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From: "Kang, Shan" <shan.kang@intel.com>
To: "Li, Xin3" <xin3.li@intel.com>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-kselftest@vger.kernel.org"
	<linux-kselftest@vger.kernel.org>
Cc: "corbet@lwn.net" <corbet@lwn.net>,
	"seanjc@google.com" <seanjc@google.com>,
	"x86@kernel.org" <x86@kernel.org>,
	"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
	"vkuznets@redhat.com" <vkuznets@redhat.com>,
	"bp@alien8.de" <bp@alien8.de>,
	"mingo@redhat.com" <mingo@redhat.com>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"hpa@zytor.com" <hpa@zytor.com>,
	"pbonzini@redhat.com" <pbonzini@redhat.com>,
	"peterz@infradead.org" <peterz@infradead.org>,
	"shuah@kernel.org" <shuah@kernel.org>,
	"Shankar, Ravi V" <ravi.v.shankar@intel.com>,
	"xin@zytor.com" <xin@zytor.com>
Subject: Re: [PATCH v2 00/25] Enable FRED with KVM VMX
Date: Wed, 27 Mar 2024 08:08:14 +0000	[thread overview]
Message-ID: <608b37dbc59a80d32719c8fde8b6979a2b839e10.camel@intel.com> (raw)
In-Reply-To: <20240207172646.3981-1-xin3.li@intel.com>

On Wed, 2024-02-07 at 09:26 -0800, Xin Li wrote:
> This patch set enables the Intel flexible return and event delivery
> (FRED) architecture with KVM VMX to allow guests to utilize FRED.
> 
We tested this FRED KVM patch set on a 7th Intel(R) Core(TM) CPU and the Intel 
Simics® Simulator with the following four configurations:

The first config is the baseline on bare metal.
The second config is the baseline on Intel Simics® Simulator.
The third config enables host FRED, but disables guest FRED.
The last config enables both host and guest FRED.

Following are the Kselftest results on KVM guests.

+---------------------------------------------+-------+-------+-------+-------+
|                  Config                     |  Pass |  Fail |  Skip |  Hang |
+---------------------------------------------+-------+-------+-------+-------+
|the 7th Intel(R) Core(TM) CPU                |       |       |       |       |
|  L0: 6.8.0-rc3+ w/ FRED native/KVM patch set|  1775 |  526  |  332  |   6   |
|  L1: 6.8.0-rc3+                             |       |       |       |       |
+---------------------------------------------+-------+-------+-------+-------+
|Intel Simics® Simulator w/o FRED model       |       |       |       |       |
|  L0: 6.8.0-rc3+ w/ FRED native/KVM patch set|  1770 |  526  |  331  |   12  |
|  L1: 6.8.0-rc3+ w/ FRED native/KVM patch set|       |       |       |       |
+---------------------------------------------+-------+-------+-------+-------+
|Intel Simics® Simulator w/ FRED model        |       |       |       |       |
|  L0: 6.8.0-rc3+ w/ FRED native/KVM patch set|  1770 |  526  |  331  |   12  |
|  L1: 6.8.0-rc3+ w/ FRED native/KVM patch set|       |       |       |       |
|         but FRED disabled                   |       |       |       |       |
+---------------------------------------------+-------+-------+-------+-------+
|Intel Simics® Simulator w/ FRED model        |       |       |       |       |
|  L0: 6.8.0-rc3+ w/ FRED native/KVM patch set|  1769 |  528  |  330  |   12  |
|  L1: 6.8.0-rc3+ w/ FRED native/KVM patch set|       |       |       |       |
+---------------------------------------------+-------+-------+-------+-------+

First of all we don't see any major issue. One major differences come from
perf tests. Another variances are from timer tests due to Intel Simics®
emulator's slowness.

The tests "x86:sysret_rip_64" and "x86:sigreturn_32" fail on the last config,
because they are not valid tests for FRED:
https://lore.kernel.org/lkml/20230220030959.119222-1-ammarfaizi2@gnuweeb.org/T/#u
https://lore.kernel.org/lkml/20230706052231.2183-1-xin3.li@intel.com/

NB: Some tests pass on Intel Simics® emulator, but not bare metal. If needed,
we can share the data.

We conducted local live migration tests with LKGS/FRED/WRMSRNS enabled/disabled
on Intel Simics® Simulator, and see no problems.

We also tested KVM Kselftest on a nested FRED KVM guest, 48 out of 83 cases
passed and the rest cases failed due to the slowness of Intel Simics® emulator.

