From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AAF693234 for ; Fri, 2 May 2025 00:43:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746146591; cv=none; b=OIUjEa8R4i9F3lyq95yGSGrU4C7J7UfeUMHWy5fW4KtBvRY4Bwnf5+AWD9CYMa0b9vSknkUXaL57IpLbNsyprV3JG0hH3pXK2twTGoEh+fJ6y5cvlYhUupoGBnQ/O4ExIM9tbaVrYzTr+ytMftDyikCcr/Tl2JQuGTni78VnMAY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746146591; c=relaxed/simple; bh=N/IKlgcH/53ekFkp11146OzS1pCDieBZKgyZIMpnYTg=; h=Date:To:From:Subject:Message-Id; b=px0MXmKfdHuOAh932pSoISr8543hyKIjkVTHCRYIvsK4hlXObp5s/72ZgElDMjM2XOy1jzYa7ZykZDYXSdhaaSpmu36HpGGz7v/WWFutm4iwoyRkg1RmBkXw8M9MqocuQ+26yKkybqjlXgEiSWmMoFVX8h0O2TCdv16XtzuLNAg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=sYNg3Esj; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="sYNg3Esj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0AE1DC4CEE3; Fri, 2 May 2025 00:43:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1746146590; bh=N/IKlgcH/53ekFkp11146OzS1pCDieBZKgyZIMpnYTg=; h=Date:To:From:Subject:From; b=sYNg3EsjSJlJiog96PmTa5D+wwYwRr5DgNEFrrbI7cbQM180319mKYPmm9MszUhrX FBRuy/P+UED7u+i335EzK9aaaLj6R00VYB4tdetStTpNLnUpdVsxS6qgbcIUBaOqWO TdgKB6DwCbo/XeZe/mL6y8joSIL7FpCqzv7R20Js= Date: Thu, 01 May 2025 17:43:09 -0700 To: mm-commits@vger.kernel.org,will@kernel.org,thomas.lendacky@amd.com,tglx@linutronix.de,skinsburskii@linux.microsoft.com,saravanak@google.com,rostedt@goodmis.org,robh@kernel.org,ptyadav@amazon.de,peterz@infradead.org,pbonzini@redhat.com,pasha.tatashin@soleen.com,mingo@redhat.com,mark.rutland@arm.com,luto@kernel.org,krzk@kernel.org,jgowans@amazon.com,hpa@zytor.com,graf@amazon.com,ebiederm@xmission.com,dwmw2@infradead.org,corbet@lwn.net,changyuanl@google.com,catalin.marinas@arm.com,bp@alien8.de,benh@kernel.crashing.org,ashish.kalra@amd.com,arnd@arndb.de,anthony.yznaga@oracle.com,rppt@kernel.org,akpm@linux-foundation.org From: Andrew Morton Subject: + memblock-add-memblock_rsrv_kern-flag.patch added to mm-unstable branch Message-Id: <20250502004310.0AE1DC4CEE3@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: memblock: add MEMBLOCK_RSRV_KERN flag has been added to the -mm mm-unstable branch. Its filename is memblock-add-memblock_rsrv_kern-flag.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/memblock-add-memblock_rsrv_kern-flag.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: "Mike Rapoport (Microsoft)" Subject: memblock: add MEMBLOCK_RSRV_KERN flag Date: Thu, 1 May 2025 15:54:08 -0700 Patch series "kexec: introduce Kexec HandOver (KHO)", v7. Kexec today considers itself purely a boot loader: When we enter the new kernel, any state the previous kernel left behind is irrelevant and the new kernel reinitializes the system. However, there are use cases where this mode of operation is not what we actually want. In virtualization hosts for example, we want to use kexec to update the host kernel while virtual machine memory stays untouched. When we add device assignment to the mix, we also need to ensure that IOMMU and VFIO states are untouched. If we add PCIe peer to peer DMA, we need to do the same for the PCI subsystem. If we want to kexec while an SEV-SNP enabled virtual machine is running, we need to preserve the VM context pages and physical memory. See "pkernfs: Persisting guest memory