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Re: [Qemu-devel] [PATCH v1 4/5] kvm/x86: Hyper-V VMBus hypercall userspa
From: |
'Roman Kagan' |
Subject: |
Re: [Qemu-devel] [PATCH v1 4/5] kvm/x86: Hyper-V VMBus hypercall userspace exit |
Date: |
Wed, 20 Jan 2016 20:31:07 +0300 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
On Wed, Jan 20, 2016 at 06:02:25PM +0100, Paolo Bonzini wrote:
>
>
> On 20/01/2016 16:20, 'Roman Kagan' wrote:
> >> > So we should not add a new exit
> > Why? VCPU exit codes are not a scarse resource.
>
> Indeed, but grouping makes things easier to understand.
>
> > So far we've envisaged two reasons for VCPU exit related to hyper-v: one
> > for hyper-v MSRs and the other for hypercalls. Since there was a
> > discussion on implementing generic MSR access by Peter we thought it
> > wiser to introduce a new VCPU exit for hyper-v hypercalls to avoid
> > interfering with the MSR implementation.
>
> That's a good idea. However, I think I'm not going to accept the MSR
> exit feature, and then the current Hyper-V exit API makes some sense
> indeed (it's just 3 values, transferring them all at once is not
> expensive at all).
OK can we please sum up (as I'm now a bit confused) what we do now:
1) use a single vcpu exit for both Hyper-V cases (which implies we need
to fix this patchset to add the subcode for hypercalls)
or
2) use individual vcpu exits for Hyper-V MSRs and for Hyper-V hypercalls
(which implies we need to submit an incremental patch dropping the
subcode from Hyper-V MSR exit and renaming it to better describe the
reality)?
Thanks,
Roman.
- [Qemu-devel] [PATCH v1 5/5] kvm/x86: Reject Hyper-V hypercall continuation, (continued)
- [Qemu-devel] [PATCH v1 5/5] kvm/x86: Reject Hyper-V hypercall continuation, Andrey Smetanin, 2016/01/12
- [Qemu-devel] [PATCH v1 4/5] kvm/x86: Hyper-V VMBus hypercall userspace exit, Andrey Smetanin, 2016/01/12
- Re: [Qemu-devel] [PATCH v1 4/5] kvm/x86: Hyper-V VMBus hypercall userspace exit, Paolo Bonzini, 2016/01/20
- Re: [Qemu-devel] [PATCH v1 4/5] kvm/x86: Hyper-V VMBus hypercall userspace exit, Pavel Fedin, 2016/01/20
- Re: [Qemu-devel] [PATCH v1 4/5] kvm/x86: Hyper-V VMBus hypercall userspace exit, 'Roman Kagan', 2016/01/20
- Re: [Qemu-devel] [PATCH v1 4/5] kvm/x86: Hyper-V VMBus hypercall userspace exit, Paolo Bonzini, 2016/01/20
- Re: [Qemu-devel] [PATCH v1 4/5] kvm/x86: Hyper-V VMBus hypercall userspace exit,
'Roman Kagan' <=
- Re: [Qemu-devel] [PATCH v1 4/5] kvm/x86: Hyper-V VMBus hypercall userspace exit, Paolo Bonzini, 2016/01/20
Re: [Qemu-devel] [PATCH v1 4/5] kvm/x86: Hyper-V VMBus hypercall userspace exit, Paolo Bonzini, 2016/01/20
Re: [Qemu-devel] [PATCH v1 0/5] KVM: Hyper-V VMBus hypercalls, Andrey Smetanin, 2016/01/12
Re: [Qemu-devel] [PATCH v1 0/5] KVM: Hyper-V VMBus hypercalls, Denis V. Lunev, 2016/01/19