On Tue, Nov 08, 2016 at 06:40:35PM +0100, Alexander Gordeev wrote:
[...]
> > Looks like Linux is using memory barrior and volatile keywords to do
> > the protection (build_mmio_read() for x86). I think at least I can add
> > volatile here for each read/write to make it safer. Do you think
> > that'll suffice here? E.g.:
> >
> > static inline uint64_t vtd_readq(unsigned int reg)
> > {
> > return *(volatile uint64_t *)(Q35_HOST_BRIDGE_IOMMU_ADDR + reg);
> > }
>
> Yeah, I think with volatile it is better. But I am still missing
> why not just use read/write which already exist and use volatile:
>
> static inline u64 __raw_readq(const volatile void *addr)
> {
> assert(sizeof(unsigned long) == sizeof(u64));
> return *(const volatile u64 *)addr;
> }
That's nice! I'll use it. Thanks,
-- peterx
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
