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From:   Marc-Andre Lureau <mlureau@redhat.com>
Date:   Thu, 15 Feb 2018 10:25:27 +0100
Message-ID: <CAMxuvaz20UcZkiBwDUNM7H3vCQ=faRK+vC5b0HJSaEsfvy06oA@mail.gmail.com>
Subject: Re: [PATCH v14 2/9] fw_cfg: add a public uapi header
To:     "Michael S. Tsirkin" <mst@redhat.com>
Cc:     =?UTF-8?B?TWFyYy1BbmRyw6kgTHVyZWF1?= <marcandre.lureau@redhat.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Baoquan He <bhe@redhat.com>,
        Sergio Lopez Pascual <slp@redhat.com>,
        "Somlo, Gabriel" <somlo@cmu.edu>, xiaolong.ye@intel.com
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Hi

On Wed, Feb 14, 2018 at 9:41 PM, Michael S. Tsirkin <mst@redhat.com> wrote:
> On Wed, Feb 14, 2018 at 03:18:43PM +0100, Marc-André Lureau wrote:
>> Create a common header file for well-known values and structures to be
>> shared by the Linux kernel with qemu or other projects.
>>
>> Suggested-by: Michael S. Tsirkin <mst@redhat.com>
>> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
>>
>> ---
>>
>> The related qemu patch making use of it, to be submitted:
>> https://github.com/elmarco/qemu/commit/4884fc9e9c4c4467a371e5a40f3181239e1b70f5
>> ---
>>  MAINTAINERS                    |   1 +
>>  drivers/firmware/qemu_fw_cfg.c |  22 +--------
>>  include/uapi/linux/fw_cfg.h    | 102 +++++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 105 insertions(+), 20 deletions(-)
>>  create mode 100644 include/uapi/linux/fw_cfg.h
>>
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index 3bdc260e36b7..a66b65f62811 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -11352,6 +11352,7 @@ M:    "Michael S. Tsirkin" <mst@redhat.com>
>>  L:   qemu-devel@nongnu.org
>>  S:   Maintained
>>  F:   drivers/firmware/qemu_fw_cfg.c
>> +F:   include/uapi/linux/fw_cfg.h
>>
>>  QIB DRIVER
>>  M:   Dennis Dalessandro <dennis.dalessandro@intel.com>
>> diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
>> index a41b572eeeb1..90f467232777 100644
>> --- a/drivers/firmware/qemu_fw_cfg.c
>> +++ b/drivers/firmware/qemu_fw_cfg.c
>> @@ -32,30 +32,12 @@
>>  #include <linux/slab.h>
>>  #include <linux/io.h>
>>  #include <linux/ioport.h>
>> +#include <linux/fw_cfg.h>
>>
>>  MODULE_AUTHOR("Gabriel L. Somlo <somlo@cmu.edu>");
>>  MODULE_DESCRIPTION("QEMU fw_cfg sysfs support");
>>  MODULE_LICENSE("GPL");
>>
>> -/* selector key values for "well-known" fw_cfg entries */
>> -#define FW_CFG_SIGNATURE  0x00
>> -#define FW_CFG_ID         0x01
>> -#define FW_CFG_FILE_DIR   0x19
>> -
>> -/* size in bytes of fw_cfg signature */
>> -#define FW_CFG_SIG_SIZE 4
>> -
>> -/* fw_cfg "file name" is up to 56 characters (including terminating nul) */
>> -#define FW_CFG_MAX_FILE_PATH 56
>> -
>> -/* fw_cfg file directory entry type */
>> -struct fw_cfg_file {
>> -     u32 size;
>> -     u16 select;
>> -     u16 reserved;
>> -     char name[FW_CFG_MAX_FILE_PATH];
>> -};
>> -
>>  /* fw_cfg device i/o register addresses */
>>  static bool fw_cfg_is_mmio;
>>  static phys_addr_t fw_cfg_p_base;
>> @@ -597,7 +579,7 @@ MODULE_DEVICE_TABLE(of, fw_cfg_sysfs_mmio_match);
>>
>>  #ifdef CONFIG_ACPI
>>  static const struct acpi_device_id fw_cfg_sysfs_acpi_match[] = {
>> -     { "QEMU0002", },
>> +     { FW_CFG_ACPI_DEVICE_ID, },
>>       {},
>>  };
>>  MODULE_DEVICE_TABLE(acpi, fw_cfg_sysfs_acpi_match);
>> diff --git a/include/uapi/linux/fw_cfg.h b/include/uapi/linux/fw_cfg.h
>> new file mode 100644
>> index 000000000000..5b8136ce46ee
>> --- /dev/null
>> +++ b/include/uapi/linux/fw_cfg.h
>> @@ -0,0 +1,102 @@
>> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
>> +#ifndef _LINUX_FW_CFG_H
>> +#define _LINUX_FW_CFG_H
>> +
>> +#include <linux/types.h>
>> +
>> +#define FW_CFG_ACPI_DEVICE_ID        "QEMU0002"
>> +
>> +/* selector key values for "well-known" fw_cfg entries */
>> +#define FW_CFG_SIGNATURE     0x00
>> +#define FW_CFG_ID            0x01
>> +#define FW_CFG_UUID          0x02
>> +#define FW_CFG_RAM_SIZE              0x03
>> +#define FW_CFG_NOGRAPHIC     0x04
>> +#define FW_CFG_NB_CPUS               0x05
>> +#define FW_CFG_MACHINE_ID    0x06
>> +#define FW_CFG_KERNEL_ADDR   0x07
>> +#define FW_CFG_KERNEL_SIZE   0x08
>> +#define FW_CFG_KERNEL_CMDLINE        0x09
>> +#define FW_CFG_INITRD_ADDR   0x0a
>> +#define FW_CFG_INITRD_SIZE   0x0b
>> +#define FW_CFG_BOOT_DEVICE   0x0c
>> +#define FW_CFG_NUMA          0x0d
>> +#define FW_CFG_BOOT_MENU     0x0e
>> +#define FW_CFG_MAX_CPUS              0x0f
>> +#define FW_CFG_KERNEL_ENTRY  0x10
>> +#define FW_CFG_KERNEL_DATA   0x11
>> +#define FW_CFG_INITRD_DATA   0x12
>> +#define FW_CFG_CMDLINE_ADDR  0x13
>> +#define FW_CFG_CMDLINE_SIZE  0x14
>> +#define FW_CFG_CMDLINE_DATA  0x15
>> +#define FW_CFG_SETUP_ADDR    0x16
>> +#define FW_CFG_SETUP_SIZE    0x17
>> +#define FW_CFG_SETUP_DATA    0x18
>> +#define FW_CFG_FILE_DIR              0x19
>> +
>> +#define FW_CFG_FILE_FIRST    0x20
>> +#define FW_CFG_FILE_SLOTS_MIN        0x10
>> +
>> +#define FW_CFG_WRITE_CHANNEL 0x4000
>> +#define FW_CFG_ARCH_LOCAL    0x8000
>> +#define FW_CFG_ENTRY_MASK    (~(FW_CFG_WRITE_CHANNEL | FW_CFG_ARCH_LOCAL))
>> +
>> +#define FW_CFG_INVALID               0xffff
>> +
>> +/* width in bytes of fw_cfg control register */
>> +#define FW_CFG_CTL_SIZE              0x02
>> +
>> +/* fw_cfg "file name" is up to 56 characters (including terminating nul) */
>> +#define FW_CFG_MAX_FILE_PATH 56
>> +
>> +/* size in bytes of fw_cfg signature */
>> +#define FW_CFG_SIG_SIZE 4
>> +
>> +/* FW_CFG_ID bits */
>> +#define FW_CFG_VERSION               0x01
>> +#define FW_CFG_VERSION_DMA   0x02
>> +
>> +/* fw_cfg file directory entry type */
>> +struct fw_cfg_file {
>> +     __be32 size;                    /* file size */
>> +     __be16 select;                  /* write this to 0x510 to read it */
>> +     __u16 reserved;
>> +     char name[FW_CFG_MAX_FILE_PATH];
>> +};
>> +
>> +struct fw_cfg_files {
>> +     __be32 count; /* number of entries */
>> +     struct fw_cfg_file f[];
>> +};
>
> This struct wasn't there in the original file.
> Is the source of these structures QEMU or Linux?
> If Linux, then pls split this
> 1. move code out to a header
> 2. add more structs

