On Sun, Feb 05, 2023 at 05:02:29PM -0800, Dan Williams wrote: > Summary: > -------- > > CXL RAM support allows for the dynamic provisioning of new CXL RAM > regions, and more routinely, assembling a region from an existing > configuration established by platform-firmware. The latter is motivated > by CXL memory RAS (Reliability, Availability and Serviceability) > support, that requires associating device events with System Physical > Address ranges and vice versa. > > The 'Soft Reserved' policy rework arranges for performance > differentiated memory like CXL attached DRAM, or high-bandwidth memory, > to be designated for 'System RAM' by default, rather than the device-dax > dedicated access mode. That current device-dax default is confusing and > surprising for the Pareto of users that do not expect memory to be > quarantined for dedicated access by default. Most users expect all > 'System RAM'-capable memory to show up in FREE(1). Leverage the same QEMU branch, machine, and configuration as my prior tests, i'm now experiencing a kernel panic on boot. Will debug a bit in the morning, but here is the stack trace i'm seeing Saw this in both 1 and 2 root port configurations (note: I also have the region reset issue previously discussed on top of your branch). QEMU configuration: sudo /opt/qemu-cxl/bin/qemu-system-x86_64 \ -drive file=/var/lib/libvirt/images/cxl.qcow2,format=qcow2,index=0,media=disk,id=hd \ -m 2G,slots=4,maxmem=4G \ -smp 4 \ -machine type=q35,accel=kvm,cxl=on \ -enable-kvm \ -nographic \ -device pxb-cxl,id=cxl.0,bus=pcie.0,bus_nr=52 \ -device cxl-rp,id=rp0,bus=cxl.0,chassis=0,port=0,slot=0 \ -object memory-backend-file,id=mem0,mem-path=/tmp/mem0,size=1G,share=true \ -device cxl-type3,bus=rp0,volatile-memdev=mem0,id=cxl-mem0 \ -M cxl-fmw.0.targets.0=cxl.0,cxl-fmw.0.size=1G [ 13.936817] Call Trace: [ 13.970691] <TASK> [ 13.990690] device_add+0x39d/0x9a0 [ 14.024690] ? kobject_set_name_vargs+0x6d/0x90 [ 14.066690] ? dev_set_name+0x4b/0x60 [ 14.090691] devm_cxl_add_port+0x29a/0x4d0 [ 14.135946] cxl_acpi_probe+0xd9/0x2f0 [ 14.167691] ? device_pm_check_callbacks+0x36/0x100 [ 14.203691] platform_probe+0x44/0x90 [ 14.247691] really_probe+0xde/0x380 [ 14.277690] ? pm_runtime_barrier+0x50/0x90 [ 14.324693] __driver_probe_device+0x78/0x170 [ 14.356694] driver_probe_device+0x1f/0x90 [ 14.396692] __driver_attach+0xce/0x1c0 [ 14.435691] ? __pfx___driver_attach+0x10/0x10 [ 14.471692] bus_for_each_dev+0x73/0xa0 [ 14.508693] bus_add_driver+0x1ae/0x200 [ 14.551691] driver_register+0x89/0xe0 [ 14.587691] ? __pfx_cxl_acpi_init+0x10/0x10 [ 14.625690] do_one_initcall+0x59/0x230 [ 14.814691] kernel_init_freeable+0x204/0x24e [ 14.846710] ? __pfx_kernel_init+0x10/0x10 [ 14.899692] kernel_init+0x16/0x140 [ 14.954691] ret_from_fork+0x2c/0x50 [ 14.986692] </TASK> [ 15.023689] Modules linked in: [ 15.057693] CR2: 0000000000000060 [ 15.105691] ---[ end trace 0000000000000000 ]--- [ 15.162837] RIP: 0010:bus_add_device+0x5b/0x150 [ 15.217693] Code: 49 8b 74 24 20 48 89 df e8 92 88 ff ff 89 c5 85 c0 75 3b 48 8b 53 50 48 85 d2 75 03 48 8b 13 49 8b 84 24 a8 00 00 00 48 89 0 [ 15.427859] RSP: 0000:ffffbd2a40013bc0 EFLAGS: 00010246 [ 15.475692] RAX: 0000000000000000 RBX: ffff955c419e1800 RCX: 0000000000000000 [ 15.591691] RDX: ffff955c41921778 RSI: ffff955c419e1800 RDI: ffff955c419e1800 [ 15.703693] RBP: 0000000000000000 R08: 0000000000000228 R09: ffff955c4119e550 [ 15.802711] R10: ffff955c414bedc8 R11: 0000000000000000 R12: ffffffff9e259d60 [ 15.907692] R13: ffffffff9d3cee40 R14: ffff955c419e1800 R15: ffff955c41f06010 [ 15.983693] FS: 0000000000000000(0000) GS:ffff955cbdd00000(0000) knlGS:0000000000000000 [ 16.126698] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 16.206694] CR2: 0000000000000060 CR3: 0000000036010000 CR4: 00000000000006e0 [ 16.347694] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009 [ 16.348686] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009 ]---
