From 8fb8d81935fa9d8835f68d724475e1e6f0f33d5a Mon Sep 17 00:00:00 2001
From: Qian Wang <qian1.wang@intel.com>
Date: Fri, 5 Jun 2020 12:17:59 +0800
Subject: [PATCH] HV: refine pci_lookup_drhd_for_pbdf with hash

hv: pci: refine pci_lookup_drhd_for_pbdf with hash

1. Added an auxiliary function pci_find_pdev using hash to find pdev
with pbdf, thus pci_lookup_drhd_for_pbdf will have a better performance

Tracked-On: #4857
Signed-off-by: Wang Qian <qian1.wang@intel.com>
Reviewed-by: Li Fei <Fei1.Li@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
---
 hypervisor/hw/pci.c         | 35 ++++++++++++++++++++++++-----------
 hypervisor/include/hw/pci.h |  3 +++
 2 files changed, 27 insertions(+), 11 deletions(-)

diff --git a/hypervisor/hw/pci.c b/hypervisor/hw/pci.c
index 6bcd002ec..8dbe40416 100644
--- a/hypervisor/hw/pci.c
+++ b/hypervisor/hw/pci.c
@@ -43,10 +43,16 @@
 #include <bits.h>
 #include <board.h>
 #include <platform_acpi_info.h>
+#include <hash.h>
+#include <util.h>
+
+#define PDEV_HLIST_HASHBITS 6U
+#define PDEV_HLIST_HASHSIZE (1U << PDEV_HLIST_HASHBITS)
 
 static spinlock_t pci_device_lock;
 static uint32_t num_pci_pdev;
 static struct pci_pdev pci_pdevs[CONFIG_MAX_PCI_DEV_NUM];
+static struct hlist_head pdevs_hlist_heads[PDEV_HLIST_HASHSIZE];
 static uint64_t pci_mmcfg_base = DEFAULT_PCI_MMCFG_BASE;
 
 #ifdef CONFIG_ACPI_PARSE_ENABLED
@@ -258,6 +264,21 @@ void pdev_restore_bar(const struct pci_pdev *pdev)
 	}
 }
 
+static const struct pci_pdev *pci_find_pdev(uint16_t pbdf)
+{
+	struct hlist_node *n;
+	const struct pci_pdev *found = NULL, *tmp;
+
+	hlist_for_each (n, &pdevs_hlist_heads[hash64(pbdf, PDEV_HLIST_HASHBITS)]) {
+		tmp = hlist_entry(n, struct pci_pdev, link);
+		if (pbdf == tmp->bdf.value) {
+			found = tmp;
+			break;
+		}
+	}
+	return found;
+}
+
 /* @brief: Find the DRHD index corresponding to a PCI device
  * Runs through the pci_pdevs and returns the value in drhd_idx
  * member from pdev structure that matches matches B:D.F
@@ -269,17 +290,8 @@ void pdev_restore_bar(const struct pci_pdev *pdev)
 
 uint32_t pci_lookup_drhd_for_pbdf(uint16_t pbdf)
 {
-	uint32_t drhd_index = INVALID_DRHD_INDEX;
-	uint32_t index;
-
-	for (index = 0U; index < num_pci_pdev; index++) {
-		if (pci_pdevs[index].bdf.value == pbdf) {
-			drhd_index = pci_pdevs[index].drhd_index;
-			break;
-		}
-	}
-
-	return drhd_index;
+	const struct pci_pdev *pdev = pci_find_pdev(pbdf);
+	return (pdev != NULL) ? pdev->drhd_index : INVALID_DRHD_INDEX;
 }
 
 /* enable: 1: enable INTx; 0: Disable INTx */
@@ -765,6 +777,7 @@ struct pci_pdev *init_pdev(uint16_t pbdf, uint32_t drhd_index)
 				pci_enumerate_cap(pdev);
 			}
 
+			hlist_add_head(&pdev->link, &pdevs_hlist_heads[hash64(pbdf, PDEV_HLIST_HASHBITS)]);
 			pdev->drhd_index = drhd_index;
 			num_pci_pdev++;
 			reserve_vmsix_on_msi_irtes(pdev);
diff --git a/hypervisor/include/hw/pci.h b/hypervisor/include/hw/pci.h
index a48e6523e..2efc2d569 100644
--- a/hypervisor/include/hw/pci.h
+++ b/hypervisor/include/hw/pci.h
@@ -31,6 +31,8 @@
 #ifndef PCI_H_
 #define PCI_H_
 
+#include <list.h>
+
 /*
  * PCIM_xxx: mask to locate subfield in register
  * PCIR_xxx: config register offset
@@ -248,6 +250,7 @@ struct pci_pdev {
 	bool has_pm_reset;
 	bool has_flr;
 	bool has_af_flr;
+	struct hlist_node link;
 };
 
 struct pci_cfg_ops {