On 12/17/18 6:16 PM, Jan Kiszka wrote:
> On 06.11.18 00:05, Ralf Ramsauer wrote:
>> The final step: remove arch_handle_exit, and dispatch things directly in
>> assembly. As a consequence, we get a faster exit path, as we save the
>> double-dispatching.
>>
>> We also save one instruction inside the interrupt vector. :-)
>>
>> For the union registers, replace the exit_reason with __padding. For
>> easier
>> handling, the padding is located at the beginning of the structure.
>
> What do we need that padding still for?
There was a reason...
Aah -- Afair, we have an odd number of registers, and the stack needs to
be aligned after pushing all registers.
Ralf
>
>>
>> Signed-off-by: Ralf Ramsauer <ralf.ramsa...@oth-regensburg.de>
>> ---
>> hypervisor/arch/arm64/entry.S | 18 +++++--------
>> .../arch/arm64/include/arch/asm/traps.h | 3 +++
>> hypervisor/arch/arm64/include/asm/processor.h | 6 +----
>> hypervisor/arch/arm64/traps.c | 26 ++-----------------
>> 4 files changed, 13 insertions(+), 40 deletions(-)
>>
>> diff --git a/hypervisor/arch/arm64/entry.S
>> b/hypervisor/arch/arm64/entry.S
>> index e0240f00..498a8d64 100644
>> --- a/hypervisor/arch/arm64/entry.S
>> +++ b/hypervisor/arch/arm64/entry.S
>> @@ -271,19 +271,15 @@ bootstrap_vectors:
>> ventry .
>> -.macro handle_vmexit exit_reason
>> +.macro handle_vmexit handler
>> .align 7
>> /* We need to save EL1 context, reserve some space on the stack */
>> sub sp, sp, #(16 * 16)
>> /* And push [x1-x4] early, we need registers to work on */
>> + str x0, [sp, #(1 * 8)]
>> stp x1, x2, [sp, #(1 * 16)]
>> stp x3, x4, [sp, #(2 * 16)]
>> - /* x1 is available, use it to hold the exit reason */
>> - mov x1, #\exit_reason
>> - /* ... and push it together with x0 */
>> - stp x1, x0, [sp, #(0 * 16)]
>> -
>> /* [x0-x4] may now be clobbered. */
>> /*
>> @@ -314,7 +310,7 @@ bootstrap_vectors:
>> mov x29, xzr /* reset fp,lr */
>> mov x30, xzr
>> mov x0, sp
>> - bl arch_handle_exit
>> + bl \handler
>> /* take the fast exit path, sp is already in place */
>> b __vmreturn
>> .endm
>> @@ -326,13 +322,13 @@ hyp_vectors:
>> ventry .
>> ventry .
>> - handle_vmexit EXIT_REASON_EL2_ABORT
>> + handle_vmexit arch_el2_abt
>> ventry .
>> ventry .
>> ventry .
>> - handle_vmexit EXIT_REASON_EL1_ABORT
>> - handle_vmexit EXIT_REASON_EL1_IRQ
>> + handle_vmexit arch_handle_trap
>> + handle_vmexit irqchip_handle_irq
>> ventry .
>> ventry .
>> @@ -429,8 +425,8 @@ __vmreturn:
>> ldp x7, x8, [sp, #(4 * 16)]
>> ldp x5, x6, [sp, #(3 * 16)]
>> ldp x3, x4, [sp, #(2 * 16)]
>> - ldp x1, x0, [sp, #(0 * 16)] /* x1 is the exit_reason */
>> ldp x1, x2, [sp, #(1 * 16)]
>> + ldr x0, [sp, #(1 * 8)]
>> add sp, sp, #(16 * 16)
>> eret
>> .popsection
>> diff --git a/hypervisor/arch/arm64/include/arch/asm/traps.h
>> b/hypervisor/arch/arm64/include/arch/asm/traps.h
>> index aec6de5a..e2164ad9 100644
>> --- a/hypervisor/arch/arm64/include/arch/asm/traps.h
>> +++ b/hypervisor/arch/arm64/include/arch/asm/traps.h
>> @@ -16,3 +16,6 @@ struct trap_context {
>> u64 spsr;
>> u64 sp;
>> };
>> +
>> +void arch_handle_trap(union registers *guest_regs);
>> +void arch_el2_abt(union registers *regs);
>> diff --git a/hypervisor/arch/arm64/include/asm/processor.h
>> b/hypervisor/arch/arm64/include/asm/processor.h
>> index 6396a356..5bedb20a 100644
>> --- a/hypervisor/arch/arm64/include/asm/processor.h
>> +++ b/hypervisor/arch/arm64/include/asm/processor.h
>> @@ -16,17 +16,13 @@
>> #include <jailhouse/types.h>
>> #include <jailhouse/utils.h>
>> -#define EXIT_REASON_EL2_ABORT 0x0
>> -#define EXIT_REASON_EL1_ABORT 0x1
>> -#define EXIT_REASON_EL1_IRQ 0x2
>> -
>> #define NUM_USR_REGS 31
>> #ifndef __ASSEMBLY__
>> union registers {
>> struct {
>> - unsigned long exit_reason;
>> + unsigned long __padding;
>> unsigned long usr[NUM_USR_REGS];
>> };
>> };
>> diff --git a/hypervisor/arch/arm64/traps.c
>> b/hypervisor/arch/arm64/traps.c
>> index 71f6da6f..0174edae 100644
>> --- a/hypervisor/arch/arm64/traps.c
>> +++ b/hypervisor/arch/arm64/traps.c
>> @@ -159,7 +159,7 @@ static const trap_handler trap_handlers[0x40] =
>> [ESR_EC_DABT_LOW] = arch_handle_dabt,
>> };
>> -static void arch_handle_trap(union registers *guest_regs)
>> +void arch_handle_trap(union registers *guest_regs)
>> {
>> struct trap_context ctx;
>> trap_handler handler;
>> @@ -182,7 +182,7 @@ static void arch_handle_trap(union registers
>> *guest_regs)
>> }
>> }
>> -static void arch_el2_abt(union registers *regs)
>> +void arch_el2_abt(union registers *regs)
>> {
>> struct trap_context ctx;
>> @@ -193,25 +193,3 @@ static void arch_el2_abt(union registers *regs)
>> dump_hyp_stack(&ctx);
>> panic_stop();
>> }
>> -
>> -union registers *arch_handle_exit(union registers *regs)
>> -{
>> - switch (regs->exit_reason) {
>> - case EXIT_REASON_EL1_IRQ:
>> - irqchip_handle_irq();
>> - break;
>> -
>> - case EXIT_REASON_EL1_ABORT:
>> - arch_handle_trap(regs);
>> - break;
>> -
>> - case EXIT_REASON_EL2_ABORT:
>> - arch_el2_abt(regs);
>> - break;
>> -
>> - default:
>> - panic_stop();
>> - }
>> -
>> - return regs;
>> -}
>>
>
> Nice refactoring!
>
> Jan
>
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