diff options
Diffstat (limited to 'arch/arm64/kvm/hyp.S')
| -rw-r--r-- | arch/arm64/kvm/hyp.S | 27 |
1 files changed, 25 insertions, 2 deletions
diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S index 3b47c36e10ff..2c56012cb2d2 100644 --- a/arch/arm64/kvm/hyp.S +++ b/arch/arm64/kvm/hyp.S @@ -694,6 +694,24 @@ __hyp_panic_str: .align 2 +/* + * u64 kvm_call_hyp(void *hypfn, ...); + * + * This is not really a variadic function in the classic C-way and care must + * be taken when calling this to ensure parameters are passed in registers + * only, since the stack will change between the caller and the callee. + * + * Call the function with the first argument containing a pointer to the + * function you wish to call in Hyp mode, and subsequent arguments will be + * passed as x0, x1, and x2 (a maximum of 3 arguments in addition to the + * function pointer can be passed). The function being called must be mapped + * in Hyp mode (see init_hyp_mode in arch/arm/kvm/arm.c). Return values are + * passed in r0 and r1. + * + * A function pointer with a value of 0 has a special meaning, and is + * used to implement __hyp_get_vectors in the same way as in + * arch/arm64/kernel/hyp_stub.S. + */ ENTRY(kvm_call_hyp) hvc #0 ret @@ -737,7 +755,12 @@ el1_sync: // Guest trapped into EL2 pop x2, x3 pop x0, x1 - push lr, xzr + /* Check for __hyp_get_vectors */ + cbnz x0, 1f + mrs x0, vbar_el2 + b 2f + +1: push lr, xzr /* * Compute the function address in EL2, and shuffle the parameters. @@ -750,7 +773,7 @@ el1_sync: // Guest trapped into EL2 blr lr pop lr, xzr - eret +2: eret el1_trap: /* |