[Xen-changelog] [xen stable-4.4] x86/MSI: fix MSI-X case of freeing IRQ

[patchbot@xxxxxxx]

commit 4e08d1280f026e48bdf38e95a7c2a175b8256369
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Fri Oct 17 15:54:31 2014 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Fri Oct 17 15:54:31 2014 +0200

    x86/MSI: fix MSI-X case of freeing IRQ
    
    Commit d1b6d0a024 ("x86: enable multi-vector MSI") went a little too
    far with moving things around in msi_free_irqs() in order to streamline
    the code: We shouldn't drop the MSI-X control page reference before
    calling destroy_irq(), as the latter will call us back via
    desc->handler->shutdown() (effectively invoking to msi_set_mask_bit()).
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    master commit: 44d20c69516f8d5e71fc14bf216e230a9910d729
    master date: 2014-10-06 11:11:28 +0200
---
 xen/arch/x86/msi.c |   15 ++++++---------
 1 files changed, 6 insertions(+), 9 deletions(-)

diff --git a/xen/arch/x86/msi.c b/xen/arch/x86/msi.c
index 61d6dd0..99312d9 100644
--- a/xen/arch/x86/msi.c
+++ b/xen/arch/x86/msi.c
@@ -496,15 +496,8 @@ int __setup_msi_irq(struct irq_desc *desc, struct msi_desc 
*msidesc,
 
 int msi_free_irq(struct msi_desc *entry)
 {
-    unsigned int nr = entry->msi.nvec;
-
-    if ( entry->msi_attrib.type == PCI_CAP_ID_MSIX )
-    {
-        unsigned long start;
-        start = (unsigned long)entry->mask_base & ~(PAGE_SIZE - 1);
-        msix_put_fixmap(entry->dev->msix, virt_to_fix(start));
-        nr = 1;
-    }
+    unsigned int nr = entry->msi_attrib.type != PCI_CAP_ID_MSIX
+                      ? entry->msi.nvec : 1;
 
     while ( nr-- )
     {
@@ -515,6 +508,10 @@ int msi_free_irq(struct msi_desc *entry)
             iommu_update_ire_from_msi(entry + nr, NULL);
     }
 
+    if ( entry->msi_attrib.type == PCI_CAP_ID_MSIX )
+        msix_put_fixmap(entry->dev->msix,
+                        virt_to_fix((unsigned long)entry->mask_base));
+
     list_del(&entry->list);
     xfree(entry);
     return 0;
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.4

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