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From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
To: Balbir Singh <bsingharora@gmail.com>, Paul Mackerras <paulus@ozlabs.org>
Cc: kvm@vger.kernel.org, kvm-ppc@vger.kernel.org
Subject: Re: [RFC][PATCH] Remove duplicate setting of the B field in tlbie
Date: Wed, 14 Sep 2016 10:25:09 +0530	[thread overview]
Message-ID: <8737l3jd1u.fsf@linux.vnet.ibm.com> (raw)
In-Reply-To: <4bbac7fd-ed99-a5c4-1bda-94345b88f18c@gmail.com>

Balbir Singh <bsingharora@gmail.com> writes:

> Remove duplicate setting of the the "B" field when doing a tlbie(l).
> In compute_tlbie_rb(), the "B" field is set again just before
> returning the rb value to be used for tlbie(l).
>
> Signed-off-by: Balbir Singh <bsingharora@gmail.com>
> ---
> Quickly boot tested a VM with these changes in kvm with 64k
> as the page size for the guest.
>
>  arch/powerpc/include/asm/kvm_book3s_64.h | 1 -
>  1 file changed, 1 deletion(-)
>
> diff --git a/arch/powerpc/include/asm/kvm_book3s_64.h b/arch/powerpc/include/asm/kvm_book3s_64.h
> index 88d17b4..63b6900 100644
> --- a/arch/powerpc/include/asm/kvm_book3s_64.h
> +++ b/arch/powerpc/include/asm/kvm_book3s_64.h
> @@ -159,7 +159,6 @@ static inline unsigned long compute_tlbie_rb(unsigned long v, unsigned long r,
>  	/* This covers 14..54 bits of va*/
>  	rb = (v & ~0x7fUL) << 16;		/* AVA field */
>
> -	rb |= (v >> HPTE_V_SSIZE_SHIFT) << 8;	/*  B field */
>  	/*
>  	 * AVA in v had cleared lower 23 bits. We need to derive
>  	 * that from pteg index

Can we keep this and remove the other. This is much easier to follow
than

	rb |= (v >> 54) & 0x300;		/* B field */

-aneesh


  reply	other threads:[~2016-09-14  4:55 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-13  7:45 [RFC][PATCH] Remove duplicate setting of the B field in tlbie Balbir Singh
2016-09-14  4:55 ` Aneesh Kumar K.V [this message]
2016-09-14  6:15   ` Balbir Singh

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