and kernel/device state safely across kexec" Linux Plumbers Conference 2023 presentation for details: https://lpc.events/event/17/contributions/1485/ To start us on the journey to support all the use cases above, this patch implements basic infrastructure to allow hand over of kernel state across kexec (Kexec HandOver, aka KHO). As a really simple example target, we use memblock's reserve_mem. With this patch set applied, memory that was reserved using "reserve_mem" command line options remains intact after kexec and it is guaranteed to reside at the same physical address. == Alternatives == There are alternative approaches to (parts of) the problems above: * Memory Pools [1] - preallocated persistent memory region + allocator * PRMEM [2] - resizable persistent memory regions with fixed metadata pointer on the kernel command line + allocator * Pkernfs [3] - preallocated file system for in-kernel data with fixed address location on the kernel command line * PKRAM [4] - handover of user space pages using a fixed metadata page specified via command line All of the approaches above fundamentally have the same problem: They require the administrator to explicitly carve out a physical memory location because they have no mechanism outside of the kernel command line to pass data (including memory reservations) between kexec'ing kernels. KHO provides that base foundation. We will determine later whether we still need any of the approaches above for fast bulk memory handover of for example IOMMU page tables. But IMHO they would all be users of KHO, with KHO providing the foundational primitive to pass metadata and bulk memory reservations as well as provide easy versioning for data. == Overview == We introduce a metadata file that the kernels pass between each other. How they pass it is architecture specific. The file's format is a Flattened Device Tree (fdt) which has a generator and parser already included in Linux. KHO is enabled in the kernel command line by `kho=on`. When the root user enables KHO through /sys/kernel/debug/kho/out/finalize, the kernel invokes callbacks to every KHO users to register preserved memory regions, which contain drivers' states. When the actual kexec happens, the fdt is part of the image set that we boot into. In addition, we keep "scratch regions" available for kexec: physically contiguous memory regions that are guaranteed to not have any memory that KHO would preserve. The new kernel bootstraps itself using the scratch regions and sets all handed over memory as in use. When drivers initialize that support KHO, they introspect the fdt, restore preserved memory regions, and retrieve their states stored in the preserved memory. == Limitations == Currently KHO is only implemented for file based kexec. The kernel interfaces in the patch set are already in place to support user space kexec as well, but it is still not implemented it yet inside kexec tools. == How to Use == To use the code, please boot the kernel with the "kho=on" command line parameter. KHO will automatically create scratch regions. If you want to set the scratch size explicitly you can use "kho_scratch=" command line parameter. For instance, "kho_scratch=16M,512M,256M" will reserve a 16 MiB low memory scratch area, a 512 MiB global scratch