Re: [PATCH v4 3/3] block: make BlockConf.*_size properties 32-bit

2020-05-25 Thread Kevin Wolf
Am 20.05.2020 um 23:50 hat Roman Kagan geschrieben:
> On Wed, May 20, 2020 at 05:54:44PM +0200, Kevin Wolf wrote:
> > Am 20.05.2020 um 10:06 hat Roman Kagan geschrieben:
> > > Devices (virtio-blk, scsi, etc.) and the block layer are happy to use
> > > 32-bit for logical_block_size, physical_block_size, and min_io_size.
> > > However, the properties in BlockConf are defined as uint16_t limiting
> > > the values to 32768.
> > > 
> > > This appears unnecessary tight, and we've seen bigger block sizes handy
> > > at times.
> > > 
> > > Make them 32 bit instead and lift the limitation up to 2 MiB which
> > > appears to be good enough for everybody, and matches the qcow2 cluster
> > > size limit.
> > > 
> > > As the values can now be fairly big and awkward to type, make the
> > > property setter accept common size suffixes (k, m).
> > > 
> > > Also as the devices which use min_io_size (virtio-blk and scsi) pass its
> > > value to the guest in units of logical blocks in a 16bit field, to
> > > prevent its silent truncation add a corresponding check to
> > > blkconf_blocksizes.
> > > 
> > > Signed-off-by: Roman Kagan 
> > > ---
> > > v3 -> v4:
> > > - check min_io_size against truncation [Kevin]
> > > 
> > > v2 -> v3:
> > > - mention qcow2 cluster size limit in the log and comment [Eric]
> > > 
> > > v1 -> v2:
> > > - cap the property at 2 MiB [Eric]
> > > - accept size suffixes
> > > 
> > >  include/hw/block/block.h |  8 
> > >  include/hw/qdev-properties.h |  2 +-
> > >  hw/block/block.c | 11 +++
> > >  hw/core/qdev-properties.c| 34 --
> > >  4 files changed, 40 insertions(+), 15 deletions(-)
> > > 
> > > diff --git a/include/hw/block/block.h b/include/hw/block/block.h
> > > index 784953a237..2fa09aa0b1 100644
> > > --- a/include/hw/block/block.h
> > > +++ b/include/hw/block/block.h
> > > @@ -18,9 +18,9 @@
> > >  
> > >  typedef struct BlockConf {
> > >  BlockBackend *blk;
> > > -uint16_t physical_block_size;
> > > -uint16_t logical_block_size;
> > > -uint16_t min_io_size;
> > > +uint32_t physical_block_size;
> > > +uint32_t logical_block_size;
> > > +uint32_t min_io_size;
> > >  uint32_t opt_io_size;
> > >  int32_t bootindex;
> > >  uint32_t discard_granularity;
> > > @@ -51,7 +51,7 @@ static inline unsigned int 
> > > get_physical_block_exp(BlockConf *conf)
> > >_conf.logical_block_size),\
> > >  DEFINE_PROP_BLOCKSIZE("physical_block_size", _state,\
> > >_conf.physical_block_size),   \
> > > -DEFINE_PROP_UINT16("min_io_size", _state, _conf.min_io_size, 0),\
> > > +DEFINE_PROP_UINT32("min_io_size", _state, _conf.min_io_size, 0),\
> > >  DEFINE_PROP_UINT32("opt_io_size", _state, _conf.opt_io_size, 0),\
> > >  DEFINE_PROP_UINT32("discard_granularity", _state,   \
> > > _conf.discard_granularity, -1),  \
> > > diff --git a/include/hw/qdev-properties.h b/include/hw/qdev-properties.h
> > > index f161604fb6..f9e0f8c041 100644
> > > --- a/include/hw/qdev-properties.h
> > > +++ b/include/hw/qdev-properties.h
> > > @@ -197,7 +197,7 @@ extern const PropertyInfo qdev_prop_pcie_link_width;
> > >  #define DEFINE_PROP_BIOS_CHS_TRANS(_n, _s, _f, _d) \
> > >  DEFINE_PROP_SIGNED(_n, _s, _f, _d, qdev_prop_bios_chs_trans, int)
> > >  #define DEFINE_PROP_BLOCKSIZE(_n, _s, _f) \
> > > -DEFINE_PROP_UNSIGNED(_n, _s, _f, 0, qdev_prop_blocksize, uint16_t)
> > > +DEFINE_PROP_UNSIGNED(_n, _s, _f, 0, qdev_prop_blocksize, uint32_t)
> > >  #define DEFINE_PROP_PCI_HOST_DEVADDR(_n, _s, _f) \
> > >  DEFINE_PROP(_n, _s, _f, qdev_prop_pci_host_devaddr, 
> > > PCIHostDeviceAddress)
> > >  #define DEFINE_PROP_OFF_AUTO_PCIBAR(_n, _s, _f, _d) \
> > > diff --git a/hw/block/block.c b/hw/block/block.c
> > > index 5f8ebff59c..cd95e7e38f 100644
> > > --- a/hw/block/block.c
> > > +++ b/hw/block/block.c
> > > @@ -96,6 +96,17 @@ bool blkconf_blocksizes(BlockConf *conf, Error **errp)
> > >  return false;
> > >  }
> > >  
> > > +/*
> > > + * all devices which support min_io_size (scsi and virtio-blk) 
> > > expose it to
> > > + * the guest as a uint16_t in units of logical blocks
> > > + */
> > > +if ((conf->min_io_size / conf->logical_block_size) > UINT16_MAX) {
> > > +error_setg(errp,
> > > +   "min_io_size must be no more than " 
> > > stringify(UINT16_MAX)
> > > +   " of logical_block_size");
> > 
> > I'm not a native speaker, but "no more than 65536 of
> > logical_block_size" sounds odd to me.
> 
> Neither am I but I agree with the feeling.
> 
> > Maybe "65536 times the logical_block_size"?
> 
> Sounds better indeed, will do in the respin.
> Or perhaps "no more than 65536 logical blocks"?

