From: Chao Peng <chao.p.peng@linux.intel.com>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
qemu-devel@nongnu.org, Paolo Bonzini <pbonzini@redhat.com>,
Jonathan Corbet <corbet@lwn.net>,
Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
x86@kernel.org, "H . Peter Anvin" <hpa@zytor.com>,
Hugh Dickins <hughd@google.com>, Jeff Layton <jlayton@kernel.org>,
"J . Bruce Fields" <bfields@fieldses.org>,
Andrew Morton <akpm@linux-foundation.org>,
Yu Zhang <yu.c.zhang@linux.intel.com>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
luto@kernel.org, jun.nakajima@intel.com, dave.hansen@intel.com,
ak@linux.intel.com, david@redhat.com
Subject: Re: [PATCH v4 01/12] mm/shmem: Introduce F_SEAL_INACCESSIBLE
Date: Thu, 17 Feb 2022 20:56:57 +0800 [thread overview]
Message-ID: <20220217125656.GA32679@chaop.bj.intel.com> (raw)
In-Reply-To: <64407833-1387-0c46-c569-8b6a3db8e88c@suse.cz>
On Mon, Feb 07, 2022 at 01:24:42PM +0100, Vlastimil Babka wrote:
> On 1/18/22 14:21, Chao Peng wrote:
> > From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
> >
> > /*
> > diff --git a/mm/shmem.c b/mm/shmem.c
> > index 18f93c2d68f1..72185630e7c4 100644
> > --- a/mm/shmem.c
> > +++ b/mm/shmem.c
> > @@ -1098,6 +1098,13 @@ static int shmem_setattr(struct user_namespace *mnt_userns,
> > (newsize > oldsize && (info->seals & F_SEAL_GROW)))
> > return -EPERM;
> >
> > + if (info->seals & F_SEAL_INACCESSIBLE) {
> > + if(i_size_read(inode))
>
> Is this needed? The rest of the function seems to trust oldsize obtained by
> plain reading inode->i_size well enough, so why be suddenly paranoid here?
oldsize sounds enough here, unless kirill has different mind.
>
> > + return -EPERM;
> > + if (newsize & ~PAGE_MASK)
> > + return -EINVAL;
> > + }
> > +
> > if (newsize != oldsize) {
> > error = shmem_reacct_size(SHMEM_I(inode)->flags,
> > + if ((info->seals & F_SEAL_INACCESSIBLE) &&
> > + (offset & ~PAGE_MASK || len & ~PAGE_MASK)) {
>
> Could we use PAGE_ALIGNED()?
Yes, definitely, thanks.
Chao
>
> > + error = -EINVAL;
> > + goto out;
> > + }
> > +
> > shmem_falloc.waitq = &shmem_falloc_waitq;
> > shmem_falloc.start = (u64)unmap_start >> PAGE_SHIFT;
> > shmem_falloc.next = (unmap_end + 1) >> PAGE_SHIFT;
next prev parent reply other threads:[~2022-02-17 12:57 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-18 13:21 [PATCH v4 00/12] KVM: mm: fd-based approach for supporting KVM guest private memory Chao Peng
2022-01-18 13:21 ` [PATCH v4 01/12] mm/shmem: Introduce F_SEAL_INACCESSIBLE Chao Peng
2022-02-07 12:24 ` Vlastimil Babka
2022-02-17 12:56 ` Chao Peng [this message]
2022-02-11 23:33 ` Andy Lutomirski
2022-02-17 13:06 ` Chao Peng
2022-02-17 19:09 ` Andy Lutomirski
2022-02-23 11:49 ` Chao Peng
2022-02-23 12:05 ` Steven Price
2022-03-04 19:24 ` Andy Lutomirski
2022-03-07 13:26 ` Chao Peng
2022-03-08 12:17 ` Paolo Bonzini
2022-01-18 13:21 ` [PATCH v4 02/12] mm/memfd: Introduce MFD_INACCESSIBLE flag Chao Peng
2022-01-21 15:50 ` Steven Price
2022-01-24 13:29 ` Chao Peng
2022-02-07 18:51 ` Vlastimil Babka
2022-02-08 8:49 ` David Hildenbrand
2022-02-08 18:22 ` Mike Rapoport
2022-01-18 13:21 ` [PATCH v4 03/12] mm: Introduce memfile_notifier Chao Peng
2022-03-07 15:42 ` Vlastimil Babka
2022-03-08 1:45 ` Chao Peng
2022-01-18 13:21 ` [PATCH v4 04/12] mm/shmem: Support memfile_notifier Chao Peng
2022-02-08 18:29 ` Mike Rapoport
2022-02-17 13:10 ` Chao Peng
2022-02-11 23:40 ` Andy Lutomirski
2022-02-17 13:23 ` Chao Peng
2022-01-18 13:21 ` [PATCH v4 05/12] KVM: Extend the memslot to support fd-based private memory Chao Peng
2022-01-18 13:21 ` [PATCH v4 06/12] KVM: Use kvm_userspace_memory_region_ext Chao Peng
2022-01-18 13:21 ` [PATCH v4 07/12] KVM: Add KVM_EXIT_MEMORY_ERROR exit Chao Peng
2022-01-18 13:21 ` [PATCH v4 08/12] KVM: Use memfile_pfn_ops to obtain pfn for private pages Chao Peng
2022-01-18 13:21 ` [PATCH v4 09/12] KVM: Handle page fault for private memory Chao Peng
2022-01-18 13:21 ` [PATCH v4 10/12] KVM: Register private memslot to memory backing store Chao Peng
2022-01-18 13:21 ` [PATCH v4 11/12] KVM: Zap existing KVM mappings when pages changed in the private fd Chao Peng
2022-01-18 13:21 ` [PATCH v4 12/12] KVM: Expose KVM_MEM_PRIVATE Chao Peng
2022-01-25 20:20 ` Maciej S. Szmigiero
2022-02-17 13:45 ` Chao Peng
2022-02-22 1:16 ` Maciej S. Szmigiero
2022-02-23 12:00 ` Chao Peng
2022-02-23 18:32 ` Maciej S. Szmigiero
2022-02-24 8:07 ` Chao Peng
2022-01-28 16:47 ` [PATCH v4 00/12] KVM: mm: fd-based approach for supporting KVM guest private memory Steven Price
2022-02-02 2:28 ` Nakajima, Jun
2022-02-02 9:23 ` Steven Price
2022-02-02 20:47 ` Nakajima, Jun
2022-02-08 18:33 ` Mike Rapoport
2022-02-17 13:47 ` Chao Peng
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