Detailed report upon request.

  parent reply	other threads:[~2024-03-27  8:08 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-07 17:26 [PATCH v2 00/25] Enable FRED with KVM VMX Xin Li
2024-02-07 17:26 ` [PATCH v2 01/25] KVM: VMX: Cleanup VMX basic information defines and usages Xin Li
2024-02-07 17:26 ` [PATCH v2 02/25] KVM: VMX: Cleanup VMX misc " Xin Li
2024-02-07 17:26 ` [PATCH v2 03/25] KVM: VMX: Add support for the secondary VM exit controls Xin Li
2024-04-19 10:21   ` Chao Gao
2024-02-07 17:26 ` [PATCH v2 04/25] KVM: x86: Mark CR4.FRED as not reserved Xin Li
2024-04-19 10:22   ` Chao Gao
2024-02-07 17:26 ` [PATCH v2 05/25] KVM: VMX: Initialize FRED VM entry/exit controls in vmcs_config Xin Li
2024-04-19 10:24   ` Chao Gao
2024-02-07 17:26 ` [PATCH v2 06/25] KVM: VMX: Defer enabling FRED MSRs save/load until after set CPUID Xin Li
2024-04-19 11:02   ` Chao Gao
2024-02-07 17:26 ` [PATCH v2 07/25] KVM: VMX: Set intercept for FRED MSRs Xin Li
2024-04-19 13:35   ` Chao Gao
2024-04-19 17:06     ` Li, Xin3
2024-02-07 17:26 ` [PATCH v2 08/25] KVM: VMX: Initialize VMCS FRED fields Xin Li
2024-04-19 14:01   ` Chao Gao
2024-04-19 17:02     ` Li, Xin3
2024-02-07 17:26 ` [PATCH v2 09/25] KVM: VMX: Switch FRED RSP0 between host and guest Xin Li
2024-04-19 14:23   ` Chao Gao
2024-04-19 16:37     ` Li, Xin3
2024-02-07 17:26 ` [PATCH v2 10/25] KVM: VMX: Add support for FRED context save/restore Xin Li
2024-04-29  6:31   ` Chao Gao
2024-02-07 17:26 ` [PATCH v2 11/25] KVM: x86: Add kvm_is_fred_enabled() Xin Li
2024-04-29  8:24   ` Chao Gao
2024-05-11  1:24     ` Li, Xin3
2024-05-11  1:53       ` Chao Gao
2024-02-07 17:26 ` [PATCH v2 12/25] KVM: VMX: Handle FRED event data Xin Li
2024-04-30  3:14   ` Chao Gao
2024-05-10  9:36     ` Li, Xin3
2024-05-11  3:03       ` Chao Gao
2024-02-07 17:26 ` [PATCH v2 13/25] KVM: VMX: Handle VMX nested exception for FRED Xin Li
2024-04-30  7:34   ` Chao Gao
2024-02-07 17:26 ` [PATCH v2 14/25] KVM: VMX: Disable FRED if FRED consistency checks fail Xin Li
2024-04-30  8:21   ` Chao Gao
2024-02-07 17:26 ` [PATCH v2 15/25] KVM: VMX: Dump FRED context in dump_vmcs() Xin Li
2024-04-30  9:09   ` Chao Gao
2024-02-07 17:26 ` [PATCH v2 16/25] KVM: VMX: Invoke vmx_set_cpu_caps() before nested setup Xin Li
2024-02-07 17:26 ` [PATCH v2 17/25] KVM: nVMX: Add support for the secondary VM exit controls Xin Li
2024-02-07 17:26 ` [PATCH v2 18/25] KVM: nVMX: Add a prerequisite to SHADOW_FIELD_R[OW] macros Xin Li
2024-02-07 17:26 ` [PATCH v2 19/25] KVM: nVMX: Add FRED VMCS fields Xin Li
2024-02-07 17:26 ` [PATCH v2 20/25] KVM: nVMX: Add support for VMX FRED controls Xin Li
2024-02-07 17:26 ` [PATCH v2 21/25] KVM: nVMX: Add VMCS FRED states checking Xin Li
2024-02-07 17:26 ` [PATCH v2 22/25] KVM: x86: Allow FRED/LKGS/WRMSRNS to be exposed to guests Xin Li
2024-02-07 17:26 ` [PATCH v2 23/25] KVM: selftests: Run debug_regs test with FRED enabled Xin Li
2024-02-07 17:26 ` [PATCH v2 24/25] KVM: selftests: Add a new VM guest mode to run user level code Xin Li
2024-02-07 17:26 ` [PATCH v2 25/25] KVM: selftests: Add fred exception tests Xin Li
2024-03-29 20:18   ` Muhammad Usama Anjum
2024-03-29 20:18     ` Muhammad Usama Anjum
2024-04-24 16:08       ` Sean Christopherson
2024-03-27  8:08 ` Kang, Shan [this message]
2024-04-15 17:58 ` [PATCH v2 00/25] Enable FRED with KVM VMX Li, Xin3

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