[RFC v3 0/7] PCI: hv: Support host bridge probing on ARM64

[RFC v3 0/7] PCI: hv: Support host bridge probing on ARM64

[Boqun Feng]

Hi Bjorn, Arnd and Marc,

This is the v3 for the preparation of virtual PCI support on Hyper-V
ARM64. Previous versions:

v1:	https://lore.kernel.org/lkml/20210319161956.2838291-1-boqun.feng@gmail.com/
v2:	https://lore.kernel.org/lkml/20210503144635.2297386-1-boqun.feng@gmail.com/

Changes since last version:

*	Use a sentinel value approach instead of calling
	pci_bus_find_domain_nr() for every CONFIG_PCI_DOMAIN_GENERIC=y
	arch as per suggestion from

*	Improve the commit log and comments for patch #6.

*	Rebase to the latest mainline.

The basic problem we need to resolve is that ARM64 is an arch with
PCI_DOMAINS_GENERIC=y, so the bus sysdata is pci_config_window. However,
Hyper-V PCI provides a paravirtualized PCI interface, so there is no
actual pci_config_window for a PCI host bridge, so no information can be
retrieve from the pci_config_window of a Hyper-V virtual PCI bus. Also
there is no corresponding ACPI device for the Hyper-V PCI root bridge.

With this patchset, we could enable the virtual PCI on Hyper-V ARM64
guest with other code under development.

Comments and suggestions are welcome.

Regards,
Boqun

Arnd Bergmann (1):
  PCI: hv: Generify PCI probing

Boqun Feng (6):
  PCI: Introduce domain_nr in pci_host_bridge
  PCI: Allow msi domain set-up at host probing time
  PCI: hv: Use pci_host_bridge::domain_nr for PCI domain
  PCI: hv: Set up msi domain at bridge probing time
  arm64: PCI: Support root bridge preparation for Hyper-V PCI
  PCI: hv: Turn on the host bridge probing on ARM64

 arch/arm64/kernel/pci.c             |  7 ++-
 drivers/pci/controller/pci-hyperv.c | 87 +++++++++++++++++------------
 drivers/pci/probe.c                 |  9 ++-
 include/linux/pci.h                 | 10 ++++
 4 files changed, 73 insertions(+), 40 deletions(-)

-- 
2.30.2

[RFC v3 1/7] PCI: Introduce domain_nr in pci_host_bridge

[Boqun Feng]

Currently we retrieve the PCI domain number of the host bridge from the
bus sysdata (or pci_config_window if PCI_DOMAINS_GENERIC=y). Actually
we have the information at PCI host bridge probing time, and it makes
sense that we store it into pci_host_bridge. One benefit of doing so is
the requirement for supporting PCI on Hyper-V for ARM64, because the
host bridge of Hyper-V doesn't have pci_config_window, whereas ARM64 is
a PCI_DOMAINS_GENERIC=y arch, so we cannot retrieve the PCI domain
number from pci_config_window on ARM64 Hyper-V guest.

As the preparation for ARM64 Hyper-V PCI support, we introduce the
domain_nr in pci_host_bridge and a sentinel value to allow drivers to
set domain numbers properly at probing time. Currently
CONFIG_PCI_DOMAINS_GENERIC=y archs are only users of this
newly-introduced field.

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
---
 drivers/pci/probe.c |  4 +++-
 include/linux/pci.h | 10 ++++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 275204646c68..d2753097a1b0 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -594,6 +594,7 @@ static void pci_init_host_bridge(struct pci_host_bridge *bridge)
 	bridge->native_pme = 1;
 	bridge->native_ltr = 1;
 	bridge->native_dpc = 1;
+	bridge->domain_nr = PCI_DOMAIN_NR_NOT_SET;
 
 	device_initialize(&bridge->dev);
 }
@@ -898,7 +899,8 @@ static int pci_register_host_bridge(struct pci_host_bridge *bridge)
 	bus->ops = bridge->ops;
 	bus->number = bus->busn_res.start = bridge->busnr;
 #ifdef CONFIG_PCI_DOMAINS_GENERIC
-	bus->domain_nr = pci_bus_find_domain_nr(bus, parent);
+	if (bridge->domain_nr == PCI_DOMAIN_NR_NOT_SET)
+		bus->domain_nr = pci_bus_find_domain_nr(bus, parent);
 #endif
 
 	b = pci_find_bus(pci_domain_nr(bus), bridge->busnr);
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 24306504226a..d85d41b5abbd 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -526,6 +526,15 @@ static inline int pci_channel_offline(struct pci_dev *pdev)
 	return (pdev->error_state != pci_channel_io_normal);
 }
 