region, and 256 MiB per NUMA node scratch regions on boot. Make sure to have a reserved memory range requested with reserv_mem command line option, for example, "reserve_mem=64m:4k:n1". Then before you invoke file based "kexec -l", finalize KHO FDT: # echo 1 > /sys/kernel/debug/kho/out/finalize You can preview the generated FDT using `dtc`, # dtc /sys/kernel/debug/kho/out/fdt # dtc /sys/kernel/debug/kho/out/sub_fdts/memblock `dtc` is available on ubuntu by `sudo apt-get install device-tree-compiler`. Now kexec into the new kernel, # kexec -l Image --initrd=initrd -s # kexec -e (The order of KHO finalization and "kexec -l" does not matter.) The new kernel will boot up and contain the previous kernel's reserve_mem contents at the same physical address as the first kernel. You can also review the FDT passed from the old kernel, # dtc /sys/kernel/debug/kho/in/fdt # dtc /sys/kernel/debug/kho/in/sub_fdts/memblock This patch (of 17): To denote areas that were reserved for kernel use either directly with memblock_reserve_kern() or via memblock allocations. Link: https://lore.kernel.org/all/20250212152336.GA3848889@nvidia.com/ [1] Link: https://lore.kernel.org/all/20250321134629.GA252045@nvidia.com/` [2] Link: https://github.com/devicetree-org/dt-schema/pull/158 [3] Link: https://lore.kernel.org/all/55a5e3f3-1b3f-469b-bde0-69abfff826e4@kernel.org/ [4] Link: https://lkml.kernel.org/r/20250501225425.635167-1-changyuanl@google.com Link: https://lkml.kernel.org/r/20250501225425.635167-2-changyuanl@google.com Signed-off-by: Mike Rapoport (Microsoft) Co-developed-by: Changyuan Lyu Signed-off-by: Changyuan Lyu Cc: Alexander Graf Cc: Andy Lutomirski Cc: Anthony Yznaga Cc: Arnd Bergmann Cc: Ashish Kalra Cc: Ben Herrenschmidt Cc: Borislav Betkov Cc: Catalin Marinas Cc: David Woodhouse Cc: Eric Biederman Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: James Gowans Cc: Jonathan Corbet Cc: Krzysztof Kozlowski Cc: Marc Rutland Cc: Paolo Bonzini Cc: Pasha Tatashin Cc: Peter Zijlstra Cc: Pratyush Yadav Cc: Rob Herring Cc: Saravana Kannan Cc: Stanislav Kinsburskii Cc: Steven Rostedt Cc: Thomas Gleinxer Cc: Thomas Lendacky Cc: Will Deacon Signed-off-by: Andrew Morton --- include/linux/memblock.h | 19 +++++- mm/memblock.c | 40 ++++++++++--- tools/testing/memblock/tests/alloc_api.c | 22 +++---- tools/testing/memblock/tests/alloc_helpers_api.c | 4 - tools/testing/memblock/tests/alloc_nid_api.c | 20 +++--- 5 files changed, 73 insertions(+), 32 deletions(-) --- a/include/linux/memblock.h~memblock-add-memblock_rsrv_kern-flag +++ a/include/linux/memblock.h @@ -42,6 +42,9 @@ extern unsigned long long max_possible_p * kernel resource tree. * @MEMBLOCK_RSRV_NOINIT: memory region for which struct pages are * not initialized (only for reserved regions). + * @MEMBLOCK_RSRV_KERN: memory region that is reserved for kernel use, + * either explictitly with memblock_reserve_kern() or via memblock + * allocation APIs. All memblock allocations set this flag. */ enum memblock_flags { MEMBLOCK_NONE = 0x0, /* No special request */ @@ -50,6 +53,7 @@ enum memblock_flags { MEMBLOCK_NOMAP = 0x4, /* don't add to kernel direct mapping */ MEMBLOCK_DRIVER_MANAGED = 0x8, /* always detected via a driver */ MEMBLOCK_RSRV_NOINIT = 0x10, /* don't initialize struct pages */ + MEMBLOCK_RSRV_KERN = 0x20, /* memory reserved for kernel use */ }; /** @@ -116,7 +120,19 @@ int memblock_add_node(phys_addr_t base, int memblock_add(phys_addr_t base, phys_addr_t size); int memblock_remove(phys_addr_t base, phys_addr_t size); int memblock_phys_free(phys_addr_t base, phys_addr_t size); -int memblock_reserve(phys_addr_t base, phys_addr_t size); +int __memblock_reserve(phys_addr_t base, phys_addr_t size, int nid, + enum memblock_flags flags); + +static __always_inline int memblock_reserve(phys_addr_t base, phys_addr_t size) +{ + return __memblock_reserve(base, size, NUMA_NO_NODE, 0); +} + +static __always_inline int memblock_reserve_kern(phys_addr_t base, phys_addr_t size) +{ + return __memblock_reserve(base, size, NUMA_NO_NODE, MEMBLOCK_RSRV_KERN); +} + #ifdef CONFIG_HAVE_MEMBLOCK_PHYS_MAP int memblock_physmem_add(phys_addr_t base, phys_addr_t size); #endif @@ -476,6 +492,7 @@ static inline __init_memblock bool membl phys_addr_t memblock_phys_mem_size(void); phys_addr_t memblock_reserved_size(void); +phys_addr_t memblock_reserved_kern_size(phys_addr_t limit, int nid); unsigned long memblock_estimated_nr_free_pages(void); phys_addr_t memblock_start_of_DRAM(void); phys_addr_t memblock_end_of_DRAM(void); --- a/mm/memblock.c~memblock-add-memblock_rsrv_kern-flag +++ a/mm/memblock.c @@ -492,7 +492,7 @@ static int __init_memblock memblock_doub * needn't do it */ if (!use_slab) - BUG_ON(memblock_reserve(addr, new_alloc_size)); + BUG_ON(memblock_reserve_kern(addr, new_alloc_size)); /* Update slab flag */ *in_slab = use_slab; @@ -642,7 +642,7 @@ repeat: #ifdef CONFIG_NUMA WARN_ON(nid != memblock_get_region_node(rgn)); #endif - WARN_ON(flags != rgn->flags); + WARN_ON(flags != MEMBLOCK_NONE && flags != rgn->flags); nr_new++; if (insert) { if (start_rgn == -1) @@ -902,14 +902,15 @@ int __init_memblock memblock_phys_free(p return memblock_remove_range(&memblock.reserved, base, size); } -int __init_memblock memblock_reserve(phys_addr_t base, phys_addr_t size) +int __init_memblock __memblock_reserve(phys_addr_t base, phys_addr_t size, + int nid, enum memblock_flags flags) { phys_addr_t end = base + size - 1; - memblock_dbg("%s: [%pa-%pa] %pS\n", __func__, - &base, &end, (void *)_RET_IP_); + memblock_dbg("%s: [%pa-%pa] nid=%d flags=%x %pS\n", __func__, + &base, &end, nid, flags, (void *)_RET_IP_); - return memblock_add_range(&memblock.reserved, base, size, MAX_NUMNODES, 0); + return memblock_add_range(&memblock.reserved, base, size, nid, flags); } #ifdef CONFIG_HAVE_MEMBLOCK_PHYS_MAP @@ -1460,14 +1461,14 @@ phys_addr_t __init memblock_alloc_range_ again: found = memblock_find_in_range_node(size, align, start, end, nid, flags); - if (found && !memblock_reserve(found, size)) + if (found && !__memblock_reserve(found, size, nid, MEMBLOCK_RSRV_KERN)) goto done; if (numa_valid_node(nid) && !exact_nid) { found = memblock_find_in_range_node(size, align, start, end, NUMA_NO_NODE, flags); - if (found && !memblock_reserve(found, size)) + if (found && !memblock_reserve_kern(found, size)) goto done; } @@ -1752,6 +1753,28 @@ phys_addr_t __init_memblock memblock_res return memblock.reserved.total_size; } +phys_addr_t __init_memblock memblock_reserved_kern_size(phys_addr_t limit, int nid) +{ + struct memblock_region *r; + phys_addr_t total = 