arm/arm64: KVM: detect CPU reset on CPU_PM_EXIT

[~andy/linux] / arch / arm64 / kvm / hyp.S

diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
index 3b47c36e10ffcdac920a08277ee9e3e1df00a211..2c56012cb2d2c8d82588063058f4444e188d13f6 100644 (file)
--- 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:
        /*