Messages in this thread Patch in this message | | | Date | Fri, 29 Apr 2022 01:04:07 +0000 | Subject | [PATCH 01/10] KVM: Do not zero initialize 'pfn' in hva_to_pfn() | From | Sean Christopherson <> |
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Drop the unnecessary initialization of the local 'pfn' variable in hva_to_pfn(). First and foremost, '0' is not an invalid pfn, it's a perfectly valid pfn on most architectures. I.e. if hva_to_pfn() were to return an "uninitializd" pfn, it would actually be interpeted as a legal pfn by most callers.
Second, hva_to_pfn() can't return an uninitialized pfn as hva_to_pfn() explicitly sets pfn to an error value (or returns an error value directly) if a helper returns failure, and all helpers set the pfn on success.
Note, the zeroing of 'pfn' was introduced by commit 2fc843117d64 ("KVM: reorganize hva_to_pfn"), and was unnecessary and misguided paranoia even then.
Signed-off-by: Sean Christopherson <seanjc@google.com> --- virt/kvm/kvm_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 0848430f36c6..04ed4334473c 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2567,7 +2567,7 @@ kvm_pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool *async, bool write_fault, bool *writable) { struct vm_area_struct *vma; - kvm_pfn_t pfn = 0; + kvm_pfn_t pfn; int npages, r; /* we can do it either atomically or asynchronously, not both */ -- 2.36.0.464.gb9c8b46e94-goog
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