qemu-xen-trad: free all the pirqs for msi/msix when driver unload

Pirqs are not freed when driver unloads, then new pirqs are allocated when driver reloads. This could exhaust pirqs if do it in a loop.

This patch fixes the bug by freeing pirqs when ENABLE bit is cleared in msi/msix control reg.

There is also other way of fixing it such as reuse pirqs between driver reload, but this way is better.
Xen-devel: http://marc.info/?l=xen-devel&m=136800120304275&w=2

Signed-off-by Zhenzhong Duan <[email protected]>

From what I understand following the conversation, I think this is

Quoted 11 lines · Zhenzhong Duan

Pirqs are not freed when driver unloads, then new pirqs are allocated when driver reloads. This could exhaust pirqs if do it in a loop.

This patch fixes the bug by freeing pirqs when ENABLE bit is cleared in msi/msix control reg.

There is also other way of fixing it such as reuse pirqs between driver reload, but this way is better.
Xen-devel: http://marc.info/?l=xen-devel&m=136800120304275&w=2

Signed-off-by Zhenzhong Duan <[email protected]>

Thanks Zhenzhong.

Quoted 1 line

From what I understand following the conversation, I think this is

probably the right way to solve the problem, but given that it's only really a problem when you load and unload drivers, which is the uncommon case, I think at this point we should probably hold off on this one until 4.3.1.

Stefano, thoughts?

Pirqs are not freed when driver unloads, then new pirqs are allocated when driver reloads. This could exhaust pirqs if do it in a loop.

This patch fixes the bug by freeing pirqs when ENABLE bit is cleared in msi/msix control reg.

There is also other way of fixing it such as reuse pirqs between driver reload, but this way is better.
Xen-devel: http://marc.info/?l=xen-devel&m=136800120304275&w=2

Signed-off-by Zhenzhong Duan <[email protected]>

 hw/pass-through.c |    8 +++++++-
 hw/pt-msi.c       |    5 +++--
 2 files changed, 10 insertions(+), 3 deletions(-)

hw/pass-through.c +7 -1

index 304c438..4821182 100644
@@ -3866,7 +3866,11 @@ static int pt_msgctrl_reg_write(struct pt_dev *ptdev,
         ptdev->msi->flags |= PCI_MSI_FLAGS_ENABLE;
     }
     else
-        ptdev->msi->flags &= ~PCI_MSI_FLAGS_ENABLE;
+    {
+        if (ptdev->msi->flags & PT_MSI_MAPPED) {
+            pt_msi_disable(ptdev);
+        }
+    }
 
     /* pass through MSI_ENABLE bit when no MSI-INTx translation */
     if (!ptdev->msi_trans_en) {

@@ -4013,6 +4017,8 @@ static int pt_msixctrl_reg_write(struct pt_dev *ptdev,
             pt_disable_msi_translate(ptdev);
         }
         pt_msix_update(ptdev);
+    } else if (!(*value & PCI_MSIX_ENABLE) && ptdev->msix->enabled) {
+        pt_msix_disable(ptdev);
     }
 
     ptdev->msix->enabled = !!(*value & PCI_MSIX_ENABLE);

hw/pt-msi.c +3 -2

index b03b989..3f5f94b 100644
@@ -213,7 +213,8 @@ void pt_msi_disable(struct pt_dev *dev)
 
 out:
     /* clear msi info */
-    dev->msi->flags &= ~(MSI_FLAG_UNINIT | PT_MSI_MAPPED | PCI_MSI_FLAGS_ENABLE);
+    dev->msi->flags &= ~(PT_MSI_MAPPED | PCI_MSI_FLAGS_ENABLE);
+    dev->msi->flags |= MSI_FLAG_UNINIT;
     dev->msi->pirq = -1;
     dev->msi_trans_en = 0;
 }

@@ -447,7 +448,7 @@ static void pci_msix_writel(void *opaque, target_phys_addr_t addr, uint32_t val)
     {
         const volatile uint32_t *vec_ctrl;
 
-        if ( entry->io_mem[offset] == val )
+        if ( entry->io_mem[offset] == val && entry->pirq != -1)
             return;
 
         /*

Signature · 1 line

1.7.3