* [PATCH v1] KVM: VMX: Remove unnecessary parentheses
@ 2026-03-05 23:54 Xin Li (Intel)
2026-03-06 6:17 ` BillXiang
0 siblings, 1 reply; 3+ messages in thread
From: Xin Li (Intel) @ 2026-03-05 23:54 UTC (permalink / raw)
To: kvm, linux-kernel
Cc: seanjc, pbonzini, tglx, mingo, bp, dave.hansen, x86, hpa, xin
From: Xin Li <xin@zytor.com>
Drop redundant parentheses; & takes precedence over &&.
Signed-off-by: Xin Li <xin@zytor.com>
---
arch/x86/kvm/vmx/capabilities.h | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kvm/vmx/capabilities.h b/arch/x86/kvm/vmx/capabilities.h
index 4e371c93ae16..0dad9e7c4ff4 100644
--- a/arch/x86/kvm/vmx/capabilities.h
+++ b/arch/x86/kvm/vmx/capabilities.h
@@ -107,7 +107,7 @@ static inline bool cpu_has_load_perf_global_ctrl(void)
static inline bool cpu_has_load_cet_ctrl(void)
{
- return (vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_CET_STATE);
+ return vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_CET_STATE;
}
static inline bool cpu_has_save_perf_global_ctrl(void)
@@ -162,7 +162,7 @@ static inline bool cpu_has_vmx_ept(void)
static inline bool vmx_umip_emulated(void)
{
return !boot_cpu_has(X86_FEATURE_UMIP) &&
- (vmcs_config.cpu_based_2nd_exec_ctrl & SECONDARY_EXEC_DESC);
+ vmcs_config.cpu_based_2nd_exec_ctrl & SECONDARY_EXEC_DESC;
}
static inline bool cpu_has_vmx_rdtscp(void)
@@ -376,9 +376,9 @@ static inline bool cpu_has_vmx_invvpid_global(void)
static inline bool cpu_has_vmx_intel_pt(void)
{
- return (vmcs_config.misc & VMX_MISC_INTEL_PT) &&
- (vmcs_config.cpu_based_2nd_exec_ctrl & SECONDARY_EXEC_PT_USE_GPA) &&
- (vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_IA32_RTIT_CTL);
+ return vmcs_config.misc & VMX_MISC_INTEL_PT &&
+ vmcs_config.cpu_based_2nd_exec_ctrl & SECONDARY_EXEC_PT_USE_GPA &&
+ vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_IA32_RTIT_CTL;
}
/*
base-commit: 5128b972fb2801ad9aca54d990a75611ab5283a9
--
2.53.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v1] KVM: VMX: Remove unnecessary parentheses
2026-03-05 23:54 [PATCH v1] KVM: VMX: Remove unnecessary parentheses Xin Li (Intel)
@ 2026-03-06 6:17 ` BillXiang
2026-03-06 16:24 ` Sean Christopherson
0 siblings, 1 reply; 3+ messages in thread
From: BillXiang @ 2026-03-06 6:17 UTC (permalink / raw)
To: Xin Li (Intel), kvm, linux-kernel
Cc: seanjc, pbonzini, tglx, mingo, bp, dave.hansen, x86, hpa
On 3/6/2026 7:54 AM, Xin Li (Intel) wrote:
> From: Xin Li <xin@zytor.com>
>
> Drop redundant parentheses; & takes precedence over &&.
I would not recommend relying on default operator precedence.
>
> Signed-off-by: Xin Li <xin@zytor.com>
> ---
> arch/x86/kvm/vmx/capabilities.h | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx/capabilities.h b/arch/x86/kvm/vmx/capabilities.h
> index 4e371c93ae16..0dad9e7c4ff4 100644
> --- a/arch/x86/kvm/vmx/capabilities.h
> +++ b/arch/x86/kvm/vmx/capabilities.h
> @@ -107,7 +107,7 @@ static inline bool cpu_has_load_perf_global_ctrl(void)
>
> static inline bool cpu_has_load_cet_ctrl(void)
> {
> - return (vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_CET_STATE);
> + return vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_CET_STATE;
> }
>
> static inline bool cpu_has_save_perf_global_ctrl(void)
> @@ -162,7 +162,7 @@ static inline bool cpu_has_vmx_ept(void)
> static inline bool vmx_umip_emulated(void)
> {
> return !boot_cpu_has(X86_FEATURE_UMIP) &&
> - (vmcs_config.cpu_based_2nd_exec_ctrl & SECONDARY_EXEC_DESC);
> + vmcs_config.cpu_based_2nd_exec_ctrl & SECONDARY_EXEC_DESC;
> }
>
> static inline bool cpu_has_vmx_rdtscp(void)
> @@ -376,9 +376,9 @@ static inline bool cpu_has_vmx_invvpid_global(void)
>
> static inline bool cpu_has_vmx_intel_pt(void)
> {
> - return (vmcs_config.misc & VMX_MISC_INTEL_PT) &&
> - (vmcs_config.cpu_based_2nd_exec_ctrl & SECONDARY_EXEC_PT_USE_GPA) &&
> - (vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_IA32_RTIT_CTL);
> + return vmcs_config.misc & VMX_MISC_INTEL_PT &&
> + vmcs_config.cpu_based_2nd_exec_ctrl & SECONDARY_EXEC_PT_USE_GPA &&
> + vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_IA32_RTIT_CTL;
> }
Removing the parentheses could significantly reduce code readability here.
