From: Megha Dey <megha.dey@intel.com>
To: tglx@linutronix.de
Cc: alex.williamson@redhat.com, kevin.tian@intel.com,
tony.luck@intel.com, dave.jiang@intel.com, ashok.raj@intel.com,
kvm@vger.kernel.org, ravi.v.shankar@intel.com, maz@kernel.org,
x86@kernel.org, linux-kernel@vger.kernel.org,
iommu@lists.linux-foundation.org, jgg@mellanox.com,
megha.dey@intel.com, linux-pci@vger.kernel.org,
bhelgaas@google.com, dan.j.williams@intel.com, dwmw@amazon.co.uk
Subject: [Patch V2 05/13] genirq/msi: Provide and use msi_domain_set_default_info_flags()
Date: Fri, 26 Feb 2021 12:11:09 -0800 [thread overview]
Message-ID: <1614370277-23235-6-git-send-email-megha.dey@intel.com> (raw)
In-Reply-To: <1614370277-23235-1-git-send-email-megha.dey@intel.com>
From: Thomas Gleixner <tglx@linutronix.de>
MSI interrupts have some common flags which should be set not only for
PCI/MSI interrupts.
Move the PCI/MSI flag setting into a common function so it can be reused.
Reviewed-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Megha Dey <megha.dey@intel.com>
---
drivers/pci/msi.c | 7 +------
include/linux/msi.h | 1 +
kernel/irq/msi.c | 24 ++++++++++++++++++++++++
3 files changed, 26 insertions(+), 6 deletions(-)
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 3162f88..20d2512 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -1492,12 +1492,7 @@ struct irq_domain *pci_msi_create_irq_domain(struct fwnode_handle *fwnode,
if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
pci_msi_domain_update_chip_ops(info);
- info->flags |= MSI_FLAG_ACTIVATE_EARLY;
- if (IS_ENABLED(CONFIG_GENERIC_IRQ_RESERVATION_MODE))
- info->flags |= MSI_FLAG_MUST_REACTIVATE;
-
- /* PCI-MSI is oneshot-safe */
- info->chip->flags |= IRQCHIP_ONESHOT_SAFE;
+ msi_domain_set_default_info_flags(info);
domain = msi_create_irq_domain(fwnode, info, parent);
if (!domain)
diff --git a/include/linux/msi.h b/include/linux/msi.h
index f3e54d2..f6e52de 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -454,6 +454,7 @@ int platform_msi_domain_alloc(struct irq_domain *domain, unsigned int virq,
void platform_msi_domain_free(struct irq_domain *domain, unsigned int virq,
unsigned int nvec);
void *platform_msi_get_host_data(struct irq_domain *domain);
+void msi_domain_set_default_info_flags(struct msi_domain_info *info);
#endif /* CONFIG_GENERIC_MSI_IRQ_DOMAIN */
#ifdef CONFIG_PCI_MSI_IRQ_DOMAIN
diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
index b338d62..c54316d 100644
--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -70,6 +70,30 @@ void get_cached_msi_msg(unsigned int irq, struct msi_msg *msg)
EXPORT_SYMBOL_GPL(get_cached_msi_msg);
#ifdef CONFIG_GENERIC_MSI_IRQ_DOMAIN
+void msi_domain_set_default_info_flags(struct msi_domain_info *info)
+{
+ /* Required so that a device latches a valid MSI message on startup */
+ info->flags |= MSI_FLAG_ACTIVATE_EARLY;
+
+ /*
+ * Interrupt reservation mode allows to stear the MSI message of an
+ * inactive device to a special (usually spurious interrupt) target.
+ * This allows to prevent interrupt vector exhaustion e.g. on x86.
+ * But (PCI)MSI interrupts are activated early - see above - so the
+ * interrupt request/startup sequence would not try to allocate a
+ * usable vector which means that the device interrupts would end
+ * up on the special vector and issue spurious interrupt messages.
+ * Setting the reactivation flag ensures that when the interrupt
+ * is requested the activation is invoked again so that a real
+ * vector can be allocated.
+ */
+ if (IS_ENABLED(CONFIG_GENERIC_IRQ_RESERVATION_MODE))
+ info->flags |= MSI_FLAG_MUST_REACTIVATE;
+
+ /* MSI is oneshot-safe at least in theory */
+ info->chip->flags |= IRQCHIP_ONESHOT_SAFE;
+}
+
static inline void irq_chip_write_msi_msg(struct irq_data *data,
struct msi_msg *msg)
{
--
2.7.4
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next prev parent reply other threads:[~2021-02-26 20:11 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-26 20:11 [Patch V2 00/13] Introduce dev-msi and interrupt message store Megha Dey
2021-02-26 20:11 ` [Patch V2 01/13] x86/irq: Add DEV_MSI allocation type Megha Dey
2021-02-26 20:11 ` [Patch V2 02/13] x86/msi: Rename and rework pci_msi_prepare() to cover non-PCI MSI Megha Dey
2021-02-26 20:11 ` [Patch V2 03/13] platform-msi: Provide default irq_chip:: Ack Megha Dey
2021-02-26 20:11 ` [Patch V2 04/13] genirq/proc: Take buslock on affinity write Megha Dey
2021-02-26 20:11 ` Megha Dey [this message]
2021-02-26 20:11 ` [Patch V2 06/13] platform-msi: Add device MSI infrastructure Megha Dey
2021-02-26 20:11 ` [Patch V2 07/13] irqdomain/msi: Provide msi_alloc/free_store() callbacks Megha Dey
2021-03-25 17:08 ` Marc Zyngier
2021-03-25 18:44 ` Thomas Gleixner
2021-03-26 10:14 ` Marc Zyngier
2021-02-26 20:11 ` [Patch V2 08/13] genirq: Set auxiliary data for an interrupt Megha Dey
2021-03-25 17:23 ` Marc Zyngier
2021-03-25 18:59 ` Thomas Gleixner
2021-03-26 10:32 ` Marc Zyngier
2021-03-26 15:09 ` Thomas Gleixner
2021-02-26 20:11 ` [Patch V2 09/13] iommu/vt-d: Add DEV-MSI support Megha Dey
2021-02-26 20:11 ` [Patch V2 10/13] iommu: Add capability IOMMU_CAP_VIOMMU_HINT Megha Dey
2021-02-26 20:11 ` [Patch V2 11/13] platform-msi: Add platform check for subdevice irq domain Megha Dey
2021-02-26 20:11 ` [Patch V2 12/13] irqchip: Add IMS (Interrupt Message Store) driver Megha Dey
2021-03-25 17:43 ` Marc Zyngier
2021-03-25 19:07 ` Thomas Gleixner
2021-03-26 1:03 ` Dey, Megha
2021-02-26 20:11 ` [Patch V2 13/13] genirq/msi: Provide helpers to return Linux IRQ/dev_msi hw IRQ number Megha Dey
2021-03-25 17:53 ` Marc Zyngier
2021-03-26 1:02 ` Dey, Megha
2021-03-26 12:58 ` Marc Zyngier
2021-03-30 1:57 ` Dey, Megha
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