[PATCH 0/3] PCI/MSI: Remove IMS (Interrupt Message Store) support for now

[PATCH 0/3] PCI/MSI: Remove IMS (Interrupt Message Store) support for now

[Bjorn Helgaas]

From: Bjorn Helgaas <bhelgaas@google.com>

IMS (Interrupt Message Store) support appeared in v6.2, but there are no
users yet.

Remove it for now.  We can add it back when a user comes along.

Bjorn Helgaas (3):
  Revert "PCI/MSI: Provide stubs for IMS functions"
  Revert "PCI/MSI: Provide pci_ims_alloc/free_irq()"
  Revert "PCI/MSI: Provide IMS (Interrupt Message Store) support"

 drivers/pci/msi/api.c       | 50 -------------------------------
 drivers/pci/msi/irqdomain.c | 59 -------------------------------------
 include/linux/pci.h         | 26 ----------------
 3 files changed, 135 deletions(-)

-- 
2.34.1

[PATCH 1/3] Revert "PCI/MSI: Provide stubs for IMS functions"

[Bjorn Helgaas]

From: Bjorn Helgaas <bhelgaas@google.com>

This reverts commit 41efa431244f6498833ff8ee8dde28c4924c5479.

IMS (Interrupt Message Store) support appeared in v6.2, but there are no
users yet.

Remove it for now.  We can add it back when a user comes along.  If this is
re-added later, this could be squashed with these commits:

  0194425af0c8 ("PCI/MSI: Provide IMS (Interrupt Message Store) support")
  c9e5bea27383 ("PCI/MSI: Provide pci_ims_alloc/free_irq()")

which added the non-stub implementations.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
 include/linux/pci.h | 34 ++++++++--------------------------
 1 file changed, 8 insertions(+), 26 deletions(-)

diff --git a/include/linux/pci.h b/include/linux/pci.h
index 16493426a04f..abbef75b2b92 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1658,8 +1658,6 @@ struct msix_entry {
 	u16	entry;	/* Driver uses to specify entry, OS writes */
 };
 
-struct msi_domain_template;
-
 #ifdef CONFIG_PCI_MSI
 int pci_msi_vec_count(struct pci_dev *dev);
 void pci_disable_msi(struct pci_dev *dev);
@@ -1692,11 +1690,6 @@ void pci_msix_free_irq(struct pci_dev *pdev, struct msi_map map);
 void pci_free_irq_vectors(struct pci_dev *dev);
 int pci_irq_vector(struct pci_dev *dev, unsigned int nr);
 const struct cpumask *pci_irq_get_affinity(struct pci_dev *pdev, int vec);
-bool pci_create_ims_domain(struct pci_dev *pdev, const struct msi_domain_template *template,
-			   unsigned int hwsize, void *data);
-struct msi_map pci_ims_alloc_irq(struct pci_dev *pdev, union msi_instance_cookie *icookie,
-				 const struct irq_affinity_desc *affdesc);
-void pci_ims_free_irq(struct pci_dev *pdev, struct msi_map map);
 
 #else
 static inline int pci_msi_vec_count(struct pci_dev *dev) { return -ENOSYS; }
@@ -1760,25 +1753,6 @@ static inline const struct cpumask *pci_irq_get_affinity(struct pci_dev *pdev,
 {
 	return cpu_possible_mask;
 }
-
-static inline bool pci_create_ims_domain(struct pci_dev *pdev,
-					 const struct msi_domain_template *template,
-					 unsigned int hwsize, void *data)
-{ return false; }
-
-static inline struct msi_map pci_ims_alloc_irq(struct pci_dev *pdev,
-					       union msi_instance_cookie *icookie,
-					       const struct irq_affinity_desc *affdesc)
-{
-	struct msi_map map = { .index = -ENOSYS, };
-
-	return map;
-}
-
-static inline void pci_ims_free_irq(struct pci_dev *pdev, struct msi_map map)
-{
-}
-
 #endif
 
 /**
@@ -2690,6 +2664,14 @@ static inline bool pci_is_thunderbolt_attached(struct pci_dev *pdev)
 void pci_uevent_ers(struct pci_dev *pdev, enum  pci_ers_result err_type);
 #endif
 
+struct msi_domain_template;
+
+bool pci_create_ims_domain(struct pci_dev *pdev, const struct msi_domain_template *template,
+			   unsigned int hwsize, void *data);
+struct msi_map pci_ims_alloc_irq(struct pci_dev *pdev, union msi_instance_cookie *icookie,
+				 const struct irq_affinity_desc *affdesc);
+void pci_ims_free_irq(struct pci_dev *pdev, struct msi_map map);
+
 #include <linux/dma-mapping.h>
 
