From 55c4f093b3a527c52cc8ed7138c330512973c9e6 Mon Sep 17 00:00:00 2001
From: fangying <[email protected]>
Date: Wed, 18 Mar 2020 12:49:33 +0800
Subject: [PATCH 1/2] pcie: Add pcie-root-port fast plug/unplug feature

If a device is plugged in the pcie-root-port when VM kernel is
booting, the kernel may wrongly disable the device.
This bug was brought in by two patches of the linux kernel:

https://patchwork.kernel.org/patch/10575355/
https://patchwork.kernel.org/patch/10766219/

VM runtime like kata uses this feature to boot microVM,
so we must fix it up. We hack into the pcie native hotplug
patch so that hotplug/unplug will work under this circumstance.

Signed-off-by: Ying Fang <[email protected]>
---
 hw/core/machine.c                  |  1 +
 hw/pci-bridge/gen_pcie_root_port.c |  3 ++-
 hw/pci/pcie.c                      | 23 +++++++++++++++++++----
 include/hw/pci/pcie_port.h         |  3 ++-
 4 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/hw/core/machine.c b/hw/core/machine.c
index 2baf9ec3..3138f97b 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -33,6 +33,7 @@ GlobalProperty hw_compat_3_1[] = {
     { "pcie-root-port", "x-speed", "2_5" },
     { "pcie-root-port", "x-width", "1" },
     { "pcie-root-port", "fast-plug", "0" },
+    { "pcie-root-port", "fast-unplug", "0" },
     { "memory-backend-file", "x-use-canonical-path-for-ramblock-id", "true" },
     { "memory-backend-memfd", "x-use-canonical-path-for-ramblock-id", "true" },
     { "tpm-crb", "ppi", "false" },
diff --git a/hw/pci-bridge/gen_pcie_root_port.c b/hw/pci-bridge/gen_pcie_root_port.c
index 3179c4ea..2fbb11d0 100644
--- a/hw/pci-bridge/gen_pcie_root_port.c
+++ b/hw/pci-bridge/gen_pcie_root_port.c
@@ -131,7 +131,8 @@ static Property gen_rp_props[] = {
                                 speed, PCIE_LINK_SPEED_16),
     DEFINE_PROP_PCIE_LINK_WIDTH("x-width", PCIESlot,
                                 width, PCIE_LINK_WIDTH_32),
-    DEFINE_PROP_UINT8("fast-plug", PCIESlot, disable_lnksta_dllla, 0),
+    DEFINE_PROP_UINT8("fast-plug", PCIESlot, fast_plug, 0),
+    DEFINE_PROP_UINT8("fast-unplug", PCIESlot, fast_unplug, 0),
     DEFINE_PROP_END_OF_LIST()
 };
 
diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c
index c0d6ff13..2a8ff86d 100644
--- a/hw/pci/pcie.c
+++ b/hw/pci/pcie.c
@@ -85,7 +85,7 @@ pcie_cap_v1_fill(PCIDevice *dev, uint8_t port, uint8_t type, uint8_t version)
      * To fix this up, let's enable the PCI_EXP_LNKSTA_DLLLA
      * only if it is a PCIESlot device.
      */
-    if (s == NULL || s->disable_lnksta_dllla == 0) {
+    if (s == NULL || s->fast_plug == 0) {
         if (dev->cap_present & QEMU_PCIE_LNKSTA_DLLLA) {
             pci_word_test_and_set_mask(exp_cap + PCI_EXP_LNKSTA,
                                        PCI_EXP_LNKSTA_DLLLA);
@@ -136,8 +136,11 @@ static void pcie_cap_fill_slot_lnk(PCIDevice *dev)
          */
         pci_long_test_and_set_mask(exp_cap + PCI_EXP_LNKCAP,
                                    PCI_EXP_LNKCAP_DLLLARC);
-        pci_word_test_and_set_mask(exp_cap + PCI_EXP_LNKSTA,
-                                   PCI_EXP_LNKSTA_DLLLA);
+
+        if(s->fast_plug == 0) {
+            pci_word_test_and_set_mask(exp_cap + PCI_EXP_LNKSTA,
+                                       PCI_EXP_LNKSTA_DLLLA);
+        }
 
         /*
          * Target Link Speed defaults to the highest link speed supported by
@@ -477,6 +480,8 @@ void pcie_cap_slot_unplug_request_cb(HotplugHandler *hotplug_dev,
     Error *local_err = NULL;
     PCIDevice *pci_dev = PCI_DEVICE(dev);
     PCIBus *bus = pci_get_bus(pci_dev);
+    PCIESlot *s = PCIE_SLOT(PCI_DEVICE(hotplug_dev));
+    uint8_t *exp_cap = pci_dev->config + pci_dev->exp.exp_cap;
 
     pcie_cap_slot_plug_common(PCI_DEVICE(hotplug_dev), dev, &local_err);
     if (local_err) {
@@ -495,7 +500,17 @@ void pcie_cap_slot_unplug_request_cb(HotplugHandler *hotplug_dev,
         return;
     }
 
-    pcie_cap_slot_push_attention_button(PCI_DEVICE(hotplug_dev));
+    if ((pci_dev->cap_present & QEMU_PCIE_LNKSTA_DLLLA) && s->fast_plug) {
+        pci_word_test_and_clear_mask(exp_cap+ PCI_EXP_LNKSTA,
+                                    PCI_EXP_LNKSTA_DLLLA);
+    }
+
+    if (s->fast_unplug) {
+        pcie_cap_slot_event(PCI_DEVICE(hotplug_dev),
+                            PCI_EXP_HP_EV_PDC | PCI_EXP_HP_EV_ABP);
+    } else {
+        pcie_cap_slot_push_attention_button(PCI_DEVICE(hotplug_dev));
+    }
 }
 
 /* pci express slot for pci express root/downstream port
diff --git a/include/hw/pci/pcie_port.h b/include/hw/pci/pcie_port.h
index c3969921..b57af4ee 100644
--- a/include/hw/pci/pcie_port.h
+++ b/include/hw/pci/pcie_port.h
@@ -50,7 +50,8 @@ struct PCIESlot {
     uint8_t     chassis;
     uint16_t    slot;
 
-    uint8_t     disable_lnksta_dllla;
+    uint8_t     fast_plug;
+    uint8_t     fast_unplug;
 
     PCIExpLinkSpeed speed;
     PCIExpLinkWidth width;
-- 
2.19.1