+/*
+ * PCI Conventional has at most 256 PCI bus segments and PCI Express has at
+ * most 65536 "PCI Segments Groups", therefore -1 is not a valid PCI domain
+ * number, and can be used as a sentinel value indicating ->domain_nr is not
+ * set by the driver (and CONFIG_PCI_DOMAINS_GENERIC=y can set it in generic
+ * code).
+ */
+#define PCI_DOMAIN_NR_NOT_SET (-1)
+
 struct pci_host_bridge {
 	struct device	dev;
 	struct pci_bus	*bus;		/* Root bus */
@@ -533,6 +542,7 @@ struct pci_host_bridge {
 	struct pci_ops	*child_ops;
 	void		*sysdata;
 	int		busnr;
+	int		domain_nr;
 	struct list_head windows;	/* resource_entry */
 	struct list_head dma_ranges;	/* dma ranges resource list */
 	u8 (*swizzle_irq)(struct pci_dev *, u8 *); /* Platform IRQ swizzler */
-- 
2.30.2

[RFC v3 2/7] PCI: Allow msi domain set-up at host probing time

[Boqun Feng]

For GENERIC_MSI_IRQ_DOMAIN drivers, we can set up the msi domain via
dev_set_msi_domain() at probing time, and drivers can use this more
generic way to set up the msi domain for the host bridge.

This is the preparation for ARM64 Hyper-V PCI support.

Originally-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
---
 drivers/pci/probe.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index d2753097a1b0..38bee41dedcc 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -829,11 +829,14 @@ static struct irq_domain *pci_host_bridge_msi_domain(struct pci_bus *bus)
 {
 	struct irq_domain *d;
 
+	/* Default set by host bridge driver */
+	d = dev_get_msi_domain(bus->bridge);
 	/*
 	 * Any firmware interface that can resolve the msi_domain
 	 * should be called from here.
 	 */
-	d = pci_host_bridge_of_msi_domain(bus);
+	if (!d)
+		d = pci_host_bridge_of_msi_domain(bus);
 	if (!d)
 		d = pci_host_bridge_acpi_msi_domain(bus);
 
-- 
2.30.2

[RFC v3 3/7] PCI: hv: Generify PCI probing

[Boqun Feng]

From: Arnd Bergmann <arnd@arndb.de>

In order to support ARM64 Hyper-V PCI, we need to set up the bridge at
probing time because ARM64 is a PCI_DOMAIN_GENERIC arch and we don't
have pci_config_window (ARM64 sysdata) for a PCI root bus on Hyper-V, so
it's impossible to retrieve the information (e.g. PCI domains, irq
domains) from bus sysdata on ARM64 after creation.

Originally in create_root_hv_pci_bus(), pci_create_root_bus() is used to
create the root bus and the corresponding bridge based on x86 sysdata.
Now we create a bridge first and then call pci_scan_root_bus_bridge(),
which allows us to do the necessary set-ups for the bridge.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
---
 drivers/pci/controller/pci-hyperv.c | 58 +++++++++++++++--------------
 1 file changed, 30 insertions(+), 28 deletions(-)

diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
index 6511648271b2..ee9f8e27e2e8 100644
--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c
@@ -450,6 +450,7 @@ enum hv_pcibus_state {
 
 struct hv_pcibus_device {
 	struct pci_sysdata sysdata;
+	struct pci_host_bridge *bridge;
 	/* Protocol version negotiated with the host */
 	enum pci_protocol_version_t protocol_version;
 	enum hv_pcibus_state state;
@@ -462,13 +463,10 @@ struct hv_pcibus_device {
 	struct resource *high_mmio_res;
 	struct completion *survey_event;
 	struct completion remove_event;
-	struct pci_bus *pci_bus;
 	spinlock_t config_lock;	/* Avoid two threads writing index page */
 	spinlock_t device_list_lock;	/* Protect lists below */
 	void __iomem *cfg_addr;
 
-	struct list_head resources_for_children;
-
 	struct list_head children;
 	struct list_head dr_list;
 
