Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.31 as permitted sender) client-ip=23.128.96.31;
Message-ID: <7d07bea9-02a5-7113-8cc1-f7aed073cf96@linux.intel.com>
Date:   Wed, 20 Sep 2023 13:05:15 +0800
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.15.1
Cc:     baolu.lu@linux.intel.com, cohuck@redhat.com, eric.auger@redhat.com,
        nicolinc@nvidia.com, kvm@vger.kernel.org, mjrosato@linux.ibm.com,
        chao.p.peng@linux.intel.com, yi.y.sun@linux.intel.com,
        peterx@redhat.com, jasowang@redhat.com,
        shameerali.kolothum.thodi@huawei.com, lulu@redhat.com,
        suravee.suthikulpanit@amd.com, iommu@lists.linux.dev,
        linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
        zhenzhong.duan@intel.com, joao.m.martins@oracle.com
Subject: Re: [PATCH 4/6] iommufd/hw_pagetable: Support allocating nested
 parent domain
To:     Yi Liu <yi.l.liu@intel.com>, joro@8bytes.org,
        alex.williamson@redhat.com, jgg@nvidia.com, kevin.tian@intel.com,
        robin.murphy@arm.com
References: <20230919092523.39286-1-yi.l.liu@intel.com>
 <20230919092523.39286-5-yi.l.liu@intel.com>
Content-Language: en-US
From:   Baolu Lu <baolu.lu@linux.intel.com>
In-Reply-To: <20230919092523.39286-5-yi.l.liu@intel.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 9/19/23 5:25 PM, Yi Liu wrote:
> This extends IOMMU_HWPT_ALLOC to allocate domains used as parent (stage-2)
> in nested translation.
> 
> Signed-off-by: Yi Liu <yi.l.liu@intel.com>
> ---
>   drivers/iommu/iommufd/hw_pagetable.c | 5 ++++-
>   1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c
> index 5be7a31cbd9c..26a8a818ffa3 100644
> --- a/drivers/iommu/iommufd/hw_pagetable.c
> +++ b/drivers/iommu/iommufd/hw_pagetable.c
> @@ -83,6 +83,9 @@ iommufd_hw_pagetable_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas,
>   
>   	lockdep_assert_held(&ioas->mutex);
>   
> +	if ((flags & IOMMU_HWPT_ALLOC_NEST_PARENT) && !ops->domain_alloc_user)
> +		return ERR_PTR(-EOPNOTSUPP);
> +
>   	hwpt = iommufd_object_alloc(ictx, hwpt, IOMMUFD_OBJ_HW_PAGETABLE);
>   	if (IS_ERR(hwpt))
>   		return hwpt;
> @@ -154,7 +157,7 @@ int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd)
>   	struct iommufd_ioas *ioas;
>   	int rc;
>   
> -	if (cmd->flags || cmd->__reserved)
> +	if (cmd->flags & ~IOMMU_HWPT_ALLOC_NEST_PARENT || cmd->__reserved)
>   		return -EOPNOTSUPP;

Need a parenthesis here, otherwise the compiler will interpret it as a
different condition.

	if ((cmd->flags & ~IOMMU_HWPT_ALLOC_NEST_PARENT) || cmd->__reserved)
		return -EOPNOTSUPP;

Best regards,
baolu