On Thu, 19 Oct 2023 18:06:57 +0200, Maciej S. Szmigiero wrote: > Hyper-V enabled Windows Server 2022 KVM VM cannot be started on Zen1 Ryzen > since it crashes at boot with SYSTEM_THREAD_EXCEPTION_NOT_HANDLED + > STATUS_PRIVILEGED_INSTRUCTION (in other words, because of an unexpected #GP > in the guest kernel). > > This is because Windows tries to set bit 8 in MSR_AMD64_TW_CFG and can't > handle receiving a #GP when doing so. > > [...] Applied to kvm-x86 misc, thanks! I added a paragraph at the end of the changelog to capture the gist of the discussion on why we agreed that having KVM eat MSR accesses is the least awful option. I also tagged this for stable. Paolo, holler if you want to grab this for v6.6 and I'll drop my copy. [1/1] KVM: x86: Ignore MSR_AMD64_TW_CFG access https://github.com/kvm-x86/linux/commit/2770d4722036 -- https://github.com/kvm-x86/linux/tree/next