I guess that would work, too, and result in a shorter error message,
though logic

Re: [PATCH v4 3/3] block: make BlockConf.*_size properties 32-bit

2020-05-20 Thread Roman Kagan
On Wed, May 20, 2020 at 05:54:44PM +0200, Kevin Wolf wrote:
> Am 20.05.2020 um 10:06 hat Roman Kagan geschrieben:
> > Devices (virtio-blk, scsi, etc.) and the block layer are happy to use
> > 32-bit for logical_block_size, physical_block_size, and min_io_size.
> > However, the properties in BlockConf are defined as uint16_t limiting
> > the values to 32768.
> > 
> > This appears unnecessary tight, and we've seen bigger block sizes handy
> > at times.
> > 
> > Make them 32 bit instead and lift the limitation up to 2 MiB which
> > appears to be good enough for everybody, and matches the qcow2 cluster
> > size limit.
> > 
> > As the values can now be fairly big and awkward to type, make the
> > property setter accept common size suffixes (k, m).
> > 
> > Also as the devices which use min_io_size (virtio-blk and scsi) pass its
> > value to the guest in units of logical blocks in a 16bit field, to
> > prevent its silent truncation add a corresponding check to
> > blkconf_blocksizes.
> > 
> > Signed-off-by: Roman Kagan 
> > ---
> > v3 -> v4:
> > - check min_io_size against truncation [Kevin]
> > 
> > v2 -> v3:
> > - mention qcow2 cluster size limit in the log and comment [Eric]
> > 
> > v1 -> v2:
> > - cap the property at 2 MiB [Eric]
> > - accept size suffixes
> > 
> >  include/hw/block/block.h |  8 
> >  include/hw/qdev-properties.h |  2 +-
> >  hw/block/block.c | 11 +++
> >  hw/core/qdev-properties.c| 34 --
> >  4 files changed, 40 insertions(+), 15 deletions(-)
> > 
> > diff --git a/include/hw/block/block.h b/include/hw/block/block.h
> > index 784953a237..2fa09aa0b1 100644
> > --- a/include/hw/block/block.h
> > +++ b/include/hw/block/block.h
> > @@ -18,9 +18,9 @@
> >  
> >  typedef struct BlockConf {
> >  BlockBackend *blk;
> > -uint16_t physical_block_size;
> > -uint16_t logical_block_size;
> > -uint16_t min_io_size;
> > +uint32_t physical_block_size;
> > +uint32_t logical_block_size;
> > +uint32_t min_io_size;
> >  uint32_t opt_io_size;
> >  int32_t bootindex;
> >  uint32_t discard_granularity;
> > @@ -51,7 +51,7 @@ static inline unsigned int 
> > get_physical_block_exp(BlockConf *conf)
> >_conf.logical_block_size),\
> >  DEFINE_PROP_BLOCKSIZE("physical_block_size", _state,\
> >_conf.physical_block_size),   \
> > -DEFINE_PROP_UINT16("min_io_size", _state, _conf.min_io_size, 0),\
> > +DEFINE_PROP_UINT32("min_io_size", _state, _conf.min_io_size, 0),\
> >  DEFINE_PROP_UINT32("opt_io_size", _state, _conf.opt_io_size, 0),\
> >  DEFINE_PROP_UINT32("discard_granularity", _state,   \
> > _conf.discard_granularity, -1),  \
> > diff --git a/include/hw/qdev-properties.h b/include/hw/qdev-properties.h
> > index f161604fb6..f9e0f8c041 100644
> > --- a/include/hw/qdev-properties.h
> > +++ b/include/hw/qdev-properties.h
> > @@ -197,7 +197,7 @@ extern const PropertyInfo qdev_prop_pcie_link_width;
> >  #define DEFINE_PROP_BIOS_CHS_TRANS(_n, _s, _f, _d) \
> >  DEFINE_PROP_SIGNED(_n, _s, _f, _d, qdev_prop_bios_chs_trans, int)
> >  #define DEFINE_PROP_BLOCKSIZE(_n, _s, _f) \
> > -DEFINE_PROP_UNSIGNED(_n, _s, _f, 0, qdev_prop_blocksize, uint16_t)
> > +DEFINE_PROP_UNSIGNED(_n, _s, _f, 0, qdev_prop_blocksize, uint32_t)
> >  #define DEFINE_PROP_PCI_HOST_DEVADDR(_n, _s, _f) \
> >  DEFINE_PROP(_n, _s, _f, qdev_prop_pci_host_devaddr, 
> > PCIHostDeviceAddress)
> >  #define DEFINE_PROP_OFF_AUTO_PCIBAR(_n, _s, _f, _d) \
> > diff --git a/hw/block/block.c b/hw/block/block.c
> > index 5f8ebff59c..cd95e7e38f 100644
> > --- a/hw/block/block.c
> > +++ b/hw/block/block.c
> > @@ -96,6 +96,17 @@ bool blkconf_blocksizes(BlockConf *conf, Error **errp)
> >  return false;
> >  }
> >  
> > +/*
> > + * all devices which support min_io_size (scsi and virtio-blk) expose 
> > it to
> > + * the guest as a uint16_t in units of logical blocks
> > + */
> > +if ((conf->min_io_size / conf->logical_block_size) > UINT16_MAX) {
> > +error_setg(errp,
> > +   "min_io_size must be no more than " 
> > stringify(UINT16_MAX)
> > +   " of logical_block_size");
> 
> I'm not a native speaker, but "no more than 65536 of
> logical_block_size" sounds odd to me.

Neither am I but I agree with the feeling.

> Maybe "65536 times the logical_block_size"?

Sounds better indeed, will do in the respin.
Or perhaps "no more than 65536 logical blocks"?

Thanks,
Roman.

> 
> > +return false;
> > +}
> > +
> >  if (conf->opt_io_size % conf->logical_block_size) {
> >  error_setg(errp,
> > "opt_io_size must be a multple of logical_block_size");
> 
> Kevin
> 



