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d="scan'208";a="58888019" Received: from fmviesa009.fm.intel.com ([10.60.135.149]) by orvoesa104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Apr 2025 23:15:50 -0700 X-CSE-ConnectionGUID: hL/PpME8Qz2SjoN3Tm+rlQ== X-CSE-MsgGUID: k0NPyEOXRYmpI9s1uLRPIQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.15,248,1739865600"; d="scan'208";a="134687731" Received: from allen-sbox.sh.intel.com (HELO [10.239.159.30]) ([10.239.159.30]) by fmviesa009-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Apr 2025 23:15:44 -0700 Message-ID: <8af1a3c7-d5e6-46ca-a946-5d349e843ed6@linux.intel.com> Date: Tue, 29 Apr 2025 14:11:32 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 10/22] iommufd/viommmu: Add IOMMUFD_CMD_VCMDQ_ALLOC ioctl To: Nicolin Chen Cc: jgg@nvidia.com, kevin.tian@intel.com, corbet@lwn.net, will@kernel.org, bagasdotme@gmail.com, robin.murphy@arm.com, joro@8bytes.org, thierry.reding@gmail.com, vdumpa@nvidia.com, jonathanh@nvidia.com, shuah@kernel.org, jsnitsel@redhat.com, nathan@kernel.org, peterz@infradead.org, yi.l.liu@intel.com, mshavit@google.com, praan@google.com, zhangzekun11@huawei.com, iommu@lists.linux.dev, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-tegra@vger.kernel.org, linux-kselftest@vger.kernel.org, patches@lists.linux.dev, mochs@nvidia.com, alok.a.tiwari@oracle.com, vasant.hegde@amd.com References: <094992b874190ffdcf6012104b419c8649b5e4b4.1745646960.git.nicolinc@nvidia.com> Content-Language: en-US From: Baolu Lu In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250429_071559_494289_034BFA9B X-CRM114-Status: GOOD ( 11.29 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 4/29/25 02:58, Nicolin Chen wrote: > On Mon, Apr 28, 2025 at 09:32:04AM +0800, Baolu Lu wrote: >> On 4/26/25 13:58, Nicolin Chen wrote: >>> +int iommufd_vcmdq_alloc_ioctl(struct iommufd_ucmd *ucmd) >>> +{ >>> + struct iommu_vcmdq_alloc *cmd = ucmd->cmd; >>> + struct iommufd_viommu *viommu; >>> + struct iommufd_vcmdq *vcmdq; >>> + struct page **pages; >>> + int max_npages, i; >>> + dma_addr_t end; >>> + int rc; >>> + >>> + if (cmd->flags || cmd->type == IOMMU_VCMDQ_TYPE_DEFAULT) >> I don't follow the check of 'cmd->type == IOMMU_VCMDQ_TYPE_DEFAULT' >> here. My understanding is that it states that "other values of type are >> not supported". If so, shouldn't it be, >> >> if (cmd->flags || cmd->type != IOMMU_VCMDQ_TYPE_DEFAULT) >> >> ? > No. Only other (new) types will be supported. We have this: > "* @IOMMU_VCMDQ_TYPE_DEFAULT: Reserved for future use" > which means driver should define a new type. > > We have the same DEFAULT type in vIOMMU/vEVENTQ allocators by > the way. Okay, thanks for the explanation. The iommu driver's callback will return a failure if the type is not supported. Then it's fine. Thanks, baolu