x86/PCI: VMD: Request userspace control of PCIe hotplug indicators

Add set_dev_domain_options() to set PCI domain-specific options as devices
are added.  The first usage is to request exclusive userspace control of
PCIe hotplug indicators in VMD domains.

Devices in a VMD domain use PCIe hotplug Attention and Power Indicators in
a non-standard way; tell pciehp to ignore the indicators so userspace can
control them via the sysfs "attention" file.

To determine whether a bus is within a VMD domain, add a bool to the
pci_sysdata structure that the VMD driver sets during initialization.

[bhelgaas: changelog]
Requested-by: NKapil Karkra <kapil.karkra@intel.com>
Tested-by: NArtur Paszkiewicz <artur.paszkiewicz@intel.com>
Signed-off-by: NKeith Busch <keith.busch@intel.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

arch/x86/include/asm/pci.h

@@ -23,6 +23,9 @@ struct pci_sysdata {
 #ifdef CONFIG_PCI_MSI_IRQ_DOMAIN
 	void		*fwnode;	/* IRQ domain for MSI assignment */
 #endif
+#if IS_ENABLED(CONFIG_VMD)
+	bool vmd_domain;		/* True if in Intel VMD domain */
+#endif
 };
 
 extern int pci_routeirq;
@@ -56,6 +59,17 @@ static inline void *_pci_root_bus_fwnode(struct pci_bus *bus)
 #define pci_root_bus_fwnode	_pci_root_bus_fwnode
 #endif
 
+static inline bool is_vmd(struct pci_bus *bus)
+{
+#if IS_ENABLED(CONFIG_VMD)
+	struct pci_sysdata *sd = bus->sysdata;
+
+	return sd->vmd_domain;
+#else
+	return false;
+#endif
+}
+
 /* Can be used to override the logic in pci_scan_bus for skipping
    already-configured bus numbers - to be used for buggy BIOSes
    or architectures with incomplete PCI setup by the loader */

arch/x86/pci/common.c

@@ -677,6 +677,12 @@ static void set_dma_domain_ops(struct pci_dev *pdev)
 static void set_dma_domain_ops(struct pci_dev *pdev) {}
 #endif
 
+static void set_dev_domain_options(struct pci_dev *pdev)
+{
+	if (is_vmd(pdev->bus))
+		pdev->hotplug_user_indicators = 1;
+}
+
 int pcibios_add_device(struct pci_dev *dev)
 {
 	struct setup_data *data;
@@ -707,6 +713,7 @@ int pcibios_add_device(struct pci_dev *dev)
 		iounmap(data);
 	}
 	set_dma_domain_ops(dev);
+	set_dev_domain_options(dev);
 	return 0;
 }
 

arch/x86/pci/vmd.c

@@ -596,6 +596,7 @@ static int vmd_enable_domain(struct vmd_dev *vmd)
 		.parent = res,
 	};
 
+	sd->vmd_domain = true;
 	sd->domain = vmd_find_free_domain();
 	if (sd->domain < 0)
 		return sd->domain;