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Date:   Mon, 27 Nov 2023 12:06:21 +0800
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Subject: Re: [PATCH v7 03/26] x86/fpu/xstate: Add CET supervisor mode state
 support
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To:     Peter Zijlstra <peterz@infradead.org>
CC:     <seanjc@google.com>, <pbonzini@redhat.com>,
        <dave.hansen@intel.com>, <kvm@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <chao.gao@intel.com>,
        <rick.p.edgecombe@intel.com>, <mlevitsk@redhat.com>,
        <john.allen@amd.com>
References: <20231124055330.138870-1-weijiang.yang@intel.com>
 <20231124055330.138870-4-weijiang.yang@intel.com>
 <20231124094502.GL3818@noisy.programming.kicks-ass.net>
From:   "Yang, Weijiang" <weijiang.yang@intel.com>
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On 11/24/2023 5:45 PM, Peter Zijlstra wrote:
> On Fri, Nov 24, 2023 at 12:53:07AM -0500, Yang Weijiang wrote:
>
>> Note, in KVM case, guest CET supervisor state i.e., IA32_PL{0,1,2}_MSRs,
>> are preserved after VM-Exit until host/guest fpstates are swapped, but
>> since host supervisor shadow stack is disabled, the preserved MSRs won't
>> hurt host.
> Just to be clear, with FRED all this changes, right? Then we get more
> VMCS fields for SSS state.

Yes, I think so, KVM needs to properly handle guest SSS state and host FRED states.

Thanks!