Skip to contentSkip to conversation

New: nVMX: Downgrading nested VMX features from user-space

Bug 54461 [email protected] 1 participant 3 messages Feb 25, 2013 – Mar 17, 2015 KVM

lore
Share & tools
lore

[email protected]

author
#0 lore raw

https://bugzilla.kernel.org/show_bug.cgi?id=54461

Summary: nVMX: Downgrading nested VMX features from user-space
Product: Virtualization
Version: unspecified
Platform: All
OS/Version: Linux
Tree: Mainline
Status: NEW
Severity: enhancement
Priority: P1
Component: kvm
AssignedTo: [email protected]
ReportedBy: [email protected]
Regression: No

In nested SVM, the sub-features of SVM are all part of CPUID, so we already have a user-space interface (KVM_GET_SUPPORTED_CPUID/KVM_SET_CPUID2) to set a guest's features - which is, for example, useful for dictating a fixed set of features across different hosts.

However, in nested VMX, the VMX sub-features offered or not to the guest are not in CPUID, but rather in MSRs, and currently the nested_vmx_setup_ctls_msrs() function determines their value - without any option for user space to control this. We need some sort of new KVM_SET_READONLY_MSRS ioctl for overriding (downgrading) nested_vmx_setup_ctls_msrs()'s decisions for a particular guest.

Signature · 3 lines
Configure bugmail: https://bugzilla.kernel.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are watching the assignee of the bug.
author
#1 lore raw

[Bug 54461] nVMX: Downgrading nested VMX features from user-space

https://bugzilla.kernel.org/show_bug.cgi?id=54461

Nadav Har'El <[email protected]> changed:

What |Removed |Added
----------------------------------------------------------------------------

             Blocks|                            |53601
Signature · 3 lines
Configure bugmail: https://bugzilla.kernel.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are watching the assignee of the bug.