Commit 07036cff authored by Will Deacon's avatar Will Deacon Committed by Marc Zyngier
Browse files

KVM: arm64: Prevent re-finalisation of pKVM for a given CPU 



__pkvm_prot_finalize() completes the deprivilege of the host when pKVM
is in use by installing a stage-2 translation table for the calling CPU.

Issuing the hypercall multiple times for a given CPU makes little sense,
but in such a case just return early with -EPERM rather than go through
the whole page-table dance again.

Cc: Marc Zyngier <maz@kernel.org>
Cc: Quentin Perret <qperret@google.com>
Signed-off-by: default avatarWill Deacon <will@kernel.org>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211008135839.1193-6-will@kernel.org
parent 2f2e1a50

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

+3 −0
Original line number Diff line number Diff line
@@ -123,6 +123,9 @@ int __pkvm_prot_finalize(void) 
	struct kvm_s2_mmu *mmu = &host_kvm.arch.mmu;

	struct kvm_nvhe_init_params *params = this_cpu_ptr(&kvm_init_params);



	if (params->hcr_el2 & HCR_VM)

		return -EPERM;



	params->vttbr = kvm_get_vttbr(mmu);

	params->vtcr = host_kvm.arch.vtcr;

	params->hcr_el2 |= HCR_VM;