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

[Zhenzhong Duan <zhenzhong.duan@oracle.com>]

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

zduan
>>>> commit adf74189dd58014744a4b8c9d64407d629da5e2f
>>>> Author: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
>>>> 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@eu.citrix.com>
>>>>      Tested-by: G.R. <firemeteor@users.sourceforge.net>
>>>>      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@oracle.com>
>>>>>>
>>>>>> 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.