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Subject[PATCH] xen: add support for MSI message groups
Date
Add support for MSI message groups for Xen Dom0 using the
MAP_PIRQ_TYPE_MULTI_MSI pirq map type.

In order to keep track of which pirq is the first one in the group all
pirqs in the MSI group except for the first one have the newly
introduced PIRQ_MSI_GROUP flag set. This prevents calling
PHYSDEVOP_unmap_pirq on them, since the unmap must be done with the
first pirq in the group.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
---
Tested with an Intel ICH8 AHCI SATA controller.
---
arch/x86/pci/xen.c | 29 ++++++++++++++------
drivers/xen/events/events_base.c | 47 +++++++++++++++++++++++-----------
drivers/xen/events/events_internal.h | 1 +
include/xen/events.h | 2 +-
include/xen/interface/physdev.h | 1 +
5 files changed, 55 insertions(+), 25 deletions(-)

diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
index 103e702..905956f 100644
--- a/arch/x86/pci/xen.c
+++ b/arch/x86/pci/xen.c
@@ -178,6 +178,7 @@ static int xen_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
i = 0;
list_for_each_entry(msidesc, &dev->msi_list, list) {
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",
@@ -245,6 +246,7 @@ static int xen_hvm_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
"xen: msi already 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);
@@ -269,9 +271,6 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
int ret = 0;
struct msi_desc *msidesc;

- if (type == PCI_CAP_ID_MSI && nvec > 1)
- return 1;
-
list_for_each_entry(msidesc, &dev->msi_list, list) {
struct physdev_map_pirq map_irq;
domid_t domid;
@@ -291,7 +290,10 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
(pci_domain_nr(dev->bus) << 16);
map_irq.devfn = dev->devfn;

- if (type == PCI_CAP_ID_MSIX) {
+ 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;
u32 table_offset, bir;

@@ -308,6 +310,16 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
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;
@@ -324,11 +336,10 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
goto out;
}

- ret = xen_bind_pirq_msi_to_irq(dev, msidesc,
- map_irq.pirq,
- (type == PCI_CAP_ID_MSIX) ?
- "msi-x" : "msi",
- domid);
+ 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;
}
diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index f4a9e33..ff20ae2 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -391,10 +391,10 @@ static void xen_irq_init(unsigned irq)
list_add_tail(&info->list, &xen_irq_list_head);
}

-static int __must_check xen_allocate_irq_dynamic(void)
+static int __must_check xen_allocate_irqs_dynamic(int nvec)
{
int first = 0;
- int irq;
+ int i, irq;

#ifdef CONFIG_X86_IO_APIC
/*
@@ -408,14 +408,22 @@ static int __must_check xen_allocate_irq_dynamic(void)
first = get_nr_irqs_gsi();
#endif

- irq = irq_alloc_desc_from(first, -1);
+ irq = irq_alloc_descs_from(first, nvec, -1);

- if (irq >= 0)
- xen_irq_init(irq);
+ if (irq >= 0) {
+ for (i = 0; i < nvec; i++)
+ xen_irq_init(irq + i);
+ }

return irq;
}

+static inline int __must_check xen_allocate_irq_dynamic(void)
+{
+
+ return xen_allocate_irqs_dynamic(1);
+}
+
static int __must_check xen_allocate_irq_gsi(unsigned gsi)
{
int irq;
@@ -741,22 +749,25 @@ int xen_allocate_pirq_msi(struct pci_dev *dev, struct msi_desc *msidesc)
}

int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
- int pirq, const char *name, domid_t domid)
+ int pirq, int nvec, const char *name, domid_t domid)
{
- int irq, ret;
+ int i, irq, ret;

mutex_lock(&irq_mapping_update_lock);

- irq = xen_allocate_irq_dynamic();
+ irq = xen_allocate_irqs_dynamic(nvec);
if (irq < 0)
goto out;

- irq_set_chip_and_handler_name(irq, &xen_pirq_chip, handle_edge_irq,
- name);
+ for (i = 0; i < nvec; i++) {
+ irq_set_chip_and_handler_name(irq + i, &xen_pirq_chip, handle_edge_irq, name);
+
+ ret = xen_irq_info_pirq_setup(irq + i, 0, pirq + i, 0, domid,
+ i == 0 ? 0 : PIRQ_MSI_GROUP);
+ if (ret < 0)
+ goto error_irq;
+ }

- ret = xen_irq_info_pirq_setup(irq, 0, pirq, 0, domid, 0);
- if (ret < 0)
- goto error_irq;
ret = irq_set_msi_desc(irq, msidesc);
if (ret < 0)
goto error_irq;
@@ -764,7 +775,8 @@ out:
mutex_unlock(&irq_mapping_update_lock);
return irq;
error_irq:
- __unbind_from_irq(irq);
+ for (; i >= 0; i--)
+ __unbind_from_irq(irq + i);
mutex_unlock(&irq_mapping_update_lock);
return ret;
}
@@ -783,7 +795,12 @@ int xen_destroy_irq(int irq)
if (!desc)
goto out;

- if (xen_initial_domain()) {
+ /*
+ * If trying to remove a vector in a MSI group different
+ * than the first one skip the PIRQ unmap unless this vector
+ * is the first one in the group.
+ */
+ if (xen_initial_domain() && !(info->u.pirq.flags & PIRQ_MSI_GROUP)) {
unmap_irq.pirq = info->u.pirq.pirq;
unmap_irq.domid = info->u.pirq.domid;
rc = HYPERVISOR_physdev_op(PHYSDEVOP_unmap_pirq, &unmap_irq);
diff --git a/drivers/xen/events/events_internal.h b/drivers/xen/events/events_internal.h
index 677f41a..50c2050a 100644
--- a/drivers/xen/events/events_internal.h
+++ b/drivers/xen/events/events_internal.h
@@ -53,6 +53,7 @@ struct irq_info {

#define PIRQ_NEEDS_EOI (1 << 0)
#define PIRQ_SHAREABLE (1 << 1)
+#define PIRQ_MSI_GROUP (1 << 2)

struct evtchn_ops {
unsigned (*max_channels)(void);
diff --git a/include/xen/events.h b/include/xen/events.h
index c9c85cf..2ae7e03 100644
--- a/include/xen/events.h
+++ b/include/xen/events.h
@@ -102,7 +102,7 @@ int xen_bind_pirq_gsi_to_irq(unsigned gsi,
int xen_allocate_pirq_msi(struct pci_dev *dev, struct msi_desc *msidesc);
/* Bind an PSI pirq to an irq. */
int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
- int pirq, const char *name, domid_t domid);
+ int pirq, int nvec, const char *name, domid_t domid);
#endif

/* De-allocates the above mentioned physical interrupt. */
diff --git a/include/xen/interface/physdev.h b/include/xen/interface/physdev.h
index 42721d1..eb13326d 100644
--- a/include/xen/interface/physdev.h
+++ b/include/xen/interface/physdev.h
@@ -131,6 +131,7 @@ struct physdev_irq {
#define MAP_PIRQ_TYPE_GSI 0x1
#define MAP_PIRQ_TYPE_UNKNOWN 0x2
#define MAP_PIRQ_TYPE_MSI_SEG 0x3
+#define MAP_PIRQ_TYPE_MULTI_MSI 0x4

#define PHYSDEVOP_map_pirq 13
struct physdev_map_pirq {
--
1.7.7.5 (Apple Git-26)
--
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