU |
MSI_ADDR_DEST_ID(pirq);
msg->data = XEN_PIRQ_MSI_DATA;
}
static int xen_hvm_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
{
int irq, pirq, ret = 0;
struct msi_desc *msidesc;
struct msi_msg msg;
list_for_each_entry(msidesc, &dev->msi_list, list) {
__read_msi_msg(msidesc, &msg);
pirq = MSI_ADDR_EXT_DEST_ID(msg.address_hi) |
((msg.address_lo >> MSI_ADDR_DEST_ID_SHIFT) & 0xff);
if (xen_irq_from_pirq(pirq) >= 0 && msg.data == XEN_PIRQ_MSI_DATA) {
xen_allocate_pirq_msi((type == PCI_CAP_ID_MSIX) ?
"msi-x" : "msi", &irq, &pirq, XEN_ALLOC_IRQ);
if (irq < 0)
goto error;
ret = set_irq_msi(irq, msidesc);
if (ret < 0)
goto error_while;
printk(KERN_DEBUG "xen: msi already setup: msi --> irq=%d"
" pirq=%d\n", irq, pirq);
return 0;
}
xen_allocate_pirq_msi((type == PCI_CAP_ID_MSIX) ?
"msi-x" : "msi", &irq, &pirq, (XEN_ALLOC_IRQ | XEN_ALLOC_PIRQ));
if (irq < 0 || pirq < 0)
goto error;
printk(KERN_DEBUG "xen: msi --> irq=%d, pirq=%d\n", irq, pirq);
xen_msi_compose_msg(dev, pirq, &msg);
ret = set_irq_msi(irq, msidesc);
if (ret < 0)
goto error_while;
write_msi_msg(irq, &msg);
}
return 0;
error_while:
unbind_from_irqhandler(irq, NULL);
error:
if (ret == -ENODEV)
dev_err(&dev->dev, "Xen PCI frontend has not registered" \
" MSI/MSI-X support!\n");
return ret;
}
/*
* For MSI interrupts we have to use drivers/xen/event.s functions to
* allocate an irq_desc and setup the right */
static int xen_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
{
int irq, ret, i;
struct msi_desc *msidesc;
int *v;
v = kzalloc(sizeof(int) * max(1, nvec), GFP_KERNEL);
if (!v)
return -ENOMEM;
if (type == PCI_CAP_ID_MSIX)
ret = xen_pci_frontend_enable_msix(dev, &v, nvec);
else
ret = xen_pci_frontend_enable_msi(dev, &v);
if (ret)
goto error;
i = 0;
list_for_each_entry(msidesc, &dev->msi_list, list) {
irq = xen_allocate_pirq(v[i], 0, /* not sharable */
(type == PCI_CAP_ID_MSIX) ?
"pcifront-msi-x" : "pcifront-msi");
if (irq < 0) {
ret = -1;
goto free;
}
ret = set_irq_msi(irq, msidesc);
if (ret)
goto error_while;
i++;
}
kfree(v);
return 0;
error_while:
unbind_from_irqhandler(irq, NULL);
error:
if (ret == -ENODEV)
dev_err(&dev->dev, "Xen PCI frontend has not registered" \
" MSI/MSI-X support!\n");
free:
kfree(v);
return ret;
}
static void xen_teardown_msi_irqs(struct pci_dev *dev)
{
struct msi_desc *msidesc;
msidesc = list_entry(dev->msi_list.next, struct msi_desc, list);
if (msidesc->msi_attrib.is_msix)
xen_pci_frontend_disable_msix(dev);
else
xen_pci_frontend_disable_msi(dev);
}
static void xen_teardown_msi_irq(unsigned int irq)
{
xen_destroy_irq(irq);
}
static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
{
int irq, ret;
struct msi_desc *msidesc;
list_for_each_entry(msidesc, &dev->msi_list, list) {
irq = xen_create_msi_irq(dev, msidesc, type);
if (irq < 0)
return -1;
ret = set_irq_msi(irq, msidesc);
if (ret)
goto error;
}
return 0;
error:
xen_destroy_irq(irq);
return ret;
}
#endif
static int xen_pcifront_enable_irq(struct pci_dev *dev)
{
int rc;
int share = 1;
dev_info(&dev->dev, "Xen PCI enabling IRQ: %d\n", dev->irq);
if (dev->irq < 0)
return -EINVAL;
if (dev->irq < NR_IRQS_LEGACY)
share = 0;
rc = xen_allocate_pirq(dev->irq, share, "pcifront");
if (rc < 0) {
dev_warn(&dev->dev, "Xen PCI IRQ: %d, failed to register:%d\n",
dev->irq, rc);
return rc;
}
return 0;
}
int __init pci_xen_init(void)
{
if (!xen_pv_domain() || xen_initial_domain())
return -ENODEV;
printk(KERN_INFO "PCI: setting up Xen PCI frontend stub\n");
pcibios_set_cache_line_size();
pcibios_enable_irq = xen_pcifront_enable_irq;
pcibios_disable_irq = NULL;
#ifdef CONFIG_ACPI
/* Keep ACPI out of the picture */
acpi_noirq = 1;
#endif
#ifdef CONFIG_PCI_MSI
x86_msi.setup_msi_irqs = xen_setup_msi_irqs;
x86_msi.teardown_msi_irq = xen_teardown_msi_irq;
x86_msi.teardown_msi_irqs = xen_teardown_msi_irqs;
#endif
return 0;
}
int __init pci_xen_hvm_init(void)
{
if (!xen_feature(XENFEAT_hvm_pirqs))
return 0;
#ifdef CONFIG_ACPI
/*
* We don't want to change the actual ACPI delivery model,
* just how GSIs get registered.
