Hi Geert, On Tue, Mar 19, 2019 at 10:34 PM Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote: > > Hi Magnus, > > On Tue, Mar 19, 2019 at 2:24 PM Magnus Damm <magnus.damm@xxxxxxxxx> wrote: > > From: Magnus Damm <damm+renesas@xxxxxxxxxxxxx> > > > > Add a memory bank location check to the whitelist handling. > > > > Signed-off-by: Magnus Damm <damm+renesas@xxxxxxxxxxxxx> > > Thanks for your patch! > > > --- 0001/drivers/iommu/ipmmu-vmsa.c > > +++ work/drivers/iommu/ipmmu-vmsa.c 2019-03-19 21:04:43.000000000 +0900 > > @@ -17,6 +17,7 @@ > > #include <linux/io.h> > > #include <linux/io-pgtable.h> > > #include <linux/iommu.h> > > +#include <linux/memblock.h> > > #include <linux/of.h> > > #include <linux/of_device.h> > > #include <linux/of_iommu.h> > > @@ -797,6 +798,12 @@ static bool ipmmu_slave_whitelist(struct > > if (!soc_device_match(soc_rcar_gen3_whitelist)) > > return false; > > > > + /* In case all system memory fits within 32 bits of physical space > > + * then assume the IPMMU will not be needed for address expansion. > > + */ > > + if (memblock_end_of_DRAM() <= SZ_4G) > > + return false; > > The IPMMU may still be useful for IO virtualization, with KVM+VFIO. You're right. > Perhaps the check can be enhanced to keep it enabled when the CPU cores > are running in HYP mode? That might indeed be useful. Next quarter perhaps you and I can discuss a bit about IO virtualization with KVM? Cheers, / magnus
