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, Dave Hansen <dave.hansen@linux.intel.com>,
Tony Luck <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>,
Kai Huang <kai.huang@intel.com>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
Robert Hu <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: Sat, 17 Jul 2021 11:55:37 +0800 [thread overview]
Message-ID: <89f240cb-cb3a-c362-7ded-ee500cc12dc3@intel.com> (raw)
In-Reply-To: <8aed2541-082d-d115-09ac-e7fcc05f96dc@redhat.com>
On 7/16/2021 5:52 PM, Paolo Bonzini wrote:
> On 16/07/21 08:48, Zeng Guang wrote:
>>
>> + if (!(_cpu_based_3rd_exec_control & TERTIARY_EXEC_IPI_VIRT))
>> + enable_ipiv = 0;
>> +
>> }
>
> Please move this to hardware_setup(), using a new function
> cpu_has_vmx_ipiv() in vmx/capabilities.h.
>
ok, we will change it to follow current framework.
>> if (_cpu_based_exec_control &
>> CPU_BASED_ACTIVATE_TERTIARY_CONTROLS) {
>> - u64 opt3 = 0;
>> + u64 opt3 = enable_ipiv ? TERTIARY_EXEC_IPI_VIRT : 0;
>> u64 min3 = 0;
>
> I like the idea of changing opt3, but it's different from how
> setup_vmcs_config works for the other execution controls. Let me
> think if it makes sense to clean this up, and move the handling of
> other module parameters from hardware_setup() to setup_vmcs_config().
>
May be an exception for ipiv feature ?
>> +
>> + 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.
>> + if (!enable_apicv) {
>> + enable_ipiv = 0;
>> + vmcs_config.cpu_based_3rd_exec_ctrl &= ~TERTIARY_EXEC_IPI_VIRT;
>> + }
>
> The assignment to vmcs_config.cpu_based_3rd_exec_ctrl should not be
> necessary; kvm_vcpu_apicv_active will always be false in that case and
> IPI virtualization would never be enabled.
>
We originally intend to make vmcs_config consistent with the actual ipiv
capability and decouple it from other factors. As you mentioned , it's
not necessary to update vmcs_config.cpu_based_3rd_exec_ctrl in this
case. We will remove it.
Thanks.
> Paolo
>
next prev parent reply other threads:[~2021-07-17 3:56 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 [this message]
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
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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