[PATCH v4 09/28] arm64: KVM: Implement HVC_SOFT_RESTART in the init code

Marc Zyngier
2017-03-21T19:20:39Z

Another missing stub hypercall is HVC_SOFT_RESTART. It turns out
that it is pretty easy to implement in terms of HVC_RESET_VECTORS
(since it needs to turn the MMU off).

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
arch/arm64/kvm/hyp-init.S | 31 +++++++++++++++++++++++--------
1 file changed, 23 insertions(+), 8 deletions(-)

diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index b53e95efc1c5..128d6e9732b9 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -129,21 +129,36 @@ ENTRY(__kvm_handle_stub_hvc)
mrs x0, vbar_el2
b exit

+1: cmp x0, #HVC_SOFT_RESTART
+ b.ne 1f
+
+ /* This is where we're about to jump, staying at EL2 */
+ msr elr_el2, x1
+ mov x0, #(PSR_F_BIT | PSR_I_BIT | PSR_A_BIT | PSR_D_BIT | PSR_MODE_EL2h)
+ msr spsr_el2, x0
+
+ /* Shuffle the arguments, and don't come back */
+ mov x0, x2
+ mov x1, x3
+ mov x2, x4
+ b reset
+
1: cmp x0, #HVC_RESET_VECTORS
b.ne 1f
+reset:
/*
- * Reset kvm back to the hyp stub.
+ * Reset kvm back to the hyp stub. Do not clobber x0-x4 in
+ * case we coming via HVC_SOFT_RESTART.
*/
- /* We're now in idmap, disable MMU */
- mrs x0, sctlr_el2
- ldr x1, =SCTLR_ELx_FLAGS
- bic x0, x0, x1 // Clear SCTL_M and etc
- msr sctlr_el2, x0
+ mrs x5, sctlr_el2
+ ldr x6, =SCTLR_ELx_FLAGS
+ bic x5, x5, x6 // Clear SCTL_M and etc
+ msr sctlr_el2, x5
isb

/* Install stub vectors */
- adr_l x0, __hyp_stub_vectors
- msr vbar_el2, x0
+ adr_l x5, __hyp_stub_vectors
+ msr vbar_el2, x5
b exit

1: mov x0, #-1
--
2.11.0