Re: [PATCH v4 3/3] block: make BlockConf.*_size properties 32-bit

2020-05-20 Thread Roman Kagan
On Wed, May 20, 2020 at 11:04:44AM +0200, Philippe Mathieu-Daudé wrote:
> On 5/20/20 10:06 AM, Roman Kagan wrote:
> > Devices (virtio-blk, scsi, etc.) and the block layer are happy to use
> > 32-bit for logical_block_size, physical_block_size, and min_io_size.
> > However, the properties in BlockConf are defined as uint16_t limiting
> > the values to 32768.
> > 
> > This appears unnecessary tight, and we've seen bigger block sizes handy
> > at times.
> > 
> > Make them 32 bit instead and lift the limitation up to 2 MiB which
> > appears to be good enough for everybody, and matches the qcow2 cluster
> > size limit.
> > 
> > As the values can now be fairly big and awkward to type, make the
> > property setter accept common size suffixes (k, m).
> > 
> > Also as the devices which use min_io_size (virtio-blk and scsi) pass its
> > value to the guest in units of logical blocks in a 16bit field, to
> > prevent its silent truncation add a corresponding check to
> > blkconf_blocksizes.
> > 
> > Signed-off-by: Roman Kagan 
> > ---
> > v3 -> v4:
> > - check min_io_size against truncation [Kevin]
> > 
> > v2 -> v3:
> > - mention qcow2 cluster size limit in the log and comment [Eric]
> > 
> > v1 -> v2:
> > - cap the property at 2 MiB [Eric]
> > - accept size suffixes
> > 
> >   include/hw/block/block.h |  8 
> >   include/hw/qdev-properties.h |  2 +-
> >   hw/block/block.c | 11 +++
> >   hw/core/qdev-properties.c| 34 --
> >   4 files changed, 40 insertions(+), 15 deletions(-)
> > 
> > diff --git a/include/hw/block/block.h b/include/hw/block/block.h
> > index 784953a237..2fa09aa0b1 100644
> > --- a/include/hw/block/block.h
> > +++ b/include/hw/block/block.h
> > @@ -18,9 +18,9 @@
> >   typedef struct BlockConf {
> >   BlockBackend *blk;
> > -uint16_t physical_block_size;
> > -uint16_t logical_block_size;
> > -uint16_t min_io_size;
> > +uint32_t physical_block_size;
> > +uint32_t logical_block_size;
> > +uint32_t min_io_size;
> >   uint32_t opt_io_size;
> >   int32_t bootindex;
> >   uint32_t discard_granularity;
> > @@ -51,7 +51,7 @@ static inline unsigned int 
> > get_physical_block_exp(BlockConf *conf)
> > _conf.logical_block_size),\
> >   DEFINE_PROP_BLOCKSIZE("physical_block_size", _state,\
