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

[Zhenzhong Duan <zhenzhong.duan@xxxxxxxxxx>]

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
> >      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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