On Thu, Oct 4, 2018 at 4:49 PM Burakov, Anatoly <anatoly.bura...@intel.com> wrote:
> On 04-Oct-18 2:35 PM, Alejandro Lucero wrote: > > > > > > On Wed, Oct 3, 2018 at 1:56 PM Burakov, Anatoly > > <anatoly.bura...@intel.com <mailto:anatoly.bura...@intel.com>> wrote: > > > > On 31-Aug-18 1:50 PM, Alejandro Lucero wrote: > > > Although VT-d emulation currently only supports 39 bits, it could > > > be iovas being within that supported range. This patch allows > > > IOVA mode in such a case. > > > > > > Indeed, memory initialization code can be modified for using lower > > > virtual addresses than those used by the kernel for 64 bits > processes > > > by default, and therefore memsegs iovas can use 39 bits or less > for > > > most system. And this is likely 100% true for VMs. > > > > > > Signed-off-by: Alejandro Lucero <alejandro.luc...@netronome.com > > <mailto:alejandro.luc...@netronome.com>> > > > --- > > > drivers/bus/pci/linux/pci.c | 15 ++++++++++----- > > > 1 file changed, 10 insertions(+), 5 deletions(-) > > > > > > diff --git a/drivers/bus/pci/linux/pci.c > > b/drivers/bus/pci/linux/pci.c > > > index 04648ac..215dc10 100644 > > > --- a/drivers/bus/pci/linux/pci.c > > > +++ b/drivers/bus/pci/linux/pci.c > > > @@ -588,10 +588,11 @@ > > > fclose(fp); > > > > > > mgaw = ((vtd_cap_reg & VTD_CAP_MGAW_MASK) >> > > VTD_CAP_MGAW_SHIFT) + 1; > > > - if (mgaw < X86_VA_WIDTH) > > > - return false; > > > > > > - return true; > > > + if (!rte_eal_check_dma_mask(mgaw)) > > > + return true; > > > + else > > > + return false; > > > > return rte_eal_check_dma_mask(mgaw) == 0; ? > > > > > > I guess that works and is more elegant. > > Thanks. > > > > > > > } > > > #elif defined(RTE_ARCH_PPC_64) > > > static bool > > > @@ -615,13 +616,17 @@ > > > { > > > struct rte_pci_device *dev = NULL; > > > struct rte_pci_driver *drv = NULL; > > > + int iommu_dma_mask_check_done = 0; > > > > > > FOREACH_DRIVER_ON_PCIBUS(drv) { > > > FOREACH_DEVICE_ON_PCIBUS(dev) { > > > if (!rte_pci_match(drv, dev)) > > > continue; > > > - if (!pci_one_device_iommu_support_va(dev)) > > > - return false; > > > + if (!iommu_dma_mask_check_done) { > > > + if > > (!pci_one_device_iommu_support_va(dev)) > > > + return false; > > > + iommu_dma_mask_check_done = 1; > > > + } > > > } > > > > The commit message doesn't explain why are we only checking a single > > device. Indeed, i am not 100% clear as to why, so some explanation in > > the commit message and preferably a comment in code would be more > than > > welcome :) > > > > > > Because the pci_one_device_iommu_support_va function does always the > > same whatever the device is used in the call. > > So, this code was always wrong and needlessly checked each device when > it could've checked it a single time? OK, that makes it a bit clearer. > Still, needs to be documented in comments/commit message :) The commit > message IMO looks quite irrelevant to what happens in the commit. It > almost feels like this commit should be split in two - first change the > mgaw check, and then fix the PCI bus code to not check needlessly. > > Ok. Maybe that's better. I will do that in next version. Thanks > -- > Thanks, > Anatoly >
