The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x ec4308ecfc887128a468f03fb66b767559c57c23 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2024022650-washroom-undusted-2aff@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

ec4308ecfc88 ("irqchip/gic-v3-its: Do not assume vPE tables are preallocated") c0cdc89072a3 ("irqchip/gic-v3-its: Give the percpu rdist struct its own flags field")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From ec4308ecfc887128a468f03fb66b767559c57c23 Mon Sep 17 00:00:00 2001 From: Oliver Upton oliver.upton@linux.dev Date: Mon, 19 Feb 2024 18:58:06 +0000 Subject: [PATCH] irqchip/gic-v3-its: Do not assume vPE tables are preallocated

The GIC/ITS code is designed to ensure to pick up any preallocated LPI tables on the redistributors, as enabling LPIs is a one-way switch. There is no such restriction for vLPIs, and for GICv4.1 it is expected to allocate a new vPE table at boot.

This works as intended when initializing an ITS, however when setting up a redistributor in cpu_init_lpis() the early return for preallocated RD tables skips straight past the GICv4 setup. This all comes to a head when trying to kexec() into a new kernel, as the new kernel silently fails to set up GICv4, leading to a complete loss of SGIs and LPIs for KVM VMs.

Slap a band-aid on the problem by ensuring its_cpu_init_lpis() always initializes GICv4 on the way out, even if the other RD tables were preallocated.

Fixes: 6479450f72c1 ("irqchip/gic-v4: Fix occasional VLPI drop") Reported-by: George Cherian gcherian@marvell.com Co-developed-by: Marc Zyngier maz@kernel.org Signed-off-by: Marc Zyngier maz@kernel.org Signed-off-by: Oliver Upton oliver.upton@linux.dev Signed-off-by: Thomas Gleixner tglx@linutronix.de Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20240219185809.286724-2-oliver.upton@linux.dev

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c index 53abd4779914..b822752c4261 100644 --- a/drivers/irqchip/irq-gic-v3-its.c +++ b/drivers/irqchip/irq-gic-v3-its.c @@ -3181,6 +3181,7 @@ static void its_cpu_init_lpis(void) val |= GICR_CTLR_ENABLE_LPIS; writel_relaxed(val, rbase + GICR_CTLR);

+out: if (gic_rdists->has_vlpis && !gic_rdists->has_rvpeid) { void __iomem *vlpi_base = gic_data_rdist_vlpi_base();

@@ -3216,7 +3217,6 @@ static void its_cpu_init_lpis(void)

/* Make sure the GIC has seen the above */ dsb(sy); -out: gic_data_rdist()->flags |= RD_LOCAL_LPI_ENABLED; pr_info("GICv3: CPU%d: using %s LPI pending table @%pa\n", smp_processor_id(),