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From:   Wanpeng Li <kernellwp@gmail.com>
Date:   Mon, 24 Aug 2020 09:25:01 +0800
Message-ID: <CANRm+Cx57G2mRLQ4=Kt+0f0K9Ls+vbfHdMb1No8hfyAb9xEpZQ@mail.gmail.com>
Subject: Re: [PATCH 1/2] KVM: LAPIC: Fix updating DFR missing apic map recalculation
To:     LKML <linux-kernel@vger.kernel.org>, kvm <kvm@vger.kernel.org>
Cc:     Paolo Bonzini <pbonzini@redhat.com>,
        Sean Christopherson <sean.j.christopherson@intel.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Joerg Roedel <joro@8bytes.org>
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Sender: linux-kernel-owner@vger.kernel.org
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ping, :)
On Wed, 19 Aug 2020 at 16:55, Wanpeng Li <kernellwp@gmail.com> wrote:
>
> From: Wanpeng Li <wanpengli@tencent.com>
>
> There is missing apic map recalculation after updating DFR, if it is
> INIT RESET, in x2apic mode, local apic is software enabled before.
> This patch fix it by introducing the function kvm_apic_set_dfr() to
> be called in INIT RESET handling path.
>
> Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
> ---
>  arch/x86/kvm/lapic.c | 15 ++++++++++-----
>  1 file changed, 10 insertions(+), 5 deletions(-)
>
> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> index 5ccbee7..248095a 100644
> --- a/arch/x86/kvm/lapic.c
> +++ b/arch/x86/kvm/lapic.c
> @@ -310,6 +310,12 @@ static inline void kvm_apic_set_ldr(struct kvm_lapic *apic, u32 id)
>         atomic_set_release(&apic->vcpu->kvm->arch.apic_map_dirty, DIRTY);
>  }
>
> +static inline void kvm_apic_set_dfr(struct kvm_lapic *apic, u32 val)
> +{
> +       kvm_lapic_set_reg(apic, APIC_DFR, val);
> +       atomic_set_release(&apic->vcpu->kvm->arch.apic_map_dirty, DIRTY);
> +}
> +
>  static inline u32 kvm_apic_calc_x2apic_ldr(u32 id)
>  {
>         return ((id >> 4) << 16) | (1 << (id & 0xf));
> @@ -1984,10 +1990,9 @@ int kvm_lapic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
>                 break;
>
>         case APIC_DFR:
> -               if (!apic_x2apic_mode(apic)) {
> -                       kvm_lapic_set_reg(apic, APIC_DFR, val | 0x0FFFFFFF);
> -                       atomic_set_release(&apic->vcpu->kvm->arch.apic_map_dirty, DIRTY);
> -               } else
> +               if (!apic_x2apic_mode(apic))
> +                       kvm_apic_set_dfr(apic, val | 0x0FFFFFFF);
> +               else
>                         ret = 1;
>                 break;
>
> @@ -2303,7 +2308,7 @@ void kvm_lapic_reset(struct kvm_vcpu *vcpu, bool init_event)
>                              SET_APIC_DELIVERY_MODE(0, APIC_MODE_EXTINT));
>         apic_manage_nmi_watchdog(apic, kvm_lapic_get_reg(apic, APIC_LVT0));
>
> -       kvm_lapic_set_reg(apic, APIC_DFR, 0xffffffffU);
> +       kvm_apic_set_dfr(apic, 0xffffffffU);
>         apic_set_spiv(apic, 0xff);
>         kvm_lapic_set_reg(apic, APIC_TASKPRI, 0);
>         if (!apic_x2apic_mode(apic))
> --
> 2.7.4
>