Re: [Qemu-devel] RFC: altering the NVDIMM acpi table

[Dan Williams]

On Mon, Apr 23, 2018 at 1:35 PM, Schmauss, Erik <address@hidden> wrote:
> Hello,
>
> I work on ACPICA and we have recently made changes to the behavior of
> the Linux AML interpreter to match other OS implementations. After
> sending the patches to upstream Linux, we have identified that
> hw/acpi/nvdimm.c specifies an ACPI table with a forward reference
>  (MEMA is a forward reference that is no longer supported as of Linux
> 4.17-rc1).
>
> We would like to change this file to move the declaration of Name
> (MEMA,...) to appear as the very first declaration in the SSDT. Below is a 
> patch outlining the change that I would like to make.
> However, I am having a hard time getting make check to run
>  to completion in a reasonable amount of time. It always seems to fail
> on some sort of checksum test... It would be great if you could let me
> know what you think of the change and what I can do to speed up the
> execution time of make check...
>
>
> Thanks,
>
> Erik Schmauss
>
> diff --git a/hw/acpi/nvdimm.c b/hw/acpi/nvdimm.c
> index 59d6e4254c..7c9efd9ac7 100644
> --- a/hw/acpi/nvdimm.c
> +++ b/hw/acpi/nvdimm.c
> @@ -1234,6 +1234,9 @@ static void nvdimm_build_ssdt(GArray *table_offsets, 
> GArray *table_data,
>      ssdt = init_aml_allocator();
>      acpi_data_push(ssdt->buf, sizeof(AcpiTableHeader));
>
> +    mem_addr_offset = build_append_named_dword(table_data,
> +                                               NVDIMM_ACPI_MEM_ADDR);
> +
>      sb_scope = aml_scope("\\_SB");
>
>      dev = aml_device("NVDR");
> @@ -1266,9 +1269,6 @@ static void nvdimm_build_ssdt(GArray *table_offsets, 
> GArray *table_data,
>
>      /* copy AML table into ACPI tables blob and patch header there */
>      g_array_append_vals(table_data, ssdt->buf->data, ssdt->buf->len);
> -    mem_addr_offset = build_append_named_dword(table_data,
> -                                               NVDIMM_ACPI_MEM_ADDR);
> -
>      bios_linker_loader_alloc(linker,
>                               NVDIMM_DSM_MEM_FILE, dsm_dma_arrea,
>                               sizeof(NvdimmDsmIn), false /* high memory */);

I gave this a shot and it appears to breaking some assumption of where
this device is mapped relative to System RAM:

 ioremap on RAM at 0x00000000bffe0000 - 0x000000019ffe1fff
 WARNING: CPU: 0 PID: 0 at arch/x86/mm/ioremap.c:166
__ioremap_caller+0x28b/0x300
 Modules linked in:
 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.17.0-rc1+ #1734
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.11.1-0-g0551a4be2c-prebuilt.qemu-project.org 04/01/2014
 RIP: 0010:__ioremap_caller+0x28b/0x300
 RSP: 0000:ffffffff82603db0 EFLAGS: 00010286
 RAX: 0000000000000000 RBX: 00000000bffe0000 RCX: 0000000000000006
 RDX: 0000000000000168 RSI: ffffffff82618f90 RDI: 0000000000000246
 RBP: 00000000e0002000 R08: 0000000000000000 R09: 0000000000000000
 R10: ffff88043e7d8000 R11: 0000000000000000 R12: 0000000000000000
 R13: 00000000bffe0000 R14: ffffffff81a731e9 R15: ffffffff82603ee4
 FS:  0000000000000000(0000) GS:ffff880431400000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 00000000ffffffff CR3: 0000000002610000 CR4: 00000000000406b0
 Call Trace:
  ? acpi_os_map_iomem+0x7b/0x1c0
  acpi_os_map_iomem+0x189/0x1c0
  acpi_tb_acquire_table+0x39/0x64
  acpi_tb_validate_table+0x21/0x33
  acpi_tb_verify_temp_table+0x37/0x213
  acpi_reallocate_root_table+0xe1/0x112
  acpi_early_init+0x4b/0x102
  start_kernel+0x419/0x4ee
  secondary_startup_64+0xa5/0xb0