From 07036cffe17ec07e8fb630d86f8ea21832d9e57d Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Fri, 8 Oct 2021 14:58:38 +0100 Subject: [PATCH] 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 Cc: Quentin Perret Signed-off-by: Will Deacon Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20211008135839.1193-6-will@kernel.org --- arch/arm64/kvm/hyp/nvhe/mem_protect.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c index bacd493a4eacd..cafe17e5fa8f1 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c @@ -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; -- 2.30.2