 #define pci_printk(level, pdev, fmt, arg...) \
-- 
2.34.1

RE: [PATCH 1/3] Revert "PCI/MSI: Provide stubs for IMS functions"

[Tian, Kevin]

> From: Bjorn Helgaas <helgaas@kernel.org>
> Sent: Tuesday, April 2, 2024 7:23 AM
> 
> From: Bjorn Helgaas <bhelgaas@google.com>
> 
> This reverts commit 41efa431244f6498833ff8ee8dde28c4924c5479.
> 
> IMS (Interrupt Message Store) support appeared in v6.2, but there are no
> users yet.
> 
> Remove it for now.  We can add it back when a user comes along.  If this is
> re-added later, this could be squashed with these commits:
> 
>   0194425af0c8 ("PCI/MSI: Provide IMS (Interrupt Message Store) support")
>   c9e5bea27383 ("PCI/MSI: Provide pci_ims_alloc/free_irq()")
> 
> which added the non-stub implementations.
> 
> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

Reviewed-by: Kevin Tian <kevin.tian@intel.com>

[PATCH 2/3] Revert "PCI/MSI: Provide pci_ims_alloc/free_irq()"

[Bjorn Helgaas]

From: Bjorn Helgaas <bhelgaas@google.com>

This reverts commit c9e5bea273834a63b5e9ba90ad94b305ba50704e.

IMS (Interrupt Message Store) support appeared in v6.2, but there are no
users yet.

Remove it for now.  We can add it back when a user comes along.  If this is
re-added later, the relevant part of 41efa431244f ("PCI/MSI: Provide stubs
for IMS functions") should be squashed into it.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
 drivers/pci/msi/api.c | 50 -------------------------------------------
 include/linux/pci.h   |  3 ---
 2 files changed, 53 deletions(-)

diff --git a/drivers/pci/msi/api.c b/drivers/pci/msi/api.c
index be679aa5db64..3c1cd29c5cf2 100644
--- a/drivers/pci/msi/api.c
+++ b/drivers/pci/msi/api.c
@@ -365,56 +365,6 @@ const struct cpumask *pci_irq_get_affinity(struct pci_dev *dev, int nr)
 }
 EXPORT_SYMBOL(pci_irq_get_affinity);
 
-/**
- * pci_ims_alloc_irq - Allocate an interrupt on a PCI/IMS interrupt domain
- * @dev:	The PCI device to operate on
- * @icookie:	Pointer to an IMS implementation specific cookie for this
- *		IMS instance (PASID, queue ID, pointer...).
- *		The cookie content is copied into the MSI descriptor for the
- *		interrupt chip callbacks or domain specific setup functions.
- * @affdesc:	Optional pointer to an interrupt affinity descriptor
- *
- * There is no index for IMS allocations as IMS is an implementation
- * specific storage and does not have any direct associations between
- * index, which might be a pure software construct, and device
- * functionality. This association is established by the driver either via
- * the index - if there is a hardware table - or in case of purely software
- * managed IMS implementation the association happens via the
- * irq_write_msi_msg() callback of the implementation specific interrupt
- * chip, which utilizes the provided @icookie to store the MSI message in
- * the appropriate place.
- *
- * Return: A struct msi_map
- *
- *	On success msi_map::index contains the allocated index (>= 0) and
- *	msi_map::virq the allocated Linux interrupt number (> 0).
- *
- *	On fail msi_map::index contains the error code and msi_map::virq
- *	is set to 0.
- */
-struct msi_map pci_ims_alloc_irq(struct pci_dev *dev, union msi_instance_cookie *icookie,
-				 const struct irq_affinity_desc *affdesc)
-{
-	return msi_domain_alloc_irq_at(&dev->dev, MSI_SECONDARY_DOMAIN, MSI_ANY_INDEX,
-				       affdesc, icookie);
-}
-EXPORT_SYMBOL_GPL(pci_ims_alloc_irq);
-
-/**
- * pci_ims_free_irq - Allocate an interrupt on a PCI/IMS interrupt domain
- *		      which was allocated via pci_ims_alloc_irq()
- * @dev:	The PCI device to operate on
- * @map:	A struct msi_map describing the interrupt to free as
- *		returned from pci_ims_alloc_irq()
- */
-void pci_ims_free_irq(struct pci_dev *dev, struct msi_map map)
-{
-	if (WARN_ON_ONCE(map.index < 0 || map.virq <= 0))
-		return;
-	msi_domain_free_irqs_range(&dev->dev, MSI_SECONDARY_DOMAIN, map.index, map.index);
-}
-EXPORT_SYMBOL_GPL(pci_ims_free_irq);
-
 /**
  * pci_free_irq_vectors() - Free previously allocated IRQs for a device
  * @dev: the PCI device to operate on
diff --git a/include/linux/pci.h b/include/linux/pci.h
index abbef75b2b92..3deb3e42d990 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -2668,9 +2668,6 @@ struct msi_domain_template;
 
 bool pci_create_ims_domain(struct pci_dev *pdev, const struct msi_domain_template *template,
 			   unsigned int hwsize, void *data);
-struct msi_map pci_ims_alloc_irq(struct pci_dev *pdev, union msi_instance_cookie *icookie,
-				 const struct irq_affinity_desc *affdesc);
-void pci_ims_free_irq(struct pci_dev *pdev, struct msi_map map);
 
