[patch 12/22] PCI/MSI: Make arch_restore_msi_irqs() less horrible.

Thomas Gleixner
2021-11-27T01:21:14Z

Make arch_restore_msi_irqs() return a boolean which indicates whether the
core code should restore the MSI message or not. Get rid of the indirection
in x86.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Juergen Gross <jgross@suse.com>
Cc: x86@kernel.org
Cc: xen-devel@lists.xenproject.org
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
---
arch/s390/pci/pci_irq.c | 4 +-
arch/x86/include/asm/x86_init.h | 6 ---
arch/x86/include/asm/xen/hypervisor.h | 8 +++++
arch/x86/kernel/apic/msi.c | 6 +++
arch/x86/kernel/x86_init.c | 12 -------
arch/x86/pci/xen.c | 13 ++++----
drivers/pci/msi.c | 54 +++++++++++-----------------------
include/linux/msi.h | 7 +---
8 files changed, 45 insertions(+), 65 deletions(-)

--- a/arch/s390/pci/pci_irq.c
+++ b/arch/s390/pci/pci_irq.c
@@ -387,13 +387,13 @@ void arch_teardown_msi_irqs(struct pci_d
airq_iv_free(zpci_ibv[0], zdev->msi_first_bit, zdev->msi_nr_irqs);
}

-void arch_restore_msi_irqs(struct pci_dev *pdev)
+bool arch_restore_msi_irqs(struct pci_dev *pdev)
{
struct zpci_dev *zdev = to_zpci(pdev);

if (!zdev->irqs_registered)
zpci_set_irq(zdev);
- default_restore_msi_irqs(pdev);
+ return true;
}

static struct airq_struct zpci_airq = {
--- a/arch/x86/include/asm/x86_init.h
+++ b/arch/x86/include/asm/x86_init.h
@@ -289,12 +289,6 @@ struct x86_platform_ops {
struct x86_hyper_runtime hyper;
};

-struct pci_dev;
-
-struct x86_msi_ops {
- void (*restore_msi_irqs)(struct pci_dev *dev);
-};
-
struct x86_apic_ops {
unsigned int (*io_apic_read) (unsigned int apic, unsigned int reg);
void (*restore)(void);
--- a/arch/x86/include/asm/xen/hypervisor.h
+++ b/arch/x86/include/asm/xen/hypervisor.h
@@ -57,6 +57,14 @@ static inline bool __init xen_x2apic_par
}
#endif

+struct pci_dev;
+
+#ifdef CONFIG_XEN_DOM0
+bool xen_initdom_restore_msi(struct pci_dev *dev);
+#else
+static inline bool xen_initdom_restore_msi(struct pci_dev *dev) { return true; }
+#endif
+
#ifdef CONFIG_HOTPLUG_CPU
void xen_arch_register_cpu(int num);
void xen_arch_unregister_cpu(int num);
--- a/arch/x86/kernel/apic/msi.c
+++ b/arch/x86/kernel/apic/msi.c
@@ -17,6 +17,7 @@
#include <asm/irqdomain.h>
#include <asm/hpet.h>
#include <asm/hw_irq.h>
+#include <asm/hypervisor.h>
#include <asm/apic.h>
#include <asm/irq_remapping.h>

@@ -345,3 +346,8 @@ void dmar_free_hwirq(int irq)
irq_domain_free_irqs(irq, 1);
}
#endif
+
+bool arch_restore_msi_irqs(struct pci_dev *dev)
+{
+ return xen_initdom_restore_msi(dev);
+}
--- a/arch/x86/kernel/x86_init.c
+++ b/arch/x86/kernel/x86_init.c
@@ -145,18 +145,6 @@ struct x86_platform_ops x86_platform __r

EXPORT_SYMBOL_GPL(x86_platform);

-#if defined(CONFIG_PCI_MSI)
-struct x86_msi_ops x86_msi __ro_after_init = {
- .restore_msi_irqs = default_restore_msi_irqs,
-};
-
-/* MSI arch specific hooks */
-void arch_restore_msi_irqs(struct pci_dev *dev)
-{
- x86_msi.restore_msi_irqs(dev);
-}
-#endif
-
struct x86_apic_ops x86_apic_ops __ro_after_init = {
.io_apic_read = native_io_apic_read,
.restore = native_restore_boot_irq_mode,
--- a/arch/x86/pci/xen.c
+++ b/arch/x86/pci/xen.c
@@ -351,10 +351,13 @@ static int xen_initdom_setup_msi_irqs(st
return ret;
}

-static void xen_initdom_restore_msi_irqs(struct pci_dev *dev)
+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;

