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| author | Shanker Donthineni <shankerd@codeaurora.org> | 2016-08-31 05:08:32 +0300 |
|---|---|---|
| committer | Christoffer Dall <christoffer.dall@linaro.org> | 2016-09-08 13:53:00 +0300 |
| commit | 68381b2b00f728a6c910e777bd62986c951323a3 (patch) | |
| tree | 7cb8545925f173dc1968a519390237e11847fa01 /arch/arm64/kvm/hyp/hyp-entry.S | |
| parent | 1fe0009833892f950d6955b8c77c5b00e7700802 (diff) | |
| download | linux-68381b2b00f728a6c910e777bd62986c951323a3.tar.xz | |
arm64: KVM: Optimize __guest_enter/exit() to save a few instructions
We are doing an unnecessary stack push/pop operation when restoring
the guest registers x0-x18 in __guest_enter(). This patch saves the
two instructions by using x18 as a base register. No need to store
the vcpu context pointer in stack because it is redundant, the same
information is available in tpidr_el2. The function __guest_exit()
calling convention is slightly modified, caller only pushes the regs
x0-x1 to stack instead of regs x0-x3.
Signed-off-by: Shanker Donthineni <shankerd@codeaurora.org>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Diffstat (limited to 'arch/arm64/kvm/hyp/hyp-entry.S')
| -rw-r--r-- | arch/arm64/kvm/hyp/hyp-entry.S | 37 |
1 files changed, 13 insertions, 24 deletions
diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S index f6d9694ae3b1..d6cae5428b95 100644 --- 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) |