Re: [PATCH] treewide: replace qemu_hw_version() with QEMU_HW_VERSION

["Daniel P. Berrangé" <berrange@redhat.com>]

On Tue, Mar 24, 2026 at 05:57:05PM +0100, Paolo Bonzini wrote:
> The version is never set on 2.5+ machine types, so qemu_hw_version() and
> qemu_set_hw_version() are not needed anymore.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  include/hw/core/boards.h  |  6 ------
>  include/qemu/hw-version.h | 15 ---------------
>  hw/ide/core.c             |  2 +-
>  hw/scsi/megasas.c         |  2 +-
>  hw/scsi/scsi-bus.c        |  2 +-
>  hw/scsi/scsi-disk.c       |  2 +-
>  system/vl.c               |  4 ----
>  target/s390x/cpu_models.c |  2 +-
>  util/osdep.c              | 12 ------------
>  9 files changed, 5 insertions(+), 42 deletions(-)
> 
> diff --git a/include/hw/core/boards.h b/include/hw/core/boards.h
> index f85f31bd90d..b8dad0a1074 100644
> --- a/include/hw/core/boards.h
> +++ b/include/hw/core/boards.h
> @@ -197,11 +197,6 @@ typedef struct {
>   *    used to provide @cpu_index to socket number mapping, allowing
>   *    a machine to group CPU threads belonging to the same socket/package
>   *    Returns: socket number given cpu_index belongs to.
> - * @hw_version:
> - *    Value of QEMU_VERSION when the machine was added to QEMU.
> - *    Set only by old machines because they need to keep
> - *    compatibility on code that exposed QEMU_VERSION to guests in
> - *    the past (and now use qemu_hw_version()).
>   * @possible_cpu_arch_ids:
>   *    Returns an array of @CPUArchId architecture-dependent CPU IDs
>   *    which includes CPU IDs for present and possible to hotplug CPUs.
> @@ -297,7 +292,6 @@ struct MachineClass {
>      const char *default_display;
>      const char *default_nic;
>      GPtrArray *compat_props;
> -    const char *hw_version;
>      ram_addr_t default_ram_size;
>      const char *default_cpu_type;
>      bool default_kernel_irqchip_split;
> diff --git a/include/qemu/hw-version.h b/include/qemu/hw-version.h
> index 730a8c904d9..a40a6c204a6 100644
> --- a/include/qemu/hw-version.h
> +++ b/include/qemu/hw-version.h
> @@ -7,21 +7,6 @@
>  #ifndef QEMU_HW_VERSION_H
>  #define QEMU_HW_VERSION_H
>  
> -/*
> - * Starting on QEMU 2.5, qemu_hw_version() returns "2.5+" by default
> - * instead of QEMU_VERSION, so setting hw_version on MachineClass
> - * is no longer mandatory.
> - *
> - * Do NOT change this string, or it will break compatibility on all
> - * machine classes that don't set hw_version.
> - */

I feel like we should be keeping a comment statement that
this must never be changed due to ABI compat.

>  #define QEMU_HW_VERSION "2.5+"

Also, is there any better place this can live now that this
header file has a single #define and nothing else ?