*/
__acpi_register_gsi = acpi_register_gsi_xen_hvm;
#endif
#ifdef CONFIG_PCI_MSI
x86_msi.setup_msi_irqs = xen_hvm_setup_msi_irqs;
x86_msi.teardown_msi_irq = xen_teardown_msi_irq;
#endif
return 0;
}
#ifdef CONFIG_XEN_DOM0
static int xen_register_pirq(u32 gsi, int triggering)
{
int rc, irq;
struct physdev_map_pirq map_irq;
int shareable = 0;
char *name;
if (!xen_pv_domain())
return -1;
if (triggering == ACPI_EDGE_SENSITIVE) {
shareable = 0;
name = "ioapic-edge";
} else {
shareable = 1;
name = "ioapic-level";
}
irq = xen_allocate_pirq(gsi, shareable, name);
printk(KERN_DEBUG "xen: --> irq=%d\n", irq);
if (irq < 0)
goto out;
map_irq.domid = DOMID_SELF;
map_irq.type = MAP_PIRQ_TYPE_GSI;
map_irq.index = gsi;
map_irq.pirq = irq;
rc = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq, &map_irq);
if (rc) {
printk(KERN_WARNING "xen map irq failed %d\n", rc);
return -1;
}
out:
return irq;
}
static int xen_register_gsi(u32 gsi, int triggering, int polarity)
{
int rc, irq;
struct physdev_setup_gsi setup_gsi;
if (!xen_pv_domain())
return -1;
printk(KERN_DEBUG "xen: registering gsi %u triggering %d polarity %d\n",
gsi, triggering, polarity);
irq = xen_register_pirq(gsi, triggering);
setup_gsi.gsi = gsi;
setup_gsi.triggering = (triggering == ACPI_EDGE_SENSITIVE ? 0 : 1);
setup_gsi.polarity = (polarity == ACPI_ACTIVE_HIGH ? 0 : 1);
rc = HYPERVISOR_physdev_op(PHYSDEVOP_setup_gsi, &setup_gsi);
if (rc == -EEXIST)
printk(KERN_INFO "Already setup the GSI :%d\n", gsi);
else if (rc) {
printk(KERN_ERR "Failed to setup GSI :%d, err_code:%d\n",
gsi, rc);
}
return irq;
}
static __init void xen_setup_acpi_sci(void)
{
int rc;
int trigger, polarity;
int gsi = acpi_sci_override_gsi;
if (!gsi)
return;
rc = acpi_get_override_irq(gsi, &trigger, &polarity);
if (rc) {
printk(KERN_WARNING "xen: acpi_get_override_irq failed for acpi"
" sci, rc=%d\n", rc);
return;
}
trigger = trigger ? ACPI_LEVEL_SENSITIVE : ACPI_EDGE_SENSITIVE;
polarity = polarity ? ACPI_ACTIVE_LOW : ACPI_ACTIVE_HIGH;
printk(KERN_INFO "xen: sci override: global_irq=%d trigger=%d "
"polarity=%d\n", gsi, trigger, polarity);
gsi = xen_register_gsi(gsi, trigger, polarity);
printk(KERN_INFO "xen: acpi sci %d\n", gsi);
return;
}
static int acpi_register_gsi_xen(struct device *dev, u32 gsi,
int trigger, int polarity)
{
return xen_register_gsi(gsi, trigger, polarity);
}
static int __init pci_xen_initial_domain(void)
{
#ifdef CONFIG_PCI_MSI
x86_msi.setup_msi_irqs = xen_initdom_setup_msi_irqs;
x86_msi.teardown_msi_irq = xen_teardown_msi_irq;
#endif
xen_setup_acpi_sci();
__acpi_register_gsi = acpi_register_gsi_xen;
return 0;
}
void __init xen_setup_pirqs(void)
{
int irq;
pci_xen_initial_domain();
if (0 == nr_ioapics) {
for (irq = 0; irq < NR_IRQS_LEGACY; irq++)
xen_allocate_pirq(irq, 0, "xt-pic");
return;
}
/* Pre-allocate legacy irqs */
for (irq = 0; irq < NR_IRQS_LEGACY; irq++) {
int trigger, polarity;
if (acpi_get_override_irq(irq, &trigger, &polarity) == -1)
continue;
xen_register_pirq(irq,
trigger ? ACPI_LEVEL_SENSITIVE : ACPI_EDGE_SENSITIVE);
}
}
#endif
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