Re: [Qemu-devel] [PATCH v2 1/1] i386: expose floppy-related objects in SSDT

[John Snow <jsnow@redhat.com>]

On 12/16/2015 02:45 AM, Denis V. Lunev wrote:
> From: Roman Kagan <rkagan@virtuozzo.com>
> 
> On x86-based systems Linux determines the presence and the type of
> floppy drives via a query of a CMOS field.  So does SeaBIOS when
> populating the return data for int 0x13 function 0x08.
> 
> Windows doesn't; instead, it requests this information from BIOS via int
> 0x13/0x08 or through ACPI objects _FDE (Floppy Drive Enumerate) and _FDI
> (Floppy Drive Information).  On UEFI systems only ACPI-based detection
> is supported.
> 
> QEMU used not to provide those objects in its ACPI tables; as a result
> floppy drives were invisible to Windows on UEFI/OVMF.
> 
> This patch implements those objects in SSDT, populating them via AML
> API.  For that, a couple of functions are extern-ified to facilitate
> populating those objects in acpi-build.c.
> 
> Signed-off-by: Roman Kagan <rkagan@virtuozzo.com>
> Signed-off-by: Denis V. Lunev <den@openvz.org>
> CC: Michael S. Tsirkin <mst@redhat.com>
> CC: Igor Mammedov <imammedo@redhat.com>
> CC: Paolo Bonzini <pbonzini@redhat.com>
> CC: Richard Henderson <rth@twiddle.net>
> CC: Eduardo Habkost <ehabkost@redhat.com>
> CC: John Snow <jsnow@redhat.com>
> CC: Kevin Wolf <kwolf@redhat.com>
> ---
> - The patch is made against QEMU upstream
> 
>  hw/block/fdc.c         | 11 +++++++
>  hw/i386/acpi-build.c   | 78 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  hw/i386/pc.c           | 46 +++++++++++++++++------------
>  include/hw/block/fdc.h |  2 ++
>  include/hw/i386/pc.h   |  3 ++
>  5 files changed, 121 insertions(+), 19 deletions(-)
> 
> diff --git a/hw/block/fdc.c b/hw/block/fdc.c
> index 4292ece..c858c5f 100644
> --- a/hw/block/fdc.c
> +++ b/hw/block/fdc.c
> @@ -2408,6 +2408,17 @@ FDriveType isa_fdc_get_drive_type(ISADevice *fdc, int i)
>      return isa->state.drives[i].drive;
>  }
>  
> +void isa_fdc_get_drive_geometry(ISADevice *fdc, int i, uint8_t *cylinders,
> +                                uint8_t *heads, uint8_t *sectors)
> +{
> +    FDCtrlISABus *isa = ISA_FDC(fdc);
> +    FDrive *drv = &isa->state.drives[i];
> +
> +    *cylinders = drv->max_track;
> +    *heads = (drv->flags & FDISK_DBL_SIDES) ? 2 : 1;
> +    *sectors = drv->last_sect;
> +}
> +
>  static const VMStateDescription vmstate_isa_fdc ={
>      .name = "fdc",
>      .version_id = 2,
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index 95e0c65..7f902b1 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -38,6 +38,7 @@
>  #include "hw/acpi/bios-linker-loader.h"
>  #include "hw/loader.h"
>  #include "hw/isa/isa.h"
> +#include "hw/block/fdc.h"
>  #include "hw/acpi/memory_hotplug.h"
>  #include "sysemu/tpm.h"
>  #include "hw/acpi/tpm.h"
> @@ -105,6 +106,13 @@ typedef struct AcpiPmInfo {
>      uint16_t pcihp_io_len;
>  } AcpiPmInfo;
>  
> +typedef struct AcpiFDInfo {
> +    uint8_t type;
> +    uint8_t cylinders;
> +    uint8_t heads;
> +    uint8_t sectors;
> +} AcpiFDInfo;
> +
>  typedef struct AcpiMiscInfo {
>      bool has_hpet;
>      TPMVersion tpm_version;
> @@ -112,6 +120,7 @@ typedef struct AcpiMiscInfo {
>      unsigned dsdt_size;
>      uint16_t pvpanic_port;
>      uint16_t applesmc_io_base;
> +    AcpiFDInfo fdinfo[2];
>  } AcpiMiscInfo;
>  
>  typedef struct AcpiBuildPciBusHotplugState {
> @@ -235,10 +244,25 @@ static void acpi_get_pm_info(AcpiPmInfo *pm)
>  
>  static void acpi_get_misc_info(AcpiMiscInfo *info)
>  {
> +    int i;
> +    ISADevice *fdc;
> +
>      info->has_hpet = hpet_find();
>      info->tpm_version = tpm_get_version();
>      info->pvpanic_port = pvpanic_port();
>      info->applesmc_io_base = applesmc_port();
> +
> +    fdc = pc_find_fdc0();
> +    if (fdc != NULL) {
> +        for (i = 0; i < ARRAY_SIZE(info->fdinfo); i++) {
> +            AcpiFDInfo *fdinfo = &info->fdinfo[i];
> +            fdinfo->type = isa_fdc_get_drive_type(fdc, i);
> +            if (fdinfo->type < FDRIVE_DRV_NONE) {
> +                isa_fdc_get_drive_geometry(fdc, i, &fdinfo->cylinders,
