On 10/1/24 10:51, Xin Li wrote: ...>> Also, what's the purpose of clearing GUEST_IA32_FRED_RSP[123] at >> init_vmcs() time? I would have thought that those values wouldn't >> matter until the VMCS gets loaded at vmx_vcpu_load_vmcs() when they are >> overwritten anyway. Or, I could be just totally misunderstanding how >> KVM consumes the VMCS. 🙂 > > I don't see any misunderstanding. However we just do what the SDM > claims, even it seems that it's not a must *logically*. > > FRED spec says: > The RESET state of each of the new MSRs is zero. INIT does not change > the value of the new MSRs Oh, sorry. I was misreading the "HOST_" and "GUEST_" MSR prefixes. I thought the same VMCS field was being written at VMCS load *and* init time (which it isn't). Sorry for the noise.