## USING HOST CPU ONLY:

sudo /usr/bin/qemu-system-x86_64 -name guest="guest" -machine accel=kvm
-cpu host -m 2048 -realtime mlock=off -smp 1,sockets=1,cores=1,threads=1
-uuid 7e55c71a-558f-412c-8445-db0e95fc549f -display none -no-user-config
-nodefaults -rtc base=utc,driftfix=slew -global kvm-
pit.lost_tick_policy=delay -no-shutdown -global PIIX4_PM.disable_s3=1
-global PIIX4_PM.disable_s4=1 -boot strict=on -kernel
/var/lib/libvirt/images/guest/vmlinuz -initrd
/var/lib/libvirt/images/guest/initrd.img -append "root=/dev/vda noresume
console=tty0 console=ttyS0,38400n8 apparmor=0 net.ifnames=0
crashkernel=256M" -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2
-drive
file=/var/lib/libvirt/images/guest/disk01.ext4.qcow2,format=qcow2,if=none,id
=drive-virtio-disk0 -device virtio-blk-
pci,scsi=off,bus=pci.0,addr=0x3,drive=drive-virtio-disk0,id=virtio-
disk0,bootindex=1 -device virtio-balloon-
pci,id=balloon0,bus=pci.0,addr=0x4 -msg timestamp=on -serial stdio

flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
mca cmov pat pse36 clflush mmx fxsr sse sse2 ss syscall nx pdpe1gb
rdtscp lm constant_tsc arch_perfmon rep_good nopl xtopology cpuid
tsc_known_freq pni pclmulqdq vmx ssse3 fma cx16 pcid sse4_1 sse4_2
x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand
hypervisor lahf_lm abm 3dnowprefetch cpuid_fault invpcid_single ssbd
ibrs ibpb ibrs_enhanced tpr_shadow vnmi flexpriority ept vpid fsgsbase
tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid rtm mpx avx512f avx512dq
rdseed adx smap clflushopt clwb avx512cd avx512bw avx512vl xsaveopt
xsavec xgetbv1 xsaves arat umip pku ospke avx512_vnni md_clear
arch_capabilities

bugs            : spectre_v1 spectre_v2 spec_store_bypass mds

## ARCH_CAPABILITIES + MITIGATION FLAGS ARGUMENTS GIVEN

sudo /usr/bin/qemu-system-x86_64 -name guest="guest" -machine accel=kvm
-cpu host,arch_capabilities=on,ssbd=on,md-clear=on,rdctl-no=yes,ibrs-
all=yes,skip-l1dfl-vmentry=yes -m 2048 -realtime mlock=off -smp
1,sockets=1,cores=1,threads=1 -uuid 7e55c71a-558f-412c-8445-db0e95fc549f
-display none -no-user-config -nodefaults -rtc base=utc,driftfix=slew
-global kvm-pit.lost_tick_policy=delay -no-shutdown -global
PIIX4_PM.disable_s3=1 -global PIIX4_PM.disable_s4=1 -boot strict=on
-kernel /var/lib/libvirt/images/guest/vmlinuz -initrd
/var/lib/libvirt/images/guest/initrd.img -append "root=/dev/vda noresume
console=tty0 console=ttyS0,38400n8 apparmor=0 net.ifnames=0
crashkernel=256M" -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2
-drive
file=/var/lib/libvirt/images/guest/disk01.ext4.qcow2,format=qcow2,if=none,id
=drive-virtio-disk0 -device virtio-blk-
pci,scsi=off,bus=pci.0,addr=0x3,drive=drive-virtio-disk0,id=virtio-
disk0,bootindex=1 -device virtio-balloon-
pci,id=balloon0,bus=pci.0,addr=0x4 -msg timestamp=on -serial stdio

flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
mca cmov pat pse36 clflush mmx fxsr sse sse2 ss syscall nx pdpe1gb
rdtscp lm constant_tsc arch_perfmon rep_good nopl xtopology cpuid
tsc_known_freq pni pclmulqdq vmx ssse3 fma cx16 pcid sse4_1 sse4_2
x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand
hypervisor lahf_lm abm 3dnowprefetch cpuid_fault invpcid_single ssbd
ibrs ibpb ibrs_enhanced tpr_shadow vnmi flexpriority ept vpid fsgsbase
tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid rtm mpx avx512f avx512dq
rdseed adx smap clflushopt clwb avx512cd avx512bw avx512vl xsaveopt
xsavec xgetbv1 xsaves arat umip pku ospke avx512_vnni md_clear
arch_capabilities

bugs            : spectre_v1 spectre_v2 spec_store_bypass mds

-- 
You received this bug notification because you are a member of Kernel
Packages, which is subscribed to linux in Ubuntu.
https://bugs.launchpad.net/bugs/1828495

Title:
  [KVM][CLX] CPUID_7_0_EDX_ARCH_CAPABILITIES is not enabled in VM.

