Re: [PATCH] qemu-xen-trad: free all the pirqs for msi/msix when driver unloads

[Zhenzhong Duan <zhenzhong.duan@oracle.com>]

There is a patch dependency missed.

commit adf74189dd58014744a4b8c9d64407d629da5e2f
Author: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Date:   Mon Dec 10 12:43:33 2012 +0000

     qemu-xen-trad/pt_msi_disable: do not clear all MSI flags

     "qemu-xen-trad: fix msi_translate with PV event delivery" added a
     pt_msi_disable() call into pt_msgctrl_reg_write, clearing the MSI flags
     as a consequence. MSIs get enabled again soon after by calling
     pt_msi_setup.

     However the MSI flags are only setup once in the pt_msgctrl_reg_init
     function, so from the QEMU point of view the device has lost some
     important properties, like for example PCI_MSI_FLAGS_64BIT.

     This patch fixes the bug by clearing only the MSI
     enabled/mapped/initialized flags in pt_msi_disable.

     Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
     Tested-by: G.R. <firemeteor@users.sourceforge.net>
     Xen-devel: http://marc.info/?l=xen-devel&m=135489879503075

diff --git a/hw/pt-msi.c b/hw/pt-msi.c
index 73f737d..b03b989 100644
--- a/hw/pt-msi.c
+++ b/hw/pt-msi.c
@@ -213,7 +213,7 @@ void pt_msi_disable(struct pt_dev *dev)

  out:
      /* clear msi info */
-    dev->msi->flags = 0;
+    dev->msi->flags &= ~(MSI_FLAG_UNINIT | PT_MSI_MAPPED | 
PCI_MSI_FLAGS_ENABLE);
      dev->msi->pirq = -1;
      dev->msi_trans_en = 0;
  }

On 2014-7-2 23:06, Ian Jackson wrote:
> Konrad Rzeszutek Wilk writes ("[Xen-devel] [PATCH] qemu-xen-trad: free all the pirqs for msi/msix when driver unloads"):
>> From: Zhenzhong Duan<zhenzhong.duan@oracle.com>
>>
>> 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.
> I have backported this to 4.4 and 4.3.  It did not apply cleanly to
> 4.2 (and I have not investgated why).
>
> Thanks,
> Ian.