From: Chao Gao <chao.gao@intel.com>
To: Sean Christopherson <seanjc@google.com>
Cc: Maxim Levitsky <mlevitsk@redhat.com>,
Zeng Guang <guang.zeng@intel.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
"Luck, Tony" <tony.luck@intel.com>,
Kan Liang <kan.liang@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Kim Phillips <kim.phillips@amd.com>,
Jarkko Sakkinen <jarkko@kernel.org>,
Jethro Beekman <jethro@fortanix.com>,
"Huang, Kai" <kai.huang@intel.com>,
"x86@kernel.org" <x86@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Hu, Robert" <robert.hu@intel.com>
Subject: Re: [PATCH v5 7/8] KVM: VMX: Update PID-pointer table entry when APIC ID is changed
Date: Fri, 14 Jan 2022 10:58:27 +0800 [thread overview]
Message-ID: <20220114025825.GA3010@gao-cwp> (raw)
In-Reply-To: <YeClaZWM1cM+WLjH@google.com>
On Thu, Jan 13, 2022 at 10:19:21PM +0000, Sean Christopherson wrote:
>On Tue, Jan 11, 2022, Maxim Levitsky wrote:
>> Both Intel and AMD's PRM also state that changing APIC ID is implementation
>> dependent.
>>
>> I vote to forbid changing apic id, at least in the case any APIC acceleration
>> is used, be that APICv or AVIC.
>
>That has my vote as well. For IPIv in particular there's not much concern with
>backwards compability, i.e. we can tie the behavior to enable_ipiv.
Hi Sean and Levitsky,
Let's align on the implementation.
To disable changes for xAPIC ID when IPIv/AVIC is enabled:
1. introduce a variable (forbid_apicid_change) for this behavior in kvm.ko
and export it so that kvm-intel, kvm-amd can set it when IPIv/AVIC is
enabled. To reduce complexity, this variable is a module level setting.
2. when guest attempts to change xAPIC ID but it is forbidden, KVM prints
a warning on host and injects a #GP to guest.
3. remove AVIC code that deals with changes to xAPIC ID.
next prev parent reply other threads:[~2022-01-14 2:47 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-31 14:28 [PATCH v5 0/8] IPI virtualization support for VM Zeng Guang
2021-12-31 14:28 ` [PATCH v5 1/8] x86/cpu: Add new VMX feature, Tertiary VM-Execution control Zeng Guang
2021-12-31 14:28 ` [PATCH v5 2/8] KVM: VMX: Extend BUILD_CONTROLS_SHADOW macro to support 64-bit variation Zeng Guang
2021-12-31 14:28 ` [PATCH v5 3/8] KVM: VMX: Detect Tertiary VM-Execution control when setup VMCS config Zeng Guang
2021-12-31 14:28 ` [PATCH v5 4/8] KVM: VMX: dump_vmcs() reports tertiary_exec_control field as well Zeng Guang
2022-01-13 21:03 ` Sean Christopherson
2022-01-14 4:19 ` Zeng Guang
2022-01-20 1:06 ` Sean Christopherson
2022-01-20 5:34 ` Zeng Guang
2021-12-31 14:28 ` [PATCH v5 5/8] KVM: x86: Support interrupt dispatch in x2APIC mode with APIC-write VM exit Zeng Guang
2022-01-13 21:29 ` Sean Christopherson
2022-01-14 7:52 ` Zeng Guang
2022-01-14 17:34 ` Sean Christopherson
2022-01-15 2:08 ` Zeng Guang
2022-01-18 0:44 ` Yuan Yao
2022-01-18 3:06 ` Zeng Guang
2022-01-18 18:17 ` Sean Christopherson
2022-01-19 2:48 ` Zeng Guang
2021-12-31 14:28 ` [PATCH v5 6/8] KVM: VMX: enable IPI virtualization Zeng Guang
2022-01-13 21:47 ` Sean Christopherson
2022-01-14 5:36 ` Zeng Guang
2021-12-31 14:28 ` [PATCH v5 7/8] KVM: VMX: Update PID-pointer table entry when APIC ID is changed Zeng Guang
2022-01-05 19:13 ` Tom Lendacky
2022-01-06 1:44 ` Zeng Guang
2022-01-06 14:06 ` Tom Lendacky
2022-01-07 8:05 ` Zeng Guang
2022-01-07 8:31 ` Maxim Levitsky
2022-01-10 7:45 ` Chao Gao
2022-01-10 22:24 ` Maxim Levitsky
2022-01-13 22:19 ` Sean Christopherson
2022-01-14 2:58 ` Chao Gao [this message]
2022-01-14 8:17 ` Maxim Levitsky
2022-01-17 3:17 ` Chao Gao
2022-02-02 23:23 ` Sean Christopherson
2022-02-03 20:22 ` Sean Christopherson
2022-02-23 6:10 ` Chao Gao
2022-02-23 10:26 ` Maxim Levitsky
2022-01-14 0:22 ` Yuan Yao
2021-12-31 14:28 ` [PATCH v5 8/8] KVM: VMX: Resize PID-ponter table on demand for IPI virtualization Zeng Guang
2022-01-13 22:09 ` Sean Christopherson
2022-01-14 15:59 ` Zeng Guang
2022-01-14 16:18 ` Sean Christopherson
2022-01-17 15:04 ` Zeng Guang
2022-01-18 17:15 ` Sean Christopherson
2022-01-19 7:55 ` Zeng Guang
2022-01-20 1:01 ` Sean Christopherson
2022-01-24 16:40 ` Zeng Guang
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