Messages in this thread | | | Subject | Re: [PATCH v7 6/6] x86/split_lock: Fix the split lock #AC handling when running as guest | From | Xiaoyao Li <> | Date | Fri, 15 Oct 2021 09:30:06 +0800 |
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On 10/14/2021 11:04 PM, Sean Christopherson wrote: > On Thu, Oct 14, 2021, Xiaoyao Li wrote: >> On 10/14/2021 5:32 AM, Sathyanarayanan Kuppuswamy wrote: >>> + Xiaoyao >>> >>> On 10/13/21 1:30 PM, Sean Christopherson wrote: >>>> On Tue, Oct 05, 2021, Kuppuswamy Sathyanarayanan wrote: >>>>> From: Xiaoyao Li <xiaoyao.li@intel.com> >>>>> >>>>> If running as guest and hypervisor enables >>>>> MSR_TEST_CTRL.SPLIT_LOCK_DETECT during its running, it can get split >>>>> lock #AC even though sld_state is sld_off. >>>> That's a hypervisor bug, no? The hypervisor should never inject a fault >>>> that the guest cannot reasonably expect. >> >> What if hypervisor doesn't intercept #AC and host enables SPLIT_LOCK_DETECT >> during guest running? That's exactly the case TDX is facing. > > That's a hypervisor bug. Since it sounds like the TDX Module buries its head in > the sand for split-lock #AC, KVM should refuse to run TDX guests if split-lock #AC > is enabled. Ideally the TDX Module would provide support for conditionally > intercepting #AC, e.g. intercept and re-inject "normal" #AC, and exit to the VMM > for split-lock #AC. That would give VMMs the option of enabling split-lock > detection in fatal mode for guests. >
We have bus lock VM exit for it.
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