[libvirt] [PATCH v2] virt-host-validate: Fix warning for IOMMU detection on PPC

[Nitesh Konkar]

Hello John,

In case of PPC, IOMMU in the host kernel either has it or not compiled in.
The  /sys/kernel/iommu_groups check is good enough to verify if it was
compiled with the kernel or not.

If not, then we can have a ppc specific message there:


    virHostMsgCheck(hvname, "%s", _("if IOMMU is enabled by kernel"));
    if (sb.st_nlink <= 2) {
        if(!isPPC) {
            virHostMsgFail(level,
                           "IOMMU appears to be disabled in kernel. "
                           "Add %s to kernel cmdline arguments", bootarg);
        } else {
            virHostMsgFail(level,
                           "IOMMU capability not compiled into kernel. ");

        }
        return -1;
    }
    virHostMsgPass();
    return 0;



On Wed, Aug 23, 2017 at 7:06 PM, John Ferlan <jferlan at redhat.com> wrote:

>
>
> On 08/17/2017 09:48 AM, Nitesh Konkar wrote:
> > Fix the warning generated on PPC by virt-host-validate
> > for IOMMU
> >
> > Signed-off-by: Nitesh Konkar <nitkon12 at linux.vnet.ibm.com>
> > ---
> >  tools/virt-host-validate-common.c | 10 +++++++---
> >  1 file changed, 7 insertions(+), 3 deletions(-)
> >
> > diff --git a/tools/virt-host-validate-common.c
> b/tools/virt-host-validate-common.c
> > index 6faed04..51fa8c0 100644
> > --- a/tools/virt-host-validate-common.c
> > +++ b/tools/virt-host-validate-common.c
> > @@ -35,6 +35,7 @@
> >  #include "virfile.h"
> >  #include "virt-host-validate-common.h"
> >  #include "virstring.h"
> > +#include "virarch.h"
> >
> >  #define VIR_FROM_THIS VIR_FROM_NONE
> >
> > @@ -442,8 +443,7 @@ int virHostValidateIOMMU(const char *hvname,
> >      virBitmapPtr flags;
> >      struct stat sb;
> >      const char *bootarg = NULL;
> > -    bool isAMD = false, isIntel = false;
> > -
> > +    bool isAMD = false, isIntel = false, isPPC = false;
> >      flags = virHostValidateGetCPUFlags();
> >
> >      if (flags && virBitmapIsBitSet(flags, VIR_HOST_VALIDATE_CPU_FLAG_
> VMX))
> > @@ -453,9 +453,10 @@ int virHostValidateIOMMU(const char *hvname,
> >
> >      virBitmapFree(flags);
> >
> > -    virHostMsgCheck(hvname, "%s", _("for device assignment IOMMU
> support"));
> > +    isPPC = ARCH_IS_PPC64(virArchFromHost());
> >
> >      if (isIntel) {
> > +        virHostMsgCheck(hvname, "%s", _("for device assignment IOMMU
> support"));
> >          if (access("/sys/firmware/acpi/tables/DMAR", F_OK) == 0) {
> >              virHostMsgPass();
> >              bootarg = "intel_iommu=on";
> > @@ -467,6 +468,7 @@ int virHostValidateIOMMU(const char *hvname,
> >              return -1;
> >          }
> >      } else if (isAMD) {
> > +        virHostMsgCheck(hvname, "%s", _("for device assignment IOMMU
> support"));
> >          if (access("/sys/firmware/acpi/tables/IVRS", F_OK) == 0) {
> >              virHostMsgPass();
> >              bootarg = "iommu=pt iommu=1";
> > @@ -477,6 +479,8 @@ int virHostValidateIOMMU(const char *hvname,
> >                             "hardware platform");
> >              return -1;
> >          }
> > +    } else if (isPPC) {
> > +        /* Empty Block */
>
> So there's nothing to check at all? Perhaps elaborate in the commit
> message...
>
>
> Still what happens when @bootarg isn't populated and by chance we fall
> into the:
>
> if (sb.st_nlink <= 2) {
> }
>
> condition below here?  You'll get "Add <nil>..."
>
> Or can we not get to that code?  I'm not PPC and IOMMU aware, so I'm
> asking...
>
> Tks,
>
> John
>
> >      } else {
> >          virHostMsgFail(level,
> >                         "Unknown if this platform has IOMMU support");
> >
>
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