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, 35 insertions, 0 deletions

diff --git a/include/keys/asymmetric-parser.h b/include/keys/asymmetric-parser.h
new file mode 100644
index 000000000..516a3f511
--- /dev/null
+++ b/include/keys/asymmetric-parser.h
@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* Asymmetric public-key cryptography data parser
+ *
+ * See Documentation/crypto/asymmetric-keys.rst
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#ifndef _KEYS_ASYMMETRIC_PARSER_H
+#define _KEYS_ASYMMETRIC_PARSER_H
+
+struct key_preparsed_payload;
+
+/*
+ * Key data parser.  Called during key instantiation.
+ */
+struct asymmetric_key_parser {
+	struct list_head	link;
+	struct module		*owner;
+	const char		*name;
+
+	/* Attempt to parse a key from the data blob passed to add_key() or
+	 * keyctl_instantiate().  Should also generate a proposed description
+	 * that the caller can optionally use for the key.
+	 *
+	 * Return EBADMSG if not recognised.
+	 */
+	int (*parse)(struct key_preparsed_payload *prep);
+};
+
+extern int register_asymmetric_key_parser(struct asymmetric_key_parser *);
+extern void unregister_asymmetric_key_parser(struct asymmetric_key_parser *);
+
+#endif /* _KEYS_ASYMMETRIC_PARSER_H */