> > _conf.physical_block_size),   \
> > -DEFINE_PROP_UINT16("min_io_size", _state, _conf.min_io_size, 0),\
> > +DEFINE_PROP_UINT32("min_io_size", _state, _conf.min_io_size, 0),\
> >   DEFINE_PROP_UINT32("opt_io_size", _state, _conf.opt_io_size, 0),\
> >   DEFINE_PROP_UINT32("discard_granularity", _state,   \
> >  _conf.discard_granularity, -1),  \
> > diff --git a/include/hw/qdev-properties.h b/include/hw/qdev-properties.h
> > index f161604fb6..f9e0f8c041 100644
> > --- a/include/hw/qdev-properties.h
> > +++ b/include/hw/qdev-properties.h
> > @@ -197,7 +197,7 @@ extern const PropertyInfo qdev_prop_pcie_link_width;
> >   #define DEFINE_PROP_BIOS_CHS_TRANS(_n, _s, _f, _d) \
> >   DEFINE_PROP_SIGNED(_n, _s, _f, _d, qdev_prop_bios_chs_trans, int)
> >   #define DEFINE_PROP_BLOCKSIZE(_n, _s, _f) \
> > -DEFINE_PROP_UNSIGNED(_n, _s, _f, 0, qdev_prop_blocksize, uint16_t)
> > +DEFINE_PROP_UNSIGNED(_n, _s, _f, 0, qdev_prop_blocksize, uint32_t)
> >   #define DEFINE_PROP_PCI_HOST_DEVADDR(_n, _s, _f) \
> >   DEFINE_PROP(_n, _s, _f, qdev_prop_pci_host_devaddr, 
> > PCIHostDeviceAddress)
> >   #define DEFINE_PROP_OFF_AUTO_PCIBAR(_n, _s, _f, _d) \
> > diff --git a/hw/block/block.c b/hw/block/block.c
> > index 5f8ebff59c..cd95e7e38f 100644
> > --- a/hw/block/block.c
> > +++ b/hw/block/block.c
> > @@ -96,6 +96,17 @@ bool blkconf_blocksizes(BlockConf *conf, Error **errp)
> >   return false;
> >   }
> > +/*
> > + * all devices which support min_io_size (scsi and virtio-blk) expose 
> > it to
> > + * the guest as a uint16_t in units of logical blocks
> > + */
> > +if ((conf->min_io_size / conf->logical_block_size) > UINT16_MAX) {
> > +error_setg(errp,
> > +   "min_io_size must be no more than " 
> > stringify(UINT16_MAX)
> > +   " of logical_block_size");
> > +return false;
> > +}
> > +
> >   if (conf->opt_io_size % conf->logical_block_size) {
> >   error_setg(errp,
> >  "opt_io_size must be a multple of logical_block_size");
> > diff --git a/hw/core/qdev-properties.c b/hw/core/qdev-properties.c
> > index cc924815da..fd03cc7597 100644
> > --- a/hw/core/qdev-properties.c
> > +++ b/hw/core/qdev-properties.c
> > @@ -14,6 +14,7 @@
> >   #include "qapi/visitor.h"
> >   #include "chardev/char.h"
> >   #include "qemu/uuid.h"
> > +#include "qemu/units.h"
> >   void qdev_prop_set_after_realize(DeviceState *dev, const char *name,
> >

