Re: [PATCH 2/2] iommu/amd: Remove performance counter pre-initialization test

[David Coe]

Hi Suravee!

Just in case (!), I've run your revert+update patch on kernel 5.11.0-13, 
Ubuntu 21.04β running on an AMD FX-8350 (pre Zen and IOMMUv2). As with 
the AMD Ryzen 2400G and 4700U, I'm finding no obvious issues.


$ sudo dmesg | grep IOMMU
[    0.948890] pci 0000:00:00.2: AMD-Vi: Found IOMMU cap 0x40
[    4.393773] AMD-Vi: AMD IOMMUv2 driver by Joerg Roedel <jroedel@xxxxxxx>
[    4.393776] AMD-Vi: AMD IOMMUv2 functionality not available on this 
system


$ systool -m kvm_amd -v
Module = "kvm_amd"

  Attributes:
    coresize            = "114688"
    initsize            = "0"
    initstate           = "live"
    refcnt              = "0"
    srcversion          = "4371BA17A41823101F90761"
    taint               = ""
    uevent              = <store method only>

  Parameters:
    avic                = "0"
    dump_invalid_vmcb   = "N"
    nested              = "1"
    npt                 = "1"
    nrips               = "1"
    pause_filter_count_grow= "2"
    pause_filter_count_max= "65535"
    pause_filter_count_shrink= "0"
    pause_filter_count  = "3000"
    pause_filter_thresh = "128"
    sev_es              = "0"
    sev                 = "0"
    vgif                = "0"
    vls                 = "0"

  Sections:


$ compgen -G "/sys/kernel/iommu_groups/*/devices/*"
/sys/kernel/iommu_groups/9/devices/0000:00:14.2
/sys/kernel/iommu_groups/0/devices/0000:00:00.0
/sys/kernel/iommu_groups/10/devices/0000:00:14.3
/sys/kernel/iommu_groups/2/devices/0000:00:04.0
/sys/kernel/iommu_groups/12/devices/0000:00:14.5
/sys/kernel/iommu_groups/4/devices/0000:00:0d.0
/sys/kernel/iommu_groups/14/devices/0000:00:16.0
/sys/kernel/iommu_groups/14/devices/0000:00:16.2
/sys/kernel/iommu_groups/6/devices/0000:00:12.0
/sys/kernel/iommu_groups/6/devices/0000:00:12.2
/sys/kernel/iommu_groups/16/devices/0000:02:00.0
/sys/kernel/iommu_groups/8/devices/0000:00:14.0
/sys/kernel/iommu_groups/1/devices/0000:00:02.0
/sys/kernel/iommu_groups/11/devices/0000:00:14.4
/sys/kernel/iommu_groups/3/devices/0000:00:0b.0
/sys/kernel/iommu_groups/13/devices/0000:00:15.3
/sys/kernel/iommu_groups/13/devices/0000:00:15.0
/sys/kernel/iommu_groups/13/devices/0000:06:00.0
/sys/kernel/iommu_groups/13/devices/0000:00:15.2
/sys/kernel/iommu_groups/13/devices/0000:07:00.0
/sys/kernel/iommu_groups/13/devices/0000:08:00.0
/sys/kernel/iommu_groups/13/devices/0000:00:15.1
/sys/kernel/iommu_groups/13/devices/0000:09:00.0
/sys/kernel/iommu_groups/5/devices/0000:00:11.0
/sys/kernel/iommu_groups/15/devices/0000:01:00.1
/sys/kernel/iommu_groups/15/devices/0000:01:00.0
/sys/kernel/iommu_groups/7/devices/0000:00:13.0
/sys/kernel/iommu_groups/7/devices/0000:00:13.2
/sys/kernel/iommu_groups/17/devices/0000:04:00.0


$ sudo kvm-ok
INFO: /dev/kvm exists
KVM acceleration can be used


$ perf list | grep iommu
No amd_iommu events

Best regards and many thanks.

--
David Coe