Commit cd931bd6 authored by Marc Zyngier's avatar Marc Zyngier Committed by Oliver Upton
Browse files

KVM: arm64: nv: Add additional trap setup for CPTR_EL2 



We need to teach KVM a couple of new tricks. CPTR_EL2 and its
VHE accessor CPACR_EL1 need to be handled specially:

- CPACR_EL1 is trapped on VHE so that we can track the TCPAC
  and TTA bits

- CPTR_EL2.{TCPAC,E0POE} are propagated from L1 to L2

Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240620164653.1130714-15-oliver.upton@linux.dev


Signed-off-by: default avatarOliver Upton <oliver.upton@linux.dev>
parent e19d5331

arch/arm64/kvm/hyp/vhe/switch.c

+18 −1
Original line number Diff line number Diff line
@@ -87,11 +87,23 @@ static void __activate_cptr_traps(struct kvm_vcpu *vcpu) 
		__activate_traps_fpsimd32(vcpu);

	}



	if (!vcpu_has_nv(vcpu))

		goto write;



	/*

	 * The architecture is a bit crap (what a surprise): an EL2 guest

	 * writing to CPTR_EL2 via CPACR_EL1 can't set any of TCPAC or TTA,

	 * as they are RES0 in the guest's view. To work around it, trap the

	 * sucker using the very same bit it can't set...

	 */

	if (vcpu_el2_e2h_is_set(vcpu) && is_hyp_ctxt(vcpu))

		val |= CPTR_EL2_TCPAC;



	/*

	 * Layer the guest hypervisor's trap configuration on top of our own if

	 * we're in a nested context.

	 */

	if (!vcpu_has_nv(vcpu) || is_hyp_ctxt(vcpu))

	if (is_hyp_ctxt(vcpu))

		goto write;



	cptr = vcpu_sanitised_cptr_el2(vcpu);
@@ -115,6 +127,11 @@ static void __activate_cptr_traps(struct kvm_vcpu *vcpu) 
	if (!(SYS_FIELD_GET(CPACR_ELx, ZEN, cptr) & BIT(0)))

		val &= ~CPACR_ELx_ZEN;



	if (kvm_has_feat(vcpu->kvm, ID_AA64MMFR3_EL1, S2POE, IMP))

		val |= cptr & CPACR_ELx_E0POE;



	val |= cptr & CPTR_EL2_TCPAC;



write:

	write_sysreg(val, cpacr_el1);

}