Re: [PATCH v3 0/4] Restrict PV features to only enabled guests

[Oliver Upton <oupton@google.com>]

On Thu, Aug 6, 2020 at 10:14 AM Oliver Upton <oupton@google.com> wrote:
>
> To date, KVM has allowed guests to use paravirtual interfaces regardless
> of the configured CPUID. While almost any guest will consult the
> KVM_CPUID_FEATURES leaf _before_ using PV features, it is still
> undesirable to have such interfaces silently present.
>
> This series aims to address the issue by adding explicit checks against
> the guest's CPUID when servicing any paravirtual feature. Since this
> effectively changes the guest/hypervisor ABI, a KVM_CAP is warranted to
> guard the new behavior.
>
> Patches 1-2 refactor some of the PV code in anticipation of the change.
> Patch 3 introduces the checks + KVM_CAP. Finally, patch 4 fixes some doc
> typos that were noticed when working on this series.
>
> v1 => v2:
>  - Strip Change-Id footers (checkpatch is your friend!)
>
> v2 => v3:
>  - Mark kvm_write_system_time() as static
>
> Parent commit: f3633c268354 ("Merge tag 'kvm-s390-next-5.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into kvm-next-5.6")
>
> Oliver Upton (4):
>   kvm: x86: encapsulate wrmsr(MSR_KVM_SYSTEM_TIME) emulation in helper
>     fn
>   kvm: x86: set wall_clock in kvm_write_wall_clock()
>   kvm: x86: only provide PV features if enabled in guest's CPUID
>   Documentation: kvm: fix some typos in cpuid.rst
>
>  Documentation/virt/kvm/api.rst   |  11 +++
>  Documentation/virt/kvm/cpuid.rst |  88 +++++++++++-----------
>  arch/x86/include/asm/kvm_host.h  |   6 ++
>  arch/x86/kvm/cpuid.h             |  16 ++++
>  arch/x86/kvm/x86.c               | 122 +++++++++++++++++++++++--------
>  include/uapi/linux/kvm.h         |   1 +
>  6 files changed, 171 insertions(+), 73 deletions(-)
>
> --
> 2.28.0.236.gb10cc79966-goog
>

Ping :)