[PATCH 6.12.y] arm64/boot: Disable trapping of PMZR_EL0 writes to EL2

[Fuad Tabba <fuad.tabba@linux.dev>]

commit 2bc6b218717b9d08f466f88209251d54bc09b207 upstream.

__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>
[Fuad: dropped the nPMSDSFR_EL1 hunk, 6.12 lacks FEAT_SPE_FDS support]
Signed-off-by: Fuad Tabba <fuad.tabba@linux.dev>
---
 Documentation/arch/arm64/booting.rst | 1 +
 arch/arm64/include/asm/el2_setup.h   | 8 +++++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/Documentation/arch/arm64/booting.rst b/Documentation/arch/arm64/booting.rst
index 15bcd1b4003a7..4c43d38d5d70b 100644
--- a/Documentation/arch/arm64/booting.rst
+++ b/Documentation/arch/arm64/booting.rst
@@ -400,6 +400,7 @@ Before jumping into the kernel, the following conditions must be met:
     - HDFGWTR2_EL2.nPMICNTR_EL0 (bit 2) must be initialised to 0b1.
     - HDFGWTR2_EL2.nPMICFILTR_EL0 (bit 3) must be initialised to 0b1.
     - HDFGWTR2_EL2.nPMUACR_EL1 (bit 4) must be initialised to 0b1.
+    - HDFGWTR2_EL2.nPMZR_EL0 (bit 21) must be initialised to 0b1.
 
   For CPUs with Memory Copy and Memory Set instructions (FEAT_MOPS):
 
diff --git a/arch/arm64/include/asm/el2_setup.h b/arch/arm64/include/asm/el2_setup.h
index 9d1c88536ee43..e05218fbd58b4 100644
--- a/arch/arm64/include/asm/el2_setup.h
+++ b/arch/arm64/include/asm/el2_setup.h
@@ -274,6 +274,7 @@
 	b.lt	.Lskip_fgt2_\@
 
 	mov	x0, xzr
+	mov	x2, xzr
 	mrs	x1, id_aa64dfr0_el1
 	ubfx	x1, x1, #ID_AA64DFR0_EL1_PMUVer_SHIFT, #4
 	cmp	x1, #ID_AA64DFR0_EL1_PMUVer_V3P9
@@ -282,9 +283,14 @@
 	orr	x0, x0, #HDFGRTR2_EL2_nPMICNTR_EL0
 	orr	x0, x0, #HDFGRTR2_EL2_nPMICFILTR_EL0
 	orr	x0, x0, #HDFGRTR2_EL2_nPMUACR_EL1
+	orr	x2, x2, #HDFGWTR2_EL2_nPMICNTR_EL0
+	orr	x2, x2, #HDFGWTR2_EL2_nPMICFILTR_EL0
+	orr	x2, x2, #HDFGWTR2_EL2_nPMUACR_EL1
+	/* PMZR_EL0 is write-only, so it has no read trap to disable */
+	orr	x2, x2, #HDFGWTR2_EL2_nPMZR_EL0
 .Lskip_pmuv3p9_\@:
 	msr_s   SYS_HDFGRTR2_EL2, x0
-	msr_s   SYS_HDFGWTR2_EL2, x0
+	msr_s   SYS_HDFGWTR2_EL2, x2
 	msr_s   SYS_HFGRTR2_EL2, xzr
 	msr_s   SYS_HFGWTR2_EL2, xzr
 	msr_s   SYS_HFGITR2_EL2, xzr
-- 
2.39.5