Re: [Qemu-devel] [PATCH 3/3] m25p80: change cur_addr to 32 bit integer

[Paolo Bonzini <pbonzini@redhat.com>]

> On 06/28/2016 10:39 AM, Paolo Bonzini wrote:
> > The maximum amount of storage that can be addressed by the m25p80 command
> > set is 4 GiB.  However, cur_addr is currently a 64-bit integer.  To avoid
> > further problems related to sign extension of signed 32-bit integer
> > expressions, change cur_addr to a 32 bit integer.  Preserve migration
> > format by adding a dummy 4-byte field in place of the (big-endian)
> > high four bytes in the formerly 64-bit cur_addr field.
> 
> I do not think that migration ever worked before. did it ?

Who knows. :)  But it is pretty easy to not break it further...

Paolo

> > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> 
> Reviewed-by: Cédric Le Goater <clg@kaod.org>
> 
> > ---
> >  hw/block/m25p80.c | 15 ++++++++-------
> >  1 file changed, 8 insertions(+), 7 deletions(-)
> > 
> > diff --git a/hw/block/m25p80.c b/hw/block/m25p80.c
> > index 76a9bcf..7668b22 100644
> > --- a/hw/block/m25p80.c
> > +++ b/hw/block/m25p80.c
> > @@ -389,7 +389,7 @@ typedef struct Flash {
> >      uint32_t pos;
> >      uint8_t needed_bytes;
> >      uint8_t cmd_in_progress;
> > -    uint64_t cur_addr;
> > +    uint32_t cur_addr;
> >      uint32_t nonvolatile_cfg;
> >      /* Configuration register for Macronix */
> >      uint32_t volatile_cfg;
> > @@ -535,9 +535,9 @@ static inline void flash_sync_dirty(Flash *s, int64_t
> > newpage)
> >  }
> >  
> >  static inline
> > -void flash_write8(Flash *s, uint64_t addr, uint8_t data)
> > +void flash_write8(Flash *s, uint32_t addr, uint8_t data)
> >  {
> > -    int64_t page = addr / s->pi->page_size;
> > +    uint32_t page = addr / s->pi->page_size;
> >      uint8_t prev = s->storage[s->cur_addr];
> 
> This routine needs a cleanup. It takes an 'addr' parameter (it is called
> with s->cur_addr) and uses s->cur_addr at the same time.
> 
> C.
> 
> >      if (!s->write_enable) {
> > @@ -545,7 +545,7 @@ void flash_write8(Flash *s, uint64_t addr, uint8_t
> > data)
> >      }
> >  
> >      if ((prev ^ data) & data) {
> > -        DB_PRINT_L(1, "programming zero to one! addr=%" PRIx64 "  %" PRIx8
> > +        DB_PRINT_L(1, "programming zero to one! addr=%" PRIx32 "  %" PRIx8
> >                     " -> %" PRIx8 "\n", addr, prev, data);
> >      }
> >  
> > @@ -1094,7 +1094,7 @@ static uint32_t m25p80_transfer8(SSISlave *ss,
> > uint32_t tx)
> >      switch (s->state) {
> >  
> >      case STATE_PAGE_PROGRAM:
> > -        DB_PRINT_L(1, "page program cur_addr=%#" PRIx64 " data=%" PRIx8
> > "\n",
> > +        DB_PRINT_L(1, "page program cur_addr=%#" PRIx32 " data=%" PRIx8
> > "\n",
> >                     s->cur_addr, (uint8_t)tx);
> >          flash_write8(s, s->cur_addr, (uint8_t)tx);
> >          s->cur_addr = (s->cur_addr + 1) & (s->size - 1);
> > @@ -1102,7 +1102,7 @@ static uint32_t m25p80_transfer8(SSISlave *ss,
> > uint32_t tx)
> >  
> >      case STATE_READ:
> >          r = s->storage[s->cur_addr];
> > -        DB_PRINT_L(1, "READ 0x%" PRIx64 "=%" PRIx8 "\n", s->cur_addr,
> > +        DB_PRINT_L(1, "READ 0x%" PRIx32 "=%" PRIx8 "\n", s->cur_addr,
> >                     (uint8_t)r);
> >          s->cur_addr = (s->cur_addr + 1) & (s->size - 1);
> >          break;
> > @@ -1199,7 +1199,8 @@ static const VMStateDescription vmstate_m25p80 = {
> >          VMSTATE_UINT32(pos, Flash),
> >          VMSTATE_UINT8(needed_bytes, Flash),
> >          VMSTATE_UINT8(cmd_in_progress, Flash),
> > -        VMSTATE_UINT64(cur_addr, Flash),
> > +        VMSTATE_UNUSED(4),
> > +        VMSTATE_UINT32(cur_addr, Flash),
> >          VMSTATE_BOOL(write_enable, Flash),
> >          VMSTATE_BOOL_V(reset_enable, Flash, 2),
> >          VMSTATE_UINT8_V(ear, Flash, 2),
> > 
> 
>