From: Chao Peng <chao.p.peng@linux.intel.com> To: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Wanpeng Li <wanpengli@tencent.com>, jun.nakajima@intel.com, kvm@vger.kernel.org, david@redhat.com, qemu-devel@nongnu.org, "J . Bruce Fields" <bfields@fieldses.org>, dave.hansen@intel.com, "H . Peter Anvin" <hpa@zytor.com>, ak@linux.intel.com, Jonathan Corbet <corbet@lwn.net>, Joerg Roedel <joro@8bytes.org>, x86@kernel.org, Hugh Dickins <hughd@google.com>, Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>, luto@kernel.org, Thomas Gleixner <tglx@linutronix.de>, Andrew Morton <akpm@linux-foundation.org>, Jim Mattson <jmattson@google.com>, linux-mm@kvack.org, Sean Christopherson <seanjc@google.com>, susie.li@intel.com, Jeff Layton <jlayton@kernel.org>, linux-kernel@vger.kernel.org, john.ji@intel.com, Yu Zhang <yu.c.zhang@linux.intel.com>, linux-fsdevel@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>, Vitaly Kuznetsov <vkuznets@redhat.com>, "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Subject: Re: [RFC v2 PATCH 13/13] KVM: Enable memfd based page invalidation/fallocate Date: Tue, 23 Nov 2021 09:06:39 +0800 [thread overview] Message-ID: <20211123010639.GA32088@chaop.bj.intel.com> (raw) In-Reply-To: <20211122141647.3pcsywilrzcoqvbf@box.shutemov.name> On Mon, Nov 22, 2021 at 05:16:47PM +0300, Kirill A. Shutemov wrote: > On Fri, Nov 19, 2021 at 09:47:39PM +0800, Chao Peng wrote: > > Since the memory backing store does not get notified when VM is > > destroyed so need check if VM is still live in these callbacks. > > > > Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com> > > Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com> > > --- > > virt/kvm/memfd.c | 22 ++++++++++++++++++++++ > > 1 file changed, 22 insertions(+) > > > > diff --git a/virt/kvm/memfd.c b/virt/kvm/memfd.c > > index bd930dcb455f..bcfdc685ce22 100644 > > --- a/virt/kvm/memfd.c > > +++ b/virt/kvm/memfd.c > > @@ -12,16 +12,38 @@ > > #include <linux/memfd.h> > > const static struct guest_mem_ops *memfd_ops; > > > > +static bool vm_is_dead(struct kvm *vm) > > +{ > > + struct kvm *kvm; > > + > > + list_for_each_entry(kvm, &vm_list, vm_list) { > > + if (kvm == vm) > > + return false; > > + } > > I don't think this is enough. The struct kvm can be freed and re-allocated > from the slab and this function will give false-negetive. Right. > > Maybe the kvm has to be tagged with a sequential id that incremented every > allocation. This id can be checked here. Sounds like a sequential id will be needed, no existing fields in struct kvm can work for this. > > > + > > + return true; > > +} > > -- > Kirill A. Shutemov
WARNING: multiple messages have this Message-ID (diff)
From: Chao Peng <chao.p.peng@linux.intel.com> To: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Wanpeng Li <wanpengli@tencent.com>, jun.nakajima@intel.com, kvm@vger.kernel.org, david@redhat.com, qemu-devel@nongnu.org, "J . Bruce Fields" <bfields@fieldses.org>, dave.hansen@intel.com, "H . Peter Anvin" <hpa@zytor.com>, ak@linux.intel.com, Jonathan Corbet <corbet@lwn.net>, Joerg Roedel <joro@8bytes.org>, x86@kernel.org, Hugh Dickins <hughd@google.com>, Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>, luto@kernel.org, Thomas Gleixner <tglx@linutronix.de>, Vitaly