Messages in this thread | | | Subject | Re: [PATCH 1/5] KVM: nVMX: Fix VMX controls MSRs setup when nested VMX enabled | From | Xiaoyao Li <> | Date | Sat, 29 Aug 2020 10:51:47 +0800 |
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On 8/29/2020 9:49 AM, Chenyi Qiang wrote: > > > On 8/29/2020 1:43 AM, Jim Mattson wrote: >> On Fri, Aug 28, 2020 at 1:54 AM Chenyi Qiang <chenyi.qiang@intel.com> >> wrote: >>> >>> KVM supports the nested VM_{EXIT, ENTRY}_LOAD_IA32_PERF_GLOBAL_CTRL and >>> VM_{ENTRY_LOAD, EXIT_CLEAR}_BNDCFGS, but they doesn't expose during >>> the setup of nested VMX controls MSR. >>> >> >> Aren't these features added conditionally in >> nested_vmx_entry_exit_ctls_update() and >> nested_vmx_pmu_entry_exit_ctls_update()? >> > > Yes, but I assume vmcs_config.nested should reflect the global > capability of VMX MSR. KVM supports these two controls, so should be > exposed here.
No. I prefer to say they are removed conditionally in nested_vmx_entry_exit_ctls_update() and nested_vmx_pmu_entry_exit_ctls_update().
Userspace calls vmx_get_msr_feature() to query what KVM supports for these VMX MSR. In vmx_get_msr_feature(), it returns the value of vmcs_config.nested. As KVM supports these two bits, we should advertise them in vmcs_config.nested and report to userspace.
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