On Wed, 12 Jun 2024 at 03:05, Zhenyu Zhang <zheny...@redhat.com> wrote: > > Multiple warning messages and corresponding backtraces are observed when Linux > guest is booted on the host with Fujitsu CPUs. One of them is shown as below. > > [ 0.032443] ------------[ cut here ]------------ > [ 0.032446] uart-pl011 9000000.pl011: ARCH_DMA_MINALIGN smaller than > CTR_EL0.CWG (128 < 256) > [ 0.032454] WARNING: CPU: 0 PID: 1 at arch/arm64/mm/dma-mapping.c:54 > arch_setup_dma_ops+0xbc/0xcc > [ 0.032470] Modules linked in: > [ 0.032475] CPU: 0 PID: 1 Comm: swapper/0 Not tainted > 5.14.0-452.el9.aarch64 > [ 0.032481] Hardware name: linux,dummy-virt (DT) > [ 0.032484] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) > [ 0.032490] pc : arch_setup_dma_ops+0xbc/0xcc > [ 0.032496] lr : arch_setup_dma_ops+0xbc/0xcc > [ 0.032501] sp : ffff80008003b860 > [ 0.032503] x29: ffff80008003b860 x28: 0000000000000000 x27: > ffffaae4b949049c > [ 0.032510] x26: 0000000000000000 x25: 0000000000000000 x24: > 0000000000000000 > [ 0.032517] x23: 0000000000000100 x22: 0000000000000000 x21: > 0000000000000000 > [ 0.032523] x20: 0000000100000000 x19: ffff2f06c02ea400 x18: > ffffffffffffffff > [ 0.032529] x17: 00000000208a5f76 x16: 000000006589dbcb x15: > ffffaae4ba071c89 > [ 0.032535] x14: 0000000000000000 x13: ffffaae4ba071c84 x12: > 455f525443206e61 > [ 0.032541] x11: 68742072656c6c61 x10: 0000000000000029 x9 : > ffffaae4b7d21da4 > [ 0.032547] x8 : 0000000000000029 x7 : 4c414e494d5f414d x6 : > 0000000000000029 > [ 0.032553] x5 : 000000000000000f x4 : ffffaae4b9617a00 x3 : > 0000000000000001 > [ 0.032558] x2 : 0000000000000000 x1 : 0000000000000000 x0 : > ffff2f06c029be40 > [ 0.032564] Call trace: > [ 0.032566] arch_setup_dma_ops+0xbc/0xcc > [ 0.032572] of_dma_configure_id+0x138/0x300 > [ 0.032591] amba_dma_configure+0x34/0xc0 > [ 0.032600] really_probe+0x78/0x3dc > [ 0.032614] __driver_probe_device+0x108/0x160 > [ 0.032619] driver_probe_device+0x44/0x114 > [ 0.032624] __device_attach_driver+0xb8/0x14c > [ 0.032629] bus_for_each_drv+0x88/0xe4 > [ 0.032634] __device_attach+0xb0/0x1e0 > [ 0.032638] device_initial_probe+0x18/0x20 > [ 0.032643] bus_probe_device+0xa8/0xb0 > [ 0.032648] device_add+0x4b4/0x6c0 > [ 0.032652] amba_device_try_add.part.0+0x48/0x360 > [ 0.032657] amba_device_add+0x104/0x144 > [ 0.032662] of_amba_device_create.isra.0+0x100/0x1c4 > [ 0.032666] of_platform_bus_create+0x294/0x35c > [ 0.032669] of_platform_populate+0x5c/0x150 > [ 0.032672] of_platform_default_populate_init+0xd0/0xec > [ 0.032697] do_one_initcall+0x4c/0x2e0 > [ 0.032701] do_initcalls+0x100/0x13c > [ 0.032707] kernel_init_freeable+0x1c8/0x21c > [ 0.032712] kernel_init+0x28/0x140 > [ 0.032731] ret_from_fork+0x10/0x20 > [ 0.032735] ---[ end trace 0000000000000000 ]--- > > In Linux, a check is applied to every device which is exposed through > device-tree node. The warning message is raised when the device isn't > DMA coherent and the cache line size is larger than ARCH_DMA_MINALIGN > (128 bytes). The cache line is sorted from CTR_EL0[CWG], which corresponds > to 256 bytes on the guest CPUs. The DMA coherent capability is claimed > through 'dma-coherent' in their device-tree nodes or parent nodes. > > Fix the issue by adding 'dma-coherent' property to the device-tree root > node, meaning all devices are capable of DMA coherent by default. > > Signed-off-by: Zhenyu Zhang <zheny...@redhat.com>
Applied to target-arm.next, thanks. -- PMM
