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[Qemu-devel] [PATCH v2 1/4] i386/kvm: use a switch statement for MSR detection

Ladi Prosek posted 4 patches 8 years, 6 months ago
[Qemu-devel] [PATCH v2 1/4] i386/kvm: use a switch statement for MSR detection
Posted by Ladi Prosek 8 years, 6 months ago 
Switch is easier on the eye and might lead to better codegen.

Signed-off-by: Ladi Prosek <lprosek@redhat.com>
---
 target/i386/kvm.c | 75 +++++++++++++++++++++++--------------------------------
 1 file changed, 31 insertions(+), 44 deletions(-)

diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index 6db7783..b14a0db 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -1081,65 +1081,52 @@ static int kvm_get_supported_msrs(KVMState *s)
             int i;
 
             for (i = 0; i < kvm_msr_list->nmsrs; i++) {
-                if (kvm_msr_list->indices[i] == MSR_STAR) {
+                switch (kvm_msr_list->indices[i]) {
+                case MSR_STAR:
                     has_msr_star = true;
-                    continue;
-                }
-                if (kvm_msr_list->indices[i] == MSR_VM_HSAVE_PA) {
+                    break;
+                case MSR_VM_HSAVE_PA:
                     has_msr_hsave_pa = true;
-                    continue;
-                }
-                if (kvm_msr_list->indices[i] == MSR_TSC_AUX) {
+                    break;
+                case MSR_TSC_AUX:
                     has_msr_tsc_aux = true;
-                    continue;
-                }
-                if (kvm_msr_list->indices[i] == MSR_TSC_ADJUST) {
+                    break;
+                case MSR_TSC_ADJUST:
                     has_msr_tsc_adjust = true;
-                    continue;
-                }
-                if (kvm_msr_list->indices[i] == MSR_IA32_TSCDEADLINE) {
+                    break;
+                case MSR_IA32_TSCDEADLINE:
                     has_msr_tsc_deadline = true;
-                    continue;
-                }
-                if (kvm_msr_list->indices[i] == MSR_IA32_SMBASE) {
+                    break;
+                case MSR_IA32_SMBASE:
                     has_msr_smbase = true;
-                    continue;
-                }
-                if (kvm_msr_list->indices[i] == MSR_IA32_MISC_ENABLE) {
+                    break;
+                case MSR_IA32_MISC_ENABLE:
                     has_msr_misc_enable = true;
-                    continue;
-                }
-                if (kvm_msr_list->indices[i] == MSR_IA32_BNDCFGS) {
+                    break;
+                case MSR_IA32_BNDCFGS:
                     has_msr_bndcfgs = true;
-                    continue;
-                }
-                if (kvm_msr_list->indices[i] == MSR_IA32_XSS) {
+                    break;
+                case MSR_IA32_XSS:
                     has_msr_xss = true;
-                    continue;
-                }
-                if (kvm_msr_list->indices[i] == HV_X64_MSR_CRASH_CTL) {
+                    break;;
+                case HV_X64_MSR_CRASH_CTL:
                     has_msr_hv_crash = true;
-                    continue;
-                }
-                if (kvm_msr_list->indices[i] == HV_X64_MSR_RESET) {
+                    break;
+                case HV_X64_MSR_RESET:
                     has_msr_hv_reset = true;
-                    continue;
-                }
-                if (kvm_msr_list->indices[i] == HV_X64_MSR_VP_INDEX) {
+                    break;
+                case HV_X64_MSR_VP_INDEX:
                     has_msr_hv_vpindex = true;
-                    continue;
-                }
-                if (kvm_msr_list->indices[i] == HV_X64_MSR_VP_RUNTIME) {
+                    break;
+                case HV_X64_MSR_VP_RUNTIME:
                     has_msr_hv_runtime = true;
-                    continue;
-                }
-                if (kvm_msr_list->indices[i] == HV_X64_MSR_SCONTROL) {
+                    break;
+                case HV_X64_MSR_SCONTROL:
                     has_msr_hv_synic = true;
-                    continue;
-                }
-                if (kvm_msr_list->indices[i] == HV_X64_MSR_STIMER0_CONFIG) {
+                    break;
+                case HV_X64_MSR_STIMER0_CONFIG:
                     has_msr_hv_stimer = true;
-                    continue;
+                    break;
                 }
             }
         }
-- 
2.9.3
Re: [Qemu-devel] [PATCH v2 1/4] i386/kvm: use a switch statement for MSR detection
