linux-kernel - [patch V4-1 01/21] PCI/MSI: Provide MSI_FLAG_PCI_MSI_MASK

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Date: Wed, 26 Jun 2024 21:05:12 +0200
From: Thomas Gleixner <tglx@...utronix.de>
To: LKML <linux-kernel@...r.kernel.org>
Cc: linux-arm-kernel@...ts.infradead.org, linux-pci@...r.kernel.org,
 maz@...nel.org, anna-maria@...utronix.de, shawnguo@...nel.org,
 s.hauer@...gutronix.de, festevam@...il.com, bhelgaas@...gle.com,
 rdunlap@...radead.org, vidyas@...dia.com, ilpo.jarvinen@...ux.intel.com,
 apatel@...tanamicro.com, kevin.tian@...el.com, nipun.gupta@....com,
 den@...inux.co.jp, andrew@...n.ch, gregory.clement@...tlin.com,
 sebastian.hesselbarth@...il.com, gregkh@...uxfoundation.org,
 rafael@...nel.org, alex.williamson@...hat.com, will@...nel.org,
 lorenzo.pieralisi@....com, jgg@...lanox.com, ammarfaizi2@...weeb.org,
 robin.murphy@....com, lpieralisi@...nel.org, nm@...com, kristo@...nel.org,
 vkoul@...nel.org, okaya@...nel.org, agross@...nel.org,
 andersson@...nel.org, mark.rutland@....com,
 shameerali.kolothum.thodi@...wei.com, yuzenghui@...wei.com,
 shivamurthy.shastri@...utronix.de
Subject: [patch V4-1 01/21] PCI/MSI: Provide MSI_FLAG_PCI_MSI_MASK_PARENT

From: Shivamurthy Shastri <shivamurthy.shastri@...utronix.de>

Most ARM(64) PCI/MSI domains mask and unmask in the parent domain after or
before the PCI mask/unmask operation takes place. So there are more than a
dozen of the same wrapper implementation all over the place.

Don't make the same mistake with the new per device PCI/MSI domains and
provide a new MSI feature flag, which lets the domain implementation
enable this sequence in the PCI/MSI code.

Signed-off-by: Shivamurthy Shastri <shivamurthy.shastri@...utronix.de>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Acked-by: Bjorn Helgaas <bhelgaas@...gle.com>
---
v4-1: Remove MSI_FLAG_PCI_MSI_MASK_PARENT from the defaults - Rob
v3: new patch to replace the global static key - Marc Zyngier
---
 drivers/pci/msi/irqdomain.c |   20 ++++++++++++++++++++
 include/linux/msi.h         |    2 ++
 2 files changed, 22 insertions(+)

--- a/drivers/pci/msi/irqdomain.c
+++ b/drivers/pci/msi/irqdomain.c
@@ -148,17 +148,35 @@ static void pci_device_domain_set_desc(m
 	arg->hwirq = desc->msi_index;
 }
 
+static __always_inline void cond_mask_parent(struct irq_data *data)
+{
+	struct msi_domain_info *info = data->domain->host_data;
+
+	if (unlikely(info->flags & MSI_FLAG_PCI_MSI_MASK_PARENT))
+		irq_chip_mask_parent(data);
+}
+
+static __always_inline void cond_unmask_parent(struct irq_data *data)
+{
+	struct msi_domain_info *info = data->domain->host_data;
+
+	if (unlikely(info->flags & MSI_FLAG_PCI_MSI_MASK_PARENT))
+		irq_chip_unmask_parent(data);
+}
+
 static void pci_irq_mask_msi(struct irq_data *data)
 {
 	struct msi_desc *desc = irq_data_get_msi_desc(data);
 
 	pci_msi_mask(desc, BIT(data->irq - desc->irq));
+	cond_mask_parent(data);
 }
 
 static void pci_irq_unmask_msi(struct irq_data *data)
 {
 	struct msi_desc *desc = irq_data_get_msi_desc(data);
 
+	cond_unmask_parent(data);
 	pci_msi_unmask(desc, BIT(data->irq - desc->irq));
 }
 
@@ -195,10 +213,12 @@ static const struct msi_domain_template
 static void pci_irq_mask_msix(struct irq_data *data)
 {
 	pci_msix_mask(irq_data_get_msi_desc(data));
+	cond_mask_parent(data);
 }
 
 static void pci_irq_unmask_msix(struct irq_data *data)
 {
+	cond_unmask_parent(data);
 	pci_msix_unmask(irq_data_get_msi_desc(data));
 }
 
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -556,6 +556,8 @@ enum {
 	MSI_FLAG_USE_DEV_FWNODE		= (1 << 7),
 	/* Set parent->dev into domain->pm_dev on device domain creation */
 	MSI_FLAG_PARENT_PM_DEV		= (1 << 8),
+	/* Support for parent mask/unmask */
+	MSI_FLAG_PCI_MSI_MASK_PARENT	= (1 << 9),
 
 	/* Mask for the generic functionality */
 	MSI_GENERIC_FLAGS_MASK		= GENMASK(15, 0),