arm64/boot: Disable trapping of PMZR_EL0 writes to EL2grafted

__init_el2_fgt2() writes one mask to both HDFGRTR2_EL2 and HDFGWTR2_EL2.
PMZR_EL0 is write-only, so its trap bit, nPMZR_EL0, exists only in
HDFGWTR2_EL2 and is therefore never set: a PMZR_EL0 write from the host
traps to EL2, where the nVHE hypervisor has no handler and BUG()s. The
kernel never writes PMZR_EL0, but kernel.perf_user_access=1 has the PMU
driver set PMUSERENR_EL0.UEN for a task with a user-read event, so a
write from EL0 reaches the trap and takes the host down without a panic
message.

Accumulate the HDFGWTR2_EL2 bits separately, as __init_el2_fgt() already
does for HDFGWTR_EL2, and set nPMZR_EL0 with the other FEAT_PMUv3p9
bits.

Fixes: 858c7bfcb35e1 ("arm64/boot: Enable EL2 requirements for FEAT_PMUv3p9")
Cc: stable@vger.kernel.org
Signed-off-by: Fuad Tabba <fuad.tabba@linux.dev>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Oliver Upton <oupton@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>

1 files changed, 96 insertions, 0 deletions

diff --git a/drivers/base/platform-msi.c b/drivers/base/platform-msi.c
new file mode 100644
index 000000000..69eed058e
--- /dev/null
+++ b/drivers/base/platform-msi.c
@@ -0,0 +1,96 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * MSI framework for platform devices
+ *
+ * Copyright (C) 2015 ARM Limited, All Rights Reserved.
+ * Author: Marc Zyngier <marc.zyngier@arm.com>
+ * Copyright (C) 2022 Linutronix GmbH
+ */
+
+#include <linux/device.h>
+#include <linux/irqdomain.h>
+#include <linux/msi.h>
+
+/*
+ * This indirection can go when platform_device_msi_init_and_alloc_irqs()
+ * is switched to a proper irq_chip::irq_write_msi_msg() callback. Keep it
+ * simple for now.
+ */
+static void platform_msi_write_msi_msg(struct irq_data *d, struct msi_msg *msg)
+{
+	irq_write_msi_msg_t cb = d->chip_data;
+
+	cb(irq_data_get_msi_desc(d), msg);
+}
+
+static void platform_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc)
+{
+	arg->desc = desc;
+	arg->hwirq = desc->msi_index;
+}
+
+static const struct msi_domain_template platform_msi_template = {
+	.chip = {
+		.name			= "pMSI",
+		.irq_mask		= irq_chip_mask_parent,
+		.irq_unmask		= irq_chip_unmask_parent,
+		.irq_write_msi_msg	= platform_msi_write_msi_msg,
+		/* The rest is filled in by the platform MSI parent */
+	},
+
+	.ops = {
+		.set_desc		= platform_msi_set_desc,
+	},
+
+	.info = {
+		.bus_token		= DOMAIN_BUS_DEVICE_MSI,
+	},
+};
+
+/**
+ * platform_device_msi_init_and_alloc_irqs - Initialize platform device MSI
+ *					     and allocate interrupts for @dev
+ * @dev:		The device for which to allocate interrupts
+ * @nvec:		The number of interrupts to allocate
+ * @write_msi_msg:	Callback to write an interrupt message for @dev
+ *
+ * Returns:
+ * Zero for success, or an error code in case of failure
+ *
+ * This creates a MSI domain on @dev which has @dev->msi.domain as
+ * parent. The parent domain sets up the new domain. The domain has
+ * a fixed size of @nvec. The domain is managed by devres and will
+ * be removed when the device is removed.
+ */
+int platform_device_msi_init_and_alloc_irqs(struct device *dev, unsigned int nvec,
+					    irq_write_msi_msg_t write_msi_msg)
+{
+	struct irq_domain *domain = dev->msi.domain;
+
+	if (!domain || !write_msi_msg)
+		return -EINVAL;
+
+	/*
+	 * @write_msi_msg is stored in the resulting msi_domain_info::data.
+	 * The underlying domain creation mechanism will assign that
+	 * callback to the resulting irq chip.
+	 */
+	if (!msi_create_device_irq_domain(dev, MSI_DEFAULT_DOMAIN,
+					  &platform_msi_template,
+					  nvec, NULL, write_msi_msg))
+		return -ENODEV;
+
+	return msi_domain_alloc_irqs_range(dev, MSI_DEFAULT_DOMAIN, 0, nvec - 1);
+}
+EXPORT_SYMBOL_GPL(platform_device_msi_init_and_alloc_irqs);
+
+/**
+ * platform_device_msi_free_irqs_all - Free all interrupts for @dev
+ * @dev:	The device for which to free interrupts
+ */
+void platform_device_msi_free_irqs_all(struct device *dev)
+{
+	msi_domain_free_irqs_all(dev, MSI_DEFAULT_DOMAIN);
+	msi_remove_device_irq_domain(dev, MSI_DEFAULT_DOMAIN);
+}
+EXPORT_SYMBOL_GPL(platform_device_msi_free_irqs_all);