@@ -1803,7 +1801,7 @@ static void hv_pci_assign_slots(struct hv_pcibus_device *hbus)
 
 		slot_nr = PCI_SLOT(wslot_to_devfn(hpdev->desc.win_slot.slot));
 		snprintf(name, SLOT_NAME_SIZE, "%u", hpdev->desc.ser);
-		hpdev->pci_slot = pci_create_slot(hbus->pci_bus, slot_nr,
+		hpdev->pci_slot = pci_create_slot(hbus->bridge->bus, slot_nr,
 					  name, NULL);
 		if (IS_ERR(hpdev->pci_slot)) {
 			pr_warn("pci_create slot %s failed\n", name);
@@ -1833,7 +1831,7 @@ static void hv_pci_remove_slots(struct hv_pcibus_device *hbus)
 static void hv_pci_assign_numa_node(struct hv_pcibus_device *hbus)
 {
 	struct pci_dev *dev;
-	struct pci_bus *bus = hbus->pci_bus;
+	struct pci_bus *bus = hbus->bridge->bus;
 	struct hv_pci_dev *hv_dev;
 
 	list_for_each_entry(dev, &bus->devices, bus_list) {
@@ -1856,21 +1854,22 @@ static void hv_pci_assign_numa_node(struct hv_pcibus_device *hbus)
  */
 static int create_root_hv_pci_bus(struct hv_pcibus_device *hbus)
 {
-	/* Register the device */
-	hbus->pci_bus = pci_create_root_bus(&hbus->hdev->device,
-					    0, /* bus number is always zero */
-					    &hv_pcifront_ops,
-					    &hbus->sysdata,
-					    &hbus->resources_for_children);
-	if (!hbus->pci_bus)
-		return -ENODEV;
+	int error;
+	struct pci_host_bridge *bridge = hbus->bridge;
+
+	bridge->dev.parent = &hbus->hdev->device;
+	bridge->sysdata = &hbus->sysdata;
+	bridge->ops = &hv_pcifront_ops;
+
+	error = pci_scan_root_bus_bridge(bridge);
+	if (error)
+		return error;
 
 	pci_lock_rescan_remove();
-	pci_scan_child_bus(hbus->pci_bus);
 	hv_pci_assign_numa_node(hbus);
-	pci_bus_assign_resources(hbus->pci_bus);
+	pci_bus_assign_resources(bridge->bus);
 	hv_pci_assign_slots(hbus);
-	pci_bus_add_devices(hbus->pci_bus);
+	pci_bus_add_devices(bridge->bus);
 	pci_unlock_rescan_remove();
 	hbus->state = hv_pcibus_installed;
 	return 0;
@@ -2135,7 +2134,7 @@ static void pci_devices_present_work(struct work_struct *work)
 		 * because there may have been changes.
 		 */
 		pci_lock_rescan_remove();
-		pci_scan_child_bus(hbus->pci_bus);
+		pci_scan_child_bus(hbus->bridge->bus);
 		hv_pci_assign_numa_node(hbus);
 		hv_pci_assign_slots(hbus);
 		pci_unlock_rescan_remove();
@@ -2306,8 +2305,8 @@ static void hv_eject_device_work(struct work_struct *work)
 	/*
 	 * Ejection can come before or after the PCI bus has been set up, so
 	 * attempt to find it and tear down the bus state, if it exists.  This
-	 * must be done without constructs like pci_domain_nr(hbus->pci_bus)
-	 * because hbus->pci_bus may not exist yet.
+	 * must be done without constructs like pci_domain_nr(hbus->bridge->bus)
+	 * because hbus->bridge->bus may not exist yet.
 	 */
 	wslot = wslot_to_devfn(hpdev->desc.win_slot.slot);
 	pdev = pci_get_domain_bus_and_slot(hbus->sysdata.domain, 0, wslot);
@@ -2676,8 +2675,7 @@ static int hv_pci_allocate_bridge_windows(struct hv_pcibus_device *hbus)
 		/* Modify this resource to become a bridge window. */
 		hbus->low_mmio_res->flags |= IORESOURCE_WINDOW;
 		hbus->low_mmio_res->flags &= ~IORESOURCE_BUSY;
-		pci_add_resource(&hbus->resources_for_children,
-				 hbus->low_mmio_res);
+		pci_add_resource(&hbus->bridge->windows, hbus->low_mmio_res);
 	}
 
 	if (hbus->high_mmio_space) {
@@ -2696,8 +2694,7 @@ static int hv_pci_allocate_bridge_windows(struct hv_pcibus_device *hbus)
 		/* Modify this resource to become a bridge window. */
 		hbus->high_mmio_res->flags |= IORESOURCE_WINDOW;
 		hbus->high_mmio_res->flags &= ~IORESOURCE_BUSY;
-		pci_add_resource(&hbus->resources_for_children,
-				 hbus->high_mmio_res);
+		pci_add_resource(&hbus->bridge->windows, hbus->high_mmio_res);
 	}
 
 	return 0;
@@ -3027,6 +3024,7 @@ static void hv_put_dom_num(u16 dom)
 static int hv_pci_probe(struct hv_device *hdev,
 			const struct hv_vmbus_device_id *dev_id)
 {
+	struct pci_host_bridge *bridge;
 	struct hv_pcibus_device *hbus;
 	u16 dom_req, dom;
 	char *name;
@@ -3039,6 +3037,10 @@ static int hv_pci_probe(struct hv_device *hdev,
 	 */
 	BUILD_BUG_ON(sizeof(*hbus) > HV_HYP_PAGE_SIZE);
 
