[Xen-devel] [PATCH] Simulate mask bit of msix entry in qemu

[Zhenzhong Duan <zhenzhong.duan@xxxxxxxxxx>]

Since xen has its own control of mask bit in msix entry, it's better to
simulate a vmask for hvm guest.

This will let changing irq affinity of old kernel(2.6.32 no msi_pirq support)
work and avoid no irq handler error in guest.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@xxxxxxxxxx>
---
 hw/pt-msi.c |   10 +---------
 1 files changed, 1 insertions(+), 9 deletions(-)

diff --git a/hw/pt-msi.c b/hw/pt-msi.c
index 73f737d..6f28522 100644
--- a/hw/pt-msi.c
+++ b/hw/pt-msi.c
@@ -445,18 +445,10 @@ static void pci_msix_writel(void *opaque, 
target_phys_addr_t addr, uint32_t val)
 
     if ( offset != 3 )
     {
-        const volatile uint32_t *vec_ctrl;
-
         if ( entry->io_mem[offset] == val )
             return;
 
-        /*
-         * If Xen intercepts the mask bit access, io_mem[3] may not be
-         * up-to-date. Read from hardware directly.
-         */
-        vec_ctrl = msix->phys_iomem_base + 16 * entry_nr + 12;
-
-        if ( msix->enabled && !(*vec_ctrl & 0x1) )
+        if ( msix->enabled && !(entry->io_mem[3] & 0x1) )
         {
             PT_LOG("Can't update entry %d since MSI-X is already enabled"
                    " (%08"PRIx32" -> %08"PRIx32")\n",
-- 
1.7.3


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