>  
> -/* QEMU "hardware version" setting. Used to replace code that exposed
> - * QEMU_VERSION to guests in the past and need to keep compatibility.
> - * Do not use qemu_hw_version() in new code.
> - */
> -void qemu_set_hw_version(const char *);
> -const char *qemu_hw_version(void);
> -
>  #endif
> diff --git a/hw/ide/core.c b/hw/ide/core.c
> index b45abf067b2..d6719dbf31d 100644
> --- a/hw/ide/core.c
> +++ b/hw/ide/core.c
> @@ -2660,7 +2660,7 @@ int ide_init_drive(IDEState *s, IDEDevice *dev, IDEDriveKind kind, Error **errp)
>      if (dev->version) {
>          pstrcpy(s->version, sizeof(s->version), dev->version);
>      } else {
> -        pstrcpy(s->version, sizeof(s->version), qemu_hw_version());
> +        pstrcpy(s->version, sizeof(s->version), QEMU_HW_VERSION);
>      }
>  
>      ide_reset(s);
> diff --git a/hw/scsi/megasas.c b/hw/scsi/megasas.c
> index f62e420a91e..0276886d594 100644
> --- a/hw/scsi/megasas.c
> +++ b/hw/scsi/megasas.c
> @@ -782,7 +782,7 @@ static int megasas_ctrl_get_info(MegasasState *s, MegasasCmd *cmd)
>  
>      memcpy(info.product_name, base_class->product_name, 24);
>      snprintf(info.serial_number, 32, "%s", s->hba_serial);
> -    snprintf(info.package_version, 0x60, "%s-QEMU", qemu_hw_version());
> +    snprintf(info.package_version, 0x60, "%s-QEMU", QEMU_HW_VERSION);
>      memcpy(info.image_component[0].name, "APP", 3);
>      snprintf(info.image_component[0].version, 10, "%s-QEMU",
>               base_class->product_version);
> diff --git a/hw/scsi/scsi-bus.c b/hw/scsi/scsi-bus.c
> index 9b8656dd832..1a6b181b9d6 100644
> --- a/hw/scsi/scsi-bus.c
> +++ b/hw/scsi/scsi-bus.c
> @@ -703,7 +703,7 @@ static bool scsi_target_emulate_inquiry(SCSITargetReq *r)
>          r->buf[7] = 0x10 | (r->req.bus->info->tcq ? 0x02 : 0); /* Sync, TCQ.  */
>          memcpy(&r->buf[8], "QEMU    ", 8);
>          memcpy(&r->buf[16], "QEMU TARGET     ", 16);
> -        pstrcpy((char *) &r->buf[32], 4, qemu_hw_version());
> +        pstrcpy((char *) &r->buf[32], 4, QEMU_HW_VERSION);
>      }
>      return true;
>  }
> diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c
> index a5201855352..5ba5b46c4f4 100644
> --- a/hw/scsi/scsi-disk.c
> +++ b/hw/scsi/scsi-disk.c
> @@ -2543,7 +2543,7 @@ static void scsi_realize(SCSIDevice *dev, Error **errp)
>      }
>  
>      if (!s->version) {
> -        s->version = g_strdup(qemu_hw_version());
> +        s->version = g_strdup(QEMU_HW_VERSION);
>      }
>      if (!s->vendor) {
>          s->vendor = g_strdup("QEMU");
> diff --git a/system/vl.c b/system/vl.c
> index 38d7b849e0a..246623b3196 100644
> --- a/system/vl.c
> +++ b/system/vl.c
> @@ -2212,10 +2212,6 @@ static void qemu_create_machine(QDict *qdict)
>  
>      cpu_exec_init_all();
>  
> -    if (machine_class->hw_version) {
> -        qemu_set_hw_version(machine_class->hw_version);
> -    }
> -
>      /*
>       * Get the default machine options from the machine if it is not already
>       * specified either by the configuration file or by the command line.
> diff --git a/target/s390x/cpu_models.c b/target/s390x/cpu_models.c
> index 954a7a99a9e..0b88868289b 100644
> --- a/target/s390x/cpu_models.c
> +++ b/target/s390x/cpu_models.c
> @@ -955,7 +955,7 @@ static void s390_qemu_cpu_model_class_init(ObjectClass *oc, const void *data)
>  
>      xcc->is_migration_safe = true;
>      xcc->desc = g_strdup_printf("QEMU Virtual CPU version %s",
> -                                qemu_hw_version());
> +                                QEMU_HW_VERSION);
>  }
>  
>  static void s390_max_cpu_model_class_init(ObjectClass *oc, const void *data)
> diff --git a/util/osdep.c b/util/osdep.c
> index 000e7daac8b..4a8b8b5a90f 100644
> --- a/util/osdep.c
> +++ b/util/osdep.c
> @@ -31,8 +31,6 @@
>  #include "qemu/hw-version.h"
>  #include "monitor/monitor.h"
>  
> -static const char *hw_version = QEMU_HW_VERSION;
> -
>  int socket_set_cork(int fd, int v)
>  {
>  #if defined(SOL_TCP) && defined(TCP_CORK)
> @@ -533,16 +531,6 @@ ssize_t qemu_send_full(int s, const void *buf, size_t count)
>      return total;
>  }
>  
> -void qemu_set_hw_version(const char *version)
> -{
> -    hw_version = version;
> -}
> -
> -const char *qemu_hw_version(void)
> -{
> -    return hw_version;
> -}
> -
>  #ifdef _WIN32
>  static void socket_cleanup(void)
>  {
> -- 
> 2.53.0
> 
> 

With regards,
Daniel
-- 
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