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Peter Anvin" , Ingo Molnar , Jim Mattson , Joerg Roedel , Paolo Bonzini , Sean Christopherson , Thomas Gleixner , Vitaly Kuznetsov , Wanpeng Li , kvm@vger.kernel.org, x86@kernel.org Subject: Re: [PATCH 11/22] KVM: x86: hyper-v: replace bitmap_weight() with hweight64() Message-ID: <20220522145357.GA244394@roeck-us.net> References: <20220510154750.212913-1-yury.norov@gmail.com> <20220510154750.212913-12-yury.norov@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220510154750.212913-12-yury.norov@gmail.com> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Tue, May 10, 2022 at 08:47:39AM -0700, Yury Norov wrote: > kvm_hv_flush_tlb() applies bitmap API to a u64 variable valid_bank_mask. > Since valid_bank_mask has a fixed size, we can use hweight64() and avoid > excessive bloating. In kvm_hv_send_ipi(), valid_bank_mask is unsigned long, not u64. This results in: arch/x86/kvm/hyperv.c: In function 'kvm_hv_send_ipi': include/asm-generic/bitops/const_hweight.h:21:76: error: right shift count >= width of type on all 32-bit builds. Guenter > > CC: Borislav Petkov > CC: Dave Hansen > CC: H. Peter Anvin > CC: Ingo Molnar > CC: Jim Mattson > CC: Joerg Roedel > CC: Paolo Bonzini > CC: Sean Christopherson > CC: Thomas Gleixner > CC: Vitaly Kuznetsov > CC: Wanpeng Li > CC: kvm@vger.kernel.org > CC: linux-kernel@vger.kernel.org > CC: x86@kernel.org > Signed-off-by: Yury Norov > --- > arch/x86/kvm/hyperv.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c > index 41585f0edf1e..b652b856df2b 100644 > --- a/arch/x86/kvm/hyperv.c > +++ b/arch/x86/kvm/hyperv.c > @@ -1855,7 +1855,7 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc) > all_cpus = flush_ex.hv_vp_set.format != > HV_GENERIC_SET_SPARSE_4K; > > - if (hc->var_cnt != bitmap_weight((unsigned long *)&valid_bank_mask, 64)) > + if (hc->var_cnt != hweight64(valid_bank_mask)) > return HV_STATUS_INVALID_HYPERCALL_INPUT; > > if (all_cpus) > @@ -1956,7 +1956,7 @@ static u64 kvm_hv_send_ipi(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc) > valid_bank_mask = send_ipi_ex.vp_set.valid_bank_mask; > all_cpus = send_ipi_ex.vp_set.format == HV_GENERIC_SET_ALL; > > - if (hc->var_cnt != bitmap_weight(&valid_bank_mask, 64)) > + if (hc->var_cnt != hweight64(valid_bank_mask)) > return HV_STATUS_INVALID_HYPERCALL_INPUT; > > if (all_cpus) > -- > 2.32.0 >