From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: Tianyu Lan <Tianyu.Lan@microsoft.com>
Cc: "pbonzini\@redhat.com" <pbonzini@redhat.com>,
"rkrcmar\@redhat.com" <rkrcmar@redhat.com>,
"tglx\@linutronix.de" <tglx@linutronix.de>,
"mingo\@redhat.com" <mingo@redhat.com>,
"hpa\@zytor.com" <hpa@zytor.com>,
"x86\@kernel.org" <x86@kernel.org>,
"kvm\@vger.kernel.org" <kvm@vger.kernel.org>,
"linux-kernel\@vger.kernel.org" <linux-kernel@vger.kernel.org>,
KY Srinivasan <kys@microsoft.com>
Subject: Re: [RFC Patch 3/3] KVM/x86: Add tlb_remote_flush callback support for vmcs
Date: Thu, 14 Jun 2018 12:33:53 +0200 [thread overview]
Message-ID: <87d0wtpsha.fsf@vitty.brq.redhat.com> (raw)
In-Reply-To: <f868a339-03fc-4ba6-4882-4bb6232f599d@microsoft.com> (Tianyu Lan's message of "Thu, 14 Jun 2018 10:13:46 +0000")
Tianyu Lan <Tianyu.Lan@microsoft.com> writes:
> On 6/12/2018 11:12 PM, Vitaly Kuznetsov wrote:
>> Tianyu Lan <Tianyu.Lan@microsoft.com> writes:
>>
>>>
>>> +static int vmx_remote_flush_tlb(struct kvm *kvm)
>>> +{
>>> + struct kvm_vcpu *vcpu = kvm_get_vcpu(kvm, 0);
>>> +
>>> + if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
>>> + return -1;
>>
>> Why vcpu0? Can arch.mmu.root_hpa-s differ across vCPUs? What happens if
>> they do?
>
> Yes, it may take place that arch.mmu.root_hpa is differ across vCPUs.
> We may check all vcpu root_hpa and use the hypercall when there is only
> one validated ept table. If not, go back to current way.
>
I'd suggest an optimization: keep track of wether root_hpas are equal
across all vcpus (check this on change).
--
Vitaly
next prev parent reply other threads:[~2018-06-14 10:33 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-04 9:08 [RFC Patch 0/3] KVM/x86/hyper-V: Introduce PV guest address space mapping flush support Tianyu Lan
2018-06-04 9:08 ` [RFC Patch 1/3] X86/Hyper-V: Add flush HvFlushGuestPhysicalAddressSpace hypercall support Tianyu Lan
2018-06-05 16:59 ` Michael Kelley (EOSG)
2018-06-06 5:36 ` Tianyu Lan
2018-06-04 9:08 ` [RFC Patch 2/3] KVM: Add tlb remote flush callback in kvm_x86_ops Tianyu Lan
2018-06-04 9:08 ` [RFC Patch 3/3] KVM/x86: Add tlb_remote_flush callback support for vmcs Tianyu Lan
2018-06-12 15:05 ` Vitaly Kuznetsov
2018-06-12 15:12 ` Vitaly Kuznetsov
2018-06-14 10:13 ` Tianyu Lan
2018-06-14 10:33 ` Vitaly Kuznetsov [this message]
2018-06-14 14:52 ` Tianyu Lan
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