On Fri, Jul 03, 2026 at 10:19:10AM +0000, Brendan Jackman wrote: > On Fri Apr 10, 2026 at 3:18 PM UTC, Nikita Kalyazin wrote: > > My local Sashiko run pointed out that this is broken for highmem. > > There's no highmem for guest_memfd but there is for secretmem. > > ... but this isn't actually an issue with the patch, it's currently > broken in Linus' master: > > Su[ 30.071284] ------------[ cut here ]------------ > ccessfully allocated and mapped 2097152000 bytes at 0x3a449000 > Populating memor[ 30.074614] CPA: called for zero pte. vaddr = 0 cpa->vaddr > = 0 > y... > [ 30.078636] WARNING: arch/x86/mm/pat/set_memory.c:1840 at > __cpa_process_fault+0x34d/0x360, CPU#5: allocate_secret/570 > [ 30.084789] CPU: 5 UID: 0 PID: 570 Comm: allocate_secret Not tainted > 7.1.0-14063-g4edcdefd4083-dirty #10 PREEMPTLAZY > [ 30.090937] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS > rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014 > [ 30.097543] EIP: __cpa_process_fault+0x34d/0x360 > [ 30.100514] Code: ff ff 85 c0 0f 89 7d fe ff ff e9 3d fe ff ff 8b 03 8b 00 > c7 04 24 c8 ff 64 c1 89 44 24 08 8b 45 e8 89 44 24 04 e8 53 7a 00 00 <0f> 0b > c7 45 f0 f2 ff ff ff e9 fc fc ff ff 90 8d 74 26 00 55 25 00 > [ 30.110829] EAX: 00000000 EBX: f64afe98 ECX: 00000000 EDX: 00000000 > [ 30.114799] ESI: 00000000 EDI: f64afe98 EBP: f64afe04 ESP: f64afdcc > [ 30.118785] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 EFLAGS: 00010246 > [ 30.123020] CR0: 80050033 CR2: 46c48ffc CR3: 038c8000 CR4: 00000690 > [ 30.127010] Call Trace: > [ 30.129078] __change_page_attr_set_clr+0x5e7/0x870 > [ 30.132275] ? console_unlock+0x99/0x130 > [ 30.135069] ? irq_work_queue+0x36/0x70 > [ 30.137853] ? page_address+0xd3/0xf0 > [ 30.140421] set_direct_map_invalid_noflush+0x52/0x60 > [ 30.143782] secretmem_fault+0x128/0x210 > [ 30.146560] __do_fault+0x25/0x90 > [ 30.149053] handle_mm_fault+0x6d1/0xcb0 > [ 30.151759] exc_page_fault+0x135/0x3b0 > [ 30.154487] ? doublefault_shim+0x150/0x150 > [ 30.157416] handle_exception+0x130/0x130 > [ 30.160137] EIP: 0x804d29f > [ 30.162307] Code: 89 54 08 e1 89 54 08 e5 89 54 08 e9 89 54 08 ed c3 0f b6 > 44 24 08 89 7c 24 0c 69 c0 01 01 01 01 8b 7c 24 04 f7 c7 0f 00 00 00 <89> 44 > 0f fc 75 0e c1 e9 02 f3 ab 8b 44 24 04 8b 7c 24 0c c3 31 d2 > [ 30.172936] EAX: 5a5a5a5a EBX: 00000000 ECX: 0c800000 EDX: 3a449000 > [ 30.176927] ESI: 00000000 EDI: 3a449000 EBP: bfbbae18 ESP: bfbbadac > [ 30.180897] DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b EFLAGS: 00010246 > [ 30.185161] ? doublefault_shim+0x150/0x150 > [ 30.187979] ---[ end trace 0000000000000000 ]--- > Bus error (core dumped) ./allocate_secret_i686 2000M > > Fixing this directly in secretmem.c is kinda yucky but if we can just > make folio_zap_direct_map() a NOP for highmem folios it's nice and easy > so I propose to just fix it as a followup to this series. > > Alternatively, we maybe should disable secretmem for highmem systems > since it evidently doesn't have any users.
Yes, please :) -- Sincerely yours, Mike.
