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

[Zhenzhong Duan <zhenzhong.duan@xxxxxxxxxx>]

Hi Ian,

Could you cherry-pick commit adf74189dd58014744a4b8c9d64407d629da5e2f  
before backport my patch?
It seems 4.3 and 4.4 branch already has commit adf74189dd but 4.2 not.

thanks
zduan

On 2014-7-3 11:12, Zhenzhong Duan wrote:
> There is a patch dependency missed.
>
> 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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