From: Chao Gao <chao.gao@intel.com>
To: Xin Li <xin@zytor.com>
Cc: <linux-kernel@vger.kernel.org>, <kvm@vger.kernel.org>,
<linux-doc@vger.kernel.org>, <pbonzini@redhat.com>,
<seanjc@google.com>, <corbet@lwn.net>, <tglx@linutronix.de>,
<mingo@redhat.com>, <bp@alien8.de>, <dave.hansen@linux.intel.com>,
<x86@kernel.org>, <hpa@zytor.com>, <luto@kernel.org>,
<peterz@infradead.org>, <andrew.cooper3@citrix.com>,
<hch@infradead.org>, <sohil.mehta@intel.com>
Subject: Re: [PATCH v9 17/22] KVM: x86: Advertise support for FRED
Date: Tue, 20 Jan 2026 16:07:25 +0800 [thread overview]
Message-ID: <aW83vbC2KB6CZDvl@intel.com> (raw)
In-Reply-To: <71F2B269-4D29-4B23-9111-E43CDD09CF13@zytor.com>
On Mon, Jan 19, 2026 at 10:56:29PM -0800, Xin Li wrote:
>
>
>> On Nov 11, 2025, at 11:30 PM, Chao Gao <chao.gao@intel.com> wrote:
>>
>> I'm not sure if AMD CPUs support FRED, but just in case, we can clear FRED
>> i.e., kvm_cpu_cap_clear(X86_FEATURE_FRED) in svm_set_cpu_caps().
>
>AMD will support FRED, with ISA level compatibility:
>
>https://www.amd.com/en/blogs/2025/amd-and-intel-celebrate-first-anniversary-of-x86-ecosys.html
>
>Thus we don’t need to clear the bit.
In this case, we need to clear FRED for AMD.
The concern is that before AMD's FRED KVM support is implemented, FRED will be
exposed to userspace on AMD FRED-capable hardware. This may cause issues.
next prev parent reply other threads:[~2026-01-20 8:07 UTC|newest]
Thread overview: 106+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-26 20:18 [PATCH v9 00/22] Enable FRED with KVM VMX Xin Li (Intel)
2025-10-26 20:18 ` [PATCH v9 01/22] KVM: VMX: Enable support for secondary VM exit controls Xin Li (Intel)
2025-10-26 20:18 ` [PATCH v9 02/22] KVM: VMX: Initialize VM entry/exit FRED controls in vmcs_config Xin Li (Intel)
2026-01-20 9:24 ` Binbin Wu
2026-01-22 17:57 ` Xin Li
2025-10-26 20:18 ` [PATCH v9 03/22] KVM: VMX: Disable FRED if FRED consistency checks fail Xin Li (Intel)
2026-03-05 0:25 ` Sean Christopherson
2025-10-26 20:18 ` [PATCH v9 04/22] x86/cea: Prefix event stack names with ESTACK_ Xin Li (Intel)
2025-10-26 20:18 ` [PATCH v9 05/22] x86/cea: Use array indexing to simplify exception stack access Xin Li (Intel)
2025-10-27 15:49 ` Dave Hansen
2025-10-28 2:31 ` Xin Li
2026-01-30 13:42 ` Borislav Petkov
2025-10-26 20:18 ` [PATCH v9 06/22] x86/cea: Export __this_cpu_ist_top_va() to KVM Xin Li (Intel)
2025-10-27 15:50 ` Dave Hansen
2026-01-30 13:46 ` Borislav Petkov
2026-01-30 16:35 ` Xin Li
2026-01-30 17:56 ` Borislav Petkov
2026-03-07 7:38 ` Xin Li
2026-03-09 15:24 ` Sean Christopherson
2026-03-09 22:57 ` Xin Li
2025-10-26 20:18 ` [PATCH v9 07/22] KVM: VMX: Initialize VMCS FRED fields Xin Li (Intel)
2025-11-19 2:44 ` Chao Gao
2026-01-21 6:44 ` Binbin Wu
2026-01-21 18:14 ` Xin Li
2026-01-22 0:45 ` Xin Li
2026-01-22 1:56 ` Binbin Wu
2026-01-22 17:22 ` Xin Li
2026-03-04 16:23 ` Sean Christopherson
2026-03-05 5:27 ` Xin Li
2026-03-05 15:21 ` Sean Christopherson
2026-03-05 17:25 ` Xin Li
2025-10-26 20:18 ` [PATCH v9 08/22] KVM: VMX: Set FRED MSR intercepts Xin Li (Intel)
2025-11-12 5:49 ` Chao Gao
2026-03-05 0:48 ` Sean Christopherson
2026-03-05 5:56 ` Xin Li
