** Changed in: qemu (Ubuntu Disco)
Status: Confirmed => In Progress
** Changed in: qemu (Ubuntu Cosmic)
Status: Confirmed => In Progress
** Changed in: qemu (Ubuntu Eoan)
Assignee: Rafael David Tinoco (rafaeldtinoco) => Christian Ehrhardt
(paelzer)
** Changed in: qemu (Ubuntu Bionic)
Status: Confirmed => In Progress
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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 linux package in Ubuntu:
In Progress
Status in qemu package in Ubuntu:
In Progress
Status in linux source package in Bionic:
Confirmed
Status in qemu source package in Bionic:
In Progress
Status in linux source package in Cosmic:
Confirmed
Status in qemu source package in Cosmic:
In Progress
Status in linux source package in Disco:
Confirmed
Status in qemu source package in Disco:
In Progress
Status in linux source package in Eoan:
In Progress
Status in qemu source package in Eoan:
In Progress
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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