linux-kernel - Re: [PATCH 1/3] KVM, SEV: Refactor out function for unregistering encrypted regions

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Date:   Tue, 13 Jul 2021 16:18:02 -0700
From:   Marc Orr <marcorr@...gle.com>
To:     Peter Gonda <pgonda@...gle.com>
Cc:     kvm list <kvm@...r.kernel.org>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        David Rientjes <rientjes@...gle.com>,
        "Dr . David Alan Gilbert" <dgilbert@...hat.com>,
        Brijesh Singh <brijesh.singh@....com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3] KVM, SEV: Refactor out function for unregistering
 encrypted regions

On Mon, Jun 21, 2021 at 9:59 AM Peter Gonda <pgonda@...gle.com> wrote:
>
> Factor out helper function for freeing the encrypted region list.
>
> Signed-off-by: Peter Gonda <pgonda@...gle.com>
> Cc: Paolo Bonzini <pbonzini@...hat.com>
> Cc: Sean Christopherson <seanjc@...gle.com>
> Cc: David Rientjes <rientjes@...gle.com>
> Cc: Dr. David Alan Gilbert <dgilbert@...hat.com>
> Cc: Brijesh Singh <brijesh.singh@....com>
> Cc: Vitaly Kuznetsov <vkuznets@...hat.com>
> Cc: Wanpeng Li <wanpengli@...cent.com>
> Cc: Jim Mattson <jmattson@...gle.com>
> Cc: Joerg Roedel <joro@...tes.org>
> Cc: Thomas Gleixner <tglx@...utronix.de>
> Cc: Ingo Molnar <mingo@...hat.com>
> Cc: Borislav Petkov <bp@...en8.de>
> Cc: "H. Peter Anvin" <hpa@...or.com>
> Cc: kvm@...r.kernel.org
> Cc: linux-kernel@...r.kernel.org
>
> ---
>  arch/x86/kvm/svm/sev.c | 26 +++++++++++++++++---------
>  1 file changed, 17 insertions(+), 9 deletions(-)
>
> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> index 46e339c84998..5af46ff6ec48 100644
> --- a/arch/x86/kvm/svm/sev.c
> +++ b/arch/x86/kvm/svm/sev.c
> @@ -1767,11 +1767,25 @@ int svm_vm_copy_asid_from(struct kvm *kvm, unsigned int source_fd)
>         return ret;
>  }
>
> +static void __unregister_region_list_locked(struct kvm *kvm,
> +                                           struct list_head *mem_regions)
> +{
> +       struct enc_region *pos, *q;
> +
> +       lockdep_assert_held(&kvm->lock);
> +
> +       if (list_empty(mem_regions))
> +               return;
> +
> +       list_for_each_entry_safe(pos, q, mem_regions, list) {
> +               __unregister_enc_region_locked(kvm, pos);
> +               cond_resched();
> +       }
> +}
> +
>  void sev_vm_destroy(struct kvm *kvm)
>  {
>         struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
> -       struct list_head *head = &sev->regions_list;
> -       struct list_head *pos, *q;
>
>         if (!sev_guest(kvm))
>                 return;
> @@ -1795,13 +1809,7 @@ void sev_vm_destroy(struct kvm *kvm)
>          * if userspace was terminated before unregistering the memory regions
>          * then lets unpin all the registered memory.
>          */
> -       if (!list_empty(head)) {
> -               list_for_each_safe(pos, q, head) {
> -                       __unregister_enc_region_locked(kvm,
> -                               list_entry(pos, struct enc_region, list));
> -                       cond_resched();
> -               }
> -       }
> +       __unregister_region_list_locked(kvm, &sev->regions_list);
>
>         mutex_unlock(&kvm->lock);
>
> --
> 2.32.0.288.g62a8d224e6-goog

Reviewed-by: Marc Orr <marcorr@...gle.com>