It is based from Linux source + qemu docs/specs/fw_cfg.txt which
references include/hw/nvram/fw_cfg_keys.h "for the most up-to-date and
authoritative list" & vmcoreinfo.txt.

QEMU ./include/hw/nvram/fw_cfg_keys.h doesn't have specific licence
text, and QEMU as a whole is released under the GNU General Public
License, version 2.

Let me know if I still need to change the license and what you
recommend instead.

>
>> +
>> +/* FW_CFG_DMA_CONTROL bits */
>> +#define FW_CFG_DMA_CTL_ERROR 0x01
>> +#define FW_CFG_DMA_CTL_READ  0x02
>> +#define FW_CFG_DMA_CTL_SKIP  0x04
>> +#define FW_CFG_DMA_CTL_SELECT        0x08
>> +#define FW_CFG_DMA_CTL_WRITE 0x10
>> +
>> +#define FW_CFG_DMA_SIGNATURE    0x51454d5520434647ULL /* "QEMU CFG" */
>> +
>> +/* Control as first field allows for different structures selected by this
>> + * field, which might be useful in the future
>> + */
>> +struct fw_cfg_dma_access {
>> +     __be32 control;
>> +     __be32 length;
>> +     __be64 address;
>> +};
>
> Maybe this should be part of the dma patch.

I prefer to introduce all the spec defines in one patch, but I can
split it if it helps.

>
>> +
>> +#define FW_CFG_VMCOREINFO_FILENAME "etc/vmcoreinfo"
>> +
>> +#define FW_CFG_VMCOREINFO_FORMAT_NONE 0x0
>> +#define FW_CFG_VMCOREINFO_FORMAT_ELF 0x1
>> +
>> +struct fw_cfg_vmcoreinfo {
>> +     __le16 host_format;
>> +     __le16 guest_format;
>> +     __le32 size;
>> +     __le64 paddr;
>> +};
>
> Maybe this should be part of the vmcore patch.

same


Thanks