linux/arch/x86/pci/xen.c
Thomas Gleixner 7e0815b3e0 x86/pci/xen: Disable PCI/MSI[-X] masking for XEN_HVM guests
When a XEN_HVM guest uses the XEN PIRQ/Eventchannel mechanism, then
PCI/MSI[-X] masking is solely controlled by the hypervisor, but contrary to
XEN_PV guests this does not disable PCI/MSI[-X] masking in the PCI/MSI
layer.

This can lead to a situation where the PCI/MSI layer masks an MSI[-X]
interrupt and the hypervisor grants the write despite the fact that it
already requested the interrupt. As a consequence interrupt delivery on the
affected device is not happening ever.

Set pci_msi_ignore_mask to prevent that like it's done for XEN_PV guests
already.

Fixes: 809f9267bb ("xen: map MSIs into pirqs")
Reported-by: Jeremi Piotrowski <jpiotrowski@linux.microsoft.com>
Reported-by: Dusty Mabe <dustymabe@redhat.com>
Reported-by: Salvatore Bonaccorso <carnil@debian.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Noah Meyerhans <noahm@debian.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/87tuaduxj5.ffs@tglx
2022-04-29 14:37:39 +02:00

587 lines
14 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Xen PCI - handle PCI (INTx) and MSI infrastructure calls for PV, HVM and
* initial domain support. We also handle the DSDT _PRT callbacks for GSI's
* used in HVM and initial domain mode (PV does not parse ACPI, so it has no
* concept of GSIs). Under PV we hook under the pnbbios API for IRQs and
* 0xcf8 PCI configuration read/write.
*
* Author: Ryan Wilson <hap9@epoch.ncsc.mil>
* Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* Stefano Stabellini <stefano.stabellini@eu.citrix.com>
*/
#include <linux/export.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 <xen/pci.h>
#include <asm/xen/pci.h>
#include <asm/xen/cpuid.h>
#include <asm/apic.h>
#include <asm/acpi.h>
#include <asm/i8259.h>
static int xen_pcifront_enable_irq(struct pci_dev *dev)
{
int rc;
int share = 1;
int pirq;
u8 gsi;
rc = pci_read_config_byte(dev, PCI_INTERRUPT_LINE, &gsi);
if (rc < 0) {
dev_warn(&dev->dev, "Xen PCI: failed to read interrupt line: %d\n",
rc);
return rc;
}
/* In PV DomU the Xen PCI backend puts the PIRQ in the interrupt line.*/
pirq = gsi;
if (gsi < nr_legacy_irqs())
share = 0;
rc = xen_bind_pirq_gsi_to_irq(gsi, pirq, share, "pcifront");
if (rc < 0) {
dev_warn(&dev->dev, "Xen PCI: failed to bind GSI%d (PIRQ%d) to IRQ: %d\n",
gsi, pirq, rc);
return rc;
}
dev->irq = rc;
dev_info(&dev->dev, "Xen PCI mapped GSI%d to IRQ%d\n", gsi, dev->irq);
return 0;
}
#ifdef CONFIG_ACPI
static int xen_register_pirq(u32 gsi, int triggering, bool set_pirq)
{
int rc, pirq = -1, irq;
struct physdev_map_pirq map_irq;
int shareable = 0;
char *name;
irq = xen_irq_from_gsi(gsi);
if (irq > 0)
return irq;
if (set_pirq)
pirq = gsi;
map_irq.domid = DOMID_SELF;
map_irq.type = MAP_PIRQ_TYPE_GSI;
map_irq.index = gsi;
map_irq.pirq = pirq;
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_bind_pirq_gsi_to_irq(gsi, map_irq.pirq, shareable, name);
if (irq < 0)
goto out;
printk(KERN_DEBUG "xen: --> pirq=%d -> irq=%d (gsi=%d)\n", map_irq.pirq, irq, gsi);
out:
return irq;
}
static int acpi_register_gsi_xen_hvm(struct device *dev, u32 gsi,
int trigger, int polarity)
{
if (!xen_hvm_domain())
return -1;
return xen_register_pirq(gsi, trigger,
false /* no mapping of GSI to PIRQ */);
}
#ifdef CONFIG_XEN_PV_DOM0
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, true);
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 int acpi_register_gsi_xen(struct device *dev, u32 gsi,
int trigger, int polarity)
{
return xen_register_gsi(gsi, trigger, polarity);
}
#endif
#endif
#if defined(CONFIG_PCI_MSI)
#include <linux/msi.h>
struct xen_pci_frontend_ops *xen_pci_frontend;
EXPORT_SYMBOL_GPL(xen_pci_frontend);
struct xen_msi_ops {
int (*setup_msi_irqs)(struct pci_dev *dev, int nvec, int type);
void (*teardown_msi_irqs)(struct pci_dev *dev);
};
static struct xen_msi_ops xen_msi_ops __ro_after_init;
static int xen_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
{
int irq, ret, i;
struct msi_desc *msidesc;
int *v;
if (type == PCI_CAP_ID_MSI && nvec > 1)
return 1;
v = kcalloc(max(1, nvec), sizeof(int), 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;
msi_for_each_desc(msidesc, &dev->dev, MSI_DESC_NOTASSOCIATED) {
irq = xen_bind_pirq_msi_to_irq(dev, msidesc, v[i],
(type == PCI_CAP_ID_MSI) ? nvec : 1,
(type == PCI_CAP_ID_MSIX) ?
