[tip: irq/urgent] genirq/msi, platform-msi: Ensure that MSI descriptors are unreferenced

[tip-bot2 for Thomas Gleixner]

The following commit has been merged into the irq/urgent branch of tip:

Commit-ID:     0fb7fb713461e44b12e72c292bf90ee300f40710
Gitweb:        https://git.kernel.org/tip/0fb7fb713461e44b12e72c292bf90ee300f40710
Author:        Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate:    Wed, 01 Mar 2023 22:07:48 +01:00
Committer:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Thu, 02 Mar 2023 18:09:44 +01:00

genirq/msi, platform-msi: Ensure that MSI descriptors are unreferenced

Miquel reported a warning in the MSI core which is triggered when
interrupts are freed via platform_msi_device_domain_free().

This code got reworked to use core functions for freeing the MSI
descriptors, but nothing took care to clear the msi_desc->irq entry, which
then triggers the warning in msi_free_msi_desc() which uses desc->irq to
validate that the descriptor has been torn down. The same issue exists in
msi_domain_populate_irqs().

Up to the point that msi_free_msi_descs() grew a warning for this case,
this went un-noticed.

Provide the counterpart of msi_domain_populate_irqs() and invoke it in
platform_msi_device_domain_free() before freeing the interrupts and MSI
descriptors and also in the error path of msi_domain_populate_irqs().

Fixes: 2f2940d16823 ("genirq/msi: Remove filter from msi_free_descs_free_range()")
Reported-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Tested-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/87mt4wkwnv.ffs@tglx
---
 drivers/base/platform-msi.c |  1 +
 include/linux/msi.h         |  2 ++
 kernel/irq/msi.c            | 23 ++++++++++++++++++++++-
 3 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/drivers/base/platform-msi.c b/drivers/base/platform-msi.c
index 5883e76..f37ad34 100644
--- a/drivers/base/platform-msi.c
+++ b/drivers/base/platform-msi.c
@@ -324,6 +324,7 @@ void platform_msi_device_domain_free(struct irq_domain *domain, unsigned int vir
 	struct platform_msi_priv_data *data = domain->host_data;
 
 	msi_lock_descs(data->dev);
+	msi_domain_depopulate_descs(data->dev, virq, nr_irqs);
 	irq_domain_free_irqs_common(domain, virq, nr_irqs);
 	msi_free_msi_descs_range(data->dev, virq, virq + nr_irqs - 1);
 	msi_unlock_descs(data->dev);
diff --git a/include/linux/msi.h b/include/linux/msi.h
index a112b91..15dd718 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -631,6 +631,8 @@ int msi_domain_prepare_irqs(struct irq_domain *domain, struct device *dev,
 			    int nvec, msi_alloc_info_t *args);
 int msi_domain_populate_irqs(struct irq_domain *domain, struct device *dev,
 			     int virq, int nvec, msi_alloc_info_t *args);
+void msi_domain_depopulate_descs(struct device *dev, int virq, int nvec);
+
 struct irq_domain *
 __platform_msi_create_device_domain(struct device *dev,
 				    unsigned int nvec,
diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
index efd21b7..d169ee0 100644
--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -1109,14 +1109,35 @@ int msi_domain_populate_irqs(struct irq_domain *domain, struct device *dev,
 	return 0;
 
 fail:
-	for (--virq; virq >= virq_base; virq--)
+	for (--virq; virq >= virq_base; virq--) {
+		msi_domain_depopulate_descs(dev, virq, 1);
 		irq_domain_free_irqs_common(domain, virq, 1);
+	}
 	msi_domain_free_descs(dev, &ctrl);
 unlock:
 	msi_unlock_descs(dev);
 	return ret;
 }
 
+void msi_domain_depopulate_descs(struct device *dev, int virq_base, int nvec)
+{
+	struct msi_ctrl ctrl = {
+		.domid	= MSI_DEFAULT_DOMAIN,
+		.first  = virq_base,
+		.last	= virq_base + nvec - 1,
+	};
+	struct msi_desc *desc;
+	struct xarray *xa;
+	unsigned long idx;
+
+	if (!msi_ctrl_valid(dev, &ctrl))
+		return;
+
+	xa = &dev->msi.data->__domains[ctrl.domid].store;
+	xa_for_each_range(xa, idx, desc, ctrl.first, ctrl.last)
+		desc->irq = 0;
+}
+
 /*
  * Carefully check whether the device can use reservation mode. If
  * reservation mode is enabled then the early activation will assign a