From: Ben Gardon <bgardon@google.com>
To: David Hildenbrand <david@redhat.com>
Cc: LKML <linux-kernel@vger.kernel.org>, kvm <kvm@vger.kernel.org>,
Paolo Bonzini <pbonzini@redhat.com>, Peter Xu <peterx@redhat.com>,
Sean Christopherson <seanjc@google.com>,
Peter Shier <pshier@google.com>,
Yulei Zhang <yulei.kernel@gmail.com>,
Wanpeng Li <kernellwp@gmail.com>,
Xiao Guangrong <xiaoguangrong.eric@gmail.com>,
Kai Huang <kai.huang@intel.com>,
Keqian Zhu <zhukeqian1@huawei.com>
Subject: Re: [PATCH v3 2/8] KVM: x86/mmu: Factor out allocating memslot rmap
Date: Mon, 10 May 2021 09:29:14 -0700 [thread overview]
Message-ID: <CANgfPd9GMZgfHxkgGxERrqLwP2aHYMK_yxyrDjCfjao3fvf7oQ@mail.gmail.com> (raw)
In-Reply-To: <97d085a0-185d-2546-f32e-ea1c55579ba0@redhat.com>
On Fri, May 7, 2021 at 12:47 AM David Hildenbrand <david@redhat.com> wrote:
>
> On 06.05.21 20:42, Ben Gardon wrote:
> > Small refactor to facilitate allocating rmaps for all memslots at once.
> >
> > No functional change expected.
> >
> > Signed-off-by: Ben Gardon <bgardon@google.com>
> > ---
> > arch/x86/kvm/x86.c | 41 ++++++++++++++++++++++++++++++++---------
> > 1 file changed, 32 insertions(+), 9 deletions(-)
> >
> > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> > index 5bcf07465c47..fc32a7dbe4c4 100644
> > --- a/arch/x86/kvm/x86.c
> > +++ b/arch/x86/kvm/x86.c
> > @@ -10842,10 +10842,37 @@ void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot)
> > kvm_page_track_free_memslot(slot);
> > }
> >
> > +static int alloc_memslot_rmap(struct kvm_memory_slot *slot,
> > + unsigned long npages)
>
> I'd have called the functions memslot_rmap_alloc() and memslot_rmap_free()
>
>
> > +{
> > + int i;
> > +
> > + for (i = 0; i < KVM_NR_PAGE_SIZES; ++i) {
> > + int lpages;
> > + int level = i + 1;
> > +
> > + lpages = gfn_to_index(slot->base_gfn + npages - 1,
> > + slot->base_gfn, level) + 1;
> > +
> > + slot->arch.rmap[i] =
> > + kvcalloc(lpages, sizeof(*slot->arch.rmap[i]),
> > + GFP_KERNEL_ACCOUNT);
> > + if (!slot->arch.rmap[i])
> > + goto out_free;
>
> you can just avoid the goto here and do the free_memslot_rmap() right away.
Oh good catch. I'll incorporate your suggestions in v4.
>
> > + }
> > +
> > + return 0;
> > +
> > +out_free:
> > + free_memslot_rmap(slot);
> > + return -ENOMEM;
> > +}
> > +
> > static int kvm_alloc_memslot_metadata(struct kvm_memory_slot *slot,
> > unsigned long npages)
> > {
> > int i;
> > + int r;
> >
> > /*
> > * Clear out the previous array pointers for the KVM_MR_MOVE case. The
> > @@ -10854,7 +10881,11 @@ static int kvm_alloc_memslot_metadata(struct kvm_memory_slot *slot,
> > */
> > memset(&slot->arch, 0, sizeof(slot->arch));
> >
> > - for (i = 0; i < KVM_NR_PAGE_SIZES; ++i) {
> > + r = alloc_memslot_rmap(slot, npages);
> > + if (r)
> > + return r;
> > +
> > + for (i = 1; i < KVM_NR_PAGE_SIZES; ++i) {
> > struct kvm_lpage_info *linfo;
> > unsigned long ugfn;
> > int lpages;
> > @@ -10863,14 +10894,6 @@ static int kvm_alloc_memslot_metadata(struct kvm_memory_slot *slot,
> > lpages = gfn_to_index(slot->base_gfn + npages - 1,
> > slot->base_gfn, level) + 1;
> >
> > - slot->arch.rmap[i] =
> > - kvcalloc(lpages, sizeof(*slot->arch.rmap[i]),
> > - GFP_KERNEL_ACCOUNT);
> > - if (!slot->arch.rmap[i])
> > - goto out_free;
> > - if (i == 0)
> > - continue;
> > -
> > linfo = kvcalloc(lpages, sizeof(*linfo), GFP_KERNEL_ACCOUNT);
> > if (!linfo)
> > goto out_free;
> >
>
> apart from that LGTM
>
> --
> Thanks,
>
> David / dhildenb
>
next prev parent reply other threads:[~2021-05-10 16:29 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-06 18:42 [PATCH v3 0/8] Lazily allocate memslot rmaps Ben Gardon
2021-05-06 18:42 ` [PATCH v3 1/8] KVM: x86/mmu: Deduplicate rmap freeing Ben Gardon
2021-05-07 7:42 ` David Hildenbrand
2021-05-06 18:42 ` [PATCH v3 2/8] KVM: x86/mmu: Factor out allocating memslot rmap Ben Gardon
2021-05-07 7:46 ` David Hildenbrand
2021-05-10 16:29 ` Ben Gardon [this message]
2021-05-06 18:42 ` [PATCH v3 3/8] KVM: mmu: Refactor memslot copy Ben Gardon
2021-05-07 7:48 ` David Hildenbrand
2021-05-06 18:42 ` [PATCH v3 4/8] KVM: mmu: Add slots_arch_lock for memslot arch fields Ben Gardon
2021-05-06 18:42 ` [PATCH v3 5/8] KVM: x86/mmu: Add a field to control memslot rmap allocation Ben Gardon
2021-05-06 23:44 ` Ben Gardon
2021-05-07 7:50 ` David Hildenbrand
2021-05-07 8:28 ` Paolo Bonzini
2021-05-10 16:14 ` Ben Gardon
2021-05-10 16:33 ` Paolo Bonzini
2021-05-10 16:37 ` Ben Gardon
2021-05-06 18:42 ` [PATCH v3 6/8] KVM: x86/mmu: Skip rmap operations if rmaps not allocated Ben Gardon
2021-05-06 23:07 ` kernel test robot
2021-05-06 18:42 ` [PATCH v3 7/8] KVM: x86/mmu: Protect rmaps independently with SRCU Ben Gardon
2021-05-06 23:58 ` kernel test robot
2021-05-07 0:56 ` kernel test robot
2021-05-07 8:42 ` Paolo Bonzini
2021-05-10 17:45 ` Sean Christopherson
2021-05-10 17:53 ` Paolo Bonzini
2021-05-10 18:28 ` Sean Christopherson
2021-05-11 16:22 ` Ben Gardon
2021-05-11 16:45 ` Paolo Bonzini
2021-05-06 18:42 ` [PATCH v3 8/8] KVM: x86/mmu: Lazily allocate memslot rmaps Ben Gardon
2021-05-07 1:10 ` kernel test robot
2021-05-07 8:28 ` Paolo Bonzini
2021-05-07 7:40 ` [PATCH v3 0/8] " David Hildenbrand
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