+	bridge = devm_pci_alloc_host_bridge(&hdev->device, 0);
+	if (!bridge)
+		return -ENOMEM;
+
 	/*
 	 * With the recent 59bb47985c1d ("mm, sl[aou]b: guarantee natural
 	 * alignment for kmalloc(power-of-two)"), kzalloc() is able to allocate
@@ -3060,6 +3062,8 @@ static int hv_pci_probe(struct hv_device *hdev,
 	hbus = kzalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
 	if (!hbus)
 		return -ENOMEM;
+
+	hbus->bridge = bridge;
 	hbus->state = hv_pcibus_init;
 	hbus->wslot_res_allocated = -1;
 
@@ -3097,7 +3101,6 @@ static int hv_pci_probe(struct hv_device *hdev,
 	refcount_set(&hbus->remove_lock, 1);
 	INIT_LIST_HEAD(&hbus->children);
 	INIT_LIST_HEAD(&hbus->dr_list);
-	INIT_LIST_HEAD(&hbus->resources_for_children);
 	spin_lock_init(&hbus->config_lock);
 	spin_lock_init(&hbus->device_list_lock);
 	spin_lock_init(&hbus->retarget_msi_interrupt_lock);
@@ -3303,9 +3306,9 @@ static int hv_pci_remove(struct hv_device *hdev)
 	if (hbus->state == hv_pcibus_installed) {
 		/* Remove the bus from PCI's point of view. */
 		pci_lock_rescan_remove();
-		pci_stop_root_bus(hbus->pci_bus);
+		pci_stop_root_bus(hbus->bridge->bus);
 		hv_pci_remove_slots(hbus);
-		pci_remove_root_bus(hbus->pci_bus);
+		pci_remove_root_bus(hbus->bridge->bus);
 		pci_unlock_rescan_remove();
 		hbus->state = hv_pcibus_removed;
 	}
@@ -3316,7 +3319,6 @@ static int hv_pci_remove(struct hv_device *hdev)
 
 	iounmap(hbus->cfg_addr);
 	hv_free_config_window(hbus);
-	pci_free_resource_list(&hbus->resources_for_children);
 	hv_pci_free_bridge_windows(hbus);
 	irq_domain_remove(hbus->irq_domain);
 	irq_domain_free_fwnode(hbus->sysdata.fwnode);
@@ -3402,7 +3404,7 @@ static int hv_pci_restore_msi_msg(struct pci_dev *pdev, void *arg)
  */
 static void hv_pci_restore_msi_state(struct hv_pcibus_device *hbus)
 {
-	pci_walk_bus(hbus->pci_bus, hv_pci_restore_msi_msg, NULL);
+	pci_walk_bus(hbus->bridge->bus, hv_pci_restore_msi_msg, NULL);
 }
 
 static int hv_pci_resume(struct hv_device *hdev)
-- 
2.30.2

[RFC v3 4/7] PCI: hv: Use pci_host_bridge::domain_nr for PCI domain

[Boqun Feng]

No functional change, just store and maintain the PCI domain number in
the generic pci_host_bridge instead of x86 specific pci_sysdata.

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
---
 drivers/pci/controller/pci-hyperv.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
index ee9f8e27e2e8..f9a644ae3b74 100644
--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c
@@ -2309,7 +2309,7 @@ static void hv_eject_device_work(struct work_struct *work)
 	 * because hbus->bridge->bus may not exist yet.
 	 */
 	wslot = wslot_to_devfn(hpdev->desc.win_slot.slot);
-	pdev = pci_get_domain_bus_and_slot(hbus->sysdata.domain, 0, wslot);
+	pdev = pci_get_domain_bus_and_slot(hbus->bridge->domain_nr, 0, wslot);
 	if (pdev) {
 		pci_lock_rescan_remove();
 		pci_stop_and_remove_bus_device(pdev);
@@ -3095,6 +3095,7 @@ static int hv_pci_probe(struct hv_device *hdev,
 			 "PCI dom# 0x%hx has collision, using 0x%hx",
 			 dom_req, dom);
 