Posted by David Hildenbrand 8 years, 6 months ago 
On 07.08.2017 10:57, Ladi Prosek wrote:
> Switch is easier on the eye and might lead to better codegen.
> 
> Signed-off-by: Ladi Prosek <lprosek@redhat.com>
> ---
>  target/i386/kvm.c | 75 +++++++++++++++++++++++--------------------------------
>  1 file changed, 31 insertions(+), 44 deletions(-)
> 
> diff --git a/target/i386/kvm.c b/target/i386/kvm.c
> index 6db7783..b14a0db 100644
> --- a/target/i386/kvm.c
> +++ b/target/i386/kvm.c
> @@ -1081,65 +1081,52 @@ static int kvm_get_supported_msrs(KVMState *s)
>              int i;
>  
>              for (i = 0; i < kvm_msr_list->nmsrs; i++) {
> -                if (kvm_msr_list->indices[i] == MSR_STAR) {
> +                switch (kvm_msr_list->indices[i]) {
> +                case MSR_STAR:
>                      has_msr_star = true;
> -                    continue;
> -                }
> -                if (kvm_msr_list->indices[i] == MSR_VM_HSAVE_PA) {
> +                    break;
> +                case MSR_VM_HSAVE_PA:
>                      has_msr_hsave_pa = true;
> -                    continue;
> -                }
> -                if (kvm_msr_list->indices[i] == MSR_TSC_AUX) {
> +                    break;
> +                case MSR_TSC_AUX:
>                      has_msr_tsc_aux = true;
> -                    continue;
> -                }
> -                if (kvm_msr_list->indices[i] == MSR_TSC_ADJUST) {
> +                    break;
> +                case MSR_TSC_ADJUST:
>                      has_msr_tsc_adjust = true;
> -                    continue;
> -                }
> -                if (kvm_msr_list->indices[i] == MSR_IA32_TSCDEADLINE) {
> +                    break;
> +                case MSR_IA32_TSCDEADLINE:
>                      has_msr_tsc_deadline = true;
> -                    continue;
> -                }
> -                if (kvm_msr_list->indices[i] == MSR_IA32_SMBASE) {
> +                    break;
> +                case MSR_IA32_SMBASE:
>                      has_msr_smbase = true;
> -                    continue;
> -                }
> -                if (kvm_msr_list->indices[i] == MSR_IA32_MISC_ENABLE) {
> +                    break;
> +                case MSR_IA32_MISC_ENABLE:
>                      has_msr_misc_enable = true;
> -                    continue;
> -                }
> -                if (kvm_msr_list->indices[i] == MSR_IA32_BNDCFGS) {
> +                    break;
> +                case MSR_IA32_BNDCFGS:
>                      has_msr_bndcfgs = true;
> -                    continue;
> -                }
> -                if (kvm_msr_list->indices[i] == MSR_IA32_XSS) {
> +                    break;
> +                case MSR_IA32_XSS:
>                      has_msr_xss = true;
> -                    continue;
> -                }
> -                if (kvm_msr_list->indices[i] == HV_X64_MSR_CRASH_CTL) {
> +                    break;;
> +                case HV_X64_MSR_CRASH_CTL:
>                      has_msr_hv_crash = true;
> -                    continue;
> -                }
> -                if (kvm_msr_list->indices[i] == HV_X64_MSR_RESET) {
> +                    break;
> +                case HV_X64_MSR_RESET:
>                      has_msr_hv_reset = true;
> -                    continue;
> -                }
> -                if (kvm_msr_list->indices[i] == HV_X64_MSR_VP_INDEX) {
> +                    break;
> +                case HV_X64_MSR_VP_INDEX:
>                      has_msr_hv_vpindex = true;
> -                    continue;
> -                }
> -                if (kvm_msr_list->indices[i] == HV_X64_MSR_VP_RUNTIME) {
> +                    break;
> +                case HV_X64_MSR_VP_RUNTIME:
>                      has_msr_hv_runtime = true;
> -                    continue;
> -                }
> -                if (kvm_msr_list->indices[i] == HV_X64_MSR_SCONTROL) {
> +                    break;
> +                case HV_X64_MSR_SCONTROL:
>                      has_msr_hv_synic = true;
> -                    continue;
> -                }
> -                if (kvm_msr_list->indices[i] == HV_X64_MSR_STIMER0_CONFIG) {
> +                    break;
> +                case HV_X64_MSR_STIMER0_CONFIG:
>                      has_msr_hv_stimer = true;
> -                    continue;
> +                    break;
>                  }
>              }
>          }
> 

Think you forgot to add my r-b.

