Re: [Xen-devel] [PATCH qemu-xen-traditional] xen/pt: allow QEMU to request MSI unmasking at bind time

["Paraschiv, Andra-Irina" <andraprs@xxxxxxxxxx>]

>From: Woodhouse, David
>Sent: Tuesday, July 31, 2018 1:22 PM
>To: roger.pau@xxxxxxxxxx; Paraschiv, Andra-Irina
>Cc: ian.jackson@xxxxxxxxxxxxx; jbeulich@xxxxxxxx; sstabellini@xxxxxxxxxx; 
>andrew.cooper3@xxxxxxxxxx; xen->devel@xxxxxxxxxxxxxxxxxxxx
>Subject: Re: [Xen-devel] [PATCH qemu-xen-traditional] xen/pt: allow QEMU to 
>request MSI unmasking at bind >time
>
>Ian, any objections?
>
>Thanks.On Thu, 2018-06-21 at 08:37 +0000, Paraschiv, Andra-Irina wrote:
>> + Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx> for review.
>>
>> Thanks, Roger, for review and feedback.
>>
>> Andra
>> ________________________________________
>> From: Roger Pau Monné <roger.pau@xxxxxxxxxx>
>> Sent: Monday, June 18, 2018 2:43 PM
>> To: Paraschiv, Andra-Irina
>> Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx; sstabellini@xxxxxxxxxx; jbeulich@
>> suse.com; andrew.cooper3@xxxxxxxxxx; Woodhouse, David
>> Subject: Re: [PATCH qemu-xen-traditional] xen/pt: allow QEMU to
>> request MSI unmasking at bind time
>>
>> On Mon, Jun 18, 2018 at 09:35:20AM +0000, Andra Paraschiv wrote:
>> >
>> > When a MSI interrupt is bound to a guest using
> > xc_domain_update_msi_irq (XEN_DOMCTL_bind_pt_irq) the interrupt is
>> > left masked by default.
>> >
>> > This causes problems with guests that first configure interrupts
>> > and
>> > clean the per-entry MSIX table mask bit and afterwards enable MSIX
>> > globally. In such scenario the Xen internal msixtbl handlers would
>> > not
>> > detect the unmasking of MSIX entries because vectors are not yet
>> > registered since MSIX is not enabled, and vectors would be left
>> > masked.
>> >
>> > Introduce a new flag in the gflags field to signal Xen whether a
>> > MSI
>> > interrupt should be unmasked after being bound.
>> >
>> > This also requires to track the mask register for MSI interrupts,
>> > so
>> > QEMU can also notify to Xen whether the MSI interrupt should be
>> > bound
>> > masked or unmasked
>> >
>> > Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
>> > Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
>> > Reported-by: Andreas Kinzler <hfp@xxxxxxxxx>
>> > Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
>> > Signed-off-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
>> >
>> > [Backported from commit a8036336609d2e184fc3543a4c439c0ba7d7f3a2
>> >  https://git.qemu.org/?p=qemu.git;a=commit;h=a8036336609d2e184fc354
>> > 3a4c439c0ba7d7f3a2
>> >  https://xenbits.xen.org/gitweb/?p=qemu-xen.git;a=commit;h=a8036336
>> > 609d2e184fc3543a4c439c0ba7d7f3a2]
>> >
>> > Signed-off-by: Andra Paraschiv <andraprs@xxxxxxxxxx>
>> Thanks for doing the backport, LGTM.
>>

Ian, can you please take a look on this patch that is considered for 
backporting from QEMU upstream repo to QEMU traditional?

Thanks.

>>
>>
>> Amazon Development Center (Romania) S.R.L. registered office: 27A Sf.
>> Lazar Street, UBC5, floor 2, Iasi, Iasi County, 700045, Romania.
>> Registered in Romania. Registration number J22/2621/2005.
>>
>>
>> _______________________________________________
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>> Xen-devel@xxxxxxxxxxxxxxxxxxxx
>> https://lists.xenproject.org/mailman/listinfo/xen-devel



Amazon Development Center (Romania) S.R.L. registered office: 27A Sf. Lazar 
Street, UBC5, floor 2, Iasi, Iasi County, 700045, Romania. Registered in 
Romania. Registration number J22/2621/2005.


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