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

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Tue, 8 Apr 2014, konrad@xxxxxxxxxx wrote:
> From: Zhenzhong Duan <zhenzhong.duan@xxxxxxxxxx>
> 
> Pirqs are not freed when driver unload, then new pirqs are allocated when
> driver reload. 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.
> 
> There is also other way of fixing it such as reuse pirqs between driver 
> reload,
> but this way is better.
> Xen-devel: http://marc.info/?l=xen-devel&m=136800120304275&w=2
> 
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@xxxxxxxxxx>
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>

I'll add it to my queue.
At the moment they are busy with the QEMU 2.0 release, I would rather
wait for the next merge window.


>  hw/xen/xen_pt_config_init.c |    6 ++++--
>  hw/xen/xen_pt_msi.c         |    6 ++++--
>  2 files changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/hw/xen/xen_pt_config_init.c b/hw/xen/xen_pt_config_init.c
> index 8ccc2e4..de9a20f 100644
> --- a/hw/xen/xen_pt_config_init.c
> +++ b/hw/xen/xen_pt_config_init.c
> @@ -1123,8 +1123,8 @@ static int 
> xen_pt_msgctrl_reg_write(XenPCIPassthroughState *s,
>              msi->mapped = true;
>          }
>          msi->flags |= PCI_MSI_FLAGS_ENABLE;
> -    } else {
> -        msi->flags &= ~PCI_MSI_FLAGS_ENABLE;
> +    } else if (msi->mapped) {
> +        xen_pt_msi_disable(s);
>      }
>  
>      /* pass through MSI_ENABLE bit */
> @@ -1397,6 +1397,8 @@ static int 
> xen_pt_msixctrl_reg_write(XenPCIPassthroughState *s,
>      if ((*val & PCI_MSIX_FLAGS_ENABLE)
>          && !(*val & PCI_MSIX_FLAGS_MASKALL)) {
>          xen_pt_msix_update(s);
> +    } else if (!(*val & PCI_MSIX_FLAGS_ENABLE) && s->msix->enabled) {
> +        xen_pt_msix_disable(s);
>      }
>  
>      debug_msix_enabled_old = s->msix->enabled;
> diff --git a/hw/xen/xen_pt_msi.c b/hw/xen/xen_pt_msi.c
> index 6fbe0cc..12b4c45 100644
> --- a/hw/xen/xen_pt_msi.c
> +++ b/hw/xen/xen_pt_msi.c
> @@ -282,7 +282,8 @@ void xen_pt_msi_disable(XenPCIPassthroughState *s)
>                       msi->initialized);
>  
>      /* clear msi info */
> -    msi->flags = 0;
> +    msi->flags &= ~PCI_MSI_FLAGS_ENABLE;
> +    msi->initialized = false;
>      msi->mapped = false;
>      msi->pirq = XEN_PT_UNASSIGNED_PIRQ;
>  }
> @@ -446,7 +447,8 @@ static void pci_msix_write(void *opaque, hwaddr addr,
>      if (offset != PCI_MSIX_ENTRY_VECTOR_CTRL) {
>          const volatile uint32_t *vec_ctrl;
>  
> -        if (get_entry_value(entry, offset) == val) {
> +        if (get_entry_value(entry, offset) == val
> +            && entry->pirq != XEN_PT_UNASSIGNED_PIRQ) {
>              return;
>          }
>  
> -- 
> 1.7.7.6
> 

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