On 12/11/2019 13:44, Michael Ellerman wrote:
> Cédric Le Goater <c...@kaod.org> writes:
>> When the machine crash handler is invoked, all interrupts are masked
>> but interrupts which have not been started yet do not have an ESB page
>> mapped in the Linux address space. This crashes the 'crash kexec'
>> sequence on sPAPR guests.
>
> This sounds like it needs a Fixes/stable tag?
yes.
> I used these:
>
> Fixes: 243e25112d06 ("powerpc/xive: Native exploitation of the XIVE
> interrupt controller")
> Cc: sta...@vger.kernel.org # v4.12+
>
> Please tell me if you think that's wrong.
Looks OK to me.
Thanks,
C.
> cheers
>
>
>> diff --git a/arch/powerpc/sysdev/xive/common.c
>> b/arch/powerpc/sysdev/xive/common.c
>> index df832b09e3e9..f5fadbd2533a 100644
>> --- a/arch/powerpc/sysdev/xive/common.c
>> +++ b/arch/powerpc/sysdev/xive/common.c
>> @@ -1035,6 +1035,15 @@ static int xive_irq_alloc_data(unsigned int virq,
>> irq_hw_number_t hw)
>> xd->target = XIVE_INVALID_TARGET;
>> irq_set_handler_data(virq, xd);
>>
>> + /*
>> + * Turn OFF by default the interrupt being mapped. A side
>> + * effect of this check is the mapping the ESB page of the
>> + * interrupt in the Linux address space. This prevents page
>> + * fault issues in the crash handler which masks all
>> + * interrupts.
>> + */
>> + xive_esb_read(xd, XIVE_ESB_SET_PQ_01);
>> +
>> return 0;
>> }
>>
>> --
>> 2.21.0
