[PATCH v4 20/26] kvm: arm64: Add function to enter host from KVM nVHE hyp code

David Brazdil dbrazdil at google.com
Wed Dec 2 13:41:16 EST 2020

All nVHE hyp code is currently executed as handlers of host's HVCs. This
will change as nVHE starts intercepting host's PSCI CPU_ON SMCs. The
newly booted CPU will need to initialize EL2 state and then enter the
host. Add __host_enter function that branches into the existing
host state-restoring code after the trap handler would have returned.

Signed-off-by: David Brazdil <dbrazdil at google.com>
 arch/arm64/kvm/hyp/nvhe/host.S | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/arch/arm64/kvm/hyp/nvhe/host.S b/arch/arm64/kvm/hyp/nvhe/host.S
index 2b56f0bdf874..a820dfdc9c25 100644
--- a/arch/arm64/kvm/hyp/nvhe/host.S
+++ b/arch/arm64/kvm/hyp/nvhe/host.S
@@ -39,6 +39,7 @@ SYM_FUNC_START(__host_exit)
 	bl	handle_trap
 	/* Restore host regs x0-x17 */
 	ldp	x0, x1,   [x29, #CPU_XREG_OFFSET(0)]
 	ldp	x2, x3,   [x29, #CPU_XREG_OFFSET(2)]
 	ldp	x4, x5,   [x29, #CPU_XREG_OFFSET(4)]
@@ -61,6 +62,14 @@ __host_enter_without_restoring:
+ * void __noreturn __host_enter(struct kvm_cpu_context *host_ctxt);
+ */
+	mov	x29, x0
+	b	__host_enter_restore_full
  * void __noreturn __hyp_do_panic(bool restore_host, u64 spsr, u64 elr, u64 par);

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