 #include <linux/dma-mapping.h>
 
-- 
2.34.1

RE: [PATCH 2/3] Revert "PCI/MSI: Provide pci_ims_alloc/free_irq()"

[Tian, Kevin]

> From: Bjorn Helgaas <helgaas@kernel.org>
> Sent: Tuesday, April 2, 2024 7:23 AM
> 
> From: Bjorn Helgaas <bhelgaas@google.com>
> 
> This reverts commit c9e5bea273834a63b5e9ba90ad94b305ba50704e.
> 
> IMS (Interrupt Message Store) support appeared in v6.2, but there are no
> users yet.
> 
> Remove it for now.  We can add it back when a user comes along.  If this is
> re-added later, the relevant part of 41efa431244f ("PCI/MSI: Provide stubs
> for IMS functions") should be squashed into it.
> 
> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

Reviewed-by: Kevin Tian <kevin.tian@intel.com>

[PATCH 3/3] Revert "PCI/MSI: Provide IMS (Interrupt Message Store) support"

[Bjorn Helgaas]

From: Bjorn Helgaas <bhelgaas@google.com>

This reverts commit 0194425af0c87acaad457989a2c6d90dba58e776.

IMS (Interrupt Message Store) support appeared in v6.2, but there are no
users yet.

Remove it for now.  We can add it back when a user comes along.  If this is
re-added later, the relevant part of 41efa431244f ("PCI/MSI: Provide stubs
for IMS functions") should be squashed into it.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
 drivers/pci/msi/irqdomain.c | 59 -------------------------------------
 include/linux/pci.h         |  5 ----
 2 files changed, 64 deletions(-)

diff --git a/drivers/pci/msi/irqdomain.c b/drivers/pci/msi/irqdomain.c
index cfd84a899c82..03d2dd25790d 100644
--- a/drivers/pci/msi/irqdomain.c
+++ b/drivers/pci/msi/irqdomain.c
@@ -355,65 +355,6 @@ bool pci_msi_domain_supports(struct pci_dev *pdev, unsigned int feature_mask,
 	return (supported & feature_mask) == feature_mask;
 }
 
-/**
- * pci_create_ims_domain - Create a secondary IMS domain for a PCI device
- * @pdev:	The PCI device to operate on
- * @template:	The MSI info template which describes the domain
- * @hwsize:	The size of the hardware entry table or 0 if the domain
- *		is purely software managed
- * @data:	Optional pointer to domain specific data to be stored
- *		in msi_domain_info::data
- *
- * Return: True on success, false otherwise
- *
- * An IMS domain is expected to have the following constraints:
- *	- The index space is managed by the core code
- *
- *	- There is no requirement for consecutive index ranges
- *
- *	- The interrupt chip must provide the following callbacks:
- *		- irq_mask()
- *		- irq_unmask()
- *		- irq_write_msi_msg()
- *
- *	- The interrupt chip must provide the following optional callbacks
- *	  when the irq_mask(), irq_unmask() and irq_write_msi_msg() callbacks
- *	  cannot operate directly on hardware, e.g. in the case that the
- *	  interrupt message store is in queue memory:
- *		- irq_bus_lock()
- *		- irq_bus_unlock()
- *
- *	  These callbacks are invoked from preemptible task context and are
- *	  allowed to sleep. In this case the mandatory callbacks above just
- *	  store the information. The irq_bus_unlock() callback is supposed
- *	  to make the change effective before returning.
- *
- *	- Interrupt affinity setting is handled by the underlying parent
- *	  interrupt domain and communicated to the IMS domain via
- *	  irq_write_msi_msg().
- *
- * The domain is automatically destroyed when the PCI device is removed.
- */
-bool pci_create_ims_domain(struct pci_dev *pdev, const struct msi_domain_template *template,
-			   unsigned int hwsize, void *data)
-{
-	struct irq_domain *domain = dev_get_msi_domain(&pdev->dev);
-
-	if (!domain || !irq_domain_is_msi_parent(domain))
-		return false;
-
-	if (template->info.bus_token != DOMAIN_BUS_PCI_DEVICE_IMS ||
-	    !(template->info.flags & MSI_FLAG_ALLOC_SIMPLE_MSI_DESCS) ||
-	    !(template->info.flags & MSI_FLAG_FREE_MSI_DESCS) ||
-	    !template->chip.irq_mask || !template->chip.irq_unmask ||
-	    !template->chip.irq_write_msi_msg || template->chip.irq_set_affinity)
-		return false;
-
-	return msi_create_device_irq_domain(&pdev->dev, MSI_SECONDARY_DOMAIN, template,
-					    hwsize, data, NULL);
-}
-EXPORT_SYMBOL_GPL(pci_create_ims_domain);
-
 /*
  * Users of the generic MSI infrastructure expect a device to have a single ID,
  * so with DMA aliases we have to pick the least-worst compromise. Devices with
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 3deb3e42d990..98fb20bcd054 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -2664,11 +2664,6 @@ static inline bool pci_is_thunderbolt_attached(struct pci_dev *pdev)
 void pci_uevent_ers(struct pci_dev *pdev, enum  pci_ers_result err_type);
 #endif
 
