@rafaeldtinoco: I found some forther more ugly detail for the stepping change from 5 to 6. Qemu 3.1 as in Disco had Cascade lake with the stepping 5. So for Disco the SRU will change the definition. Which is different to Bionic/Cosmic where we can say "our Cascade definition will just always have been 6" since it didn't exist before the SRU
You'll spot that when you start to create the branch for disco Note: cosmic has none of the types Due to that for those users who have set up guests to use "Cascadelake- Server" the SRU on Disco (or the respective cloud archive) will make them need to restart the guest before they can migrate it to a system with the updates applied. For bionic/cosmic users things will be fine as they have nothing->stepping6 And Eoan will be released with stepping 6 I think that is a drawback, but a tradeoff that we will have to make for the overall gain for much more users. But we need to declare that in the regression considerations of the bug when pushing the SRU. @rafaeldtinoco: when you have branches and PPAs for Disco as well, could you spawn a Cascadelake-Server guest on a node without the upgrade and then migrate to a note with the upgrade? I expect an issue, but we should know how exactly it looks. Once we do we will add that to the SRU template in the description. -- 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: Confirmed Status in qemu package in Ubuntu: Confirmed Status in linux source package in Bionic: New Status in qemu source package in Bionic: Confirmed Status in linux source package in Cosmic: New Status in qemu source package in Cosmic: Confirmed Status in linux source package in Disco: New Status in qemu source package in Disco: Confirmed Status in linux source package in Eoan: Confirmed Status in qemu source package in Eoan: Confirmed 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