Re: [PATCH v4 3/3] block: make BlockConf.*_size properties 32-bit

2020-05-20 Thread Kevin Wolf
Am 20.05.2020 um 10:06 hat Roman Kagan geschrieben:
> Devices (virtio-blk, scsi, etc.) and the block layer are happy to use
> 32-bit for logical_block_size, physical_block_size, and min_io_size.
> However, the properties in BlockConf are defined as uint16_t limiting
> the values to 32768.
> 
> This appears unnecessary tight, and we've seen bigger block sizes handy
> at times.
> 
> Make them 32 bit instead and lift the limitation up to 2 MiB which
> appears to be good enough for everybody, and matches the qcow2 cluster
> size limit.
> 
> As the values can now be fairly big and awkward to type, make the
> property setter accept common size suffixes (k, m).
> 
> Also as the devices which use min_io_size (virtio-blk and scsi) pass its
> value to the guest in units of logical blocks in a 16bit field, to
> prevent its silent truncation add a corresponding check to
> blkconf_blocksizes.
> 
> Signed-off-by: Roman Kagan 
> ---
> v3 -> v4:
> - check min_io_size against truncation [Kevin]
> 
> v2 -> v3:
> - mention qcow2 cluster size limit in the log and comment [Eric]
> 
> v1 -> v2:
> - cap the property at 2 MiB [Eric]
> - accept size suffixes
> 
>  include/hw/block/block.h |  8 
>  include/hw/qdev-properties.h |  2 +-
>  hw/block/block.c | 11 +++
>  hw/core/qdev-properties.c| 34 --
>  4 files changed, 40 insertions(+), 15 deletions(-)
> 
> diff --git a/include/hw/block/block.h b/include/hw/block/block.h
> index 784953a237..2fa09aa0b1 100644
> --- a/include/hw/block/block.h
> +++ b/include/hw/block/block.h
> @@ -18,9 +18,9 @@
>  
>  typedef struct BlockConf {
>  BlockBackend *blk;
> -uint16_t physical_block_size;
> -uint16_t logical_block_size;
> -uint16_t min_io_size;
> +uint32_t physical_block_size;
> +uint32_t logical_block_size;
> +uint32_t min_io_size;
>  uint32_t opt_io_size;
>  int32_t bootindex;
>  uint32_t discard_granularity;
> @@ -51,7 +51,7 @@ static inline unsigned int get_physical_block_exp(BlockConf 
> *conf)
>_conf.logical_block_size),\
>  DEFINE_PROP_BLOCKSIZE("physical_block_size", _state,\
>_conf.physical_block_size),   \
> -DEFINE_PROP_UINT16("min_io_size", _state, _conf.min_io_size, 0),\
> +DEFINE_PROP_UINT32("min_io_size", _state, _conf.min_io_size, 0),\
>  DEFINE_PROP_UINT32("opt_io_size", _state, _conf.opt_io_size, 0),\
>  DEFINE_PROP_UINT32("discard_granularity", _state,   \
> _conf.discard_granularity, -1),  \
> diff --git a/include/hw/qdev-properties.h b/include/hw/qdev-properties.h
> index f161604fb6..f9e0f8c041 100644
> --- a/include/hw/qdev-properties.h
> +++ b/include/hw/qdev-properties.h
> @@ -197,7 +197,7 @@ extern const PropertyInfo qdev_prop_pcie_link_width;
>  #define DEFINE_PROP_BIOS_CHS_TRANS(_n, _s, _f, _d) \
>  DEFINE_PROP_SIGNED(_n, _s, _f, _d, qdev_prop_bios_chs_trans, int)
>  #define DEFINE_PROP_BLOCKSIZE(_n, _s, _f) \
> -DEFINE_PROP_UNSIGNED(_n, _s, _f, 0, qdev_prop_blocksize, uint16_t)
> +DEFINE_PROP_UNSIGNED(_n, _s, _f, 0, qdev_prop_blocksize, uint32_t)
>  #define DEFINE_PROP_PCI_HOST_DEVADDR(_n, _s, _f) \
>  DEFINE_PROP(_n, _s, _f, qdev_prop_pci_host_devaddr, PCIHostDeviceAddress)
>  #define DEFINE_PROP_OFF_AUTO_PCIBAR(_n, _s, _f, _d) \
> diff --git a/hw/block/block.c b/hw/block/block.c
> index 5f8ebff59c..cd95e7e38f 100644
> --- a/hw/block/block.c
> +++ b/hw/block/block.c
> @@ -96,6 +96,17 @@ bool blkconf_blocksizes(BlockConf *conf, Error **errp)
>  return false;
>  }
>  
> +/*
> + * all devices which support min_io_size (scsi and virtio-blk) expose it 
> to
> + * the guest as a uint16_t in units of logical blocks
> + */
> +if ((conf->min_io_size / conf->logical_block_size) > UINT16_MAX) {
> +error_setg(errp,
> +   "min_io_size must be no more than " stringify(UINT16_MAX)
> +   " of logical_block_size");

