linux-kernel - Re: [PATCH v5 15/19] KVM: Provide common implementation for generic dirty log functions

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Message-ID: <20200206212431.GF700495@xz-x1>
Date:   Thu, 6 Feb 2020 16:24:31 -0500
From:   Peter Xu <peterx@...hat.com>
To:     Sean Christopherson <sean.j.christopherson@...el.com>
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Paul Mackerras <paulus@...abs.org>,
        Christian Borntraeger <borntraeger@...ibm.com>,
        Janosch Frank <frankja@...ux.ibm.com>,
        David Hildenbrand <david@...hat.com>,
        Cornelia Huck <cohuck@...hat.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, Marc Zyngier <maz@...nel.org>,
        James Morse <james.morse@....com>,
        Julien Thierry <julien.thierry.kdev@...il.com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        linux-mips@...r.kernel.org, kvm@...r.kernel.org,
        kvm-ppc@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        kvmarm@...ts.cs.columbia.edu, linux-kernel@...r.kernel.org,
        Christoffer Dall <christoffer.dall@....com>,
        Philippe Mathieu-Daudé <f4bug@...at.org>
Subject: Re: [PATCH v5 15/19] KVM: Provide common implementation for generic
 dirty log functions

On Tue, Jan 21, 2020 at 02:31:53PM -0800, Sean Christopherson wrote:

[...]

> @@ -1333,6 +1369,7 @@ int kvm_clear_dirty_log_protect(struct kvm *kvm,
>  	unsigned long i, n;
>  	unsigned long *dirty_bitmap;
>  	unsigned long *dirty_bitmap_buffer;
> +	bool flush;
>  
>  	as_id = log->slot >> 16;
>  	id = (u16)log->slot;
> @@ -1356,7 +1393,9 @@ int kvm_clear_dirty_log_protect(struct kvm *kvm,
>  	    (log->num_pages < memslot->npages - log->first_page && (log->num_pages & 63)))
>  	    return -EINVAL;
>  
> -	*flush = false;
> +	kvm_arch_sync_dirty_log(kvm, memslot);

Do we need this even for clear dirty log?

> +
> +	flush = false;
>  	dirty_bitmap_buffer = kvm_second_dirty_bitmap(memslot);
>  	if (copy_from_user(dirty_bitmap_buffer, log->dirty_bitmap, n))
>  		return -EFAULT;

-- 
Peter Xu