From: Chao Peng <chao.p.peng@linux.intel.com> To: Steven Price <steven.price@arm.com> 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 02/12] mm/memfd: Introduce MFD_INACCESSIBLE flag Date: Mon, 24 Jan 2022 21:29:36 +0800 [thread overview] Message-ID: <20220124132936.GA55051@chaop.bj.intel.com> (raw) In-Reply-To: <8f1eba03-e5e9-e9fc-084d-0ef683093d65@arm.com> On Fri, Jan 21, 2022 at 03:50:55PM +0000, Steven Price wrote: > On 18/01/2022 13:21, Chao Peng wrote: > > Introduce a new memfd_create() flag indicating the content of the > > created memfd is inaccessible from userspace. It does this by force > > setting F_SEAL_INACCESSIBLE seal when the file is created. It also set > > F_SEAL_SEAL to prevent future sealing, which means, it can not coexist > > with MFD_ALLOW_SEALING. > > > > The pages backed by such memfd will be used as guest private memory in > > confidential computing environments such as Intel TDX/AMD SEV. Since > > page migration/swapping is not yet supported for such usages so these > > pages are currently marked as UNMOVABLE and UNEVICTABLE which makes > > them behave like long-term pinned pages. > > > > Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com> > > --- > > include/uapi/linux/memfd.h | 1 + > > mm/memfd.c | 20 +++++++++++++++++++- > > 2 files changed, 20 insertions(+), 1 deletion(-) > > > > diff --git a/include/uapi/linux/memfd.h b/include/uapi/linux/memfd.h > > index 7a8a26751c23..48750474b904 100644 > > --- a/include/uapi/linux/memfd.h > > +++ b/include/uapi/linux/memfd.h > > @@ -8,6 +8,7 @@ > > #define MFD_CLOEXEC 0x0001U > > #define MFD_ALLOW_SEALING 0x0002U > > #define MFD_HUGETLB 0x0004U > > +#define MFD_INACCESSIBLE 0x0008U > > > > /* > > * Huge page size encoding when MFD_HUGETLB is specified, and a huge page > > diff --git a/mm/memfd.c b/mm/memfd.c > > index 9f80f162791a..26998d96dc11 100644 > > --- a/mm/memfd.c > > +++ b/mm/memfd.c > > @@ -245,16 +245,19 @@ long memfd_fcntl(struct file *file, unsigned int cmd, unsigned long arg) > > #define MFD_NAME_PREFIX_LEN (sizeof(MFD_NAME_PREFIX) - 1) > > #define MFD_NAME_MAX_LEN (NAME_MAX - MFD_NAME_PREFIX_LEN) > > > > -#define MFD_ALL_FLAGS (MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_HUGETLB) > > +#define MFD_ALL_FLAGS (MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_HUGETLB | \ > > + MFD_INACCESSIBLE) > > > > SYSCALL_DEFINE2(memfd_create, > > const char __user *, uname, > > unsigned int, flags) > > { > > + struct address_space *mapping; > > unsigned int *file_seals; > > struct file *file; > > int fd, error; > > char *name; > > + gfp_t gfp; > > long len; > > > > if (!(flags & MFD_HUGETLB)) { > > @@ -267,6 +270,10 @@ SYSCALL_DEFINE2(memfd_create, > > return -EINVAL; > > } > > > > + /* Disallow sealing when MFD_INACCESSIBLE is set. */ > > + if (flags & MFD_INACCESSIBLE && flags & MFD_ALLOW_SEALING) > > + return -EINVAL; > > + > > /* length includes terminating zero */ > > len = strnlen_user(uname, MFD_NAME_MAX_LEN + 1); > > if (len <= 0) > > @@ -315,6 +322,17 @@ SYSCALL_DEFINE2(memfd_create, > > *file_seals &= ~F_SEAL_SEAL; > > } > > > > + if (flags & MFD_INACCESSIBLE) { > > + mapping = file_inode(file)->i_mapping; > > + gfp = mapping_gfp_mask(mapping); > > + gfp &= ~__GFP_MOVABLE; > > + mapping_set_gfp_mask(mapping, gfp); > > + mapping_set_unevictable(mapping); > > + > > + file_seals = memfd_file_seals_ptr(file); > > + *file_seals &= F_SEAL_SEAL | F_SEAL_INACCESSIBLE; > > This looks backwards - the flags should be set on *file_seals, but here > you are unsetting all other flags. Thanks Steve. '|=' actually should be used here. Chao > > Steve > > > + } > > + > > fd_install(fd, file); > > kfree(name); > > return fd; > >
WARNING: multiple messages have this Message-ID (diff)
