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authorWill Deacon <[email protected]>2021-10-08 14:58:38 +0100
committerMarc Zyngier <[email protected]>2021-10-11 09:07:29 +0100
commit07036cffe17ec07e8fb630d86f8ea21832d9e57d (patch)
tree52041c29e0e97601bae479d68c19dc2783ae30cc
parent2f2e1a5069679491d18cf9021da19b40c56a17f3 (diff)
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 <[email protected]> Cc: Quentin Perret <[email protected]> Signed-off-by: Will Deacon <[email protected]> Signed-off-by: Marc Zyngier <[email protected]> Link: https://lore.kernel.org/r/[email protected]
-rw-r--r--arch/arm64/kvm/hyp/nvhe/mem_protect.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
index bacd493a4eac..cafe17e5fa8f 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;