KVM: arm64: Make ID_AA64MMFR4_EL1.NV_frac writable

We want to make sure that it is possible for userspace to configure
whether recursive NV is possible. Make NV_frac writable for that
purpose.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Link: https://lore.kernel.org/r/20250220134907.554085-12-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index dacccc35a3bd5823d829603fa237a92304c8ab78..1a18a0324d9ffa95159fd903840f91ffa6dd53ca 100644 (file)
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -2683,7 +2683,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
        ID_WRITABLE(ID_AA64MMFR3_EL1, (ID_AA64MMFR3_EL1_TCRX    |
                                       ID_AA64MMFR3_EL1_S1PIE   |
                                       ID_AA64MMFR3_EL1_S1POE)),
-       ID_SANITISED(ID_AA64MMFR4_EL1),
+       ID_WRITABLE(ID_AA64MMFR4_EL1, ID_AA64MMFR4_EL1_NV_frac),
        ID_UNALLOCATED(7,5),
        ID_UNALLOCATED(7,6),
        ID_UNALLOCATED(7,7),