arm64: KVM: Optimize __guest_enter/exit() to save a few instructions

[cascardo/linux.git] / arch / arm64 / kvm / hyp / hyp-entry.S

diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
index f6d9694..d6cae54 100644 (file)
--- a/arch/arm64/kvm/hyp/hyp-entry.S
+++ b/arch/arm64/kvm/hyp/hyp-entry.S
@@ -27,16 +27,6 @@
        .text
        .pushsection    .hyp.text, "ax"
 
-.macro save_x0_to_x3
-       stp     x0, x1, [sp, #-16]!
-       stp     x2, x3, [sp, #-16]!
-.endm
-
-.macro restore_x0_to_x3
-       ldp     x2, x3, [sp], #16
-       ldp     x0, x1, [sp], #16
-.endm
-
 .macro do_el2_call
        /*
         * Shuffle the parameters before calling the function
@@ -79,23 +69,23 @@ ENTRY(__kvm_hyp_teardown)
 ENDPROC(__kvm_hyp_teardown)
        
 el1_sync:                              // Guest trapped into EL2
-       save_x0_to_x3
+       stp     x0, x1, [sp, #-16]!
 
 alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
        mrs     x1, esr_el2
 alternative_else
        mrs     x1, esr_el1
 alternative_endif
-       lsr     x2, x1, #ESR_ELx_EC_SHIFT
+       lsr     x0, x1, #ESR_ELx_EC_SHIFT
 
-       cmp     x2, #ESR_ELx_EC_HVC64
+       cmp     x0, #ESR_ELx_EC_HVC64
        b.ne    el1_trap
 
-       mrs     x3, vttbr_el2           // If vttbr is valid, the 64bit guest
-       cbnz    x3, el1_trap            // called HVC
+       mrs     x1, vttbr_el2           // If vttbr is valid, the 64bit guest
+       cbnz    x1, el1_trap            // called HVC
 
        /* Here, we're pretty sure the host called HVC. */
-       restore_x0_to_x3
+       ldp     x0, x1, [sp], #16
 
        cmp     x0, #HVC_GET_VECTORS
        b.ne    1f
@@ -113,22 +103,21 @@ alternative_endif
 
 el1_trap:
        /*
-        * x1: ESR
-        * x2: ESR_EC
+        * x0: ESR_EC
         */
 
        /* Guest accessed VFP/SIMD registers, save host, restore Guest */
-       cmp     x2, #ESR_ELx_EC_FP_ASIMD
+       cmp     x0, #ESR_ELx_EC_FP_ASIMD
        b.eq    __fpsimd_guest_restore
 
-       mrs     x0, tpidr_el2
-       mov     x1, #ARM_EXCEPTION_TRAP
+       mrs     x1, tpidr_el2
+       mov     x0, #ARM_EXCEPTION_TRAP
        b       __guest_exit
 
 el1_irq:
-       save_x0_to_x3
-       mrs     x0, tpidr_el2
-       mov     x1, #ARM_EXCEPTION_IRQ
+       stp     x0, x1, [sp, #-16]!
+       mrs     x1, tpidr_el2
+       mov     x0, #ARM_EXCEPTION_IRQ
        b       __guest_exit
 
 ENTRY(__hyp_do_panic)