From eb50f8f671aa4d4ab62151b2f1a02607fc78e1e1 Mon Sep 17 00:00:00 2001 From: =?utf8?q?C=C3=A9dric=20Le=20Goater?= Date: Thu, 31 Oct 2019 07:31:00 +0100 Subject: [PATCH] powerpc/xive: Prevent page fault issues in the machine crash handler MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit BugLink: https://bugs.launchpad.net/bugs/1858424 commit 1ca3dec2b2dff9d286ce6cd64108bda0e98f9710 upstream. 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. To fix, force the mapping of the ESB page when an interrupt is being mapped in the Linux IRQ number space. This is done by setting the initial state of the interrupt to OFF which is not necessarily the case on PowerNV. Fixes: 243e25112d06 ("powerpc/xive: Native exploitation of the XIVE interrupt controller") Cc: stable@vger.kernel.org # v4.12+ Signed-off-by: Cédric Le Goater Reviewed-by: Greg Kurz Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20191031063100.3864-1-clg@kaod.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Seth Forshee --- arch/powerpc/sysdev/xive/common.c | 9 +++++++++ 1 file changed, 9 insertions(+) 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; } -- 2.39.5