+	hbus->bridge->domain_nr = dom;
 	hbus->sysdata.domain = dom;
 
 	hbus->hdev = hdev;
@@ -3106,7 +3107,7 @@ static int hv_pci_probe(struct hv_device *hdev,
 	spin_lock_init(&hbus->retarget_msi_interrupt_lock);
 	init_completion(&hbus->remove_event);
 	hbus->wq = alloc_ordered_workqueue("hv_pci_%x", 0,
-					   hbus->sysdata.domain);
+					   hbus->bridge->domain_nr);
 	if (!hbus->wq) {
 		ret = -ENOMEM;
 		goto free_dom;
@@ -3233,7 +3234,7 @@ static int hv_pci_probe(struct hv_device *hdev,
 destroy_wq:
 	destroy_workqueue(hbus->wq);
 free_dom:
-	hv_put_dom_num(hbus->sysdata.domain);
+	hv_put_dom_num(hbus->bridge->domain_nr);
 free_bus:
 	kfree(hbus);
 	return ret;
@@ -3326,7 +3327,7 @@ static int hv_pci_remove(struct hv_device *hdev)
 	wait_for_completion(&hbus->remove_event);
 	destroy_workqueue(hbus->wq);
 
-	hv_put_dom_num(hbus->sysdata.domain);
+	hv_put_dom_num(hbus->bridge->domain_nr);
 
 	kfree(hbus);
 	return ret;
-- 
2.30.2

[RFC v3 5/7] PCI: hv: Set up msi domain at bridge probing time

[Boqun Feng]

Since PCI_HYPERV depends on PCI_MSI_IRQ_DOMAIN which selects
GENERIC_MSI_IRQ_DOMAIN, we can use dev_set_msi_domain() to set up the
msi irq domain at probing time, and this works for both x86 and ARM64.

Therefore use it as the preparation for ARM64 Hyper-V PCI support.

As a result, there is no need to set the pci_sysdata::fwnode which is
x86 specific. In addition, make hv_pcibus_device own the fwnode instead
of sysdata to make the code generic.

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
---
 drivers/pci/controller/pci-hyperv.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
index f9a644ae3b74..16a779ab9ed4 100644
--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c
@@ -451,6 +451,7 @@ enum hv_pcibus_state {
 struct hv_pcibus_device {
 	struct pci_sysdata sysdata;
 	struct pci_host_bridge *bridge;
+	struct fwnode_handle *fwnode;
 	/* Protocol version negotiated with the host */
 	enum pci_protocol_version_t protocol_version;
 	enum hv_pcibus_state state;
@@ -1570,7 +1571,7 @@ static int hv_pcie_init_irq_domain(struct hv_pcibus_device *hbus)
 	hbus->msi_info.handler = handle_edge_irq;
 	hbus->msi_info.handler_name = "edge";
 	hbus->msi_info.data = hbus;
-	hbus->irq_domain = pci_msi_create_irq_domain(hbus->sysdata.fwnode,
+	hbus->irq_domain = pci_msi_create_irq_domain(hbus->fwnode,
 						     &hbus->msi_info,
 						     x86_vector_domain);
 	if (!hbus->irq_domain) {
@@ -1579,6 +1580,8 @@ static int hv_pcie_init_irq_domain(struct hv_pcibus_device *hbus)
 		return -ENODEV;
 	}
 
+	dev_set_msi_domain(&hbus->bridge->dev, hbus->irq_domain);
+
 	return 0;
 }
 
@@ -3144,9 +3147,9 @@ static int hv_pci_probe(struct hv_device *hdev,
 		goto unmap;
 	}
 
-	hbus->sysdata.fwnode = irq_domain_alloc_named_fwnode(name);
+	hbus->fwnode = irq_domain_alloc_named_fwnode(name);
 	kfree(name);
-	if (!hbus->sysdata.fwnode) {
+	if (!hbus->fwnode) {
 		ret = -ENOMEM;
 		goto unmap;
 	}
@@ -3224,7 +3227,7 @@ static int hv_pci_probe(struct hv_device *hdev,
 free_irq_domain:
 	irq_domain_remove(hbus->irq_domain);
 free_fwnode:
-	irq_domain_free_fwnode(hbus->sysdata.fwnode);
+	irq_domain_free_fwnode(hbus->fwnode);
 unmap:
 	iounmap(hbus->cfg_addr);
 free_config:
@@ -3322,7 +3325,7 @@ static int hv_pci_remove(struct hv_device *hdev)
 	hv_free_config_window(hbus);
 	hv_pci_free_bridge_windows(hbus);
 	irq_domain_remove(hbus->irq_domain);
-	irq_domain_free_fwnode(hbus->sysdata.fwnode);
+	irq_domain_free_fwnode(hbus->fwnode);
 	put_hvpcibus(hbus);
 	wait_for_completion(&hbus->remove_event);
 	destroy_workqueue(hbus->wq);
-- 
2.30.2

