Messages in this thread | | | From | Lai Jiangshan <> | Date | Tue, 30 Nov 2021 19:18:32 +0800 | Subject | Re: [RFC PATCH v3 53/59] KVM: x86: Add a helper function to restore 4 host MSRs on exit to user space |
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On Tue, Nov 30, 2021 at 4:10 PM Chao Gao <chao.gao@intel.com> wrote:
> > No, it is already documented in public spec.
In intel-tdx-module-1.5-base-spec-348549001.pdf, page 79 "recoverability hist", I think it is a "hint".
> > TDX module spec just says some MSRs are reset to INIT state by TDX module > (un)conditionally during TD exit. When to restore these MSRs to host's > values is decided by host. >
Sigh, it is quite a common solution to reset a register to a default value here, for example in VMX, the host GDT.limit and host TSS.limit is reset after VMEXIT, so load_fixmap_gdt() and invalidate_tss_limit() have to be called in host in vmx_vcpu_put().
Off-topic: Is it a good idea to also put load_fixmap_gdt() and invalidate_tss_limit() in user-return-notfier?
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