>
> /*
>
> base-commit: 5128b972fb2801ad9aca54d990a75611ab5283a9
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v1] KVM: VMX: Remove unnecessary parentheses
2026-03-06 6:17 ` BillXiang
@ 2026-03-06 16:24 ` Sean Christopherson
0 siblings, 0 replies; 3+ messages in thread
From: Sean Christopherson @ 2026-03-06 16:24 UTC (permalink / raw)
To: BillXiang
Cc: Xin Li (Intel), kvm, linux-kernel, pbonzini, tglx, mingo, bp,
dave.hansen, x86, hpa
On Fri, Mar 06, 2026, BillXiang wrote:
> On 3/6/2026 7:54 AM, Xin Li (Intel) wrote:
> > From: Xin Li <xin@zytor.com>
> >
> > Drop redundant parentheses; & takes precedence over &&.
>
> I would not recommend relying on default operator precedence.
Eh, in practice, the kernel heavily relies on operator precedence all over the
place, so I'm not worried about correctness. But as you note below, judicious
use of parentheses can help readability.
> > Signed-off-by: Xin Li <xin@zytor.com>
> > ---
> > arch/x86/kvm/vmx/capabilities.h | 10 +++++-----
> > 1 file changed, 5 insertions(+), 5 deletions(-)
> >
> > diff --git a/arch/x86/kvm/vmx/capabilities.h b/arch/x86/kvm/vmx/capabilities.h
> > index 4e371c93ae16..0dad9e7c4ff4 100644
> > --- a/arch/x86/kvm/vmx/capabilities.h
> > +++ b/arch/x86/kvm/vmx/capabilities.h
> > @@ -107,7 +107,7 @@ static inline bool cpu_has_load_perf_global_ctrl(void)
> >
> > static inline bool cpu_has_load_cet_ctrl(void)
> > {
> > - return (vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_CET_STATE);
> > + return vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_CET_STATE;
> > }
> >
> > static inline bool cpu_has_save_perf_global_ctrl(void)
> > @@ -162,7 +162,7 @@ static inline bool cpu_has_vmx_ept(void)
> > static inline bool vmx_umip_emulated(void)
> > {
> > return !boot_cpu_has(X86_FEATURE_UMIP) &&
> > - (vmcs_config.cpu_based_2nd_exec_ctrl & SECONDARY_EXEC_DESC);
> > + vmcs_config.cpu_based_2nd_exec_ctrl & SECONDARY_EXEC_DESC;
> > }
> >
> > static inline bool cpu_has_vmx_rdtscp(void)
> > @@ -376,9 +376,9 @@ static inline bool cpu_has_vmx_invvpid_global(void)
> >
> > static inline bool cpu_has_vmx_intel_pt(void)
> > {
> > - return (vmcs_config.misc & VMX_MISC_INTEL_PT) &&
> > - (vmcs_config.cpu_based_2nd_exec_ctrl & SECONDARY_EXEC_PT_USE_GPA) &&
> > - (vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_IA32_RTIT_CTL);
> > + return vmcs_config.misc & VMX_MISC_INTEL_PT &&
> > + vmcs_config.cpu_based_2nd_exec_ctrl & SECONDARY_EXEC_PT_USE_GPA &&
> > + vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_IA32_RTIT_CTL;
> > }
>
> Removing the parentheses could significantly reduce code readability here.
+1.
For cases like cpu_has_load_cet_ctrl() where it's a single statement, I'm 100%
in favor of dropping the parentheses because they're pure noise. E.g. putting
them in the return statement is kinda like doing this:
if ((vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_CET_STATE))
But for code where there are multiple checks, IMO it's totally fine to use
parentheses, and probably even encourage.
Can you send a v2 to just clean up cpu_has_load_cet_ctrl()? Ah, and the changelog
will need to be different, because there's no &&, which is another argument for
treating "return x & y;" differently.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2026-03-05 23:54 [PATCH v1] KVM: VMX: Remove unnecessary parentheses Xin Li (Intel)
2026-03-06 6:17 ` BillXiang
2026-03-06 16:24 ` Sean Christopherson
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