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

On 2014-7-4 1:54, Konrad Rzeszutek Wilk wrote:
On Thu, Jul 03, 2014 at 11:12:18AM +0800, Zhenzhong Duan wrote:
There is a patch dependency missed.
Is that one upstream as well? Or does it not need to be?
If it is upstream, what is the title/commit id of that one?

Thank you!
It's upstream, see detail below
commit adf74189dd58014744a4b8c9d64407d629da5e2f
Author: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
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

     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@xxxxxxxxxxxxx>
     Tested-by: G.R. <firemeteor@xxxxxxxxxxxxxxxxxxxxx>
     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)

      /* clear msi info */
-    dev->msi->flags = 0;
+    dev->msi->flags &= ~(MSI_FLAG_UNINIT | PT_MSI_MAPPED |
      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@xxxxxxxxxx>

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).


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