Hello quanxian, Could you clarify exactly what is the expected behaviour and what wasn't achieved ? We'd like to understand better the requirements, rather than having patches pointed out only. Mainly because there are some rules we usually follow for already released versions and some of them might be discussable and some might not.
Based on the thread you pointed out: ---- * Patch "i386: Infrastructure for versioned CPU models" was rewritten and split in two: * i386: Register versioned CPU models * i386: Make unversioned CPU models be aliases * -IBRS, -noTSX, -IBPB CPU models are now aliases * Enable rdctl-no, ibrs-all, skip-l1dfl-vmentry in Cascadelake-Server-v2 * New patch added: * i386: Get model-id from CPU object on "-cpu help" ---- Are you looking for the CPU versioning feature ? (Rather than only having stepping increased/decreased ?). Are you looking for Cascadelake- server-v2 CPU type ? Or on having, by default, the CPU flags rdctl-no, ibrs-all, skip-l1dfl-vmentry enabled ? I'm asking you this because, for backports, we are looking forward to enabling those features ad-hoc, and not by default (as they seem to be in the PPA). Specially because we have to guarantee compatibility in between QEMU diff versions migrations. This has been done already before, for some other requested features. Thank you very much in advance for your feedback. -- 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 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 To manage notifications about this bug go to: https://bugs.launchpad.net/intel/+bug/1828495/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
