linux-kernel - [PATCH 5.16 0765/1039] irqchip/gic-v4: Disable redistributors view of the VPE table at boot time

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Message-Id: <20220124184151.026668579@linuxfoundation.org>
Date:   Mon, 24 Jan 2022 19:42:34 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Jay Chen <jkchen@...ux.alibaba.com>,
        Marc Zyngier <maz@...nel.org>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.16 0765/1039] irqchip/gic-v4: Disable redistributors view of the VPE table at boot time

From: Marc Zyngier <maz@...nel.org>

[ Upstream commit 79a7f77b9b154d572bd9d2f1eecf58c4d018d8e2 ]

Jay Chen reported that using a kdump kernel on a GICv4.1 system
results in a RAS error being delivered when the secondary kernel
configures the ITS's view of the new VPE table.

As it turns out, that's because each RD still has a pointer to
the previous instance of the VPE table, and that particular
implementation is very upset by seeing two bits of the HW that
should point to the same table with different values.

To solve this, let's invalidate any reference that any RD has to
the VPE table when discovering the RDs. The ITS can then be
programmed as expected.

Reported-by: Jay Chen <jkchen@...ux.alibaba.com>
Signed-off-by: Marc Zyngier <maz@...nel.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@....com>
Link: https://lore.kernel.org/r/20211214064716.21407-1-jkchen@linux.alibaba.com
Link: https://lore.kernel.org/r/20211216144804.1578566-1-maz@kernel.org
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/irqchip/irq-gic-v3.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index daec3309b014d..86397522e7864 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -920,6 +920,22 @@ static int __gic_update_rdist_properties(struct redist_region *region,
 {
 	u64 typer = gic_read_typer(ptr + GICR_TYPER);
 
+	/* Boot-time cleanip */
+	if ((typer & GICR_TYPER_VLPIS) && (typer & GICR_TYPER_RVPEID)) {
+		u64 val;
+
+		/* Deactivate any present vPE */
+		val = gicr_read_vpendbaser(ptr + SZ_128K + GICR_VPENDBASER);
+		if (val & GICR_VPENDBASER_Valid)
+			gicr_write_vpendbaser(GICR_VPENDBASER_PendingLast,
+					      ptr + SZ_128K + GICR_VPENDBASER);
+
+		/* Mark the VPE table as invalid */
+		val = gicr_read_vpropbaser(ptr + SZ_128K + GICR_VPROPBASER);
+		val &= ~GICR_VPROPBASER_4_1_VALID;
+		gicr_write_vpropbaser(val, ptr + SZ_128K + GICR_VPROPBASER);
+	}
+
 	gic_data.rdists.has_vlpis &= !!(typer & GICR_TYPER_VLPIS);
 
 	/* RVPEID implies some form of DirectLPI, no matter what the doc says... :-/ */
-- 
2.34.1