Re: [RFC PATCH 2/5] KVM: add KVM_EXIT_MSR exit reason and capability.

From: Paolo Bonzini <pbonzini@redhat.com>
To: Peter Hornyack <peterhornyack@google.com>,
	kvm list <kvm@vger.kernel.org>, Gleb Natapov <gleb@kernel.org>
Cc: Joerg Roedel <joro@8bytes.org>,
	Andrey Smetanin <asmetanin@virtuozzo.com>,
	Roman Kagan <rkagan@virtuozzo.com>,
	"Denis V. Lunev" <den@openvz.org>
Subject: Re: [RFC PATCH 2/5] KVM: add KVM_EXIT_MSR exit reason and capability.
Date: Fri, 18 Dec 2015 22:25:50 +0100	[thread overview]
Message-ID: <567479DE.6010805@redhat.com> (raw)
In-Reply-To: <1439923615-10600-3-git-send-email-peterhornyack@google.com>

On 18/08/2015 20:46, Peter Hornyack wrote:
> Define KVM_EXIT_MSR, a new exit reason for accesses to MSRs that kvm
> does not handle. Define KVM_CAP_UNHANDLED_MSR_EXITS, a vm-wide
> capability that guards the new exit reason and which can be enabled via
> the KVM_ENABLE_CAP ioctl.
> 
> Signed-off-by: Peter Hornyack <peterhornyack@google.com>
> ---
>  Documentation/virtual/kvm/api.txt | 48 +++++++++++++++++++++++++++++++++++++++
>  include/uapi/linux/kvm.h          | 14 ++++++++++++
>  2 files changed, 62 insertions(+)

Let's instead add:

- KVM_CAP_MSR_EXITS

- KVM_CAP_ENABLE_MSR_EXIT

- KVM_CAP_DISABLE_MSR_EXIT

and 3 kinds of exits: KVM_EXIT_MSR_READ, KVM_EXIT_MSR_WRITE,
KVM_EXIT_MSR_AFTER_WRITE.  The first two use four fields (type, msr,
data, handled) and #GP if handled=0 is zero on the next entry.  The last
one uses the first three fields and can be used for HyperV.

Paolo