From ceeaf62ea52df6cfacac8c1653ff9f7585ef0392 Mon Sep 17 00:00:00 2001
Message-Id: <ceeaf62ea52df6cfacac8c1653ff9f7585ef0392@dist-git>
From: Shivaprasad G Bhat <shivaprasadbhat@gmail.com>
Date: Wed, 2 Sep 2015 15:55:23 -0400
Subject: [PATCH] Allow vfio hotplug of a device to the domain which owns the
 iommu

The commit 7e72de4 didn't consider the hotplug scenarios. The patch addresses
the hotplug case whereby if atleast one of the pci function is owned by a
guest, the hotplug of other functions/devices in the same iommu group to the
same guest goes through successfully.

Prerequisite for the fix for:

  https://bugzilla.redhat.com/show_bug.cgi?id=1256486

Signed-off-by: Shivaprasad G Bhat <sbhat@linux.vnet.ibm.com>
(cherry picked from commit e3810db34f1acb74dfcfd69219930e23a30284f6)
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
---
 src/util/virhostdev.c | 34 +++++++++++++++++++++++++++-------
 1 file changed, 27 insertions(+), 7 deletions(-)

diff --git a/src/util/virhostdev.c b/src/util/virhostdev.c
index 809caed..529753c 100644
--- a/src/util/virhostdev.c
+++ b/src/util/virhostdev.c
@@ -54,23 +54,35 @@ static virClassPtr virHostdevManagerClass;
 static void virHostdevManagerDispose(void *obj);
 static virHostdevManagerPtr virHostdevManagerNew(void);
 
+struct virHostdevIsPCINodeDeviceUsedData {
+    virHostdevManagerPtr hostdev_mgr;
+    const char *domainName;
+    const bool usesVfio;
+};
+
 static int virHostdevIsPCINodeDeviceUsed(virPCIDeviceAddressPtr devAddr, void *opaque)
 {
     virPCIDevicePtr other;
     int ret = -1;
     virPCIDevicePtr pci = NULL;
-    virHostdevManagerPtr hostdev_mgr = opaque;
+    struct virHostdevIsPCINodeDeviceUsedData *helperData = opaque;
 
     if (!(pci = virPCIDeviceNew(devAddr->domain, devAddr->bus,
                                 devAddr->slot, devAddr->function)))
         goto cleanup;
 
-    other = virPCIDeviceListFind(hostdev_mgr->activePCIHostdevs, pci);
+    other = virPCIDeviceListFind(helperData->hostdev_mgr->activePCIHostdevs,
+                                 pci);
     if (other) {
         const char *other_drvname = NULL;
         const char *other_domname = NULL;
         virPCIDeviceGetUsedBy(other, &other_drvname, &other_domname);
 
+        if (helperData->usesVfio &&
+            (other_domname && helperData->domainName) &&
+            (STREQ(other_domname, helperData->domainName)))
+            goto iommu_owner;
+
         if (other_drvname && other_domname)
             virReportError(VIR_ERR_OPERATION_INVALID,
                            _("PCI device %s is in use by "
@@ -83,6 +95,7 @@ static int virHostdevIsPCINodeDeviceUsed(virPCIDeviceAddressPtr devAddr, void *o
                            virPCIDeviceGetName(pci));
         goto cleanup;
     }
+ iommu_owner:
     ret = 0;
  cleanup:
     virPCIDeviceFree(pci);
@@ -562,6 +575,9 @@ virHostdevPreparePCIDevices(virHostdevManagerPtr hostdev_mgr,
     for (i = 0; i < virPCIDeviceListCount(pcidevs); i++) {
         virPCIDevicePtr dev = virPCIDeviceListGet(pcidevs, i);
         bool strict_acs_check = !!(flags & VIR_HOSTDEV_STRICT_ACS_CHECK);
+        bool usesVfio = STREQ(virPCIDeviceGetStubDriver(dev), "vfio-pci");
+        struct virHostdevIsPCINodeDeviceUsedData data = {hostdev_mgr, dom_name,
+                                                         usesVfio};
 
         if (!virPCIDeviceIsAssignable(dev, strict_acs_check)) {
             virReportError(VIR_ERR_OPERATION_INVALID,
@@ -579,12 +595,12 @@ virHostdevPreparePCIDevices(virHostdevManagerPtr hostdev_mgr,
          * belonging to same iommu group can't be shared
          * across guests.
          */
-        if (STREQ(virPCIDeviceGetStubDriver(dev), "vfio-pci")) {
+        if (usesVfio) {
             if (virPCIDeviceAddressIOMMUGroupIterate(devAddr,
                                                      virHostdevIsPCINodeDeviceUsed,
-                                                     hostdev_mgr) < 0)
+                                                     &data) < 0)
                 goto cleanup;
-        } else if (virHostdevIsPCINodeDeviceUsed(devAddr, hostdev_mgr)) {
+        } else if (virHostdevIsPCINodeDeviceUsed(devAddr, &data)) {
             goto cleanup;
         }
     }
@@ -1544,6 +1560,8 @@ virHostdevPCINodeDeviceDetach(virHostdevManagerPtr hostdev_mgr,
                               virPCIDevicePtr pci)
 {
     virPCIDeviceAddressPtr devAddr = NULL;
+    struct virHostdevIsPCINodeDeviceUsedData data = { hostdev_mgr, NULL,
+                                                     false };
     int ret = -1;
 
     virObjectLock(hostdev_mgr->activePCIHostdevs);
@@ -1552,7 +1570,7 @@ virHostdevPCINodeDeviceDetach(virHostdevManagerPtr hostdev_mgr,
     if (!(devAddr = virPCIDeviceGetAddress(pci)))
         goto out;
 
-    if (virHostdevIsPCINodeDeviceUsed(devAddr, hostdev_mgr))
+    if (virHostdevIsPCINodeDeviceUsed(devAddr, &data))
         goto out;
 
     if (virPCIDeviceDetach(pci, hostdev_mgr->activePCIHostdevs,
@@ -1573,6 +1591,8 @@ virHostdevPCINodeDeviceReAttach(virHostdevManagerPtr hostdev_mgr,
                                 virPCIDevicePtr pci)
 {
     virPCIDeviceAddressPtr devAddr = NULL;
+    struct virHostdevIsPCINodeDeviceUsedData data = {hostdev_mgr, NULL,
+                                                     false};
     int ret = -1;
 
     virObjectLock(hostdev_mgr->activePCIHostdevs);
@@ -1581,7 +1601,7 @@ virHostdevPCINodeDeviceReAttach(virHostdevManagerPtr hostdev_mgr,
     if (!(devAddr = virPCIDeviceGetAddress(pci)))
         goto out;
 
-    if (virHostdevIsPCINodeDeviceUsed(devAddr, hostdev_mgr))
+    if (virHostdevIsPCINodeDeviceUsed(devAddr, &data))
         goto out;
 
     virPCIDeviceReattachInit(pci);
-- 
2.5.1