Kuznetsov <vkuznets@redhat.com>, Jim Mattson <jmattson@google.com>, linux-mm@kvack.org, Sean Christopherson <seanjc@google.com>, susie.li@intel.com, Jeff Layton <jlayton@kernel.org>, linux-kernel@vger.kernel.org, john.ji@intel.com, Yu Zhang <yu.c.zhang@linux.intel.com>, linux-fsdevel@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>, Andrew Morton <akpm@linux-foundation.org>, "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Subject: Re: [RFC v2 PATCH 13/13] KVM: Enable memfd based page invalidation/fallocate Date: Tue, 23 Nov 2021 09:06:39 +0800 [thread overview] Message-ID: <20211123010639.GA32088@chaop.bj.intel.com> (raw) In-Reply-To: <20211122141647.3pcsywilrzcoqvbf@box.shutemov.name> On Mon, Nov 22, 2021 at 05:16:47PM +0300, Kirill A. Shutemov wrote: > On Fri, Nov 19, 2021 at 09:47:39PM +0800, Chao Peng wrote: > > Since the memory backing store does not get notified when VM is > > destroyed so need check if VM is still live in these callbacks. > > > > Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com> > > Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com> > > --- > > virt/kvm/memfd.c | 22 ++++++++++++++++++++++ > > 1 file changed, 22 insertions(+) > > > > diff --git a/virt/kvm/memfd.c b/virt/kvm/memfd.c > > index bd930dcb455f..bcfdc685ce22 100644 > > --- a/virt/kvm/memfd.c > > +++ b/virt/kvm/memfd.c > > @@ -12,16 +12,38 @@ > > #include <linux/memfd.h> > > const static struct guest_mem_ops *memfd_ops; > > > > +static bool vm_is_dead(struct kvm *vm) > > +{ > > + struct kvm *kvm; > > + > > + list_for_each_entry(kvm, &vm_list, vm_list) { > > + if (kvm == vm) > > + return false; > > + } > > I don't think this is enough. The struct kvm can be freed and re-allocated > from the slab and this function will give false-negetive. Right. > > Maybe the kvm has to be tagged with a sequential id that incremented every > allocation. This id can be checked here. Sounds like a sequential id will be needed, no existing fields in struct kvm can work for this. > > > + > > + return true; > > +} > > -- > Kirill A. Shutemov
next prev parent reply other threads:[~2021-11-23 1:07 UTC|newest] Thread overview: 99+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-11-19 13:47 [RFC v2 PATCH 00/13] KVM: mm: fd-based approach for supporting KVM guest private memory Chao Peng 2021-11-19 13:47 ` Chao Peng 2021-11-19 13:47 ` [RFC v2 PATCH 01/13] mm/shmem: Introduce F_SEAL_GUEST Chao Peng 2021-11-19 13:47 ` Chao Peng 2021-11-19 13:51 ` David Hildenbrand 2021-11-19 13:51 ` David Hildenbrand 2021-11-22 13:59 ` Kirill A. Shutemov 2021-11-22 13:59 ` Kirill A. Shutemov 2021-11-19 15:19 ` Jason Gunthorpe 2021-11-19 15:19 ` Jason Gunthorpe 2021-11-19 15:39 ` David Hildenbrand 2021-11-19 15:39 ` David Hildenbrand 2021-11-19 16:00 ` Jason Gunthorpe 2021-11-19 16:00 ` Jason Gunthorpe 2021-11-22 9:26 ` David Hildenbrand 2021-11-22 9:26 ` David Hildenbrand 2021-11-22 13:31 ` Jason Gunthorpe 2021-11-22 13:31 ` Jason Gunthorpe 2021-11-22 13:35 ` David Hildenbrand 2021-11-22 13:35 ` David Hildenbrand 2021-11-22 14:01 ` Jason Gunthorpe 2021-11-22 14:01 ` Jason Gunthorpe 2021-11-22 14:57 ` David Hildenbrand 2021-11-22 14:57 ` David Hildenbrand 2021-11-22 15:09 ` Jason Gunthorpe 2021-11-22 15:09 ` Jason Gunthorpe 2021-11-22 15:15 ` David Hildenbrand 2021-11-22 15:15 ` David Hildenbrand 2021-11-19 19:18 ` Sean Christopherson 2021-11-19 19:47 ` Jason Gunthorpe 2021-11-19 19:47 ` Jason Gunthorpe 2021-11-19 22:21 ` Sean Christopherson 2021-11-19 23:33 ` Jason Gunthorpe 2021-11-19 23:33 ` Jason Gunthorpe 2021-11-20 1:23 ` Sean Christopherson 2021-11-21 0:05 ` Jason Gunthorpe 2021-11-21 0:05 ` Jason Gunthorpe 2021-11-23 9:06 ` Paolo Bonzini 2021-11-23 9:06 ` Paolo Bonzini 2021-11-23 14:33 ` Chao Peng 2021-11-23 14:33 ` Chao Peng 2021-11-23 15:20 ` David Hildenbrand 2021-11-23 15:20 ` David Hildenbrand 2021-11-23 17:17 ` Jason Gunthorpe 2021-11-23 17:17 ` Jason Gunthorpe 2021-11-23 8:54 ` Paolo Bonzini 2021-11-23 8:54 ` Paolo Bonzini 2021-12-03 1:11 ` Andy Lutomirski 2021-12-03 1:11 ` Andy Lutomirski 2021-11-19 13:47 ` [RFC v2 PATCH 02/13] KVM: Add KVM_EXIT_MEMORY_ERROR exit Chao Peng 2021-11-19 13:47 ` Chao Peng 2021-11-19 13:47 ` [RFC v2 PATCH 03/13] KVM: Extend kvm_userspace_memory_region to support fd based memslot Chao Peng 2021-11-19 13:47 ` Chao Peng 2021-11-19 13:47 ` [RFC v2 PATCH 04/13] KVM: Add fd-based memslot data structure and utils Chao Peng 2021-11-19 13:47 ` Chao Peng 2021-11-23 8:41 ` Paolo Bonzini 2021-11-23 8:41 ` Paolo Bonzini 2021-11-23 14:30 ` Chao Peng 2021-11-23 14:30 ` Chao Peng 2021-11-19 13:47 ` [RFC v2 PATCH 05/13] KVM: Implement fd-based memory using new memfd interfaces Chao Peng 2021-11-19 13:47 ` Chao Peng 2021-11-19 13:47 ` [RFC v2 PATCH 06/13] KVM: Register/unregister memfd backed memslot Chao Peng 2021-11-19 13:47 ` Chao Peng 2021-11-25 16:55 ` Steven Price 2021-11-25 16:55 ` Steven Price 2021-11-19 13:47 ` [RFC v2 PATCH 07/13] KVM: Handle page fault for fd based memslot Chao Peng 2021-11-19 13:47 ` Chao Peng 2021-11-20 1:55 ` Yao Yuan 2021-11-20 1:55 ` Yao Yuan 2021-11-22 9:18 ` Chao Peng 2021-11-22 9:18 ` Chao Peng 2021-11-19 13:47 ` [RFC v2 PATCH 08/13] KVM: Rename hva memory invalidation code to cover fd-based offset Chao Peng 2021-11-19 13:47 ` Chao Peng 2021-11-19 13:47 ` [RFC v2 PATCH 09/13] KVM: Introduce kvm_memfd_invalidate_range Chao Peng 2021-11-19 13:47 ` Chao Peng 2021-11-23 8:46 ` Paolo Bonzini 2021-11-23 8:46 ` Paolo Bonzini 2021-11-23 14:24 ` Chao Peng 2021-11-23 14:24 ` Chao Peng 2021-11-19 13:47 ` [RFC v2 PATCH 10/13] KVM: Match inode for invalidation of fd-based slot Chao Peng 2021-11-19 13:47 ` Chao Peng 2021-11-19 13:47 ` [RFC v2 PATCH 11/13] KVM: Add kvm_map_gfn_range Chao Peng 2021-11-19 13:47 ` Chao Peng 2021-11-19 13:47 ` [RFC v2 PATCH 12/13] KVM: Introduce kvm_memfd_fallocate_range Chao Peng 2021-11-19 13:47 ` Chao Peng 2021-11-19 13:47 ` [RFC v2 PATCH 13/13] KVM: Enable memfd based page invalidation/fallocate Chao Peng 2021-11-19 13:47 ` Chao Peng 2021-11-22 14:16 ` Kirill A. Shutemov 2021-11-22 14:16 ` Kirill A. Shutemov 2021-11-23 1:06 ` Chao Peng [this message] 2021-11-23 1:06 ` Chao Peng 2021-11-23 9:09 ` Paolo Bonzini 2021-11-23 9:09 ` Paolo Bonzini 2021-11-23 15:00 ` Chao Peng 2021-11-23 15:00 ` Chao Peng 2021-11-23 8:51 ` Paolo Bonzini 2021-11-23 8:51 ` Paolo Bonzini 2021-12-03 1:08 ` [RFC v2 PATCH 00/13] KVM: mm: fd-based approach for supporting KVM guest private memory Andy Lutomirski 2021-12-03 1:08 ` Andy Lutomirski
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