linux-kernel - Re: [PATCH 19/22] kvm: mmu: Support write protection for nesting in tdp MMU

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Message-ID: <20200930180620.GI32672@linux.intel.com>
Date:   Wed, 30 Sep 2020 11:06:20 -0700
From:   Sean Christopherson <sean.j.christopherson@...el.com>
To:     Ben Gardon <bgardon@...gle.com>
Cc:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        Cannon Matthews <cannonmatthews@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Peter Xu <peterx@...hat.com>, Peter Shier <pshier@...gle.com>,
        Peter Feiner <pfeiner@...gle.com>,
        Junaid Shahid <junaids@...gle.com>,
        Jim Mattson <jmattson@...gle.com>,
        Yulei Zhang <yulei.kernel@...il.com>,
        Wanpeng Li <kernellwp@...il.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Xiao Guangrong <xiaoguangrong.eric@...il.com>
Subject: Re: [PATCH 19/22] kvm: mmu: Support write protection for nesting in
 tdp MMU

On Fri, Sep 25, 2020 at 02:22:59PM -0700, Ben Gardon wrote:
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index 12892fc4f146d..e6f5093ba8f6f 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -1667,6 +1667,11 @@ bool kvm_mmu_slot_gfn_write_protect(struct kvm *kvm,
>  		write_protected |= __rmap_write_protect(kvm, rmap_head, true);
>  	}
>  
> +	if (kvm->arch.tdp_mmu_enabled)
> +		write_protected =
> +			kvm_tdp_mmu_write_protect_gfn(kvm, slot, gfn) ||
> +			write_protected;

Similar to other comments, this can use |=.

> +
>  	return write_protected;
>  }