From mboxrd@z Thu Jan  1 00:00:00 1970
From: Michael Ellerman <mpe@ellerman.id.au>
Subject: Re: [PATCH] KVM: PPC: powerpc: Add count cache flush parameters to
 kvmppc_get_cpu_char()
Date: Fri, 01 Mar 2019 17:52:51 +1100
Message-ID: <87bm2vjdbw.fsf@concordia.ellerman.id.au>
References: <20190301032516.29919-1-sjitindarsingh@gmail.com>
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Cc: linuxppc-dev@lists.ozlabs.org, paulus@samba.org,
 Suraj Jitindar Singh <sjitindarsingh@gmail.com>, kvm@vger.kernel.org
To: Suraj Jitindar Singh <sjitindarsingh@gmail.com>, kvm-ppc@vger.kernel.org
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Suraj Jitindar Singh <sjitindarsingh@gmail.com> writes:

> Add KVM_PPC_CPU_CHAR_BCCTR_FLUSH_ASSIST &
> KVM_PPC_CPU_BEHAV_FLUSH_COUNT_CACHE to the characteristics returned from
> the H_GET_CPU_CHARACTERISTICS H-CALL, as queried from either the
> hypervisor or the device tree.
>
> Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
> ---
>  arch/powerpc/include/uapi/asm/kvm.h |  2 ++
>  arch/powerpc/kvm/powerpc.c          | 18 ++++++++++++++----
>  2 files changed, 16 insertions(+), 4 deletions(-)
>
> diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
> index b90a7d154180..a99dcac91e50 100644
> --- a/arch/powerpc/kvm/powerpc.c
> +++ b/arch/powerpc/kvm/powerpc.c
> @@ -2251,12 +2253,16 @@ static int kvmppc_get_cpu_char(struct kvm_ppc_cpu_char *cp)
>  		if (have_fw_feat(fw_features, "enabled",
>  				 "fw-count-cache-disabled"))
>  			cp->character |= KVM_PPC_CPU_CHAR_COUNT_CACHE_DIS;
> +		if (have_fw_feat(fw_features, "enabled",
> +				 "fw-count-cache-flush-bcctr2,0,0"))

I don't think there's any reason KVM needs to be querying the device
tree directly, is there?

Can't it just use the security flags (security_features.h), that are
initialised by the powernv platform code based on the device tree.

I seem to remember we didn't do it that way originally just because we
didn't have time to get everything lined up.

cheers