HV: add DRHD index to pci_pdev

We add new member pci_pdev.drhd_idx associating the DRHD
(IOMMU) with this pdev, and a method to convert a pbdf of a device to
this index by searching the pdev list.

Partial patch: drhd_index initialization handled in subsequent patch.

Tracked-On: #4134
Signed-off-by: Alexander Merritt <alex.merritt@intel.com>
Signed-off-by: Sainath Grandhi <sainath.grandhi@intel.com>
Reviewed-by: Eddie Dong <eddie.dong@intel.com>
Reviewed-by: Jason Chen CJ <jason.cj.chen@intel.com>

hypervisor/include/hw/pci.h

@@ -165,6 +165,9 @@ struct pci_msix_cap {
 };
 
 struct pci_pdev {
+	/* IOMMU responsible for DMA and Interrupt Remapping for this device */
+	uint32_t drhd_index;
+
 	/* The bar info of the physical PCI device. */
 	uint32_t nr_bars; /* 6 for normal device, 2 for bridge, 1 for cardbus */
 
@@ -236,6 +239,16 @@ void enable_disable_pci_intx(union pci_bdf bdf, bool enable);
 
 void init_pci_pdev_list(void);
 
+/* @brief: Find the DRHD index corresponding to a PCI device
+ * Runs through the pci_pdev_array and returns the value in drhd_idx
+ * member from pdev strucutre that matches matches B:D.F
+ *
+ * @pbdf[in]	B:D.F of a PCI device
+ *
+ * @return if there is a matching pbdf in pci_pdev_array, pdev->drhd_idx, else -1U
+ */
+uint32_t pci_lookup_drhd_for_pbdf(uint16_t pbdf);
+
 static inline bool is_pci_vendor_valid(uint32_t vendor_id)
 {
 	return !((vendor_id == 0xFFFFFFFFU) || (vendor_id == 0U) ||