On Wed, 12 Apr 2023 16:52:23 +0200
Aleksandr Mikhalitsyn <aleksandr.mikhalitsyn@xxxxxxxxxxxxx> wrote:
> On Tue, Apr 11, 2023 at 9:47 PM Zhi Wang <zhi.wang.linux@xxxxxxxxx> wrote:
> >
> > On Tue, 4 Apr 2023 14:26:51 +0200
> > Alexander Mikhalitsyn <aleksandr.mikhalitsyn@xxxxxxxxxxxxx> wrote:
> >
> > > If misc_cg_set_capacity() fails for some reason then we have
> > > a memleak for sev_reclaim_asid_bitmap/sev_asid_bitmap. It's
> > > not a case right now, because misc_cg_set_capacity() just can't
> > > fail and check inside it is always successful.
> > >
> > > But let's fix that for code consistency.
> > >
> > > Cc: Sean Christopherson <seanjc@xxxxxxxxxx>
> > > Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> > > Cc: Stéphane Graber <stgraber@xxxxxxxxxx>
> > > Cc: kvm@xxxxxxxxxxxxxxx
> > > Cc: linux-kernel@xxxxxxxxxxxxxxx
> > > Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@xxxxxxxxxxxxx>
> > > ---
> > > arch/x86/kvm/svm/sev.c | 7 ++++++-
> > > 1 file changed, 6 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> > > index c25aeb550cd9..a42536a0681a 100644
> > > --- a/arch/x86/kvm/svm/sev.c
> > > +++ b/arch/x86/kvm/svm/sev.c
> > > @@ -2213,8 +2213,13 @@ void __init sev_hardware_setup(void)
> > > }
> > >
> > > sev_asid_count = max_sev_asid - min_sev_asid + 1;
> > > - if (misc_cg_set_capacity(MISC_CG_RES_SEV, sev_asid_count))
> > > + if (misc_cg_set_capacity(MISC_CG_RES_SEV, sev_asid_count)) {
> > > + bitmap_free(sev_reclaim_asid_bitmap);
> > > + sev_reclaim_asid_bitmap = NULL;
> > > + bitmap_free(sev_asid_bitmap);
> > > + sev_asid_bitmap = NULL;
> > > goto out;
> > > + }
> > >
> > > pr_info("SEV supported: %u ASIDs\n", sev_asid_count);
> > > sev_supported = true;
> >
> > It would be nice that another case can also be fixed:
> >
> > sev_es_asid_count = min_sev_asid - 1;
> > if (misc_cg_set_capacity(MISC_CG_RES_SEV_ES, sev_es_asid_count))
> > goto out; /* <----HERE */
>
> Nope.
>
> There is no leak. Because when we are at this point then sev_supported
> = true and everything is fine.
>
Uh. You are right. Sorry that I was giving this comment based on my on-going
development branch.
> >
> > Maybe it would be a good idea to factor out an common error handling path.
