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From: Paolo Bonzini <pbonzini@redhat.com>
To: Jim Mattson <jmattson@google.com>
Cc: "Sean Christopherson" <sean.j.christopherson@intel.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>,
	"kvm list" <kvm@vger.kernel.org>,
	"Liran Alon" <liran.alon@oracle.com>
Subject: Re: [PATCH 1/7] KVM: nVMX: Intercept VMWRITEs to read-only shadow VMCS fields
Date: Thu, 13 Jun 2019 19:59:45 +0200	[thread overview]
Message-ID: <354f636b-c26d-e053-78a7-e7880e708d5d@redhat.com> (raw)
In-Reply-To: <CALMp9eQU-OLnGX40=tCjYPWen5ee3rziMHQOTt7fyd1NVdaAsw@mail.gmail.com>

On 13/06/19 19:36, Jim Mattson wrote:
>> Also, while this may vary dynamically based on the L2 guest that is
>> running, this is much less true for unrestricted-guest processors.
>> Without data on _which_ scenarios are bad for a static set of shadowed
>> fields, I'm not really happy to add even more complexity.
>
> Data supporting which scenarios would lead you to entertain more
> complexity?

For example it would be interesting if some L1 hypervisor had 2x slower
vmexits on some L2 guests, but otherwise fits the current set of
shadowed fields.

Paolo

> Is it even worth collecting data on L3 performance, for
> example? :-)


  reply	other threads:[~2019-06-13 17:59 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-07 15:36 [PATCH 0/7] KVM: nVMX: Optimize VMCS data copying Sean Christopherson
2019-05-07 15:36 ` [PATCH 1/7] KVM: nVMX: Intercept VMWRITEs to read-only shadow VMCS fields Sean Christopherson
2019-06-06 13:26   ` Paolo Bonzini
2019-06-13 17:02   ` Jim Mattson
2019-06-13 17:18     ` Paolo Bonzini
2019-06-13 17:36       ` Jim Mattson
2019-06-13 17:59         ` Paolo Bonzini [this message]
2019-05-07 15:36 ` [PATCH 2/7] KVM: nVMX: Intercept VMWRITEs to GUEST_{CS,SS}_AR_BYTES Sean Christopherson
2019-06-06 13:31   ` Paolo Bonzini
2019-05-07 15:36 ` [PATCH 3/7] KVM: nVMX: Track vmcs12 offsets for shadowed VMCS fields Sean Christopherson
2019-05-07 15:36 ` [PATCH 4/7] KVM: nVMX: Lift sync_vmcs12() out of prepare_vmcs12() Sean Christopherson
2019-05-07 15:36 ` [PATCH 5/7] KVM: nVMX: Use descriptive names for VMCS sync functions and flags Sean Christopherson
2019-05-07 15:36 ` [PATCH 6/7] KVM: nVMX: Add helpers to identify shadowed VMCS fields Sean Christopherson
2019-05-07 15:36 ` [PATCH 7/7] KVM: nVMX: Sync rarely accessed guest fields only when needed Sean Christopherson
2019-06-06 15:29   ` Paolo Bonzini

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