linux-kernel - [PATCH] KVM: x86: Remove duplicated calls of reverse_cpuid

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Message-Id: <20230221032156.791-1-binbin.wu@linux.intel.com>
Date:   Tue, 21 Feb 2023 11:21:56 +0800
From:   Binbin Wu <binbin.wu@...ux.intel.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     seanjc@...gle.com, pbonzini@...hat.com,
        Binbin Wu <binbin.wu@...ux.intel.com>
Subject: [PATCH] KVM: x86: Remove duplicated calls of reverse_cpuid_check()

Remove duplicated calls of reverse_cpuid_check() in __kvm_cpu_cap_mask()
and kvm_cpu_cap_{clear, set, get}().

reverse_cpuid_check() is directly called by:
 - feature_bit() / __feature_bit()
 - x86_feature_cpuid()
 - kvm_cpu_cap_{clear, set, get}()
 - __kvm_cpu_cap_mask()
Also __kvm_cpu_cap_mask() calls x86_feature_cpuid(),
and kvm_cpu_cap_{clear, set, get}() calls __feature_bit().
It makes the direct call of reverse_cpuid_check() duplicated.

For functions call reverse_cpuid_check() twice indirectly (e.g. cpuid_entry_get()
calls both __feature_bit() and x86_feature_cpuid()), keep them as they are.

Signed-off-by: Binbin Wu <binbin.wu@...ux.intel.com>
---
 arch/x86/kvm/cpuid.c | 2 --
 arch/x86/kvm/cpuid.h | 3 ---
 2 files changed, 5 deletions(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 8f8edeaf8177..f4089d7a7c4c 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -545,8 +545,6 @@ static __always_inline void __kvm_cpu_cap_mask(unsigned int leaf)
 	const struct cpuid_reg cpuid = x86_feature_cpuid(leaf * 32);
 	struct kvm_cpuid_entry2 entry;
 
-	reverse_cpuid_check(leaf);
-
 	cpuid_count(cpuid.function, cpuid.index,
 		    &entry.eax, &entry.ebx, &entry.ecx, &entry.edx);
 
diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h
index b1658c0de847..d781372a01e8 100644
--- a/arch/x86/kvm/cpuid.h
+++ b/arch/x86/kvm/cpuid.h
@@ -192,7 +192,6 @@ static __always_inline void kvm_cpu_cap_clear(unsigned int x86_feature)
 {
 	unsigned int x86_leaf = __feature_leaf(x86_feature);
 
-	reverse_cpuid_check(x86_leaf);
 	kvm_cpu_caps[x86_leaf] &= ~__feature_bit(x86_feature);
 }
 
@@ -200,7 +199,6 @@ static __always_inline void kvm_cpu_cap_set(unsigned int x86_feature)
 {
 	unsigned int x86_leaf = __feature_leaf(x86_feature);
 
-	reverse_cpuid_check(x86_leaf);
 	kvm_cpu_caps[x86_leaf] |= __feature_bit(x86_feature);
 }
 
@@ -208,7 +206,6 @@ static __always_inline u32 kvm_cpu_cap_get(unsigned int x86_feature)
 {
 	unsigned int x86_leaf = __feature_leaf(x86_feature);
 
-	reverse_cpuid_check(x86_leaf);
 	return kvm_cpu_caps[x86_leaf] & __feature_bit(x86_feature);
 }
 

base-commit: e73ba25fdc241c06ab48a1f708a30305d6036e66
-- 
2.25.1