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-rw-r--r--arch/arm64/kvm/hyp/nvhe/hyp-init.S23
1 files changed, 16 insertions, 7 deletions
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-init.S b/arch/arm64/kvm/hyp/nvhe/hyp-init.S
index 47224dc62c51..b11a9d7db677 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-init.S
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-init.S
@@ -57,16 +57,25 @@ __do_hyp_init:
cmp x0, #HVC_STUB_HCALL_NR
b.lo __kvm_handle_stub_hvc
- /* Set tpidr_el2 for use by HYP to free a register */
- msr tpidr_el2, x2
-
- mov x2, #KVM_HOST_SMCCC_FUNC(__kvm_hyp_init)
- cmp x0, x2
- b.eq 1f
+ // We only actively check bits [24:31], and everything
+ // else has to be zero, which we check at build time.
+#if (KVM_HOST_SMCCC_FUNC(__kvm_hyp_init) & 0xFFFFFFFF00FFFFFF)
+#error Unexpected __KVM_HOST_SMCCC_FUNC___kvm_hyp_init value
+#endif
+
+ ror x0, x0, #24
+ eor x0, x0, #((KVM_HOST_SMCCC_FUNC(__kvm_hyp_init) >> 24) & 0xF)
+ ror x0, x0, #4
+ eor x0, x0, #((KVM_HOST_SMCCC_FUNC(__kvm_hyp_init) >> 28) & 0xF)
+ cbz x0, 1f
mov x0, #SMCCC_RET_NOT_SUPPORTED
eret
-1: phys_to_ttbr x0, x1
+1:
+ /* Set tpidr_el2 for use by HYP to free a register */
+ msr tpidr_el2, x2
+
+ phys_to_ttbr x0, x1
alternative_if ARM64_HAS_CNP
orr x0, x0, #TTBR_CNP_BIT
alternative_else_nop_endif