[RFC v3 6/7] arm64: PCI: Support root bridge preparation for Hyper-V PCI

[Boqun Feng]

Currently at root bridge preparation, the corresponding ACPI device will
be set as the companion, however for a Hyper-V virtual PCI root bridge,
there is no corresponding ACPI device, because a Hyper-V virtual PCI
root bridge is discovered via VMBus rather than ACPI table. In order to
support this, we need to make pcibios_root_bridge_prepare() work with
cfg->parent being NULL.

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
---
 arch/arm64/kernel/pci.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c
index 1006ed2d7c60..020bc268bf06 100644
--- a/arch/arm64/kernel/pci.c
+++ b/arch/arm64/kernel/pci.c
@@ -84,7 +84,12 @@ int pcibios_root_bridge_prepare(struct pci_host_bridge *bridge)
 {
 	if (!acpi_disabled) {
 		struct pci_config_window *cfg = bridge->bus->sysdata;
-		struct acpi_device *adev = to_acpi_device(cfg->parent);
+		/*
+		 * On Hyper-V, there is no corresponding APCI device for a root
+		 * bridge, therefore ->parent is set as NULL by the driver. Then
+		 * 'adev' should be NULL in this case.
+		 */
+		struct acpi_device *adev = cfg->parent ? to_acpi_device(cfg->parent) : NULL;
 		struct device *bus_dev = &bridge->bus->dev;
 
 		ACPI_COMPANION_SET(&bridge->dev, adev);
-- 
2.30.2

[RFC v3 7/7] PCI: hv: Turn on the host bridge probing on ARM64

[Boqun Feng]

Now we have everything we need, just provide a proper sysdata type for
the bus to use on ARM64 and everything else works.

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
---
 drivers/pci/controller/pci-hyperv.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
index 16a779ab9ed4..271d0b6d4796 100644
--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c
@@ -40,6 +40,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/pci.h>
+#include <linux/pci-ecam.h>
 #include <linux/delay.h>
 #include <linux/semaphore.h>
 #include <linux/irqdomain.h>
@@ -449,7 +450,11 @@ enum hv_pcibus_state {
 };
 
 struct hv_pcibus_device {
+#ifdef CONFIG_X86
 	struct pci_sysdata sysdata;
+#elif defined(CONFIG_ARM64)
+	struct pci_config_window sysdata;
+#endif
 	struct pci_host_bridge *bridge;
 	struct fwnode_handle *fwnode;
 	/* Protocol version negotiated with the host */
@@ -3099,7 +3104,9 @@ static int hv_pci_probe(struct hv_device *hdev,
 			 dom_req, dom);
 
 	hbus->bridge->domain_nr = dom;
+#ifdef CONFIG_X86
 	hbus->sysdata.domain = dom;
+#endif
 
 	hbus->hdev = hdev;
 	refcount_set(&hbus->remove_lock, 1);
-- 
2.30.2

Re: [RFC v3 0/7] PCI: hv: Support host bridge probing on ARM64

[Ard Biesheuvel]

On Wed, 9 Jun 2021 at 18:32, Boqun Feng <boqun.feng@gmail.com> wrote:
>
> Hi Bjorn, Arnd and Marc,
>

Instead of cc'ing Arnd, you cc'ed me (Ard)