> +                                           &fdinfo->heads, &fdinfo->sectors);
> +            }
> +        }
> +    }
>  }
>  
>  /*
> @@ -900,6 +924,40 @@ static Aml *build_crs(PCIHostState *host,
>      return crs;
>  }
>  
> +static Aml *build_fdinfo_aml(int idx, AcpiFDInfo *fdinfo)
> +{
> +    Aml *dev, *fdi;
> +
> +    dev = aml_device("FLP%c", 'A' + idx);
> +
> +    aml_append(dev, aml_name_decl("_ADR", aml_int(idx)));
> +
> +    fdi = aml_package(0x10);
> +    aml_append(fdi, aml_int(idx));  /* Drive Number */
> +    aml_append(fdi,
> +        aml_int(cmos_get_fd_drive_type(fdinfo->type)));  /* Device Type */
> +    aml_append(fdi,
> +        aml_int(fdinfo->cylinders - 1));  /* Maximum Cylinder Number */
> +    aml_append(fdi, aml_int(fdinfo->sectors));  /* Maximum Sector Number */
> +    aml_append(fdi, aml_int(fdinfo->heads - 1));  /* Maximum Head Number */
> +    /* SeaBIOS returns the below values for int 0x13 func 0x08 regardless of
> +     * the drive type, so shall we */
> +    aml_append(fdi, aml_int(0xAF));  /* disk_specify_1 */
> +    aml_append(fdi, aml_int(0x02));  /* disk_specify_2 */
> +    aml_append(fdi, aml_int(0x25));  /* disk_motor_wait */
> +    aml_append(fdi, aml_int(0x02));  /* disk_sector_siz */
> +    aml_append(fdi, aml_int(0x12));  /* disk_eot */
> +    aml_append(fdi, aml_int(0x1B));  /* disk_rw_gap */
> +    aml_append(fdi, aml_int(0xFF));  /* disk_dtl */
> +    aml_append(fdi, aml_int(0x6C));  /* disk_formt_gap */
> +    aml_append(fdi, aml_int(0xF6));  /* disk_fill */
> +    aml_append(fdi, aml_int(0x0F));  /* disk_head_sttl */
> +    aml_append(fdi, aml_int(0x08));  /* disk_motor_strt */
> +
> +    aml_append(dev, aml_name_decl("_FDI", fdi));
> +    return dev;
> +}
> +
>  static void
>  build_ssdt(GArray *table_data, GArray *linker,
>             AcpiCpuInfo *cpu, AcpiPmInfo *pm, AcpiMiscInfo *misc,
> @@ -1125,6 +1183,26 @@ build_ssdt(GArray *table_data, GArray *linker,
>          aml_append(ssdt, scope);
>      }
>  
> +    {
> +        uint32_t fde_buf[5] = {0, 0, 0, 0, 0x2};
> +
> +        scope = aml_scope("\\_SB.PCI0.ISA.FDC0");
> +
> +        for (i = 0; i < ARRAY_SIZE(misc->fdinfo); i++) {
> +            AcpiFDInfo *fdinfo = &misc->fdinfo[i];
> +            if (fdinfo->type != FDRIVE_DRV_NONE) {
> +                fde_buf[i] = 0x1;
> +                aml_append(scope, build_fdinfo_aml(i, fdinfo));
> +            }
> +        }
> +
> +        aml_append(scope,
> +            aml_name_decl("_FDE",
> +                aml_buffer(sizeof(fde_buf), (uint8_t *) fde_buf)));
> +
> +        aml_append(ssdt, scope);
> +    }
> +
>      sb_scope = aml_scope("\\_SB");
>      {
>          /* create PCI0.PRES device and its _CRS to reserve CPU hotplug MMIO */
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index 5e20e07..b7b8774 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -207,7 +207,7 @@ static void pic_irq_request(void *opaque, int irq, int level)
>  
>  #define REG_EQUIPMENT_BYTE          0x14
>  
> -static int cmos_get_fd_drive_type(FDriveType fd0)
> +int cmos_get_fd_drive_type(FDriveType fd0)
>  {
>      int val;
>  
> @@ -368,6 +368,31 @@ static const char * const fdc_container_path[] = {
>      "/unattached", "/peripheral", "/peripheral-anon"
>  };
>  
> +/*
> + * Locate the FDC at IO address 0x3f0, in order to configure the CMOS registers
> + * and ACPI objects.
> + */
> +ISADevice *pc_find_fdc0(void)
> +{
> +    int i;
> +    Object *container;
> +    CheckFdcState state = { 0 };
> +
> +    for (i = 0; i < ARRAY_SIZE(fdc_container_path); i++) {
> +        container = container_get(qdev_get_machine(), fdc_container_path[i]);
> +        object_child_foreach(container, check_fdc, &state);
> +    }
> +
> +    if (state.multiple) {
> +        error_report("warning: multiple floppy disk controllers with "
> +                     "iobase=0x3f0 have been found;\n"
> +                     "the one being picked for CMOS setup might not reflect "
> +                     "your intent");
> +    }
> +
> +    return state.floppy;
> +}
> +

