Re: [Qemu-devel] Re: [RESEND][PATCH] Add 40-bit DMA support to LSI scsi emulation

[M. Warner Losh]

In message: <address@hidden>
            Anthony Liguori <address@hidden> writes:
: Blue Swirl wrote:
: > On 11/17/08, Ryan Harper <address@hidden> wrote:
: >   
: >>  Looking for some feedback on this patch, MAINTAINERS points to Paul for
: >>  scsi stuff, and I saw Blue Swirl commit a scsi patch recently.
: >>
: >>  This patch fixes Linux machines configured with > 4G of ram and using a
: >>  SCSI device.  I'm working on 64-bit DMA support as well which should
: >>  hopefully fix 64-bit Windows using SCSI devices as well.
: >>     
: >
: >     addr = s->dnad;
: > +    if (lsi_dma_40bit(s))
: > +        addr |= ((uint64_t)s->dnad64 << 32UL);
: > +    else if (s->sbms)
: > +        addr |= ((uint64_t)s->sbms << 32UL);
: >
: > Maybe the address could be calculated at script parsing phase for
: > small performance gain.
: >
: > I would use ULL instead of UL, because on 32 bit host long is still 32 bits.
: >   
: 
: But both ULL and UL are wrong for a shift operation.  It always takes an 
: integer.

Yes, the real issue is for something like
        1UL << 63
vs
        1ULL << 63

Warner