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

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Fri, Jul 04, 2014 at 09:29:38AM +0800, Zhenzhong Duan wrote:
> 
> 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


[konrad@build-external qemu-xen-dir]$ pwd
/home/konrad/xtt-x86_64/xen/tools/qemu-xen-dir
[konrad@build-external qemu-xen-dir]$ git show 
adf74189dd58014744a4b8c9d64407d629da5e2f
fatal: bad object adf74189dd58014744a4b8c9d64407d629da5e2f
[konrad@build-external qemu-xen-dir]$ git log --grep="clear all MSI"
[konrad@build-external qemu-xen-dir]$ 

?

> >>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
> >>     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@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)
> >>
> >>  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@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).
> >>>
> >>>Thanks,
> >>>Ian.
> 

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