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Sampat" Cc: linux-mm@kvack.org, linux-coco@lists.linux.dev, x86@kernel.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, ardb@kernel.org, akpm@linux-foundation.org, osalvador@suse.de, thomas.lendacky@amd.com, michael.roth@amd.com References: <20260203174946.1198053-1-prsampat@amd.com> <20260203174946.1198053-2-prsampat@amd.com> <70be936e-e49d-4485-8d1e-416fdf8f40a4@amd.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 8C30D140008 X-Stat-Signature: we8hnc5o4d8fsfqx9qrcd48zuwe6etqw X-HE-Tag: 1770306499-434399 X-HE-Meta: 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 YPXV1UAL j2OpxpxN6l348NbPzyPUBZA64l31nz83qgMfJLTG2tWw802qdSlb6iREfp021MVyCPjfgKtW27L/UxxoQo/SxqyxEiPl4Fb3GkU7HFv9PkdIh2aYwk9fJ/ViwGYn9EbrQlrobtcGIwDXKb0iY/lbfSHUw9ne+5/SBVUYiiY5GgIAXcSSsROsXW80q10MSF9LuEjOqDqvCbwPluX6g+KabNT2ZuDoal6pagtTA2/cjoCuQt/6cqGLjsRWmk5a8jCip/vRtc5K18ns0n8y6Wh4XfUw3DBAR3u8WrIZMwNA5gnVMsaXhZe3FV5bg4w== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2/5/26 11:48, Kiryl Shutsemau wrote: > On Wed, Feb 04, 2026 at 09:50:09PM -0600, Pratik R. Sampat wrote: >> >> >> On 2/4/26 2:00 PM, David Hildenbrand (arm) wrote: >>> >>> I really hate that accepting (and un-accepting) hotplugged memory is different to accepting ordinary boot memory. >>> >>> Is there really no way we can get a reasonable implementation where we just call a generic accept_memory() and it will know what to do? >>> >> >> Sure, that shouldn't be impossible. >> >> The only reason I initially kept them separate is because we accept and update >> the bitmap unconditionally. This mainly applies to cold-plugged memory since >> their bitmap state after remove shouldn't matter. However, as we are now >> correctly setting the bits in the hot-remove path we should be fine accepting >> from the for_each_set_bitrange_from() logic within accept_memory(), I think. >> >> Something like so? >> >> diff --git a/drivers/firmware/efi/unaccepted_memory.c b/drivers/firmware/efi/unaccepted_memory.c >> index d11e7836200a..e56adfd382f8 100644 >> --- a/drivers/firmware/efi/unaccepted_memory.c >> +++ b/drivers/firmware/efi/unaccepted_memory.c >> @@ -36,6 +36,7 @@ void accept_memory(phys_addr_t start, unsigned long size) >> unsigned long range_start, range_end; >> struct accept_range range, *entry; >> phys_addr_t end = start + size; >> + phys_addr_t bitmap_end; >> unsigned long flags; >> u64 unit_size; >> >> @@ -44,6 +45,21 @@ void accept_memory(phys_addr_t start, unsigned long size) >> return; >> >> unit_size = unaccepted->unit_size; >> + bitmap_end = unaccepted->phys_base + unaccepted->size * unit_size * BITS_PER_BYTE; >> + >> + /* Memory completely beyond bitmap: hotplug memory, accept unconditionally */ >> + if (start >= bitmap_end) { >> + arch_accept_memory(start, end); >> + return; >> + } >> + >> + /* Memory partially beyond bitmap */ >> + if (end > bitmap_end) { >> + arch_accept_memory(bitmap_end, end); >> + end = bitmap_end; >> + } > > You are calling arch_accept_memory() on every memory allocation if the > memory is not represented in the bitmap. Hard NAK. In which scenarios would we not have memory represented in the bitmap? Guests with <4 GiB? (how does kexec work?) Anything else? -- Cheers, David