[Xen-changelog] [xen master] x86/vMSI-X: drop list lock

[patchbot@xxxxxxx]

commit 08844d189930da5b7846ed6078987fb2788d6173
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Wed Jun 22 11:59:39 2016 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Wed Jun 22 11:59:39 2016 +0200

    x86/vMSI-X: drop list lock
    
    msixtbl_pt_{,un}register() already run with both the PCI devices lock
    and the domain event lock held, so there's no need for another lock.
    Just to be on the safe side, acquire the domain event lock in the
    cleanup function (albeit I don't think this is strictly necessary).
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/arch/x86/hvm/vmsi.c          | 18 ++----------------
 xen/include/asm-x86/hvm/domain.h |  1 -
 2 files changed, 2 insertions(+), 17 deletions(-)

diff --git a/xen/arch/x86/hvm/vmsi.c b/xen/arch/x86/hvm/vmsi.c
index 81e45c8..7b0cfa9 100644
--- a/xen/arch/x86/hvm/vmsi.c
+++ b/xen/arch/x86/hvm/vmsi.c
@@ -468,8 +468,6 @@ int msixtbl_pt_register(struct domain *d, struct pirq 
*pirq, uint64_t gtable)
 
     pdev = msi_desc->dev;
 
-    spin_lock(&d->arch.hvm_domain.msixtbl_list_lock);
-
     list_for_each_entry( entry, &d->arch.hvm_domain.msixtbl_list, list )
         if ( pdev == entry->pdev )
             goto found;
@@ -480,7 +478,6 @@ int msixtbl_pt_register(struct domain *d, struct pirq 
*pirq, uint64_t gtable)
 
 found:
     atomic_inc(&entry->refcnt);
-    spin_unlock(&d->arch.hvm_domain.msixtbl_list_lock);
     r = 0;
 
 out:
@@ -530,15 +527,10 @@ void msixtbl_pt_unregister(struct domain *d, struct pirq 
*pirq)
 
     pdev = msi_desc->dev;
 
-    spin_lock(&d->arch.hvm_domain.msixtbl_list_lock);
-
     list_for_each_entry( entry, &d->arch.hvm_domain.msixtbl_list, list )
         if ( pdev == entry->pdev )
             goto found;
 
-    spin_unlock(&d->arch.hvm_domain.msixtbl_list_lock);
-
-
 out:
     spin_unlock_irq(&irq_desc->lock);
     return;
@@ -547,7 +539,6 @@ found:
     if ( !atomic_dec_and_test(&entry->refcnt) )
         del_msixtbl_entry(entry);
 
-    spin_unlock(&d->arch.hvm_domain.msixtbl_list_lock);
     spin_unlock_irq(&irq_desc->lock);
 }
 
@@ -558,7 +549,6 @@ void msixtbl_init(struct domain *d)
         return;
 
     INIT_LIST_HEAD(&d->arch.hvm_domain.msixtbl_list);
-    spin_lock_init(&d->arch.hvm_domain.msixtbl_list_lock);
 
     register_mmio_handler(d, &msixtbl_mmio_ops);
 }
@@ -566,21 +556,17 @@ void msixtbl_init(struct domain *d)
 void msixtbl_pt_cleanup(struct domain *d)
 {
     struct msixtbl_entry *entry, *temp;
-    unsigned long flags;
 
     if ( !d->arch.hvm_domain.msixtbl_list.next )
         return;
 
-    /* msixtbl_list_lock must be acquired with irq_disabled for check_lock() */
-    local_irq_save(flags); 
-    spin_lock(&d->arch.hvm_domain.msixtbl_list_lock);
+    spin_lock(&d->event_lock);
 
     list_for_each_entry_safe( entry, temp,
                               &d->arch.hvm_domain.msixtbl_list, list )
         del_msixtbl_entry(entry);
 
-    spin_unlock(&d->arch.hvm_domain.msixtbl_list_lock);
-    local_irq_restore(flags);
+    spin_unlock(&d->event_lock);
 }
 
 void msix_write_completion(struct vcpu *v)
diff --git a/xen/include/asm-x86/hvm/domain.h b/xen/include/asm-x86/hvm/domain.h
index f500ff4..f34d784 100644
--- a/xen/include/asm-x86/hvm/domain.h
+++ b/xen/include/asm-x86/hvm/domain.h
@@ -124,7 +124,6 @@ struct hvm_domain {
 
     /* hypervisor intercepted msix table */
     struct list_head       msixtbl_list;
-    spinlock_t             msixtbl_list_lock;
 
     struct viridian_domain viridian;
 
--
generated by git-patchbot for /home/xen/git/xen.git#master

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