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KVM: x86: Use boolean return value for is_{pae,pse,paging}() 

Convert is_{pae,pse,paging}() to use kvm_is_cr{0,4}_bit_set() and return
bools.  Returning an "int" requires not one, but two implicit casts, first
from "unsigned long" to "int", and then again to a "bool".  Both casts are
more than a bit dangerous; the ulong=>int casts would drop a bit on 64-bit
kernels _if_ the bits in question weren't in the lower 32 bits, and the
int=>bool cast can result in false negatives/positives, e.g. see commit
0c928ff26b ("KVM: SVM: Fix benign "bool vs. int" comparison in
svm_set_cr0()").

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Binbin Wu <binbin.wu@linux.intel.com>
Link: https://lore.kernel.org/r/20230322045824.22970-3-binbin.wu@linux.intel.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Binbin Wu 2023-03-22 12:58:22 +08:00 committed by Sean Christopherson
parent 607475cfa0
commit bede6eb4db
2 changed files with 7 additions and 7 deletions
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2
arch/x86/kvm/svm/svm.c
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@ -1802,7 +1802,7 @@ void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
if (!npt_enabled) {
hcr0 |= X86_CR0_PG | X86_CR0_WP;
if (old_paging != !!is_paging(vcpu))
if (old_paging != is_paging(vcpu))
svm_set_cr4(vcpu, kvm_read_cr4(vcpu));
}

12
arch/x86/kvm/x86.h
View File

@ -171,19 +171,19 @@ static inline bool mmu_is_nested(struct kvm_vcpu *vcpu)
return vcpu->arch.walk_mmu == &vcpu->arch.nested_mmu;
}
static inline int is_pae(struct kvm_vcpu *vcpu)
static inline bool is_pae(struct kvm_vcpu *vcpu)
{
return kvm_read_cr4_bits(vcpu, X86_CR4_PAE);
return kvm_is_cr4_bit_set(vcpu, X86_CR4_PAE);
}
static inline int is_pse(struct kvm_vcpu *vcpu)
static inline bool is_pse(struct kvm_vcpu *vcpu)
{
return kvm_read_cr4_bits(vcpu, X86_CR4_PSE);
return kvm_is_cr4_bit_set(vcpu, X86_CR4_PSE);
}
static inline int is_paging(struct kvm_vcpu *vcpu)
static inline bool is_paging(struct kvm_vcpu *vcpu)
{
return likely(kvm_read_cr0_bits(vcpu, X86_CR0_PG));
return likely(kvm_is_cr0_bit_set(vcpu, X86_CR0_PG));
}
static inline bool is_pae_paging(struct kvm_vcpu *vcpu)