0; + + for_each_reserved_mem_region(r) { + phys_addr_t size = r->size; + + if (r->base > limit) + break; + + if (r->base + r->size > limit) + size = limit - r->base; + + if (nid == memblock_get_region_node(r) || !numa_valid_node(nid)) + if (r->flags & MEMBLOCK_RSRV_KERN) + total += size; + } + + return total; +} + /** * memblock_estimated_nr_free_pages - return estimated number of free pages * from memblock point of view @@ -2441,6 +2464,7 @@ static const char * const flagname[] = { [ilog2(MEMBLOCK_NOMAP)] = "NOMAP", [ilog2(MEMBLOCK_DRIVER_MANAGED)] = "DRV_MNG", [ilog2(MEMBLOCK_RSRV_NOINIT)] = "RSV_NIT", + [ilog2(MEMBLOCK_RSRV_KERN)] = "RSV_KERN", }; static int memblock_debug_show(struct seq_file *m, void *private) --- a/tools/testing/memblock/tests/alloc_api.c~memblock-add-memblock_rsrv_kern-flag +++ a/tools/testing/memblock/tests/alloc_api.c @@ -134,7 +134,7 @@ static int alloc_top_down_before_check(v PREFIX_PUSH(); setup_memblock(); - memblock_reserve(memblock_end_of_DRAM() - total_size, r1_size); + memblock_reserve_kern(memblock_end_of_DRAM() - total_size, r1_size); allocated_ptr = run_memblock_alloc(r2_size, SMP_CACHE_BYTES); @@ -182,7 +182,7 @@ static int alloc_top_down_after_check(vo total_size = r1.size + r2_size; - memblock_reserve(r1.base, r1.size); + memblock_reserve_kern(r1.base, r1.size); allocated_ptr = run_memblock_alloc(r2_size, SMP_CACHE_BYTES); @@ -231,8 +231,8 @@ static int alloc_top_down_second_fit_che total_size = r1.size + r2.size + r3_size; - memblock_reserve(r1.base, r1.size); - memblock_reserve(r2.base, r2.size); + memblock_reserve_kern(r1.base, r1.size); + memblock_reserve_kern(r2.base, r2.size); allocated_ptr = run_memblock_alloc(r3_size, SMP_CACHE_BYTES); @@ -285,8 +285,8 @@ static int alloc_in_between_generic_chec total_size = r1.size + r2.size + r3_size; - memblock_reserve(r1.base, r1.size); - memblock_reserve(r2.base, r2.size); + memblock_reserve_kern(r1.base, r1.size); + memblock_reserve_kern(r2.base, r2.size); allocated_ptr = run_memblock_alloc(r3_size, SMP_CACHE_BYTES); @@ -422,7 +422,7 @@ static int alloc_limited_space_generic_c setup_memblock(); /* Simulate almost-full memory */ - memblock_reserve(memblock_start_of_DRAM(), reserved_size); + memblock_reserve_kern(memblock_start_of_DRAM(), reserved_size); allocated_ptr = run_memblock_alloc(available_size, SMP_CACHE_BYTES); @@ -608,7 +608,7 @@ static int alloc_bottom_up_before_check( PREFIX_PUSH(); setup_memblock(); - memblock_reserve(memblock_start_of_DRAM() + r1_size, r2_size); + memblock_reserve_kern(memblock_start_of_DRAM() + r1_size, r2_size); allocated_ptr = run_memblock_alloc(r1_size, SMP_CACHE_BYTES); @@ -655,7 +655,7 @@ static int alloc_bottom_up_after_check(v total_size = r1.size + r2_size; - memblock_reserve(r1.base, r1.size); + memblock_reserve_kern(r1.base, r1.size); allocated_ptr = run_memblock_alloc(r2_size, SMP_CACHE_BYTES); @@ -705,8 +705,8 @@ static int alloc_bottom_up_second_fit_ch total_size = r1.size + r2.size + r3_size; - memblock_reserve(r1.base, r1.size); - memblock_reserve(r2.base, r2.size); + memblock_reserve_kern(r1.base, r1.size); + memblock_reserve_kern(r2.base, r2.size); allocated_ptr = run_memblock_alloc(r3_size, SMP_CACHE_BYTES); --- a/tools/testing/memblock/tests/alloc_helpers_api.c~memblock-add-memblock_rsrv_kern-flag +++ a/tools/testing/memblock/tests/alloc_helpers_api.c @@ -163,7 +163,7 @@ static int alloc_from_top_down_no_space_ min_addr = memblock_end_of_DRAM() - SMP_CACHE_BYTES * 2; /* No space above this address */ - memblock_reserve(min_addr, r2_size); + memblock_reserve_kern(min_addr, r2_size); allocated_ptr = memblock_alloc_from(r1_size, SMP_CACHE_BYTES, min_addr); @@ -199,7 +199,7 @@ static int alloc_from_top_down_min_addr_ start_addr = (phys_addr_t)memblock_start_of_DRAM(); min_addr = start_addr - SMP_CACHE_BYTES * 3; - memblock_reserve(start_addr + r1_size, MEM_SIZE - r1_size); + memblock_reserve_kern(start_addr + r1_size, MEM_SIZE - r1_size); allocated_ptr = memblock_alloc_from(r1_size, SMP_CACHE_BYTES, min_addr); --- a/tools/testing/memblock/tests/alloc_nid_api.c~memblock-add-memblock_rsrv_kern-flag +++ a/tools/testing/memblock/tests/alloc_nid_api.c @@ -324,7 +324,7 @@ static int alloc_nid_min_reserved_generi min_addr = max_addr - r2_size; reserved_base = min_addr - r1_size; - memblock_reserve(reserved_base, r1_size); + memblock_reserve_kern(reserved_base, r1_size); allocated_ptr = run_memblock_alloc_nid(r2_size, SMP_CACHE_BYTES, min_addr, max_addr, @@ -374,7 +374,7 @@ static int alloc_nid_max_reserved_generi max_addr = memblock_end_of_DRAM() - r1_size; min_addr = max_addr - r2_size; - memblock_reserve(max_addr, r1_size); + memblock_reserve_kern(max_addr, r1_size); allocated_ptr = run_memblock_alloc_nid(r2_size, SMP_CACHE_BYTES, min_addr, max_addr, @@ -436,8 +436,8 @@ static int alloc_nid_top_down_reserved_w min_addr = r2.base + r2.size; max_addr = r1.base; - memblock_reserve(r1.base, r1.size); - memblock_reserve(r2.base, r2.size); + memblock_reserve_kern(r1.base, r1.size); + memblock_reserve_kern(r2.base, r2.size); allocated_ptr = run_memblock_alloc_nid(r3_size, SMP_CACHE_BYTES, min_addr, max_addr, @@ -499,8 +499,8 @@ static int alloc_nid_reserved_full_merge min_addr = r2.base + r2.size; max_addr = r1.base; - memblock_reserve(r1.base, r1.size); - memblock_reserve(r2.base, r2.size); + memblock_reserve_kern(r1.base, r1.size); + memblock_reserve_kern(r2.base, r2.size); allocated_ptr = run_memblock_alloc_nid(r3_size, SMP_CACHE_BYTES, min_addr, max_addr, @@ -563,8 +563,8 @@ static int alloc_nid_top_down_reserved_n min_addr = r2.base + r2.size; max_addr = r1.base; - memblock_reserve(r1.base, r1.size); - memblock_reserve(r2.base, r2.size); + memblock_reserve_kern(r1.base, r1.size); + memblock_reserve_kern(r2.base, r2.size); allocated_ptr = run_memblock_alloc_nid(r3_size, SMP_CACHE_BYTES, min_addr, max_addr, @@ -909,8 +909,8 @@ static int alloc_nid_bottom_up_reserved_ min_addr = r2.base + r2.size; max_addr = r1.base; - memblock_reserve(r1.base, r1.size); - memblock_reserve(r2.base, r2.size); + memblock_reserve_kern(r1.base, r1.size); + memblock_reserve_kern(r2.base, r2.size); allocated_ptr = run_memblock_alloc_nid(r3_size, SMP_CACHE_BYTES, min_addr, max_addr, _ Patches currently in -mm which might be from rppt@kernel.org are memblock-add-memblock_rsrv_kern-flag.patch memblock-introduce-memmap_init_kho_scratch.patch kexec-enable-kho-support-for-memory-preservation.patch x86-setup-use-memblock_reserve_kern-for-memory-used-by-kernel.patch documentation-kho-add-memblock-bindings.patch execmem-enforce-allocation-size-aligment-to-page_size.patch