linux-kernel - Re: [PATCH v2] svm/avic: Fix invalidate logical APIC id entry

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Date:   Mon, 8 Apr 2019 14:16:23 +0000
From:   "Suthikulpanit, Suravee" <Suravee.Suthikulpanit@....com>
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "kvm@...r.kernel.org" <kvm@...r.kernel.org>
CC:     "joro@...tes.org" <joro@...tes.org>,
        "pbonzini@...hat.com" <pbonzini@...hat.com>,
        "rkrcmar@...hat.com" <rkrcmar@...hat.com>,
        "vkuznets@...hat.com" <vkuznets@...hat.com>
Subject: Re: [PATCH v2] svm/avic: Fix invalidate logical APIC id entry

Ping

On 3/26/19 10:57 AM, Suthikulpanit, Suravee wrote:
> Only clear the valid bit when invalidate logical APIC id entry.
> The current logic clear the valid bit, but also set the rest of
> the bits (including reserved bits) to 1.
> 
> Fixes: 98d90582be2e ('svm: Fix AVIC DFR and LDR handling')
> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@....com>
> ---
>   arch/x86/kvm/svm.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index 7a4ce1a22ca0..8a123bd0f591 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -270,6 +270,7 @@ struct amd_svm_iommu_ir {
>   };
>   
>   #define AVIC_LOGICAL_ID_ENTRY_GUEST_PHYSICAL_ID_MASK	(0xFF)
> +#define AVIC_LOGICAL_ID_ENTRY_VALID_BIT			31
>   #define AVIC_LOGICAL_ID_ENTRY_VALID_MASK		(1 << 31)
>   
>   #define AVIC_PHYSICAL_ID_ENTRY_HOST_PHYSICAL_ID_MASK	(0xFFULL)
> @@ -4640,7 +4641,7 @@ static void avic_invalidate_logical_id_entry(struct kvm_vcpu *vcpu)
>   	u32 *entry = avic_get_logical_id_entry(vcpu, svm->ldr_reg, flat);
>   
>   	if (entry)
> -		WRITE_ONCE(*entry, (u32) ~AVIC_LOGICAL_ID_ENTRY_VALID_MASK);
> +		clear_bit(AVIC_LOGICAL_ID_ENTRY_VALID_BIT, (unsigned long *)entry);
>   }
>   
>   static int avic_handle_ldr_update(struct kvm_vcpu *vcpu)
>