linux-kernel - Re: [PATCH v3 07/34] x86/hyperv: Introduce HV_MAX_SPARSE_VCPU_BANKS/HV_VCPUS_PER_SPARSE

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Message-ID: <87ee1a3bnj.fsf@redhat.com>
Date:   Tue, 03 May 2022 16:59:12 +0200
From:   Vitaly Kuznetsov <vkuznets@...hat.com>
To:     Christophe JAILLET <christophe.jaillet@...adoo.fr>
Cc:     Sean Christopherson <seanjc@...gle.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Michael Kelley <mikelley@...rosoft.com>,
        Siddharth Chandrasekaran <sidcha@...zon.de>,
        linux-hyperv@...r.kernel.org, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org, Paolo Bonzini <pbonzini@...hat.com>
Subject: Re: [PATCH v3 07/34] x86/hyperv: Introduce
 HV_MAX_SPARSE_VCPU_BANKS/HV_VCPUS_PER_SPARSE_BANK constants

Christophe JAILLET <christophe.jaillet@...adoo.fr> writes:

> Le 14/04/2022 à 15:19, Vitaly Kuznetsov a écrit :

...

>> @@ -224,7 +225,7 @@ static inline int __cpumask_to_vpset(struct hv_vpset *vpset,
>>   	 * structs are not cleared between calls, we risk flushing unneeded
>>   	 * vCPUs otherwise.
>>   	 */
>> -	for (vcpu_bank = 0; vcpu_bank <= hv_max_vp_index / 64; vcpu_bank++)
>> +	for (vcpu_bank = 0; vcpu_bank <= max_vcpu_bank; vcpu_bank++)
>>   		vpset->bank_contents[vcpu_bank] = 0;
>
> and here:
> 	bitmap_clear(vpset->bank_contents, 0, hv_max_vp_index);
> or maybe even if it is safe to do so:
> 	bitmap_zero(vpset->bank_contents, hv_max_vp_index);

Both your suggestions (including the one for "PATCH v3 07/34]") look
good to me, thanks! I'd however want to send them to linux-hyperv@
separately when this series lands through KVM tree just to not make this
heavy series even heavier.

-- 
Vitaly