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Subject[tip: irq/urgent] genirq/msi, platform-msi: Ensure that MSI descriptors are unreferenced
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@linutronix.de>
AuthorDate: Wed, 01 Mar 2023 22:07:48 +01:00
Committer: Thomas Gleixner <tglx@linutronix.de>
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@bootlin.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: stable@vger.kernel.org
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
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