From: Michael Ellerman <mpe@ellerman•id.au>
To: "Cédric Le Goater" <clg@kaod•org>
Cc: linuxppc-dev@lists•ozlabs.org, "Greg Kurz" <groug@kaod•org>,
"Cédric Le Goater" <clg@kaod•org>
Subject: Re: [PATCH] powerpc/xive: Prevent page fault issues in the machine crash handler
Date: Tue, 12 Nov 2019 23:44:24 +1100 [thread overview]
Message-ID: <871rud2riv.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <20191031063100.3864-1-clg@kaod.org>
Cédric Le Goater <clg@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?
I used these:
Fixes: 243e25112d06 ("powerpc/xive: Native exploitation of the XIVE interrupt controller")
Cc: stable@vger•kernel.org # v4.12+
Please tell me if you think that's wrong.
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
next prev parent reply other threads:[~2019-11-12 12:49 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-31 6:31 [PATCH] powerpc/xive: Prevent page fault issues in the machine crash handler Cédric Le Goater
2019-10-31 8:43 ` Greg Kurz
2019-11-12 12:44 ` Michael Ellerman [this message]
2019-11-12 12:48 ` Cédric Le Goater
2019-11-14 9:08 ` Michael Ellerman
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