Re: [PATCH] KVM: Directly return result from kvm_arch_check_processor_compat()

Cornelia Huck
2019-04-23T08:57:35Z

On Fri, 19 Apr 2019 22:18:17 -0700
Sean Christopherson <sean.j.christopherson@intel.com> wrote:

> Add a wrapper to invoke kvm_arch_check_processor_compat() so that the
> boilerplate ugliness of checking virtualization support on all CPUs is
> hidden from the arch specific code. x86's implementation in particular
> is quite heinous, as it unnecessarily propagates the out-param pattern
> into kvm_x86_ops.
>
> While the x86 specific issue could be resolved solely by changing
> kvm_x86_ops, make the change for all architectures as returning a value
> directly is prettier and technically more robust, e.g. s390 doesn't set
> the out param, which could lead to subtle breakage in the (highly
> unlikely) scenario where the out-param was not pre-initialized by the
> caller.
>
> Opportunistically annotate svm_check_processor_compat() with __init.
>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> ---
>
> Tested on VMX only.
>
> arch/mips/kvm/mips.c | 4 ++--
> arch/powerpc/kvm/powerpc.c | 4 ++--
> arch/s390/include/asm/kvm_host.h | 1 -
> arch/s390/kvm/kvm-s390.c | 5 +++++
> arch/x86/include/asm/kvm_host.h | 2 +-
> arch/x86/kvm/svm.c | 4 ++--
> arch/x86/kvm/vmx/vmx.c | 8 ++++----
> arch/x86/kvm/x86.c | 4 ++--
> include/linux/kvm_host.h | 2 +-
> virt/kvm/arm/arm.c | 4 ++--
> virt/kvm/kvm_main.c | 9 ++++++---
> 11 files changed, 27 insertions(+), 20 deletions(-)

Yes, this does look nicer.

Reviewed-by: Cornelia Huck <cohuck@redhat.com>