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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>
This commit is contained in:
Marc Zyngier 2017-04-03 19:37:53 +01:00 committed by Christoffer Dall
parent 7d1bf4e057
commit bc845e4fbb
3 changed files with 29 additions and 7 deletions
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1
arch/arm/include/asm/virt.h
View File

@ -54,6 +54,7 @@ static inline void sync_boot_mode(void)
void __hyp_set_vectors(unsigned long phys_vector_base);
unsigned long __hyp_get_vectors(void);
void __hyp_reset_vectors(void);
#else
#define __boot_cpu_mode (SVC_MODE)
#define sync_boot_mode()

2
arch/arm/kernel/hyp-stub.S
View File

@ -280,7 +280,7 @@ ENDPROC(__hyp_reset_vectors)
#endif
.align 5
__hyp_stub_vectors:
ENTRY(__hyp_stub_vectors)
__hyp_stub_reset: W(b) .
__hyp_stub_und: W(b) .
__hyp_stub_svc: W(b) .

33
arch/arm/kvm/init.S
View File

@ -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