KVM: arm64: Move kvm_get_hyp_vector() out of header file

kvm_get_hyp_vector() has only one caller, so move it out of kvm_mmu.h
and inline it into a new function, cpu_set_hyp_vector(), for setting
the vector.

Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20201113113847.21619-4-will@kernel.org

1 files changed, 44 insertions, 2 deletions

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 476bc613d0e6..c63c0b3c9b17 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1375,13 +1375,55 @@ static void cpu_hyp_reset(void)
 		__hyp_reset_vectors();
 }
 
+/*
+ * EL2 vectors can be mapped and rerouted in a number of ways,
+ * depending on the kernel configuration and CPU present:
+ *
+ * - If the CPU is affected by Spectre-v2, the hardening sequence is
+ *   placed in one of the vector slots, which is executed before jumping
+ *   to the real vectors.
+ *
+ * - If the CPU also has the ARM64_HARDEN_EL2_VECTORS cap, the slot
+ *   containing the hardening sequence is mapped next to the idmap page,
+ *   and executed before jumping to the real vectors.
+ *
+ * - If the CPU only has the ARM64_HARDEN_EL2_VECTORS cap, then an
+ *   empty slot is selected, mapped next to the idmap page, and
+ *   executed before jumping to the real vectors.
+ *
+ * Note that ARM64_HARDEN_EL2_VECTORS is somewhat incompatible with
+ * VHE, as we don't have hypervisor-specific mappings. If the system
+ * is VHE and yet selects this capability, it will be ignored.
+ */
+static void cpu_set_hyp_vector(void)
+{
+	struct bp_hardening_data *data = arm64_get_bp_hardening_data();
+	void *vect = kern_hyp_va(kvm_ksym_ref(__kvm_hyp_vector));
+	int slot = -1;
+
+	if (cpus_have_const_cap(ARM64_SPECTRE_V2) && data->fn) {
+		vect = kern_hyp_va(kvm_ksym_ref(__bp_harden_hyp_vecs));
+		slot = data->hyp_vectors_slot;
+	}
+
+	if (this_cpu_has_cap(ARM64_HARDEN_EL2_VECTORS) && !has_vhe()) {
+		vect = __kvm_bp_vect_base;
+		if (slot == -1)
+			slot = __kvm_harden_el2_vector_slot;
+	}
+
+	if (slot != -1)
+		vect += slot * SZ_2K;
+
+	*this_cpu_ptr_hyp_sym(kvm_hyp_vector) = (unsigned long)vect;
+}
+
 static void cpu_hyp_reinit(void)
 {
 	kvm_init_host_cpu_context(&this_cpu_ptr_hyp_sym(kvm_host_data)->host_ctxt);
 
 	cpu_hyp_reset();
-
-	*this_cpu_ptr_hyp_sym(kvm_hyp_vector) = (unsigned long)kvm_get_hyp_vector();
+	cpu_set_hyp_vector();
 
 	if (is_kernel_in_hyp_mode())
 		kvm_timer_init_vhe();