Commit 8b0b98eb authored by Marc Zyngier's avatar Marc Zyngier Committed by Oliver Upton
Browse files

KVM: arm64: Advertise FEAT_ECV when possible 



We can advertise support for FEAT_ECV if supported on the HW as
long as we limit it to the basic trap bits, and not advertise
CNTPOFF_EL2 support, even if the host has it (the short story
being that CNTPOFF_EL2 is not virtualisable).

Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Reviewed-by: default avatarJoey Gouly <joey.gouly@arm.com>
Link: https://lore.kernel.org/r/20250220134907.554085-13-maz@kernel.org


Signed-off-by: default avatarOliver Upton <oliver.upton@linux.dev>
parent 642c23ea

arch/arm64/kvm/nested.c

+5 −3
Original line number Diff line number Diff line
@@ -848,14 +848,16 @@ u64 limit_nv_id_reg(struct kvm *kvm, u32 reg, u64 val) 
		break;



	case SYS_ID_AA64MMFR0_EL1:

		/* Hide ECV, ExS, Secure Memory */

		val &= ~(ID_AA64MMFR0_EL1_ECV		|

			 ID_AA64MMFR0_EL1_EXS		|

		/* Hide ExS, Secure Memory */

		val &= ~(ID_AA64MMFR0_EL1_EXS		|

			 ID_AA64MMFR0_EL1_TGRAN4_2	|

			 ID_AA64MMFR0_EL1_TGRAN16_2	|

			 ID_AA64MMFR0_EL1_TGRAN64_2	|

			 ID_AA64MMFR0_EL1_SNSMEM);



		/* Hide CNTPOFF if present */

		val = ID_REG_LIMIT_FIELD_ENUM(val, ID_AA64MMFR0_EL1, ECV, IMP);



		/* Disallow unsupported S2 page sizes */

		switch (PAGE_SIZE) {

		case SZ_64K: