[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] x86/vLAPIC: adjust types in internal read/write handling
On 22/06/15 12:49, Jan Beulich wrote: > - use 32-bit types where possible (produces slightly better code) > - drop (now) unnecessary casts > - avoid indirection where not needed > - avoid duplicate log messages in vlapic_write() > - minor other cleanup > > Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx> Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>, with two suggestions. > > @@ -847,47 +834,41 @@ static int vlapic_write(struct vcpu *v, > * According to the IA32 Manual, all accesses should be 32 bits. > * Some OSes do 8- or 16-byte accesses, however. > */ > - val = (uint32_t)val; > - if ( len != 4 ) > + if ( unlikely(len != 4) ) > { > - unsigned int tmp; > - unsigned char alignment; > - > - gdprintk(XENLOG_INFO, "Notice: Local APIC write with len = > %lx\n",len); > - > - alignment = offset & 0x3; > - (void)vlapic_read_aligned(vlapic, offset & ~0x3, &tmp); > + unsigned int tmp = vlapic_read_aligned(vlapic, offset & ~3); > + unsigned char alignment = (offset & 3) * 8; > > switch ( len ) > { > case 1: > - val = ((tmp & ~(0xff << (8*alignment))) | > - ((val & 0xff) << (8*alignment))); > + val = ((tmp & ~(0xff << alignment)) | > + ((val & 0xff) << alignment)); These should probably be explicitly unsigned constants, to avoid issues with shifting a 1 into the sign bit. (I can't quite decide whether 0xff will be interpreted as signed or unsigned, given the integer promotion rules.) > break; > > case 2: > if ( alignment & 1 ) > goto unaligned_exit_and_crash; > - val = ((tmp & ~(0xffff << (8*alignment))) | > - ((val & 0xffff) << (8*alignment))); > + val = ((tmp & ~(0xffff << alignment)) | > + ((val & 0xffff) << alignment)); > break; > > default: > - gdprintk(XENLOG_ERR, "Local APIC write with len = %lx, " > - "should be 4 instead\n", len); > + gprintk(XENLOG_ERR, "LAPIC write with len %lx\n", len); > goto exit_and_crash; > } > + > + gdprintk(XENLOG_INFO, "Notice: LAPIC write with len %lx\n", len); Probably better using %lu. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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