> This is the v3 for the preparation of virtual PCI support on Hyper-V
> ARM64. Previous versions:
>
> v1:     https://lore.kernel.org/lkml/20210319161956.2838291-1-boqun.feng@gmail.com/
> v2:     https://lore.kernel.org/lkml/20210503144635.2297386-1-boqun.feng@gmail.com/
>
> Changes since last version:
>
> *       Use a sentinel value approach instead of calling
>         pci_bus_find_domain_nr() for every CONFIG_PCI_DOMAIN_GENERIC=y
>         arch as per suggestion from
>
> *       Improve the commit log and comments for patch #6.
>
> *       Rebase to the latest mainline.
>
> The basic problem we need to resolve is that ARM64 is an arch with
> PCI_DOMAINS_GENERIC=y, so the bus sysdata is pci_config_window. However,
> Hyper-V PCI provides a paravirtualized PCI interface, so there is no
> actual pci_config_window for a PCI host bridge, so no information can be
> retrieve from the pci_config_window of a Hyper-V virtual PCI bus. Also
> there is no corresponding ACPI device for the Hyper-V PCI root bridge.
>
> With this patchset, we could enable the virtual PCI on Hyper-V ARM64
> guest with other code under development.
>
> Comments and suggestions are welcome.
>
> Regards,
> Boqun
>
> Arnd Bergmann (1):
>   PCI: hv: Generify PCI probing
>
> Boqun Feng (6):
>   PCI: Introduce domain_nr in pci_host_bridge
>   PCI: Allow msi domain set-up at host probing time
>   PCI: hv: Use pci_host_bridge::domain_nr for PCI domain
>   PCI: hv: Set up msi domain at bridge probing time
>   arm64: PCI: Support root bridge preparation for Hyper-V PCI
>   PCI: hv: Turn on the host bridge probing on ARM64
>
>  arch/arm64/kernel/pci.c             |  7 ++-
>  drivers/pci/controller/pci-hyperv.c | 87 +++++++++++++++++------------
>  drivers/pci/probe.c                 |  9 ++-
>  include/linux/pci.h                 | 10 ++++
>  4 files changed, 73 insertions(+), 40 deletions(-)
>
> --
> 2.30.2
>

Re: [RFC v3 0/7] PCI: hv: Support host bridge probing on ARM64

[Marc Zyngier]

On 2021-06-10 16:01, Ard Biesheuvel wrote:
> On Wed, 9 Jun 2021 at 18:32, Boqun Feng <boqun.feng@gmail.com> wrote:
>> 
>> Hi Bjorn, Arnd and Marc,
>> 
> 
> Instead of cc'ing Arnd, you cc'ed me (Ard)

And I don't know if you intended to Cc me, but you definitely didn't.

Thanks,

         M.

> 
>> This is the v3 for the preparation of virtual PCI support on Hyper-V
>> ARM64. Previous versions:
>> 
>> v1:     
>> https://lore.kernel.org/lkml/20210319161956.2838291-1-boqun.feng@gmail.com/
>> v2:     
>> https://lore.kernel.org/lkml/20210503144635.2297386-1-boqun.feng@gmail.com/
>> 
>> Changes since last version:
>> 
>> *       Use a sentinel value approach instead of calling
>>         pci_bus_find_domain_nr() for every CONFIG_PCI_DOMAIN_GENERIC=y
>>         arch as per suggestion from
>> 
>> *       Improve the commit log and comments for patch #6.
>> 
>> *       Rebase to the latest mainline.
>> 
>> The basic problem we need to resolve is that ARM64 is an arch with
>> PCI_DOMAINS_GENERIC=y, so the bus sysdata is pci_config_window. 
>> However,
>> Hyper-V PCI provides a paravirtualized PCI interface, so there is no
>> actual pci_config_window for a PCI host bridge, so no information can 
>> be
>> retrieve from the pci_config_window of a Hyper-V virtual PCI bus. Also
>> there is no corresponding ACPI device for the Hyper-V PCI root bridge.
>> 
>> With this patchset, we could enable the virtual PCI on Hyper-V ARM64
>> guest with other code under development.
>> 
>> Comments and suggestions are welcome.
>> 
>> Regards,
>> Boqun
>> 
>> Arnd Bergmann (1):
>>   PCI: hv: Generify PCI probing
>> 
>> Boqun Feng (6):
>>   PCI: Introduce domain_nr in pci_host_bridge
>>   PCI: Allow msi domain set-up at host probing time
>>   PCI: hv: Use pci_host_bridge::domain_nr for PCI domain
>>   PCI: hv: Set up msi domain at bridge probing time
>>   arm64: PCI: Support root bridge preparation for Hyper-V PCI
>>   PCI: hv: Turn on the host bridge probing on ARM64
>> 
>>  arch/arm64/kernel/pci.c             |  7 ++-
>>  drivers/pci/controller/pci-hyperv.c | 87 
>> +++++++++++++++++------------
>>  drivers/pci/probe.c                 |  9 ++-
>>  include/linux/pci.h                 | 10 ++++
>>  4 files changed, 73 insertions(+), 40 deletions(-)
>> 
>> --
>> 2.30.2
>> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

-- 
Who you jivin' with that Cosmik Debris?

Re: [RFC v3 0/7] PCI: hv: Support host bridge probing on ARM64

[Boqun Feng]

On Thu, Jun 10, 2021 at 04:42:45PM +0100, Marc Zyngier wrote:
> On 2021-06-10 16:01, Ard Biesheuvel wrote:
> > On Wed, 9 Jun 2021 at 18:32, Boqun Feng <boqun.feng@gmail.com> wrote:
> > > 
> > > Hi Bjorn, Arnd and Marc,
> > > 
> > 
> > Instead of cc'ing Arnd, you cc'ed me (Ard)
> 
> And I don't know if you intended to Cc me, but you definitely didn't.
> 

Weird.. seems my sending script got somewhere wrong. Apologies for you
both, and Arnd.. I did intend to Cc you and Arnd.

