The patch introduces function kvm_vfio_eeh_dev_map(), which is
expected to be called on IOCTL command issued to the VM device, in
order to build the address mapping for VFIO PCI device.

Signed-off-by: Gavin Shan <gws...@linux.vnet.ibm.com>
---
 arch/powerpc/kernel/eeh_pe.c | 88 ++++++++++++++++++++++++++++++++++++++++++++
 include/linux/kvm_host.h     | 14 +++++++
 2 files changed, 102 insertions(+)

diff --git a/arch/powerpc/kernel/eeh_pe.c b/arch/powerpc/kernel/eeh_pe.c
index 9e73188..200cd5a 100644
--- a/arch/powerpc/kernel/eeh_pe.c
+++ b/arch/powerpc/kernel/eeh_pe.c
@@ -332,6 +332,94 @@ struct eeh_dev *eeh_vfio_dev_get(struct eeh_vfio_pci_addr 
*addr)
        return NULL;
 }
 
+/**
+ * kvm_vfio_eeh_dev_map - Build the address mapping for VFIO device
+ *
+ * @kvm: VM descriptor
+ * @domain: host domain of PCI device
+ * @bdn: host bus/device/function number
+ * @buid: BUID of guest PHB
+ * @gbdn: guest bus/device/function number
+ *
+ * Build the address mapping between host and guest deivce. It's called
+ * while passing through PCI device from host to guest.
+ */
+int kvm_vfio_eeh_dev_map(struct kvm *kvm, int domain,
+                        int bdn, unsigned long buid, int gbdn)
+{
+       struct pci_bus *bus, *pe_bus;
+       struct pci_dev *dev;
+       struct eeh_dev *edev;
+       struct eeh_pe *pe;
+       int bus_no, devfn;
+
+       /* Find the PCI device in host side */
+       bus_no = (bdn >> 8) & 0xff;
+       devfn = bdn & 0xff;
+       bus = pci_find_bus(domain, bus_no);
+       if (!bus) {
+               pr_warn("%s: PCI bus %04x:%02x not found\n",
+                       __func__, domain, bus_no);
+               return -ENODEV;
+       }
+
+       dev = pci_get_slot(bus, devfn);
+       if (!dev) {
+               pr_warn("%s: PCI device %04x:%02x:%02x.%01x not found\n",
+                       __func__, domain, bus_no,
+                       PCI_SLOT(devfn), PCI_FUNC(devfn));
+               return -ENODEV;
+       }
+
+       /*
+        * Mark the EEH device as passed. We allow dynamic change
+        * on the address mapping.
+        */
+       edev = pci_dev_to_eeh_dev(dev);
+       if (!edev) {
+               pr_warn("%s: No EEH dev for PCI device %s\n",
+                       __func__, pci_name(dev));
+               return -ENODEV;
+       }
+
+       /*
+        * The PE configuration address is exactly PCI config address
+        * of the PE primary bus. That has format 00BBSS00 defined in
+        * PAPR.
+        */
+       pe = edev->pe;
+       if (!eeh_pe_passed(pe)) {
+               pe_bus = eeh_pe_bus_get(pe);
+               BUG_ON(!pe_bus);
+
+               pe->gaddr.kvm           = kvm;
+               pe->gaddr.buid_hi       = BUID_HI(buid);
+               pe->gaddr.buid_lo       = BUID_LO(buid);
+               pe->gaddr.pe_addr       = pe_bus->number << 16;
+               eeh_pe_set_passed(pe, true);
+       } else if (pe->gaddr.kvm != kvm ||
+                  pe->gaddr.buid_hi != BUID_HI(buid) ||
+                  pe->gaddr.buid_lo != BUID_LO(buid)) {
+               pr_warn("%s: Mismatched VM or PHB on passing %s\n",
+                       __func__, pci_name(dev));
+               return -EINVAL;
+       }
+
+       edev->gaddr.kvm         = kvm;
+       edev->gaddr.buid_hi     = BUID_HI(buid);
+       edev->gaddr.buid_lo     = BUID_LO(buid);
+       edev->gaddr.bus         = (gbdn >> 8) & 0xff;
+       edev->gaddr.devfn       = gbdn & 0xff;
+       eeh_dev_set_passed(edev, true);
+
+       pr_debug("EEH: Host PCI device %s passed to %lx-%02x:%02x.%01x\n",
+                pci_name(dev), buid, (gbdn >> 8) & 0xff,
+                PCI_SLOT(gbdn & 0xff), PCI_FUNC(gbdn & 0xff));
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(kvm_vfio_eeh_dev_map);
+
 static void *__kvmppc_eeh_vfio_release(void *data, void *flag)
 {
        struct eeh_pe *pe = (struct eeh_pe *)data;
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 7d21cf9..294ce48 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1102,5 +1102,19 @@ static inline void kvm_vcpu_set_dy_eligible(struct 
kvm_vcpu *vcpu, bool val)
 {
 }
 #endif /* CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT */
+
+#ifdef CONFIG_KVM_EEH
+typedef int (*kvm_vfio_dev_eeh_map)(struct kvm *kvm, int domain,
+                                   int bdn, unsigned long buid, int gbdn);
+extern int kvm_vfio_eeh_dev_map(struct kvm *kvm, int domain,
+                               int bdn, unsigned long buid, int gbdn);
+#else
+static inline int kvm_vfio_eeh_dev_map(struct kvm *kvm, int domain,
+                                      int bdn, unsigned long buid, int gbdn)
+{
+       return 0;
+}
+#endif /* CONFIG_KVM_EEH */
+
 #endif
 
-- 
1.8.3.2

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