Commit 1fea164c authored by Fuad Tabba's avatar Fuad Tabba Committed by Marc Zyngier
Browse files

KVM: arm64: Move checking protected vcpu features to a separate function 



At the moment, checks for supported vcpu features for protected
VMs are build-time bugs. In the following patch, they will become
runtime checks based on the vcpu's features registers. Therefore,
consolidate them into one function that would return an error if
it encounters an unsupported feature.

Signed-off-by: default avatarFuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20241216105057.579031-4-tabba@google.com


Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parent f5075826

arch/arm64/kvm/hyp/nvhe/pkvm.c

+32 −13
Original line number Diff line number Diff line
@@ -178,20 +178,11 @@ static void pvm_init_traps_mdcr(struct kvm_vcpu *vcpu) 
}



/*

 * Initialize trap register values in protected mode.

 * Check that cpu features that are neither trapped nor supported are not

 * enabled for protected VMs.

 */

static void pkvm_vcpu_init_traps(struct pkvm_hyp_vcpu *hyp_vcpu)

static int pkvm_check_pvm_cpu_features(struct kvm_vcpu *vcpu)

{

	struct kvm_vcpu *vcpu = &hyp_vcpu->vcpu;



	vcpu->arch.cptr_el2 = kvm_get_reset_cptr_el2(vcpu);

	vcpu->arch.mdcr_el2 = 0;



	pkvm_vcpu_reset_hcr(vcpu);



	if ((!pkvm_hyp_vcpu_is_protected(hyp_vcpu)))

		return;



	/*

	 * PAuth is allowed if supported by the system and the vcpu.

	 * Properly checking for PAuth requires checking various fields in
@@ -218,9 +209,34 @@ static void pkvm_vcpu_init_traps(struct pkvm_hyp_vcpu *hyp_vcpu) 
	BUILD_BUG_ON(!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_AdvSIMD),

				PVM_ID_AA64PFR0_ALLOW));



	return 0;

}



/*

 * Initialize trap register values in protected mode.

 */

static int pkvm_vcpu_init_traps(struct pkvm_hyp_vcpu *hyp_vcpu)

{

	struct kvm_vcpu *vcpu = &hyp_vcpu->vcpu;

	int ret;



	vcpu->arch.cptr_el2 = kvm_get_reset_cptr_el2(vcpu);

	vcpu->arch.mdcr_el2 = 0;



	pkvm_vcpu_reset_hcr(vcpu);



	if ((!pkvm_hyp_vcpu_is_protected(hyp_vcpu)))

		return 0;



	ret = pkvm_check_pvm_cpu_features(vcpu);

	if (ret)

		return ret;



	pvm_init_traps_hcr(vcpu);

	pvm_init_traps_cptr(vcpu);

	pvm_init_traps_mdcr(vcpu);



	return 0;

}



/*
@@ -417,9 +433,12 @@ static int init_pkvm_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu, 
	hyp_vcpu->vcpu.arch.cflags = READ_ONCE(host_vcpu->arch.cflags);

	hyp_vcpu->vcpu.arch.mp_state.mp_state = KVM_MP_STATE_STOPPED;



	ret = pkvm_vcpu_init_traps(hyp_vcpu);

	if (ret)

		goto done;



	pkvm_vcpu_init_sve(hyp_vcpu, host_vcpu);

	pkvm_vcpu_init_ptrauth(hyp_vcpu);

	pkvm_vcpu_init_traps(hyp_vcpu);

done:

	if (ret)

		unpin_host_vcpu(host_vcpu);