I'm not a native speaker, but "no more than 65536 of logical_block_size"
sounds odd to me. Maybe "65536 times the logical_block_size"?

> +return false;
> +}
> +
>  if (conf->opt_io_size % conf->logical_block_size) {
>  error_setg(errp,
> "opt_io_size must be a multple of logical_block_size");

Kevin




Re: [PATCH v4 3/3] block: make BlockConf.*_size properties 32-bit

2020-05-20 Thread Philippe Mathieu-Daudé

On 5/20/20 10:06 AM, Roman Kagan wrote:

Devices (virtio-blk, scsi, etc.) and the block layer are happy to use
32-bit for logical_block_size, physical_block_size, and min_io_size.
However, the properties in BlockConf are defined as uint16_t limiting
the values to 32768.

This appears unnecessary tight, and we've seen bigger block sizes handy
at times.

Make them 32 bit instead and lift the limitation up to 2 MiB which
appears to be good enough for everybody, and matches the qcow2 cluster
size limit.

As the values can now be fairly big and awkward to type, make the
property setter accept common size suffixes (k, m).

Also as the devices which use min_io_size (virtio-blk and scsi) pass its
value to the guest in units of logical blocks in a 16bit field, to
prevent its silent truncation add a corresponding check to
blkconf_blocksizes.

Signed-off-by: Roman Kagan 
---
v3 -> v4:
- check min_io_size against truncation [Kevin]

v2 -> v3:
- mention qcow2 cluster size limit in the log and comment [Eric]

v1 -> v2:
- cap the property at 2 MiB [Eric]
- accept size suffixes

  include/hw/block/block.h |  8 
  include/hw/qdev-properties.h |  2 +-
  hw/block/block.c | 11 +++
  hw/core/qdev-properties.c| 34 --
  4 files changed, 40 insertions(+), 15 deletions(-)

diff --git a/include/hw/block/block.h b/include/hw/block/block.h
index 784953a237..2fa09aa0b1 100644
--- a/include/hw/block/block.h
+++ b/include/hw/block/block.h
@@ -18,9 +18,9 @@
  
