linux-kernel - Re: [PATCH] KVM: ARM64: fix phy counter access failure in guest.

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Message-ID: <20170609084134.GC6378@cbox>
Date:   Fri, 9 Jun 2017 10:41:34 +0200
From:   Christoffer Dall <cdall@...aro.org>
To:     Hu Huajun <huhuajun@...wei.com>
Cc:     christoffer.dall@...aro.org, marc.zyngier@....com,
        rkrcmar@...hat.com, linux-arm-kernel@...ts.infradead.org,
        kvmarm@...ts.cs.columbia.edu, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, songwenjun@...wei.com,
        gengdongjiu@...wei.com
Subject: Re: [PATCH] KVM: ARM64: fix phy counter access failure in guest.

Hi,

On Sat, Jun 10, 2017 at 12:22:20AM +0800, Hu Huajun wrote:
> When reading the cntpct_el0 in guest with VHE (Virtual Host Extension)
> enabled in host, the "Unsupported guest sys_reg access" error reported.
> The reason is cnthctl_el2.EL1PCTEN is not enabled, which is expected
> to be done in kvm_timer_init_vhe(). The problem is kvm_timer_init_vhe
> is called by cpu_init_hyp_mode, and which is called when VHE is disabled.
> This patch calls kvm_timer_init_vhe() to enable cnthctl_el2.EL1PCTEN
> in cpu_hyp_reinit().
> 
> Signed-off-by: Hu Huajun <huhuajun@...wei.com>
> ---
>  virt/kvm/arm/arm.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
> index 3417e18..b703741 100644
> --- a/virt/kvm/arm/arm.c
> +++ b/virt/kvm/arm/arm.c
> @@ -1137,6 +1137,7 @@ static void cpu_hyp_reinit(void)
>  		 * event was cancelled before the CPU was reset.
>  		 */
>  		__cpu_init_stage2();
> +		kvm_timer_init_vhe();
>  	} else {
>  		cpu_init_hyp_mode(NULL);
>  	}
> -- 
> 2.10.1
> 

Could you rework this patch to remove the incorrect call to
kvm_timer_init_vhe() from cpu_init_hyp_mode() as well?

Thanks,
-Christoffer