-- 

Thanks,

David
Re: [Qemu-devel] [PATCH v2 1/4] i386/kvm: use a switch statement for MSR detection
Posted by Ladi Prosek 8 years, 6 months ago 
On Mon, Aug 7, 2017 at 4:19 PM, David Hildenbrand <david@redhat.com> wrote:
> On 07.08.2017 10:57, Ladi Prosek wrote:
>> Switch is easier on the eye and might lead to better codegen.
>>
>> Signed-off-by: Ladi Prosek <lprosek@redhat.com>
>> ---
>>  target/i386/kvm.c | 75 +++++++++++++++++++++++--------------------------------
>>  1 file changed, 31 insertions(+), 44 deletions(-)
>>
>> diff --git a/target/i386/kvm.c b/target/i386/kvm.c
>> index 6db7783..b14a0db 100644
>> --- a/target/i386/kvm.c
>> +++ b/target/i386/kvm.c
>> @@ -1081,65 +1081,52 @@ static int kvm_get_supported_msrs(KVMState *s)
>>              int i;
>>
>>              for (i = 0; i < kvm_msr_list->nmsrs; i++) {
>> -                if (kvm_msr_list->indices[i] == MSR_STAR) {
>> +                switch (kvm_msr_list->indices[i]) {
>> +                case MSR_STAR:
>>                      has_msr_star = true;
>> -                    continue;
>> -                }
>> -                if (kvm_msr_list->indices[i] == MSR_VM_HSAVE_PA) {
>> +                    break;
>> +                case MSR_VM_HSAVE_PA:
>>                      has_msr_hsave_pa = true;
>> -                    continue;
>> -                }
>> -                if (kvm_msr_list->indices[i] == MSR_TSC_AUX) {
>> +                    break;
>> +                case MSR_TSC_AUX:
>>                      has_msr_tsc_aux = true;
>> -                    continue;
>> -                }
>> -                if (kvm_msr_list->indices[i] == MSR_TSC_ADJUST) {
>> +                    break;
>> +                case MSR_TSC_ADJUST:
>>                      has_msr_tsc_adjust = true;
>> -                    continue;
>> -                }
>> -                if (kvm_msr_list->indices[i] == MSR_IA32_TSCDEADLINE) {
>> +                    break;
>> +                case MSR_IA32_TSCDEADLINE:
>>                      has_msr_tsc_deadline = true;
>> -                    continue;
>> -                }
>> -                if (kvm_msr_list->indices[i] == MSR_IA32_SMBASE) {
>> +                    break;
>> +                case MSR_IA32_SMBASE:
>>                      has_msr_smbase = true;
>> -                    continue;
>> -                }
>> -                if (kvm_msr_list->indices[i] == MSR_IA32_MISC_ENABLE) {
>> +                    break;
>> +                case MSR_IA32_MISC_ENABLE:
>>                      has_msr_misc_enable = true;
>> -                    continue;
>> -                }
>> -                if (kvm_msr_list->indices[i] == MSR_IA32_BNDCFGS) {
>> +                    break;
>> +                case MSR_IA32_BNDCFGS:
>>                      has_msr_bndcfgs = true;
>> -                    continue;
>> -                }
>> -                if (kvm_msr_list->indices[i] == MSR_IA32_XSS) {
>> +                    break;
>> +                case MSR_IA32_XSS:
>>                      has_msr_xss = true;
>> -                    continue;
>> -                }
>> -                if (kvm_msr_list->indices[i] == HV_X64_MSR_CRASH_CTL) {
>> +                    break;;
>> +                case HV_X64_MSR_CRASH_CTL:
>>                      has_msr_hv_crash = true;
>> -                    continue;
>> -                }
>> -                if (kvm_msr_list->indices[i] == HV_X64_MSR_RESET) {
>> +                    break;
>> +                case HV_X64_MSR_RESET:
>>                      has_msr_hv_reset = true;
>> -                    continue;
>> -                }
>> -                if (kvm_msr_list->indices[i] == HV_X64_MSR_VP_INDEX) {
>> +                    break;
>> +                case HV_X64_MSR_VP_INDEX:
>>                      has_msr_hv_vpindex = true;
>> -                    continue;
>> -                }
>> -                if (kvm_msr_list->indices[i] == HV_X64_MSR_VP_RUNTIME) {
>> +                    break;
>> +                case HV_X64_MSR_VP_RUNTIME:
>>                      has_msr_hv_runtime = true;
>> -                    continue;
>> -                }
>> -                if (kvm_msr_list->indices[i] == HV_X64_MSR_SCONTROL) {
>> +                    break;
>> +                case HV_X64_MSR_SCONTROL:
>>                      has_msr_hv_synic = true;
>> -                    continue;
>> -                }
>> -                if (kvm_msr_list->indices[i] == HV_X64_MSR_STIMER0_CONFIG) {
>> +                    break;
>> +                case HV_X64_MSR_STIMER0_CONFIG:
>>                      has_msr_hv_stimer = true;
>> -                    continue;
>> +                    break;
>>                  }
>>              }
>>          }
>>
>
> Think you forgot to add my r-b.

Oops, sorry about that!

> --
>
> Thanks,
>
> David

Patchew 2.1-devel-b67e4c2

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