arm64: add hypervisor stub

If booted in EL2, install an dummy hypervisor whose only purpose
is to be replaced by a full fledged one.

A minimal API allows to:
- obtain the current HYP vectors (__hyp_get_vectors)
- set new HYP vectors (__hyp_set_vectors)

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index bc6d991f8c59..5792749e34c4 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -185,6 +185,10 @@ ENTRY(el2_setup)
         msr     hstr_el2, xzr                   // Disable CP15 traps to EL2
 #endif
 
+        /* Hypervisor stub */
+        adr     x0, __hyp_stub_vectors
+        msr     vbar_el2, x0
+
         /* spsr */
         mov     x0, #(PSR_F_BIT | PSR_I_BIT | PSR_A_BIT | PSR_D_BIT |\
                       PSR_MODE_EL1h)