Status in intel:
  New
Status in libvirt package in Ubuntu:
  Fix Released
Status in linux package in Ubuntu:
  In Progress
Status in qemu package in Ubuntu:
  Fix Released
Status in libvirt source package in Bionic:
  Confirmed
Status in linux source package in Bionic:
  Confirmed
Status in qemu source package in Bionic:
  Fix Committed
Status in libvirt source package in Cosmic:
  Won't Fix
Status in linux source package in Cosmic:
  Won't Fix
Status in qemu source package in Cosmic:
  Won't Fix
Status in libvirt source package in Disco:
  Confirmed
Status in linux source package in Disco:
  Confirmed
Status in qemu source package in Disco:
  Fix Committed
Status in libvirt source package in Eoan:
  Fix Released
Status in linux source package in Eoan:
  In Progress
Status in qemu source package in Eoan:
  Fix Released

Bug description:
  [Impact]

   * QEMU does not support IceLake and CascadeLake CPUs specific features.
   * Most important feature to be supported is: IA32_ARCH_CAPABILITIES MSR.
   * With IA32_ARCH_CAPABILITIES, QEMU is able to advertise HW mitigations:
     - Rogue Data Cache Load
     - Enhanced IBRS
     - RSB Alternate
     - L1D flush need on VMENTRY
     - speculative Store Bypass
     to guests, as described in document:
     Intel 336996-Speculative-Execution-Side-Channel-Mitigations.pdf

  [Test Case]

   * From Original Description:

  """
  1. Boot up guest using: -cpu Cascadelake-Server

  [root@clx-2s2 yexin]# qemu-system-x86_64 -accel kvm -drive
  if=virtio,id=hd,file=/home/x/x,format=qcow2  -m 4096 -smp 4 -cpu
  Cascadelake-Server -serial stdio

  char device redirected to /dev/pts/3 (label serial0)

  qemu-system-x86_64: warning: host doesn't support requested feature:
  CPUID.07H:ECX [bit 4]

  qemu-system-x86_64: warning: host doesn't support requested feature:
  CPUID.07H:ECX [bit 4]

  qemu-system-x86_64: warning: host doesn't support requested feature:
  CPUID.07H:ECX [bit 4]

  qemu-system-x86_64: warning: host doesn't support requested feature:
  CPUID.07H:ECX [bit 4]

  2. To check CPU ID related to features[FEAT_7_0_EDX]
  :CPUID_7_0_EDX_ARCH_CAPABILITIES

  Expected Result: Both host and guest's CPUID.07H EDX bit 29 should be
  1.

  Actual Result:

  Host's cpuid: 0x00000007 0x00: eax=0x00000000 ebx=0xd39ffffb
  ecx=0x00000818 edx=0xbc000000  (EDX bit 29=1)

  Guest's cpuid : 0x00000007 0x00: eax=0x00000000 ebx=0xd19f0fb9
  ecx=0x00000818 edx=0x84000000 (EDX bit 29=0)

  Commit:2bdb76c015df7125783d8394d6339d181cb5bc30

  Target Kerned: 5.1
  Target Release: 19.10

  """

  [Regression Potential]

   * Most changes are related to CPU type definitions and its supported
  features. They are all based in upstream changes but, for obvious
  reasons, backporting and/or cherry-picking those could bring issues.
  Biggest concern is breaking something that currently works. Right now,
  the parts being changed that could affect other CPU types would be
  related to a small refactoring of how the features are organized, and
  that would be seen right away when trying to start a new VM after the
  package is installed.

   * Other tests, related to the features being backported, are being
  done by our KVM regression tests, including migration combinations, to
  reduce chances that a regression is introduced.

  [Other Info]
   
   * N/A

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