-struct msi_domain_template;
-
-bool pci_create_ims_domain(struct pci_dev *pdev, const struct msi_domain_template *template,
-			   unsigned int hwsize, void *data);
-
 #include <linux/dma-mapping.h>
 
 #define pci_printk(level, pdev, fmt, arg...) \
-- 
2.34.1

RE: [PATCH 3/3] Revert "PCI/MSI: Provide IMS (Interrupt Message Store) support"

[Tian, Kevin]

> From: Bjorn Helgaas <helgaas@kernel.org>
> Sent: Tuesday, April 2, 2024 7:23 AM
> 
> From: Bjorn Helgaas <bhelgaas@google.com>
> 
> This reverts commit 0194425af0c87acaad457989a2c6d90dba58e776.
> 
> IMS (Interrupt Message Store) support appeared in v6.2, but there are no
> users yet.
> 
> Remove it for now.  We can add it back when a user comes along.  If this is
> re-added later, the relevant part of 41efa431244f ("PCI/MSI: Provide stubs
> for IMS functions") should be squashed into it.
> 
> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

Reviewed-by: Kevin Tian <kevin.tian@intel.com>

RE: [PATCH 0/3] PCI/MSI: Remove IMS (Interrupt Message Store) support for now

[Tian, Kevin]

> From: Bjorn Helgaas <helgaas@kernel.org>
> Sent: Tuesday, April 2, 2024 7:23 AM
> 
> From: Bjorn Helgaas <bhelgaas@google.com>
> 
> IMS (Interrupt Message Store) support appeared in v6.2, but there are no
> users yet.
> 
> Remove it for now.  We can add it back when a user comes along.
> 
> Bjorn Helgaas (3):
>   Revert "PCI/MSI: Provide stubs for IMS functions"
>   Revert "PCI/MSI: Provide pci_ims_alloc/free_irq()"
>   Revert "PCI/MSI: Provide IMS (Interrupt Message Store) support"
> 

What about the other IMS related commits which are also dead
code after above are reverted?

fa5745aca1dc ("iommu/amd: Enable PCI/IMS")
810531a1af53 ("iommu/vt-d: Enable PCI/IMS")
6e24c8877329 ("x86/apic/msi: Enable PCI/IMS")
e23d4192bf9b ("genirq/msi: Provide constants for PCI/IMS support")

Re: [PATCH 0/3] PCI/MSI: Remove IMS (Interrupt Message Store) support for now

[Bjorn Helgaas]

On Tue, Apr 02, 2024 at 02:45:50AM +0000, Tian, Kevin wrote:
> > From: Bjorn Helgaas <helgaas@kernel.org>
> > Sent: Tuesday, April 2, 2024 7:23 AM
> > 
> > From: Bjorn Helgaas <bhelgaas@google.com>
> > 
> > IMS (Interrupt Message Store) support appeared in v6.2, but there are no
> > users yet.
> > 
> > Remove it for now.  We can add it back when a user comes along.
> > 
> > Bjorn Helgaas (3):
> >   Revert "PCI/MSI: Provide stubs for IMS functions"
> >   Revert "PCI/MSI: Provide pci_ims_alloc/free_irq()"
> >   Revert "PCI/MSI: Provide IMS (Interrupt Message Store) support"
> > 
> 
> What about the other IMS related commits which are also dead
> code after above are reverted?
> 
> fa5745aca1dc ("iommu/amd: Enable PCI/IMS")
> 810531a1af53 ("iommu/vt-d: Enable PCI/IMS")
> 6e24c8877329 ("x86/apic/msi: Enable PCI/IMS")
> e23d4192bf9b ("genirq/msi: Provide constants for PCI/IMS support")

Thanks, I didn't catch those; will add in a v2.

Also, sorry for inadvertently sending this in the middle of an
unrelated thread.  I copied --in-reply-to from my notes when I
shouldn't have.

Bjorn