On 07/03/2019 18.15, Michal Privoznik wrote:
> On 3/1/19 12:10 PM, Thomas Huth wrote:
>> When running virt-host-validate on an s390x host, the tool currently
>> warns
>> that it is "Unknown if this platform has IOMMU support". We can use the
>> common check for entries in /sys/kernel/iommu_groups here, too, but it
>> only
>> makes sense to check it if there are also PCI devices available. It's
>> also
>> common on s390x that there are no PCI devices assigned to the LPAR,
>> and in
>> that case there is no need for the PCI-related IOMMU, so without PCI
>> devices
>> we should simply skip this test.
>>
>> Signed-off-by: Thomas Huth <thuth@xxxxxxxxxx>
>> ---
>> v2:
>> - Use virDirOpen() + virDirRead() instead of stat() - this should
>> hopefully
>> work now as expected.
>>
>> tools/virt-host-validate-common.c | 22 +++++++++++++++++-----
>> 1 file changed, 17 insertions(+), 5 deletions(-)
>>
>> diff --git a/tools/virt-host-validate-common.c
>> b/tools/virt-host-validate-common.c
>> index 73e3bdb..e27b558 100644
>> --- a/tools/virt-host-validate-common.c
>> +++ b/tools/virt-host-validate-common.c
>> @@ -337,7 +337,12 @@ int virHostValidateIOMMU(const char *hvname,
>> virBitmapPtr flags;
>> struct stat sb;
>> const char *bootarg = NULL;
>> - bool isAMD = false, isIntel = false, isPPC = false;
>> + bool isAMD = false, isIntel = false;
>> + virArch arch = virArchFromHost();
>> + struct dirent *dent;
>> + DIR *dir;
>> + int rc;
>> +
>> flags = virHostValidateGetCPUFlags();
>> if (flags && virBitmapIsBitSet(flags,
>> VIR_HOST_VALIDATE_CPU_FLAG_VMX))
>> @@ -347,8 +352,6 @@ int virHostValidateIOMMU(const char *hvname,
>> virBitmapFree(flags);
>> - 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) {
>> @@ -373,8 +376,17 @@ int virHostValidateIOMMU(const char *hvname,
>> "hardware platform");
>> return -1;
>> }
>> - } else if (isPPC) {
>> + } else if (ARCH_IS_PPC64(arch)) {
>> /* Empty Block */
>> + } else if (ARCH_IS_S390(arch)) {
>> + /* On s390x, we skip the IOMMU check if there are no PCI devices
>> + * (which is quite usual on s390x) */
>> + if (!virDirOpen(&dir, "/sys/bus/pci/devices"))
>> + return 0;
>> + rc = virDirRead(dir, &dent, NULL);
>> + VIR_DIR_CLOSE(dir);
>
> Is this diropen and dirread really necessary?
Yes.
> I mean, would something
> like plain test of the path presence be okay, e.g.
> virFileExists("/sys/bus/pci/devices").
No, that's unfortunately not enough. The "/sys/bus/pci/devices"
directory is always present, even if there are no PCI devices available,
it's just empty in that case. So as far as I can see, the dirread is
necessary here.
Thomas
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