From: Zeng Guang <guang.zeng@intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <seanjc@google.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>
Cc: "x86@kernel.org" <x86@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Hu, Robert" <robert.hu@intel.com>,
"Gao, Chao" <chao.gao@intel.com>,
Emanuele Giuseppe Esposito <eesposit@redhat.com>
Subject: Re: [PATCH 6/6] KVM: VMX: enable IPI virtualization
Date: Mon, 19 Jul 2021 21:16:59 +0800 [thread overview]
Message-ID: <026dffc0-032c-72a9-dd06-a46a3efe2add@intel.com> (raw)
In-Reply-To: <0d6f7852-95b3-d628-955b-f44d88a86478@redhat.com>
On 7/19/2021 4:32 AM, Paolo Bonzini wrote:
> On 17/07/21 05:55, Zeng Guang wrote:
>>>> + if (vmx->ipiv_active)
>>>> + install_pid(vmx);
>>> This should be if (enable_ipiv) instead, I think.
>>>
>>> In fact, in all other places that are using vmx->ipiv_active, you can
>>> actually replace it with enable_ipiv; they are all reached only with
>>> kvm_vcpu_apicv_active(vcpu) == true.
>>>
>> enable_ipiv as a global variable indicates the hardware capability to
>> enable IPIv. Each VM may have different IPIv configuration according to
>> kvm_vcpu_apicv_active status. So we use ipiv_active per VM to enclose
>> IPIv related operations.
> Understood, but in practice all uses of vmx->ipiv_active are guarded by
> kvm_vcpu_apicv_active so they are always reached with vmx->ipiv_active
> == enable_ipiv.
>
> The one above instead seems wrong and should just use enable_ipiv.
enable_ipiv associate with "IPI virtualization" setting in tertiary exec
controls and
enable_apicv which depends on cpu_has_vmx_apicv(). kvm_vcpu_apicv_active
still
can be false even if enable_ipiv is true, e.g. in case irqchip not
emulated in kernel.
Though it's ok to use enable_ipiv here, vmcs setup succeed for IPIv but
it won't take into effect as
false kvm_vcpu_apicv_active runtime disable “IPI virtualization" for VM
in this case and
leads vmx->ipiv_active become false as well. So vmx->ipiv_active is more
accurate to reflect
runtime IPIv status.
> Paolo
>
next prev parent reply other threads:[~2021-07-19 13:17 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-16 6:48 [PATCH 0/5] IPI virtualization support for VM Zeng Guang
2021-07-16 6:48 ` [PATCH 1/6] x86/feat_ctl: Add new VMX feature, Tertiary VM-Execution control Zeng Guang
2021-07-28 23:44 ` Sean Christopherson
2021-07-29 15:56 ` Paolo Bonzini
2021-08-02 8:22 ` Zeng Guang
2021-08-02 16:20 ` Sean Christopherson
2021-07-16 6:48 ` [PATCH 2/6] KVM: VMX: Extend BUILD_CONTROLS_SHADOW macro to support 64-bit variation Zeng Guang
2021-07-16 6:48 ` [PATCH 3/6] KVM: VMX: Detect Tertiary VM-Execution control when setup VMCS config Zeng Guang
2021-07-29 0:03 ` Sean Christopherson
2021-08-02 6:59 ` Zeng Guang
2021-07-16 6:48 ` [PATCH 4/6] KVM: VMX: dump_vmcs() reports tertiary_exec_control field as well Zeng Guang
2021-07-16 6:48 ` [PATCH 5/6] KVM: x86: Support interrupt dispatch in x2APIC mode with APIC-write VM exit Zeng Guang
2021-07-16 6:48 ` [PATCH 6/6] KVM: VMX: enable IPI virtualization Zeng Guang
2021-07-16 9:52 ` Paolo Bonzini
2021-07-17 3:55 ` Zeng Guang
2021-07-18 20:32 ` Paolo Bonzini
2021-07-19 12:38 ` Zeng Guang
2021-07-19 13:58 ` Paolo Bonzini
2021-07-20 1:07 ` Zeng Guang
2021-07-19 13:16 ` Zeng Guang [this message]
2021-07-16 9:25 ` [PATCH 0/5] IPI virtualization support for VM Wanpeng Li
2021-07-17 1:46 ` Zeng Guang
2021-07-19 7:26 ` Zeng Guang
2021-07-19 7:37 ` Wanpeng Li
2021-07-23 6:15 ` Zeng Guang
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