From: Chao Peng <chao.p.peng@linux.intel.com> To: Steven Price <steven.price@arm.com> 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>, linux-mm@kvack.org, "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>, dave.hansen@intel.com, Sean Christopherson <seanjc@google.com>, Jeff Layton <jlayton@kernel.org>, linux-kernel@vger.kernel.org, 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: [PATCH v4 02/12] mm/memfd: Introduce MFD_INACCESSIBLE flag Date: Mon, 24 Jan 2022 21:29:36 +0800 [thread overview] Message-ID: <20220124132936.GA55051@chaop.bj.intel.com> (raw) In-Reply-To: <8f1eba03-e5e9-e9fc-084d-0ef683093d65@arm.com> On Fri, Jan 21, 2022 at 03:50:55PM +0000, Steven Price wrote: > On 18/01/2022 13:21, Chao Peng wrote: > > Introduce a new memfd_create() flag indicating the content of the > > created memfd is inaccessible from userspace. It does this by force > > setting F_SEAL_INACCESSIBLE seal when the file is created. It also set > > F_SEAL_SEAL to prevent future sealing, which means, it can not coexist > > with MFD_ALLOW_SEALING. > > > > The pages backed by such memfd will be used as guest private memory in > > confidential computing environments such as Intel TDX/AMD SEV. Since > > page migration/swapping is not yet supported for such usages so these > > pages are currently marked as UNMOVABLE and UNEVICTABLE which makes > > them behave like long-term pinned pages. > > > > Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com> > > --- > > include/uapi/linux/memfd.h | 1 + > > mm/memfd.c | 20 +++++++++++++++++++- > > 2 files changed, 20 insertions(+), 1 deletion(-) > > > > diff --git a/include/uapi/linux/memfd.h b/include/uapi/linux/memfd.h > > index 7a8a26751c23..48750474b904 100644 > > --- a/include/uapi/linux/memfd.h > > +++ b/include/uapi/linux/memfd.h > > @@ -8,6 +8,7 @@ > > #define MFD_CLOEXEC 0x0001U > > #define MFD_ALLOW_SEALING 0x0002U > > #define MFD_HUGETLB 0x0004U > > +#define MFD_INACCESSIBLE 0x0008U > > > > /* > > * Huge page size encoding when MFD_HUGETLB is specified, and a huge page > > diff --git a/mm/memfd.c b/mm/memfd.c > > index 9f80f162791a..26998d96dc11 100644 > > --- a/mm/memfd.c > > +++ b/mm/memfd.c > > @@ -245,16 +245,19 @@ long memfd_fcntl(struct file *file, unsigned int cmd, unsigned long arg) > > #define MFD_NAME_PREFIX_LEN (sizeof(MFD_NAME_PREFIX) - 1) > > #define MFD_NAME_MAX_LEN (NAME_MAX - MFD_NAME_PREFIX_LEN) > > > > -#define MFD_ALL_FLAGS (MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_HUGETLB) > > +#define MFD_ALL_FLAGS (MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_HUGETLB | \ > > + MFD_INACCESSIBLE) > > > > SYSCALL_DEFINE2(memfd_create, > > const char __user *, uname, > > unsigned int, flags) > > { > > + struct address_space *mapping; > > unsigned int *file_seals; > > struct file *file; > > int fd, error; > > char *name; > > + gfp_t gfp; > > long len; > > > > if (!(flags & MFD_HUGETLB)) { > > @@ -267,6 +270,10 @@ SYSCALL_DEFINE2(memfd_create, > > return -EINVAL; > > } > > > > + /* Disallow sealing when MFD_INACCESSIBLE is set. */ > > + if (flags & MFD_INACCESSIBLE && flags & MFD_ALLOW_SEALING) > > + return -EINVAL; > > + > > /* length includes terminating zero */ > > len = strnlen_user(uname, MFD_NAME_MAX_LEN + 1); > > if (len <= 0) > > @@ -315,6 +322,17 @@ SYSCALL_DEFINE2(memfd_create, > > *file_seals &= ~F_SEAL_SEAL; > > } > > > > + if (flags & MFD_INACCESSIBLE) { > > + mapping = file_inode(file)->i_mapping; > > + gfp = mapping_gfp_mask(mapping); > > + gfp &= ~__GFP_MOVABLE; > > + mapping_set_gfp_mask(mapping, gfp); > > + mapping_set_unevictable(mapping); > > + > > + file_seals = memfd_file_seals_ptr(file); > > + *file_seals &= F_SEAL_SEAL | F_SEAL_INACCESSIBLE; > > This looks backwards - the flags should be set on *file_seals, but here > you are unsetting all other flags. Thanks Steve. '|=' actually should be used here. Chao > > Steve > > > + } > > + > > fd_install(fd, file); > > kfree(name); > > return fd; > >