"pcifront-msi-x" :
"pcifront-msi",
DOMID_SELF);
if (irq < 0) {
ret = irq;
goto free;
}
i++;
}
kfree(v);
return 0;
error:
if (ret == -ENOSYS)
dev_err(&dev->dev, "Xen PCI frontend has not registered MSI/MSI-X support!\n");
else if (ret)
dev_err(&dev->dev, "Xen PCI frontend error: %d!\n", ret);
free:
kfree(v);
return ret;
}
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 fields
* to pass the pirq that we want.
*/
memset(msg, 0, sizeof(*msg));
msg->address_hi = X86_MSI_BASE_ADDRESS_HIGH;
msg->arch_addr_hi.destid_8_31 = pirq >> 8;
msg->arch_addr_lo.destid_0_7 = pirq & 0xFF;
msg->arch_addr_lo.base_address = X86_MSI_BASE_ADDRESS_LOW;
msg->arch_data.delivery_mode = APIC_DELIVERY_MODE_EXTINT;
}
static int xen_hvm_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
{
int irq, pirq;
struct msi_desc *msidesc;
struct msi_msg msg;
if (type == PCI_CAP_ID_MSI && nvec > 1)
return 1;
msi_for_each_desc(msidesc, &dev->dev, MSI_DESC_NOTASSOCIATED) {
pirq = xen_allocate_pirq_msi(dev, msidesc);
if (pirq < 0) {
irq = -ENODEV;
goto error;
}
xen_msi_compose_msg(dev, pirq, &msg);
__pci_write_msi_msg(msidesc, &msg);
dev_dbg(&dev->dev, "xen: msi bound to pirq=%d\n", pirq);
irq = xen_bind_pirq_msi_to_irq(dev, msidesc, pirq,
(type == PCI_CAP_ID_MSI) ? nvec : 1,
(type == PCI_CAP_ID_MSIX) ?
"msi-x" : "msi",
DOMID_SELF);
if (irq < 0)
goto error;
dev_dbg(&dev->dev,
"xen: msi --> pirq=%d --> irq=%d\n", pirq, irq);
}
return 0;
error:
dev_err(&dev->dev, "Failed to create MSI%s! ret=%d!\n",
type == PCI_CAP_ID_MSI ? "" : "-X", irq);
return irq;
}
#ifdef CONFIG_XEN_PV_DOM0
static bool __read_mostly pci_seg_supported = true;
static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
{
int ret = 0;
struct msi_desc *msidesc;
msi_for_each_desc(msidesc, &dev->dev, MSI_DESC_NOTASSOCIATED) {
struct physdev_map_pirq map_irq;
domid_t domid;
domid = ret = xen_find_device_domain_owner(dev);
/* N.B. Casting int's -ENODEV to uint16_t results in 0xFFED,
* hence check ret value for < 0. */
if (ret < 0)
domid = DOMID_SELF;
memset(&map_irq, 0, sizeof(map_irq));
map_irq.domid = domid;
map_irq.type = MAP_PIRQ_TYPE_MSI_SEG;
map_irq.index = -1;
map_irq.pirq = -1;
map_irq.bus = dev->bus->number |
(pci_domain_nr(dev->bus) << 16);
map_irq.devfn = dev->devfn;
if (type == PCI_CAP_ID_MSI && nvec > 1) {
map_irq.type = MAP_PIRQ_TYPE_MULTI_MSI;
map_irq.entry_nr = nvec;
} else if (type == PCI_CAP_ID_MSIX) {
int pos;
unsigned long flags;
u32 table_offset, bir;
pos = dev->msix_cap;
pci_read_config_dword(dev, pos + PCI_MSIX_TABLE,
&table_offset);
bir = (u8)(table_offset & PCI_MSIX_TABLE_BIR);
flags = pci_resource_flags(dev, bir);
if (!flags || (flags & IORESOURCE_UNSET))
return -EINVAL;
map_irq.table_base = pci_resource_start(dev, bir);
map_irq.entry_nr = msidesc->msi_index;
}
ret = -EINVAL;
if (pci_seg_supported)
ret = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq,
&map_irq);
if (type == PCI_CAP_ID_MSI && nvec > 1 && ret) {
/*
* If MAP_PIRQ_TYPE_MULTI_MSI is not available
* there's nothing else we can do in this case.
