[PATCH 14/14] KVM: arm64: Prevent late calls to __pkvm_create_private_mapping()
From: Quentin Perret <hidden>
Date: 2021-07-19 10:48:46
Also in:
kvmarm, lkml
Subsystem:
arm64 port (aarch64 architecture), kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers:
Catalin Marinas, Will Deacon, Marc Zyngier, Oliver Upton, Linus Torvalds
__pkvm_create_private_mapping() allows the host kernel to create arbitrary mappings the hypervisor's "private" range. However, this is only needed early on, and there should be no good reason for the host to need this past the point where the pkvm static is set. Make sure to stub the hypercall past this point to ensure it can't be used by a malicious host. Signed-off-by: Quentin Perret <redacted> --- arch/arm64/kvm/hyp/nvhe/hyp-main.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
index f05ecbd382d0..e1d12f8122a7 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c@@ -154,7 +154,10 @@ static void handle___pkvm_create_private_mapping(struct kvm_cpu_context *host_ct DECLARE_REG(size_t, size, host_ctxt, 2); DECLARE_REG(enum kvm_pgtable_prot, prot, host_ctxt, 3); - cpu_reg(host_ctxt, 1) = __pkvm_create_private_mapping(phys, size, prot); + if (static_branch_unlikely(&kvm_protected_mode_initialized)) + cpu_reg(host_ctxt, 1) = -EPERM; + else + cpu_reg(host_ctxt, 1) = __pkvm_create_private_mapping(phys, size, prot); } static void handle___pkvm_prot_finalize(struct kvm_cpu_context *host_ctxt)
--
2.32.0.402.g57bb445576-goog
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