Hmm, Didn't Laszlo Ersek work on a similar problem for 2.4? Oh, yeah,
that's literally his code you've factored out from below. :)

>  static void pc_cmos_init_late(void *opaque)
>  {
>      pc_cmos_init_late_arg *arg = opaque;
> @@ -376,8 +401,6 @@ static void pc_cmos_init_late(void *opaque)
>      int8_t heads, sectors;
>      int val;
>      int i, trans;
> -    Object *container;
> -    CheckFdcState state = { 0 };
>  
>      val = 0;
>      if (ide_get_geometry(arg->idebus[0], 0,
> @@ -407,22 +430,7 @@ static void pc_cmos_init_late(void *opaque)
>      }
>      rtc_set_memory(s, 0x39, val);
>  
> -    /*
> -     * Locate the FDC at IO address 0x3f0, and configure the CMOS registers
> -     * accordingly.
> -     */
> -    for (i = 0; i < ARRAY_SIZE(fdc_container_path); i++) {
> -        container = container_get(qdev_get_machine(), fdc_container_path[i]);
> -        object_child_foreach(container, check_fdc, &state);
> -    }
> -
> -    if (state.multiple) {
> -        error_report("warning: multiple floppy disk controllers with "
> -                     "iobase=0x3f0 have been found;\n"
> -                     "the one being picked for CMOS setup might not reflect "
> -                     "your intent");
> -    }
> -    pc_cmos_init_floppy(s, state.floppy);
> +    pc_cmos_init_floppy(s, pc_find_fdc0());
>  
>      qemu_unregister_reset(pc_cmos_init_late, opaque);
>  }
> diff --git a/include/hw/block/fdc.h b/include/hw/block/fdc.h
> index d48b2f8..adaf3dc 100644
> --- a/include/hw/block/fdc.h
> +++ b/include/hw/block/fdc.h
> @@ -22,5 +22,7 @@ void sun4m_fdctrl_init(qemu_irq irq, hwaddr io_base,
>                         DriveInfo **fds, qemu_irq *fdc_tc);
>  
>  FDriveType isa_fdc_get_drive_type(ISADevice *fdc, int i);
> +void isa_fdc_get_drive_geometry(ISADevice *fdc, int i, uint8_t *cylinders,
> +                                uint8_t *heads, uint8_t *sectors);
>  
>  #endif
> diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
> index 854c330..32ceb2f 100644
> --- a/include/hw/i386/pc.h
> +++ b/include/hw/i386/pc.h
> @@ -211,6 +211,9 @@ typedef void (*cpu_set_smm_t)(int smm, void *arg);
>  
>  void ioapic_init_gsi(GSIState *gsi_state, const char *parent_name);
>  
> +ISADevice *pc_find_fdc0(void);
> +int cmos_get_fd_drive_type(FDriveType fd0);
> +
>  /* acpi_piix.c */
>  
>  I2CBus *piix4_pm_init(PCIBus *bus, int devfn, uint32_t smb_io_base,
> 

fdc.[ch]:
Acked-by: John Snow <jsnow@redhat.com>