Commit 85592114 authored by Alexandru Elisei's avatar Alexandru Elisei Committed by Marc Zyngier
Browse files

KVM: arm64: VHE: Compute fgt traps before activating them 



On VHE, the Fine Grain Traps registers are written to hardware in
kvm_arch_vcpu_load()->..->__activate_traps_hfgxtr(), but the fgt array is
computed later, in kvm_vcpu_load_fgt(). This can lead to zero being written
to the FGT registers the first time a VCPU is loaded. Also, any changes to
the fgt array will be visible only after the VCPU is scheduled out, and
then back in, which is not the intended behaviour.

Fix it by computing the fgt array just before the fgt traps are written
to hardware.

Fixes: fb10ddf3 ("KVM: arm64: Compute per-vCPU FGTs at vcpu_load()")
Signed-off-by: default avatarAlexandru Elisei <alexandru.elisei@arm.com>
Reviewed-by: default avatarOliver Upton <oupton@kernel.org>
Link: https://patch.msgid.link/20251112102853.47759-1-alexandru.elisei@arm.com


Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parent 0f559cd9

arch/arm64/kvm/arm.c

+1 −1
Original line number Diff line number Diff line
@@ -624,6 +624,7 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) 
	kvm_timer_vcpu_load(vcpu);

	kvm_vgic_load(vcpu);

	kvm_vcpu_load_debug(vcpu);

	kvm_vcpu_load_fgt(vcpu);

	if (has_vhe())

		kvm_vcpu_load_vhe(vcpu);

	kvm_arch_vcpu_load_fp(vcpu);
@@ -642,7 +643,6 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) 
		vcpu->arch.hcr_el2 |= HCR_TWI;



	vcpu_set_pauth_traps(vcpu);

	kvm_vcpu_load_fgt(vcpu);



	if (is_protected_kvm_enabled()) {

		kvm_call_hyp_nvhe(__pkvm_vcpu_load,