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[34.83.236.195]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2b9cae3b169sm113335475ad.63.2026.05.04.11.33.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 04 May 2026 11:33:10 -0700 (PDT) Date: Mon, 4 May 2026 18:33:06 +0000 From: Samiullah Khawaja To: David Matlack Cc: David Woodhouse , Lu Baolu , Joerg Roedel , Will Deacon , Jason Gunthorpe , Robin Murphy , Kevin Tian , Alex Williamson , Shuah Khan , iommu@lists.linux.dev, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Saeed Mahameed , Adithya Jayachandran , Parav Pandit , Leon Romanovsky , William Tu , Pratyush Yadav , Pasha Tatashin , Andrew Morton , Chris Li , Pranjal Shrivastava , Vipin Sharma , YiFei Zhu Subject: Re: [PATCH v2 03/16] iommu: Implement IOMMU domain preservation Message-ID: References: <20260427175633.1978233-1-skhawaja@google.com> <20260427175633.1978233-4-skhawaja@google.com> Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: On Fri, May 01, 2026 at 10:08:47PM +0000, David Matlack wrote: >On 2026-04-27 05:56 PM, Samiullah Khawaja wrote: >> Add IOMMU domain ops that can be implemented by the IOMMU drivers if >> they support IOMMU domain preservation across liveupdate. The new IOMMU >> domain preserve, unpreserve and restore APIs call these ops to perform >> respective live update operations. >> >> Signed-off-by: Samiullah Khawaja > >> +static int alloc_object_ser(struct iommu_array_hdr_ser **curr_array_ptr, u64 max_objs) >> +{ >> + struct iommu_array_hdr_ser *curr_array = *curr_array_ptr; >> + struct iommu_array_hdr_ser *next_array; >> + > >There's a trade-off being made in this function to leak deleted array >elements instead of trying to reuse them that warrants a comment. Are you referring to the "deleted" flag in the HDR of each object? Yes we don't look for deleted objects in linked-list of arrays and reuse them for simplicity. I will add a comment that says this. > >> + if (curr_array->nr_objects >= max_objs) { >> + next_array = kho_alloc_preserve(PAGE_SIZE); >> + if (IS_ERR(next_array)) >> + return PTR_ERR(next_array); >> + >> + curr_array->next_array_phys = virt_to_phys(next_array); >> + *curr_array_ptr = next_array; >> + curr_array = next_array; >> + } >> + >> + return curr_array->nr_objects++; >> +}