Re: [Xen-devel] [PATCH] x86/domain: don't destroy IOREQ servers on soft reset

[Jan Beulich <jbeulich@xxxxxxxx>]

On 30.08.2019 14:12, Paul Durrant wrote:
>> -----Original Message-----
>> From: Igor Druzhinin <igor.druzhinin@xxxxxxxxxx>
>> Sent: 30 August 2019 12:57
>> To: xen-devel@xxxxxxxxxxxxxxxxxxxx
>> Cc: jbeulich@xxxxxxxx; Andrew Cooper <Andrew.Cooper3@xxxxxxxxxx>; Paul 
>> Durrant
>> <Paul.Durrant@xxxxxxxxxx>; wl@xxxxxxx; Roger Pau Monne 
>> <roger.pau@xxxxxxxxxx>; Igor Druzhinin
>> <igor.druzhinin@xxxxxxxxxx>
>> Subject: [PATCH] x86/domain: don't destroy IOREQ servers on soft reset
>>
>> Performing soft reset should not opportunistically kill IOREQ servers
>> for device emulators that might be currently running for a domain.
>> Every emulator is supposed to clean up IOREQ servers for itself on exit.
>> This allows a toolstack to elect whether or not a particular device
>> model should be restarted.
>>
>> The original code was introduced in 3235cbfe ("arch-specific hooks for
>> domain_soft_reset()") likely due to the fact 'default' IOREQ server
>> existed in Xen at the time and used by QEMU didn't have an API call to
>> destroy. Since the removal of 'default' IOREQ server from Xen this
>> reason has gone away.
>>
>> Since commit ba7fdd64b ("xen: cleanup IOREQ server on exit") QEMU now
>> destroys IOREQ server for itself as every other device emulator
>> is supposed to do. It's now safe to remove this code from soft reset
>> path - existing systems with old QEMU should be able to work as
>> even if there are IOREQ servers left behind, a new QEMU instance will
>> override its ranges anyway.
>>
>> Signed-off-by: Igor Druzhinin <igor.druzhinin@xxxxxxxxxx>
> 
> Reviewed-by: Paul Durrant <paul.durrant@xxxxxxxxxx>

Acked-by: Jan Beulich <jbeulich@xxxxxxxx>

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