[dpdk-stable] [PATCH v3 3/6] bus/pci: use IOVAs check when setting IOVA mode
Eelco Chaudron
echaudro at redhat.com
Tue Jul 10 12:14:30 CEST 2018
On 4 Jul 2018, at 14:53, 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.lucero at netronome.com>
> ---
> drivers/bus/pci/linux/pci.c | 15 +++++++++++----
> 1 file changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/bus/pci/linux/pci.c b/drivers/bus/pci/linux/pci.c
> index 74deef3..792c819 100644
> --- a/drivers/bus/pci/linux/pci.c
> +++ b/drivers/bus/pci/linux/pci.c
> @@ -43,6 +43,7 @@
> #include <rte_devargs.h>
> #include <rte_memcpy.h>
> #include <rte_vfio.h>
> +#include <rte_memory.h>
>
> #include "eal_private.h"
> #include "eal_filesystem.h"
> @@ -613,10 +614,12 @@
> fclose(fp);
>
> mgaw = ((vtd_cap_reg & VTD_CAP_MGAW_MASK) >> VTD_CAP_MGAW_SHIFT) +
> 1;
> - if (mgaw < X86_VA_WIDTH)
> +
> + if (!rte_eal_check_dma_mask(mgaw))
If think in this case we still need to check the X86_VA_WIDTH, i.e.
if (mgaw < X86_VA_WIDTH && !rte_eal_check_dma_mask(mgaw))
> + return true;
> + else
> return false;
>
> - return true;
> }
> #elif defined(RTE_ARCH_PPC_64)
> static bool
> @@ -640,13 +643,17 @@
> {
> 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) < 0)
> + return false;
> + iommu_dma_mask_check_done = 1;
Not sure why this change? Why do we only need to check one device on the
bus?
In addition, if this is what was intended, rather than a variable you
can return true in this case, or did you intended to clear the
iommu_dma_mask_check_done on every PCI BUS iteration?
> + }
> }
> }
> return true;
> --
> 1.9.1
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