Bug 1887368

Summary: Expose default RAM ID
Product: Red Hat Enterprise Linux Advanced Virtualization Reporter: Michal Privoznik <mprivozn>
Component: qemu-kvmAssignee: Virtualization Maintenance <virt-maint>
qemu-kvm sub component: Machine Types QA Contact: Yumei Huang <yuhuang>
Status: CLOSED CURRENTRELEASE Docs Contact:
Severity: unspecified    
Priority: medium CC: ailan, berrange, crobinso, jinqi, jinzhao, jsuchane, juzhang, lmen, marcandre.lureau, mprivozn, virt-maint, yalzhang
Version: 8.4Keywords: Triaged, Upstream
Target Milestone: rc   
Target Release: 8.4   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of: 1839034 Environment:
Last Closed: 2021-11-17 14:56:19 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 1839034    

Description Michal Privoznik 2020-10-12 09:17:04 UTC 
+++ This bug was initially created as a clone of Bug #1839034 +++

Description of problem:

When libvirt wants to use memory-backend-* even for regular guest memory it needs to know the default RAM ID which was exposed by the following commit:

commit c556600598afc6e90ae52a2e9ce910b8842244c5
Author:     Michal Privoznik <mprivozn>
AuthorDate: Tue May 26 10:25:35 2020 +0200
Commit:     Eduardo Habkost <ehabkost>
CommitDate: Wed Aug 19 10:45:21 2020 -0400

    qmp: Expose MachineClass::default_ram_id
    
    If a management application (like Libvirt) want's to preserve
    migration ability and switch to '-machine memory-backend' it
    needs to set exactly the same RAM id as QEMU would. Since the id
    is machine type dependant, expose it under 'query-machines'
    result. Some machine types don't have the attribute set (riscv
    family for example), therefore the QMP attribute must be
    optional.
    
    Signed-off-by: Michal Privoznik <mprivozn>
    Message-Id: <9384422f63fe594a54d801f9cb4539b1d2ce9b67.1590481402.git.mprivozn>
    Reviewed-by: Igor Mammedov <imammedo>
    [ehabkost: updated doc to "since 5.2"]
    Signed-off-by: Eduardo Habkost <ehabkost>


https://git.qemu.org/?p=qemu.git;a=commit;h=c556600598afc6e90ae52a2e9ce910b8842244c5


If the default RAM ID is not exposed then libvirt falls back to the old (deprecated?) -mem-path.
Comment 2 John Ferlan 2021-09-09 13:44:13 UTC 
Bulk update: Move RHEL-AV bugs to RHEL9. If necessary to resolve in RHEL8, then clone to the current RHEL8 release.
Comment 3 John Ferlan 2021-11-17 14:56:19 UTC 
Move "back" to RHEL-AV and closing as CURRENTRELEASE to follow cloned from bug 1839034 which was resolved in RHEL-AV 8.4.0