[PATCH v4 05/28] arm64: KVM: Implement HVC_RESET_VECTORS stub hypercall in the init code

Marc Zyngier
2017-03-21T19:20:35Z

In order to restore HYP mode to its original condition, KVM currently
implements __kvm_hyp_reset(). As we're moving towards a hyp-stub
defined API, it becomes necessary to implement HVC_RESET_VECTORS.

This patch adds the HVC_RESET_VECTORS hypercall to the KVM init
code, which so far lacked any form of hypercall support.

Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
arch/arm64/kvm/hyp-init.S | 12 ++++++++++++
1 file changed, 12 insertions(+)

diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index 6b29d3d9e1f2..6cf98ccd10f2 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -22,6 +22,7 @@
#include <asm/kvm_mmu.h>
#include <asm/pgtable-hwdef.h>
#include <asm/sysreg.h>
+#include <asm/virt.h>

.text
.pushsection .hyp.idmap.text, "ax"
@@ -58,6 +59,9 @@ __invalid:
* x2: HYP vectors
*/
__do_hyp_init:
+ /* Check for a stub HVC call */
+ cmp x0, #HVC_STUB_HCALL_NR
+ b.lo __kvm_handle_stub_hvc

msr ttbr0_el2, x0

@@ -119,6 +123,9 @@ __do_hyp_init:
eret
ENDPROC(__kvm_hyp_init)

+ENTRY(__kvm_handle_stub_hvc)
+ cmp x0, #HVC_RESET_VECTORS
+ b.ne 1f
/*
* Reset kvm back to the hyp stub.
*/
@@ -133,9 +140,14 @@ ENTRY(__kvm_hyp_reset)
/* Install stub vectors */
adr_l x0, __hyp_stub_vectors
msr vbar_el2, x0
+ b exit

+1: mov x0, #-1
+
+exit:
eret
ENDPROC(__kvm_hyp_reset)
+ENDPROC(__kvm_handle_stub_hvc)

.ltorg

--
2.11.0