Commit 469c4713 authored by Marc Zyngier's avatar Marc Zyngier
Browse files

KVM: arm64: nv: Allocate VNCR page when required 



If running a NV guest on an ARMv8.4-NV capable system, let's
allocate an additional page that will be used by the hypervisor
to fulfill system register accesses.

Reviewed-by: default avatarGanapatrao Kulkarni <gankulkarni@os.amperecomputing.com>
Reviewed-by: default avatarOliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20250514103501.2225951-3-maz@kernel.org


Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parent fb306690

arch/arm64/kvm/nested.c

+10 −0
Original line number Diff line number Diff line
@@ -55,6 +55,13 @@ int kvm_vcpu_init_nested(struct kvm_vcpu *vcpu) 
	    !cpus_have_final_cap(ARM64_HAS_HCR_NV1))

		return -EINVAL;



	if (!vcpu->arch.ctxt.vncr_array)

		vcpu->arch.ctxt.vncr_array = (u64 *)__get_free_page(GFP_KERNEL_ACCOUNT |

								    __GFP_ZERO);



	if (!vcpu->arch.ctxt.vncr_array)

		return -ENOMEM;



	/*

	 * Let's treat memory allocation failures as benign: If we fail to

	 * allocate anything, return an error and keep the allocated array
@@ -85,6 +92,9 @@ int kvm_vcpu_init_nested(struct kvm_vcpu *vcpu) 
		for (int i = kvm->arch.nested_mmus_size; i < num_mmus; i++)

			kvm_free_stage2_pgd(&kvm->arch.nested_mmus[i]);



		free_page((unsigned long)vcpu->arch.ctxt.vncr_array);

		vcpu->arch.ctxt.vncr_array = NULL;



		return ret;

	}

arch/arm64/kvm/reset.c

+1 −0
Original line number Diff line number Diff line
@@ -158,6 +158,7 @@ void kvm_arm_vcpu_destroy(struct kvm_vcpu *vcpu) 
	if (sve_state)

		kvm_unshare_hyp(sve_state, sve_state + vcpu_sve_state_size(vcpu));

	kfree(sve_state);

	free_page((unsigned long)vcpu->arch.ctxt.vncr_array);

	kfree(vcpu->arch.ccsidr);

}