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[142.68.128.5]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6cb9359c013sm15335776d6.18.2024.10.04.05.43.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 04 Oct 2024 05:43:43 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.95) (envelope-from ) id 1swhep-00CeVI-0I; Fri, 04 Oct 2024 09:43:43 -0300 Date: Fri, 4 Oct 2024 09:43:43 -0300 From: Jason Gunthorpe To: Yang Shi Cc: Nicolin Chen , james.morse@arm.com, will@kernel.org, robin.murphy@arm.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [v2 PATCH] iommu/arm-smmu-v3: Fix L1 stream table index calculation for 32-bit sid size Message-ID: <20241004124343.GE2456194@ziepe.ca> References: <20241002175514.1165299-1-yang@os.amperecomputing.com> <1c9767e1-4d05-4650-bc14-65a18fc63cc2@os.amperecomputing.com> <20241002194004.GT1369530@ziepe.ca> <20241003111603.GU1369530@ziepe.ca> <43c2227a-71c9-4cbf-bfec-5a2fbf698f27@os.amperecomputing.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <43c2227a-71c9-4cbf-bfec-5a2fbf698f27@os.amperecomputing.com> On Thu, Oct 03, 2024 at 08:31:23AM -0700, Yang Shi wrote: > If I understand correctly, the check is mainly used to avoid the u64 -> u32 > overflow. This check guarantee no overflow. If some crazy hardware really > requests that large memory, the allocation will fail. Sure, the kalloc will print a warn on anyhow if it is too big Jason