From: Michael Ellerman <patch-notifications@ellerman.id.au>
To: Greg Kurz <groug@kaod.org>, Paul Mackerras <paulus@ozlabs.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: pavrampu@in.ibm.com, linuxppc-dev@lists.ozlabs.org,
linux-kernel@vger.kernel.org, stable@vger.kernel.org,
"Cédric Le Goater" <clg@kaod.org>
Subject: Re: [PATCH] powerpc/pseries: Fix xive=off command line
Date: Mon, 3 Jun 2019 22:32:51 +1000 (AEST) [thread overview]
Message-ID: <45HZFv4jpmz9sNm@ozlabs.org> (raw)
In-Reply-To: <155791470178.432724.8008395673479905061.stgit@bahia.lan>
On Wed, 2019-05-15 at 10:05:01 UTC, Greg Kurz wrote:
> On POWER9, if the hypervisor supports XIVE exploitation mode, the guest OS
> will unconditionally requests for the XIVE interrupt mode even if XIVE was
> deactivated with the kernel command line xive=off. Later on, when the spapr
> XIVE init code handles xive=off, it disables XIVE and tries to fall back on
> the legacy mode XICS.
>
> This discrepency causes a kernel panic because the hypervisor is configured
> to provide the XIVE interrupt mode to the guest :
>
> [ 0.008837] kernel BUG at arch/powerpc/sysdev/xics/xics-common.c:135!
> [ 0.008877] Oops: Exception in kernel mode, sig: 5 [#1]
> [ 0.008908] LE SMP NR_CPUS=1024 NUMA pSeries
> [ 0.008939] Modules linked in:
> [ 0.008964] CPU: 0 PID: 1 Comm: swapper/0 Tainted: G W 5.0.13-200.fc29.ppc64le #1
> [ 0.009018] NIP: c000000001029ab8 LR: c000000001029aac CTR: c0000000018e0000
> [ 0.009065] REGS: c0000007f96d7900 TRAP: 0700 Tainted: G W (5.0.13-200.fc29.ppc64le)
> [ 0.009119] MSR: 8000000002029033 <SF,VEC,EE,ME,IR,DR,RI,LE> CR: 28000222 XER: 20040000
> [ 0.009168] CFAR: c0000000001b1e28 IRQMASK: 0
> [ 0.009168] GPR00: c000000001029aac c0000007f96d7b90 c0000000015e8600 0000000000000000
> [ 0.009168] GPR04: 0000000000000001 0000000000000000 0000000000000061 646f6d61696e0d0a
> [ 0.009168] GPR08: 00000007fd8f0000 0000000000000001 c0000000014c44c0 c0000007f96d76cf
> [ 0.009168] GPR12: 0000000000000000 c0000000018e0000 0000000000000001 0000000000000000
> [ 0.009168] GPR16: 0000000000000000 0000000000000001 c0000007f96d7c08 c0000000016903d0
> [ 0.009168] GPR20: c0000007fffe04e8 ffffffffffffffea c000000001620164 c00000000161fe58
> [ 0.009168] GPR24: c000000000ea6c88 c0000000011151a8 00000000006000c0 c0000007f96d7c34
> [ 0.009168] GPR28: 0000000000000000 c0000000014b286c c000000001115180 c00000000161dc70
> [ 0.009558] NIP [c000000001029ab8] xics_smp_probe+0x38/0x98
> [ 0.009590] LR [c000000001029aac] xics_smp_probe+0x2c/0x98
> [ 0.009622] Call Trace:
> [ 0.009639] [c0000007f96d7b90] [c000000001029aac] xics_smp_probe+0x2c/0x98 (unreliable)
> [ 0.009687] [c0000007f96d7bb0] [c000000001033404] pSeries_smp_probe+0x40/0xa0
> [ 0.009734] [c0000007f96d7bd0] [c0000000010212a4] smp_prepare_cpus+0x62c/0x6ec
> [ 0.009782] [c0000007f96d7cf0] [c0000000010141b8] kernel_init_freeable+0x148/0x448
> [ 0.009829] [c0000007f96d7db0] [c000000000010ba4] kernel_init+0x2c/0x148
> [ 0.009870] [c0000007f96d7e20] [c00000000000bdd4] ret_from_kernel_thread+0x5c/0x68
> [ 0.009916] Instruction dump:
> [ 0.009940] 7c0802a6 60000000 7c0802a6 38800002 f8010010 f821ffe1 3c62001c e863b9a0
> [ 0.009988] 4b1882d1 60000000 7c690034 5529d97e <0b090000> 3d22001c e929b998 3ce2ff8f
>
> Look for xive=off during prom_init and don't ask for XIVE in this case. One
> exception though: if the host only supports XIVE, we still want to boot so
> we ignore xive=off.
>
> Similarly, have the spapr XIVE init code to looking at the interrupt mode
> negociated during CAS, and ignore xive=off if the hypervisor only supports
> XIVE.
>
> Fixes: eac1e731b59e ("powerpc/xive: guest exploitation of the XIVE interrupt controller")
> Cc: stable@vger.kernel.org # v4.20
> Reported-by: Pavithra R. Prakash <pavrampu@in.ibm.com>
> Signed-off-by: Greg Kurz <groug@kaod.org>
> Reviewed-by: Cédric Le Goater <clg@kaod.org>
Applied to powerpc next, thanks.
https://git.kernel.org/powerpc/c/a3bf9fbdad600b1e4335dd90979f8d60
cheers
prev parent reply other threads:[~2019-06-03 12:41 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-15 10:05 [PATCH] powerpc/pseries: Fix xive=off command line Greg Kurz
2019-05-15 10:13 ` Cédric Le Goater
2019-05-15 10:54 ` Sasha Levin
2019-05-17 10:57 ` Greg Kurz
2019-06-03 12:32 ` Michael Ellerman [this message]
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