2026-03-06 2:30 ` Chao Gao
2026-03-06 15:54 ` Sean Christopherson
2026-01-16 19:49 ` Dave Hansen
2026-01-17 0:43 ` H. Peter Anvin
2025-10-26 20:18 ` [PATCH v9 09/22] KVM: VMX: Save/restore guest FRED RSP0 Xin Li (Intel)
2025-11-12 5:59 ` Chao Gao
2026-01-21 7:23 ` Binbin Wu
2025-10-26 20:18 ` [PATCH v9 10/22] KVM: VMX: Add support for saving and restoring FRED MSRs Xin Li (Intel)
2025-11-12 6:16 ` Chao Gao
2025-12-01 6:20 ` Xin Li
2025-10-26 20:18 ` [PATCH v9 11/22] KVM: x86: Add a helper to detect if FRED is enabled for a vCPU Xin Li (Intel)
2025-11-12 6:19 ` Chao Gao
2026-01-21 8:05 ` Binbin Wu
2026-01-21 16:46 ` Xin Li
2026-01-21 20:24 ` Sean Christopherson
2026-01-21 22:38 ` Xin Li
2025-10-26 20:19 ` [PATCH v9 12/22] KVM: VMX: Virtualize FRED event_data Xin Li (Intel)
2025-11-19 3:24 ` Chao Gao
2026-01-29 17:12 ` Xin Li
2026-01-29 17:21 ` H. Peter Anvin
2026-01-29 22:50 ` Xin Li
2026-03-04 16:42 ` Sean Christopherson
2025-10-26 20:19 ` [PATCH v9 13/22] KVM: VMX: Virtualize FRED nested exception tracking Xin Li (Intel)
2025-11-19 6:54 ` Chao Gao
2026-03-07 2:07 ` Sean Christopherson
2026-03-07 3:05 ` Xin Li
2025-10-26 20:19 ` [PATCH v9 14/22] KVM: x86: Save/restore the nested flag of an exception Xin Li (Intel)
2025-11-19 6:13 ` Chao Gao
2025-10-26 20:19 ` [PATCH v9 15/22] KVM: x86: Mark CR4.FRED as not reserved Xin Li (Intel)
2025-11-19 7:26 ` Chao Gao
2026-03-05 0:58 ` Sean Christopherson
2026-03-05 7:20 ` Xin Li
2026-03-05 15:35 ` Sean Christopherson
2026-03-05 17:09 ` Xin Li
2026-03-05 17:46 ` Xin Li
2026-03-06 5:33 ` Chao Gao
2025-10-26 20:19 ` [PATCH v9 16/22] KVM: VMX: Dump FRED context in dump_vmcs() Xin Li (Intel)
2025-11-19 7:40 ` Chao Gao
2025-11-30 18:42 ` Xin Li
2025-10-26 20:19 ` [PATCH v9 17/22] KVM: x86: Advertise support for FRED Xin Li (Intel)
2025-11-12 7:30 ` Chao Gao
2026-01-20 6:56 ` Xin Li
2026-01-20 8:07 ` Chao Gao [this message]
2026-01-20 9:09 ` Xin Li
2026-01-20 9:46 ` Binbin Wu
2026-01-20 15:25 ` Sean Christopherson
2026-01-20 18:04 ` Xin Li
2026-01-20 17:58 ` Xin Li
2025-10-26 20:19 ` [PATCH v9 18/22] KVM: nVMX: Enable support for secondary VM exit controls Xin Li (Intel)
2025-11-12 13:42 ` Chao Gao
2025-10-26 20:19 ` [PATCH v9 19/22] KVM: nVMX: Handle FRED VMCS fields in nested VMX context Xin Li (Intel)
2025-12-02 6:32 ` Chao Gao
2026-01-20 6:30 ` Xin Li
2026-01-20 16:07 ` Dave Hansen
2026-01-20 18:10 ` Xin Li
2026-01-21 0:44 ` Chao Gao
2026-01-22 16:52 ` Xin Li
2025-12-08 22:37 ` Sean Christopherson
2025-10-26 20:19 ` [PATCH v9 20/22] KVM: nVMX: Validate FRED-related VMCS fields Xin Li (Intel)
2025-11-13 3:00 ` Chao Gao
2026-01-20 9:19 ` Xin Li
2026-01-21 2:33 ` Chao Gao
2025-10-26 20:19 ` [PATCH v9 21/22] KVM: nVMX: Guard SHADOW_FIELD_R[OW] macros with VMX feature checks Xin Li (Intel)
2025-12-02 6:35 ` Chao Gao
2025-12-08 22:49 ` Sean Christopherson
2025-10-26 20:19 ` [PATCH v9 22/22] KVM: nVMX: Enable VMX FRED controls Xin Li (Intel)
2025-11-13 3:20 ` Chao Gao
2025-11-06 17:35 ` [PATCH v9 00/22] Enable FRED with KVM VMX Xin Li
2025-11-13 22:20 ` Sean Christopherson
2025-12-08 22:51 ` Sean Christopherson
2025-12-09 17:08 ` Xin Li
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