2020-11-16 22:34:49

by David Brazdil

[permalink] [raw]
Subject: [PATCH v2 18/24] kvm: arm64: Add function to enter host from KVM nVHE hyp code

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 <[email protected]>
---
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 52dae5cd5a28..170d6f6376ae 100644
--- a/arch/arm64/kvm/hyp/nvhe/host.S
+++ b/arch/arm64/kvm/hyp/nvhe/host.S
@@ -41,6 +41,7 @@ SYM_FUNC_START(__host_exit)
bl handle_trap

/* Restore host regs x0-x17 */
+__host_enter_restore_full:
ldp x0, x1, [x29, #CPU_XREG_OFFSET(0)]
ldp x2, x3, [x29, #CPU_XREG_OFFSET(2)]
ldp x4, x5, [x29, #CPU_XREG_OFFSET(4)]
@@ -63,6 +64,14 @@ __host_enter_without_restoring:
sb
SYM_FUNC_END(__host_exit)

+/*
+ * void __noreturn __host_enter(struct kvm_cpu_context *host_ctxt);
+ */
+SYM_FUNC_START(__host_enter)
+ mov x29, x0
+ b __host_enter_restore_full
+SYM_FUNC_END(__host_enter)
+
/*
* void __noreturn __hyp_do_panic(bool restore_host, u64 spsr, u64 elr, u64 par);
*/
--
2.29.2.299.gdc1121823c-goog