Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH v3] KVM: Extend MAX_IRQ_ROUTES to 4096 for all archs
To:     Wanpeng Li <kernellwp@gmail.com>, linux-kernel@vger.kernel.org,
        kvm@vger.kernel.org
Cc:     Paolo Bonzini <pbonzini@redhat.com>,
        =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= <rkrcmar@redhat.com>,
        Cornelia Huck <cohuck@redhat.com>,
        Tonny Lu <tonnylu@tencent.com>
References: <1524790503-3267-1-git-send-email-wanpengli@tencent.com>
From:   Christian Borntraeger <borntraeger@de.ibm.com>
Openpgp: preference=signencrypt
Date:   Fri, 27 Apr 2018 08:44:11 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101
 Thunderbird/52.6.0
MIME-Version: 1.0
In-Reply-To: <1524790503-3267-1-git-send-email-wanpengli@tencent.com>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Message-Id: <dc7e1da8-96ca-b40d-cac8-96243de389e9@de.ibm.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk


On 04/27/2018 02:55 AM, Wanpeng Li wrote:
> From: Wanpeng Li <wanpengli@tencent.com>
> 
> Our virtual machines make use of device assignment by configuring
> 12 NVMe disks for high I/O performance. Each NVMe device has 129 
> MSI-X Table entries:
> Capabilities: [50] MSI-X: Enable+ Count=129 Masked-Vector table: BAR=0 offset=00002000
> The windows virtual machines fail to boot since they will map the number of 
> MSI-table entries that the NVMe hardware reported to the bus to msi routing 
> table, this will exceed the 1024. This patch extends MAX_IRQ_ROUTES to 4096
> for all archs, in the future this might be extended again if needed.
> 
> Reviewed-by: Cornelia Huck <cohuck@redhat.com>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Radim Krčmář <rkrcmar@redhat.com>
> Cc: Cornelia Huck <cohuck@redhat.com>
> Cc: Christian Borntraeger <borntraeger@de.ibm.com>
> Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
> Signed-off-by: Tonny Lu <tonnylu@tencent.com>

Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>

> ---
> v2 -> v3:
>  * update comments in the code
> v1 -> v2:
>  * extend MAX_IRQ_ROUTES to 4096 for all archs 
> 
>  include/linux/kvm_host.h | 8 +-------
>  1 file changed, 1 insertion(+), 7 deletions(-)
> 
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index 6930c63..6d6e79c 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -1045,13 +1045,7 @@ static inline int mmu_notifier_retry(struct kvm *kvm, unsigned long mmu_seq)
>  
>  #ifdef CONFIG_HAVE_KVM_IRQ_ROUTING
>  
> -#ifdef CONFIG_S390
> -#define KVM_MAX_IRQ_ROUTES 4096 //FIXME: we can have more than that...
> -#elif defined(CONFIG_ARM64)
> -#define KVM_MAX_IRQ_ROUTES 4096
> -#else
> -#define KVM_MAX_IRQ_ROUTES 1024
> -#endif
> +#define KVM_MAX_IRQ_ROUTES 4096 /* might need extension/rework in the future */
>  
>  bool kvm_arch_can_set_irq_routing(struct kvm *kvm);
>  int kvm_set_irq_routing(struct kvm *kvm,
>