From 15e6a7e5324cc04a67891fc369ea834bbb7e7b42 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 22 Jan 2021 16:30:03 -0800 Subject: KVM: x86/mmu: Use boolean returns for (S)PTE accessors Return a 'bool' instead of an 'int' for various PTE accessors that are boolean in nature, e.g. is_shadow_present_pte(). Returning an int is goofy and potentially dangerous, e.g. if a flag being checked is moved into the upper 32 bits of a SPTE, then the compiler may silently squash the entire check since casting to an int is guaranteed to yield a return value of '0'. Opportunistically refactor is_last_spte() so that it naturally returns a bool value instead of letting it implicitly cast 0/1 to false/true. No functional change intended. Signed-off-by: Sean Christopherson Message-Id: <20210123003003.3137525-1-seanjc@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/mmu.h | 2 +- arch/x86/kvm/mmu/spte.h | 12 ++++-------- 2 files changed, 5 insertions(+), 9 deletions(-) (limited to 'arch/x86/kvm') diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h index 261be1d2032b..2bb42eee5d5d 100644 --- a/arch/x86/kvm/mmu.h +++ b/arch/x86/kvm/mmu.h @@ -152,7 +152,7 @@ static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, * * TODO: introduce APIs to split these two cases. */ -static inline int is_writable_pte(unsigned long pte) +static inline bool is_writable_pte(unsigned long pte) { return pte & PT_WRITABLE_MASK; } diff --git a/arch/x86/kvm/mmu/spte.h b/arch/x86/kvm/mmu/spte.h index 2b3a30bd38b0..398fd1bb13a7 100644 --- a/arch/x86/kvm/mmu/spte.h +++ b/arch/x86/kvm/mmu/spte.h @@ -185,23 +185,19 @@ static inline bool is_access_track_spte(u64 spte) return !spte_ad_enabled(spte) && (spte & shadow_acc_track_mask) == 0; } -static inline int is_shadow_present_pte(u64 pte) +static inline bool is_shadow_present_pte(u64 pte) { return (pte != 0) && !is_mmio_spte(pte); } -static inline int is_large_pte(u64 pte) +static inline bool is_large_pte(u64 pte) { return pte & PT_PAGE_SIZE_MASK; } -static inline int is_last_spte(u64 pte, int level) +static inline bool is_last_spte(u64 pte, int level) { - if (level == PG_LEVEL_4K) - return 1; - if (is_large_pte(pte)) - return 1; - return 0; + return (level == PG_LEVEL_4K) || is_large_pte(pte); } static inline bool is_executable_pte(u64 spte) -- cgit v1.2.3