  typedef struct BlockConf {

  BlockBackend *blk;
-uint16_t physical_block_size;
-uint16_t logical_block_size;
-uint16_t min_io_size;
+uint32_t physical_block_size;
+uint32_t logical_block_size;
+uint32_t min_io_size;
  uint32_t opt_io_size;
  int32_t bootindex;
  uint32_t discard_granularity;
@@ -51,7 +51,7 @@ static inline unsigned int get_physical_block_exp(BlockConf 
*conf)
_conf.logical_block_size),\
  DEFINE_PROP_BLOCKSIZE("physical_block_size", _state,\
_conf.physical_block_size),   \
-DEFINE_PROP_UINT16("min_io_size", _state, _conf.min_io_size, 0),\
+DEFINE_PROP_UINT32("min_io_size", _state, _conf.min_io_size, 0),\
  DEFINE_PROP_UINT32("opt_io_size", _state, _conf.opt_io_size, 0),\
  DEFINE_PROP_UINT32("discard_granularity", _state,   \
 _conf.discard_granularity, -1),  \
diff --git a/include/hw/qdev-properties.h b/include/hw/qdev-properties.h
index f161604fb6..f9e0f8c041 100644
--- a/include/hw/qdev-properties.h
+++ b/include/hw/qdev-properties.h
@@ -197,7 +197,7 @@ extern const PropertyInfo qdev_prop_pcie_link_width;
  #define DEFINE_PROP_BIOS_CHS_TRANS(_n, _s, _f, _d) \
  DEFINE_PROP_SIGNED(_n, _s, _f, _d, qdev_prop_bios_chs_trans, int)
  #define DEFINE_PROP_BLOCKSIZE(_n, _s, _f) \
-DEFINE_PROP_UNSIGNED(_n, _s, _f, 0, qdev_prop_blocksize, uint16_t)
+DEFINE_PROP_UNSIGNED(_n, _s, _f, 0, qdev_prop_blocksize, uint32_t)
  #define DEFINE_PROP_PCI_HOST_DEVADDR(_n, _s, _f) \
  DEFINE_PROP(_n, _s, _f, qdev_prop_pci_host_devaddr, PCIHostDeviceAddress)
  #define DEFINE_PROP_OFF_AUTO_PCIBAR(_n, _s, _f, _d) \
diff --git a/hw/block/block.c b/hw/block/block.c
index 5f8ebff59c..cd95e7e38f 100644
--- a/hw/block/block.c
+++ b/hw/block/block.c
@@ -96,6 +96,17 @@ bool blkconf_blocksizes(BlockConf *conf, Error **errp)
  return false;
  }
  
+/*

+ * all devices which support min_io_size (scsi and virtio-blk) expose it to
+ * the guest as a uint16_t in units of logical blocks
+ */
+if ((conf->min_io_size / conf->logical_block_size) > UINT16_MAX) {
+error_setg(errp,
+   "min_io_size must be no more than " stringify(UINT16_MAX)
+   " of logical_block_size");
+return false;
+}
+
  if (conf->opt_io_size % conf->logical_block_size) {
  error_setg(errp,
 "opt_io_size must be a multple of logical_block_size");
diff --git a/hw/core/qdev-properties.c b/hw/core/qdev-properties.c
index cc924815da..fd03cc7597 100644
--- a/hw/core/qdev-properties.c
+++ b/hw/core/qdev-properties.c
@@ -14,6 +14,7 @@
  #include "qapi/visitor.h"
  #include "chardev/char.h"
  #include "qemu/uuid.h"
+#include "qemu/units.h"
  
  void qdev_prop_set_after_realize(DeviceState *dev, const char *name,

Error **errp)
@@ -729,30 +730,42 @@ const PropertyInfo qdev_prop_pci_devfn = {
  
  /* --- blocksize --- */
  
+/* lower limit is sector size */

+#define MIN_BLOCK_SIZE  512
+#define MIN_BLOCK_SIZE_STR  "512 B"
+/*
+ * upper limit is arbitrary, 2 MiB looks sufficient for all sensible uses, and
+ * matches qcow2 cluster size limit
+ */
+#define MAX_BLOCK_SIZE  (2 * MiB)


Can you split this patch?

- add/use definitions (here MAX_BLOCK_SIZE = 32 * Ki