All our useful entry points into the hypervisor are starting by
saving x0 and x1 on the stack. Let's move those into the vectors
by introducing macros that annotate whether a vector is valid or
not, thus indicating whether we want to stash registers or not.

The only drawback is that we now also stash registers for el2_error,
but this should never happen, and we pop them back right at the
start of the handling sequence.

Signed-off-by: Marc Zyngier <marc.zyng...@arm.com>
---
 arch/arm64/kvm/hyp/hyp-entry.S | 56 ++++++++++++++++++++++++------------------
 1 file changed, 32 insertions(+), 24 deletions(-)

diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
index f36464bd57c5..0f62b5f76aa5 100644
--- a/arch/arm64/kvm/hyp/hyp-entry.S
+++ b/arch/arm64/kvm/hyp/hyp-entry.S
@@ -55,7 +55,6 @@ ENTRY(__vhe_hyp_call)
 ENDPROC(__vhe_hyp_call)
 
 el1_sync:                              // Guest trapped into EL2
-       stp     x0, x1, [sp, #-16]!
 
 alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
        mrs     x1, esr_el2
@@ -137,18 +136,18 @@ alternative_else_nop_endif
        b       __guest_exit
 
 el1_irq:
-       stp     x0, x1, [sp, #-16]!
        ldr     x1, [sp, #16 + 8]
        mov     x0, #ARM_EXCEPTION_IRQ
        b       __guest_exit
 
 el1_error:
-       stp     x0, x1, [sp, #-16]!
        ldr     x1, [sp, #16 + 8]
        mov     x0, #ARM_EXCEPTION_EL1_SERROR
        b       __guest_exit
 
 el2_error:
+       ldp     x0, x1, [sp], #16
+
        /*
         * Only two possibilities:
         * 1) Either we come from the exit path, having just unmasked
@@ -206,32 +205,41 @@ ENDPROC(\label)
        invalid_vector  el2h_sync_invalid
        invalid_vector  el2h_irq_invalid
        invalid_vector  el2h_fiq_invalid
-       invalid_vector  el1_sync_invalid
-       invalid_vector  el1_irq_invalid
        invalid_vector  el1_fiq_invalid
 
        .ltorg
 
        .align 11
 
+.macro valid_vect target
+       .align 7
+       stp     x0, x1, [sp, #-16]!
+       b       \target
+.endm
+
+.macro invalid_vect target
+       .align 7
+       b       \target
+.endm
+
 ENTRY(__kvm_hyp_vector)
-       ventry  el2t_sync_invalid               // Synchronous EL2t
-       ventry  el2t_irq_invalid                // IRQ EL2t
-       ventry  el2t_fiq_invalid                // FIQ EL2t
-       ventry  el2t_error_invalid              // Error EL2t
-
-       ventry  el2h_sync_invalid               // Synchronous EL2h
-       ventry  el2h_irq_invalid                // IRQ EL2h
-       ventry  el2h_fiq_invalid                // FIQ EL2h
-       ventry  el2_error                       // Error EL2h
-
-       ventry  el1_sync                        // Synchronous 64-bit EL1
-       ventry  el1_irq                         // IRQ 64-bit EL1
-       ventry  el1_fiq_invalid                 // FIQ 64-bit EL1
-       ventry  el1_error                       // Error 64-bit EL1
-
-       ventry  el1_sync                        // Synchronous 32-bit EL1
-       ventry  el1_irq                         // IRQ 32-bit EL1
-       ventry  el1_fiq_invalid                 // FIQ 32-bit EL1
-       ventry  el1_error                       // Error 32-bit EL1
+       invalid_vect    el2t_sync_invalid       // Synchronous EL2t
+       invalid_vect    el2t_irq_invalid        // IRQ EL2t
+       invalid_vect    el2t_fiq_invalid        // FIQ EL2t
+       invalid_vect    el2t_error_invalid      // Error EL2t
+
+       invalid_vect    el2h_sync_invalid       // Synchronous EL2h
+       invalid_vect    el2h_irq_invalid        // IRQ EL2h
+       invalid_vect    el2h_fiq_invalid        // FIQ EL2h
+       valid_vect      el2_error               // Error EL2h
+
+       valid_vect      el1_sync                // Synchronous 64-bit EL1
+       valid_vect      el1_irq                 // IRQ 64-bit EL1
+       invalid_vect    el1_fiq_invalid         // FIQ 64-bit EL1
+       valid_vect      el1_error               // Error 64-bit EL1
+
+       valid_vect      el1_sync                // Synchronous 32-bit EL1
+       valid_vect      el1_irq                 // IRQ 32-bit EL1
+       invalid_vect    el1_fiq_invalid         // FIQ 32-bit EL1
+       valid_vect      el1_error               // Error 32-bit EL1
 ENDPROC(__kvm_hyp_vector)
-- 
2.14.2

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