@@ -375,10 +378,10 @@ static void xen_initdom_restore_msi_irqs
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
-#define xen_initdom_restore_msi_irqs NULL
#endif /* !CONFIG_XEN_PV_DOM0 */

static void xen_teardown_msi_irqs(struct pci_dev *dev)
@@ -466,12 +469,10 @@ static __init struct irq_domain *xen_cre
static __init void xen_setup_pci_msi(void)
{
if (xen_pv_domain()) {
- if (xen_initial_domain()) {
+ if (xen_initial_domain())
xen_msi_ops.setup_msi_irqs = xen_initdom_setup_msi_irqs;
- x86_msi.restore_msi_irqs = xen_initdom_restore_msi_irqs;
- } else {
+ else
xen_msi_ops.setup_msi_irqs = xen_setup_msi_irqs;
- }
xen_msi_ops.teardown_msi_irqs = xen_pv_teardown_msi_irqs;
pci_msi_ignore_mask = 1;
} else if (xen_hvm_domain()) {
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -106,29 +106,6 @@ void __weak arch_teardown_msi_irqs(struc
}
#endif /* CONFIG_PCI_MSI_ARCH_FALLBACKS */

-static void default_restore_msi_irq(struct pci_dev *dev, int irq)
-{
- struct msi_desc *entry;
-
- entry = NULL;
- if (dev->msix_enabled) {
- for_each_pci_msi_entry(entry, dev) {
- if (irq == entry->irq)
- break;
- }
- } else if (dev->msi_enabled) {
- entry = irq_get_msi_desc(irq);
- }
-
- if (entry)
- __pci_write_msi_msg(entry, &entry->msg);
-}
-
-void __weak arch_restore_msi_irqs(struct pci_dev *dev)
-{
- return default_restore_msi_irqs(dev);
-}
-
/*
* PCI 2.3 does not specify mask bits for each MSI interrupt. Attempting to
* mask all MSI interrupts by clearing the MSI enable bit does not work
@@ -242,14 +219,6 @@ void pci_msi_unmask_irq(struct irq_data
}
EXPORT_SYMBOL_GPL(pci_msi_unmask_irq);

-void default_restore_msi_irqs(struct pci_dev *dev)
-{
- struct msi_desc *entry;
-
- for_each_pci_msi_entry(entry, dev)
- default_restore_msi_irq(dev, entry->irq);
-}
-
void __pci_read_msi_msg(struct msi_desc *entry, struct msi_msg *msg)
{
struct pci_dev *dev = msi_desc_to_pci_dev(entry);
@@ -403,10 +372,19 @@ static void pci_msi_set_enable(struct pc
pci_write_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, control);
}

+/*
+ * Architecture override returns true when the PCI MSI message should be
+ * written by the generic restore function.
+ */
+bool __weak arch_restore_msi_irqs(struct pci_dev *dev)
+{
+ return true;
+}
+
static void __pci_restore_msi_state(struct pci_dev *dev)
{
- u16 control;
struct msi_desc *entry;
+ u16 control;

if (!dev->msi_enabled)
return;
@@ -415,7 +393,8 @@ static void __pci_restore_msi_state(stru

pci_intx_for_msi(dev, 0);
pci_msi_set_enable(dev, 0);
- arch_restore_msi_irqs(dev);
+ if (arch_restore_msi_irqs(dev))
+ __pci_write_msi_msg(entry, &entry->msg);

pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &control);
pci_msi_update_mask(entry, 0, 0);
@@ -437,6 +416,7 @@ static void pci_msix_clear_and_set_ctrl(
static void __pci_restore_msix_state(struct pci_dev *dev)
{
struct msi_desc *entry;
+ bool write_msg;

if (!dev->msix_enabled)
return;
@@ -447,9 +427,13 @@ static void __pci_restore_msix_state(str
pci_msix_clear_and_set_ctrl(dev, 0,
PCI_MSIX_FLAGS_ENABLE | PCI_MSIX_FLAGS_MASKALL);

- arch_restore_msi_irqs(dev);
- for_each_pci_msi_entry(entry, dev)
+ write_msg = arch_restore_msi_irqs(dev);
+
+ for_each_pci_msi_entry(entry, dev) {
+ if (write_msg)
+ __pci_write_msi_msg(entry, &entry->msg);
pci_msix_write_vector_ctrl(entry, entry->pci.msix_ctrl);
+ }

pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_MASKALL, 0);
}
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -272,11 +272,10 @@ static inline void arch_teardown_msi_irq
#endif

/*
- * The restore hooks are still available as they are useful even
- * for fully irq domain based setups. Courtesy to XEN/X86.
+ * The restore hook is still available even for fully irq domain based
+ * setups. Courtesy to XEN/X86.
*/
-void arch_restore_msi_irqs(struct pci_dev *dev);
-void default_restore_msi_irqs(struct pci_dev *dev);
+bool arch_restore_msi_irqs(struct pci_dev *dev);

#ifdef CONFIG_GENERIC_MSI_IRQ_DOMAIN