* Just set ret > 0 so driver can retry with
* single MSI.
*/
ret = 1;
goto out;
}
if (ret == -EINVAL && !pci_domain_nr(dev->bus)) {
map_irq.type = MAP_PIRQ_TYPE_MSI;
map_irq.index = -1;
map_irq.pirq = -1;
map_irq.bus = dev->bus->number;
ret = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq,
&map_irq);
if (ret != -EINVAL)
pci_seg_supported = false;
}
if (ret) {
dev_warn(&dev->dev, "xen map irq failed %d for %d domain\n",
ret, domid);
goto out;
}
ret = xen_bind_pirq_msi_to_irq(dev, msidesc, map_irq.pirq,
(type == PCI_CAP_ID_MSI) ? nvec : 1,
(type == PCI_CAP_ID_MSIX) ? "msi-x" : "msi",
domid);
if (ret < 0)
goto out;
}
ret = 0;
out:
return ret;
}
bool xen_initdom_restore_msi(struct pci_dev *dev)
{
int ret = 0;
if (!xen_initial_domain())
return true;
if (pci_seg_supported) {
struct physdev_pci_device restore_ext;
restore_ext.seg = pci_domain_nr(dev->bus);
restore_ext.bus = dev->bus->number;
restore_ext.devfn = dev->devfn;
ret = HYPERVISOR_physdev_op(PHYSDEVOP_restore_msi_ext,
&restore_ext);
if (ret == -ENOSYS)
pci_seg_supported = false;
WARN(ret && ret != -ENOSYS, "restore_msi_ext -> %d\n", ret);
}
if (!pci_seg_supported) {
struct physdev_restore_msi restore;
restore.bus = dev->bus->number;
restore.devfn = dev->devfn;
ret = HYPERVISOR_physdev_op(PHYSDEVOP_restore_msi, &restore);
WARN(ret && ret != -ENOSYS, "restore_msi -> %d\n", ret);
}
return false;
}
#else /* CONFIG_XEN_PV_DOM0 */
#define xen_initdom_setup_msi_irqs NULL
#endif /* !CONFIG_XEN_PV_DOM0 */
static void xen_teardown_msi_irqs(struct pci_dev *dev)
{
struct msi_desc *msidesc;
int i;
msi_for_each_desc(msidesc, &dev->dev, MSI_DESC_ASSOCIATED) {
for (i = 0; i < msidesc->nvec_used; i++)
xen_destroy_irq(msidesc->irq + i);
}
}
static void xen_pv_teardown_msi_irqs(struct pci_dev *dev)
{
if (dev->msix_enabled)
xen_pci_frontend_disable_msix(dev);
else
xen_pci_frontend_disable_msi(dev);
xen_teardown_msi_irqs(dev);
}
static int xen_msi_domain_alloc_irqs(struct irq_domain *domain,
struct device *dev, int nvec)
{
int type;
if (WARN_ON_ONCE(!dev_is_pci(dev)))
return -EINVAL;
type = to_pci_dev(dev)->msix_enabled ? PCI_CAP_ID_MSIX : PCI_CAP_ID_MSI;
return xen_msi_ops.setup_msi_irqs(to_pci_dev(dev), nvec, type);
}
static void xen_msi_domain_free_irqs(struct irq_domain *domain,
struct device *dev)
{
if (WARN_ON_ONCE(!dev_is_pci(dev)))
return;
xen_msi_ops.teardown_msi_irqs(to_pci_dev(dev));
}
static struct msi_domain_ops xen_pci_msi_domain_ops = {
.domain_alloc_irqs = xen_msi_domain_alloc_irqs,
.domain_free_irqs = xen_msi_domain_free_irqs,
};
static struct msi_domain_info xen_pci_msi_domain_info = {
.ops = &xen_pci_msi_domain_ops,
};
/*
* This irq domain is a blatant violation of the irq domain design, but
* distangling XEN into real irq domains is not a job for mere mortals with
* limited XENology. But it's the least dangerous way for a mere mortal to
* get rid of the arch_*_msi_irqs() hackery in order to store the irq
* domain pointer in struct device. This irq domain wrappery allows to do
* that without breaking XEN terminally.
