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authorMarc Zyngier <marc.zyngier@arm.com>2017-04-03 19:37:53 +0100
committerChristoffer Dall <cdall@linaro.org>2017-04-09 07:49:28 -0700
commitbc845e4fbbbbe97bab3f1bcf688be0b5da420717 (patch)
tree4e5c44a617dfdde8e7d71c02800172f6b36d38bf /arch/arm/kvm/init.S
parent7d1bf4e05717d900e69b249b4f08f6b36b00fbf0 (diff)
ARM: KVM: Implement HVC_RESET_VECTORS stub hypercall in the init code
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. Tested-by: Keerthy <j-keerthy@ti.com> Acked-by: Russell King <rmk+kernel@armlinux.org.uk> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <cdall@linaro.org>
Diffstat (limited to 'arch/arm/kvm/init.S')
-rw-r--r--arch/arm/kvm/init.S33
1 files changed, 27 insertions, 6 deletions
diff --git a/arch/arm/kvm/init.S b/arch/arm/kvm/init.S
index bf89c919efc1..86a7008e75a3 100644
--- a/arch/arm/kvm/init.S
+++ b/arch/arm/kvm/init.S
@@ -23,6 +23,7 @@
#include <asm/kvm_asm.h>
#include <asm/kvm_arm.h>
#include <asm/kvm_mmu.h>
+#include <asm/virt.h>
/********************************************************************
* Hypervisor initialization
@@ -39,6 +40,10 @@
* - Setup the page tables
* - Enable the MMU
* - Profit! (or eret, if you only care about the code).
+ *
+ * Another possibility is to get a HYP stub hypercall.
+ * We discriminate between the two by checking if r0 contains a value
+ * that is less than HVC_STUB_HCALL_NR.
*/
.text
@@ -58,6 +63,10 @@ __kvm_hyp_init:
W(b) .
__do_hyp_init:
+ @ Check for a stub hypercall
+ cmp r0, #HVC_STUB_HCALL_NR
+ blo __kvm_handle_stub_hvc
+
@ Set stack pointer
mov sp, r0
@@ -112,19 +121,31 @@ __do_hyp_init:
eret
- @ r0 : stub vectors address
+ENTRY(__kvm_handle_stub_hvc)
+ cmp r0, #HVC_RESET_VECTORS
+ bne 1f
ENTRY(__kvm_hyp_reset)
/* We're now in idmap, disable MMU */
mrc p15, 4, r1, c1, c0, 0 @ HSCTLR
- ldr r2, =(HSCTLR_M | HSCTLR_A | HSCTLR_C | HSCTLR_I)
- bic r1, r1, r2
+ ldr r0, =(HSCTLR_M | HSCTLR_A | HSCTLR_C | HSCTLR_I)
+ bic r1, r1, r0
mcr p15, 4, r1, c1, c0, 0 @ HSCTLR
- /* Install stub vectors */
- mcr p15, 4, r0, c12, c0, 0 @ HVBAR
- isb
+ /*
+ * Install stub vectors, using ardb's VA->PA trick.
+ */
+0: adr r0, 0b @ PA(0)
+ movw r1, #:lower16:__hyp_stub_vectors - 0b @ VA(stub) - VA(0)
+ movt r1, #:upper16:__hyp_stub_vectors - 0b
+ add r1, r1, r0 @ PA(stub)
+ mcr p15, 4, r1, c12, c0, 0 @ HVBAR
+ b exit
+
+1: ldr r0, =HVC_STUB_ERR
+exit:
eret
+ENDPROC(__kvm_handle_stub_hvc)
ENDPROC(__kvm_hyp_reset)
.ltorg