Re: [PATCH v2 8/8] KVM: SVM: Allocate SEV command structures on local stack

[Christophe Leroy]

Le 07/04/2021 à 19:05, Sean Christopherson a écrit :
> On Wed, Apr 07, 2021, Borislav Petkov wrote:
> > First of all, I'd strongly suggest you trim your emails when you reply -
> > that would be much appreciated.
> >
> > On Wed, Apr 07, 2021 at 07:24:54AM +0200, Christophe Leroy wrote:
> > > > @@ -258,7 +240,7 @@ static int sev_issue_cmd(struct kvm *kvm, int id, void *data, int *error)
> > > >    static int sev_launch_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
> > > >    {
> > > >    	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
> > > > -	struct sev_data_launch_start *start;
> > > > +	struct sev_data_launch_start start;
> > >
> > > struct sev_data_launch_start start = {0, 0, 0, 0, 0, 0, 0};
> >
> > I don't know how this is any better than using memset...
> >
> > Also, you can do
> >
> > 	... start = { };
> >
> > which is certainly the only other alternative to memset, AFAIK.
> >
> > But whatever you do, you need to look at the resulting asm the compiler
> > generates. So let's do that:
>
> I'm ok with Boris' version, I'm not a fan of having to count zeros.  I used
> memset() to defer initialization until after the various sanity checks, and
> out of habit.

Yes I also like Boris' version 	... start = { };  better than mine.