How do you want this to proceed? I could do a resend right now, or I
could wait for a few days (and see others' feedback) and send a V4 next
week. Sorry again ;-(

Regards,
Boqun

> Thanks,
> 
>         M.
> 
> > 
> > > This is the v3 for the preparation of virtual PCI support on Hyper-V
> > > ARM64. Previous versions:
> > > 
> > > v1:     https://lore.kernel.org/lkml/20210319161956.2838291-1-boqun.feng@gmail.com/
> > > v2:     https://lore.kernel.org/lkml/20210503144635.2297386-1-boqun.feng@gmail.com/
> > > 
> > > Changes since last version:
> > > 
> > > *       Use a sentinel value approach instead of calling
> > >         pci_bus_find_domain_nr() for every CONFIG_PCI_DOMAIN_GENERIC=y
> > >         arch as per suggestion from
> > > 
> > > *       Improve the commit log and comments for patch #6.
> > > 
> > > *       Rebase to the latest mainline.
> > > 
> > > The basic problem we need to resolve is that ARM64 is an arch with
> > > PCI_DOMAINS_GENERIC=y, so the bus sysdata is pci_config_window.
> > > However,
> > > Hyper-V PCI provides a paravirtualized PCI interface, so there is no
> > > actual pci_config_window for a PCI host bridge, so no information
> > > can be
> > > retrieve from the pci_config_window of a Hyper-V virtual PCI bus. Also
> > > there is no corresponding ACPI device for the Hyper-V PCI root bridge.
> > > 
> > > With this patchset, we could enable the virtual PCI on Hyper-V ARM64
> > > guest with other code under development.
> > > 
> > > Comments and suggestions are welcome.
> > > 
> > > Regards,
> > > Boqun
> > > 
> > > Arnd Bergmann (1):
> > >   PCI: hv: Generify PCI probing
> > > 
> > > Boqun Feng (6):
> > >   PCI: Introduce domain_nr in pci_host_bridge
> > >   PCI: Allow msi domain set-up at host probing time
> > >   PCI: hv: Use pci_host_bridge::domain_nr for PCI domain
> > >   PCI: hv: Set up msi domain at bridge probing time
> > >   arm64: PCI: Support root bridge preparation for Hyper-V PCI
> > >   PCI: hv: Turn on the host bridge probing on ARM64
> > > 
> > >  arch/arm64/kernel/pci.c             |  7 ++-
> > >  drivers/pci/controller/pci-hyperv.c | 87
> > > +++++++++++++++++------------
> > >  drivers/pci/probe.c                 |  9 ++-
> > >  include/linux/pci.h                 | 10 ++++
> > >  4 files changed, 73 insertions(+), 40 deletions(-)
> > > 
> > > --
> > > 2.30.2
> > > 
> > 
> > _______________________________________________
> > linux-arm-kernel mailing list
> > linux-arm-kernel@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 
> -- 
> Who you jivin' with that Cosmik Debris?

Re: [RFC v3 0/7] PCI: hv: Support host bridge probing on ARM64

[Marc Zyngier]

On 2021-06-10 17:06, Boqun Feng wrote:
> On Thu, Jun 10, 2021 at 04:42:45PM +0100, Marc Zyngier wrote:
>> On 2021-06-10 16:01, Ard Biesheuvel wrote:
>> > On Wed, 9 Jun 2021 at 18:32, Boqun Feng <boqun.feng@gmail.com> wrote:
>> > >
>> > > Hi Bjorn, Arnd and Marc,
>> > >
>> >
>> > Instead of cc'ing Arnd, you cc'ed me (Ard)
>> 
>> And I don't know if you intended to Cc me, but you definitely didn't.
>> 
> 
> Weird.. seems my sending script got somewhere wrong. Apologies for you
> both, and Arnd.. I did intend to Cc you and Arnd.

No worries, it happens (I also used the wrong email address when
replying, so we're even).

> How do you want this to proceed? I could do a resend right now, or I
> could wait for a few days (and see others' feedback) and send a V4 next
> week. Sorry again ;-(

Let the current series simmer on the list for a few days, I can
always eyeball it there if I'm short of patches to review... ;-)

Thanks,

         M.
-- 
Jazz is not dead. It just smells funny...