Re: [PATCH v9 19/22] KVM: nVMX: Handle FRED VMCS fields in nested VMX context

From: Chao Gao

Date: Tue Jan 20 2026 - 19:45:19 EST


On Mon, Jan 19, 2026 at 10:30:01PM -0800, Xin Li wrote:
>
>
>> On Dec 1, 2025, at 10:32 PM, Chao Gao <chao.gao@xxxxxxxxx> wrote:
>>
>>> +
>>> + nested_vmx_set_intercept_for_msr(vmx, msr_bitmap_l1, msr_bitmap_l0,
>>> + MSR_IA32_FRED_RSP0, MSR_TYPE_RW);
>>
>> Why is only this specific MSR handled? What about other FRED MSRs?
>
>Peter just gave a good explanation:
>
>https://lore.kernel.org/lkml/f0768546-a767-4d74-956e-b40128272a09@xxxxxxxxx/

Do you need to set up vmcs02's MSR bitmap for other FRED MSRs?

Other FRED MSRs are passed through to L1 guests in patch 8. Is there any
concern about passing through them to L2 guests?