*/
static __init struct irq_domain *xen_create_pci_msi_domain(void)
{
struct irq_domain *d = NULL;
struct fwnode_handle *fn;
fn = irq_domain_alloc_named_fwnode("XEN-MSI");
if (fn)
d = msi_create_irq_domain(fn, &xen_pci_msi_domain_info, NULL);
/* FIXME: No idea how to survive if this fails */
BUG_ON(!d);
return d;
}
static __init void xen_setup_pci_msi(void)
{
if (xen_pv_domain()) {
if (xen_initial_domain())
xen_msi_ops.setup_msi_irqs = xen_initdom_setup_msi_irqs;
else
xen_msi_ops.setup_msi_irqs = xen_setup_msi_irqs;
xen_msi_ops.teardown_msi_irqs = xen_pv_teardown_msi_irqs;
} else if (xen_hvm_domain()) {
xen_msi_ops.setup_msi_irqs = xen_hvm_setup_msi_irqs;
xen_msi_ops.teardown_msi_irqs = xen_teardown_msi_irqs;
} else {
WARN_ON_ONCE(1);
return;
}
/*
* Override the PCI/MSI irq domain init function. No point
* in allocating the native domain and never use it.
*/
x86_init.irqs.create_pci_msi_domain = xen_create_pci_msi_domain;
/*
* With XEN PIRQ/Eventchannels in use PCI/MSI[-X] masking is solely
* controlled by the hypervisor.
*/
pci_msi_ignore_mask = 1;
}
#else /* CONFIG_PCI_MSI */
static inline void xen_setup_pci_msi(void) { }
#endif /* CONFIG_PCI_MSI */
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;
/* Keep ACPI out of the picture */
acpi_noirq_set();
xen_setup_pci_msi();
return 0;
}
#ifdef CONFIG_PCI_MSI
static void __init xen_hvm_msi_init(void)
{
if (!disable_apic) {
/*
* If hardware supports (x2)APIC virtualization (as indicated
* by hypervisor's leaf 4) then we don't need to use pirqs/
* event channels for MSI handling and instead use regular
* APIC processing
*/
uint32_t eax = cpuid_eax(xen_cpuid_base() + 4);
if (((eax & XEN_HVM_CPUID_X2APIC_VIRT) && x2apic_mode) ||
((eax & XEN_HVM_CPUID_APIC_ACCESS_VIRT) && boot_cpu_has(X86_FEATURE_APIC)))
return;
}
xen_setup_pci_msi();
}
#endif
int __init pci_xen_hvm_init(void)
{
if (!xen_have_vector_callback || !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;
__acpi_unregister_gsi = NULL;
#endif
#ifdef CONFIG_PCI_MSI
/*
* We need to wait until after x2apic is initialized
* before we can set MSI IRQ ops.
*/
x86_platform.apic_post_init = xen_hvm_msi_init;
#endif
return 0;
}
#ifdef CONFIG_XEN_PV_DOM0
int __init pci_xen_initial_domain(void)
{
int irq;
xen_setup_pci_msi();
__acpi_register_gsi = acpi_register_gsi_xen;
__acpi_unregister_gsi = NULL;
/*
* Pre-allocate the legacy IRQs. Use NR_LEGACY_IRQS here
* because we don't have a PIC and thus nr_legacy_irqs() is zero.
*/
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,
true /* Map GSI to PIRQ */);
}
if (0 == nr_ioapics) {
for (irq = 0; irq < nr_legacy_irqs(); irq++)
xen_bind_pirq_gsi_to_irq(irq, irq, 0, "xt-pic");
}
return 0;
}
#endif