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

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

On Tue, Jul 08, 2014 at 09:12:39AM +0800, Zhenzhong Duan wrote:
> 
> On 2014-7-8 4:40, Konrad Rzeszutek Wilk wrote:
> >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]$
> >
> >?
> Sorry, I mean qemu-xen-traditional upstream git

Ok, is that patch upstream? Should it be upstream? If so, had it been
posted in the past?

Thank you!
> 
> zduan
> >>>>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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