next prev parent reply other threads:[~2022-01-24 13:30 UTC|newest] Thread overview: 92+ 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 ` Chao Peng 2022-01-18 13:21 ` [PATCH v4 01/12] mm/shmem: Introduce F_SEAL_INACCESSIBLE Chao Peng 2022-01-18 13:21 ` Chao Peng 2022-02-07 12:24 ` Vlastimil Babka 2022-02-07 12:24 ` Vlastimil Babka 2022-02-17 12:56 ` Chao Peng 2022-02-17 12:56 ` Chao Peng 2022-02-11 23:33 ` Andy Lutomirski 2022-02-11 23:33 ` Andy Lutomirski 2022-02-17 13:06 ` Chao Peng 2022-02-17 13:06 ` Chao Peng 2022-02-17 19:09 ` Andy Lutomirski 2022-02-17 19:09 ` Andy Lutomirski 2022-02-23 11:49 ` Chao Peng 2022-02-23 11:49 ` Chao Peng 2022-02-23 12:05 ` Steven Price 2022-02-23 12:05 ` Steven Price 2022-03-04 19:24 ` Andy Lutomirski 2022-03-04 19:24 ` Andy Lutomirski 2022-03-07 13:26 ` Chao Peng 2022-03-07 13:26 ` Chao Peng 2022-03-08 12:17 ` Paolo Bonzini 2022-03-08 12:17 ` Paolo Bonzini 2022-01-18 13:21 ` [PATCH v4 02/12] mm/memfd: Introduce MFD_INACCESSIBLE flag Chao Peng 2022-01-18 13:21 ` Chao Peng 2022-01-21 15:50 ` Steven Price 2022-01-21 15:50 ` Steven Price 2022-01-24 13:29 ` Chao Peng [this message] 2022-01-24 13:29 ` Chao Peng 2022-02-07 18:51 ` Vlastimil Babka 2022-02-07 18:51 ` Vlastimil Babka 2022-02-08 8:49 ` David Hildenbrand 2022-02-08 8:49 ` David Hildenbrand 2022-02-08 18:22 ` Mike Rapoport 2022-02-08 18:22 ` Mike Rapoport 2022-01-18 13:21 ` [PATCH v4 03/12] mm: Introduce memfile_notifier Chao Peng 2022-01-18 13:21 ` Chao Peng 2022-03-07 15:42 ` Vlastimil Babka 2022-03-07 15:42 ` Vlastimil Babka 2022-03-08 1:45 ` Chao Peng 2022-03-08 1:45 ` Chao Peng 2022-01-18 13:21 ` [PATCH v4 04/12] mm/shmem: Support memfile_notifier Chao Peng 2022-01-18 13:21 ` Chao Peng 2022-02-08 18:29 ` Mike Rapoport 2022-02-08 18:29 ` Mike Rapoport 2022-02-17 13:10 ` Chao Peng 2022-02-17 13:10 ` Chao Peng 2022-02-11 23:40 ` Andy Lutomirski 2022-02-11 23:40 ` Andy Lutomirski 2022-02-17 13:23 ` Chao Peng 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 ` 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 ` 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 ` 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 ` 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 ` 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 ` 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 ` Chao Peng 2022-01-18 13:21 ` [PATCH v4 12/12] KVM: Expose KVM_MEM_PRIVATE Chao Peng 2022-01-18 13:21 ` Chao Peng 2022-01-25 20:20 ` Maciej S. Szmigiero 2022-01-25 20:20 ` Maciej S. Szmigiero 2022-02-17 13:45 ` Chao Peng 2022-02-17 13:45 ` Chao Peng 2022-02-22 1:16 ` Maciej S. Szmigiero 2022-02-22 1:16 ` Maciej S. Szmigiero 2022-02-23 12:00 ` Chao Peng 2022-02-23 12:00 ` Chao Peng 2022-02-23 18:32 ` Maciej S. Szmigiero 2022-02-23 18:32 ` Maciej S. Szmigiero 2022-02-24 8:07 ` Chao Peng 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 2022-01-28 16:47 ` Steven Price 2022-02-02 2:28 ` Nakajima, Jun 2022-02-02 2:28 ` Nakajima, Jun 2022-02-02 9:23 ` Steven Price 2022-02-02 9:23 ` Steven Price 2022-02-02 20:47 ` Nakajima, Jun 2022-02-02 20:47 ` Nakajima, Jun 2022-02-08 18:33 ` Mike Rapoport 2022-02-08 18:33 ` Mike Rapoport 2022-02-17 13:47 ` Chao Peng 2022-02-17 13:47 ` Chao Peng
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20220124132936.GA55051@chaop.bj.intel.com \ --to=chao.p.peng@linux.intel.com \ --cc=ak@linux.intel.com \ --cc=akpm@linux-foundation.org \ --cc=bfields@fieldses.org \ --cc=bp@alien8.de \ --cc=corbet@lwn.net \ --cc=dave.hansen@intel.com \ --cc=david@redhat.com \ --cc=hpa@zytor.com \ --cc=hughd@google.com \ --cc=jlayton@kernel.org \ --cc=jmattson@google.com \ --cc=joro@8bytes.org \ --cc=jun.nakajima@intel.com \ --cc=kirill.shutemov@linux.intel.com \ --cc=kvm@vger.kernel.org \ --cc=linux-fsdevel@vger.kernel.org \ --cc=linux-kernel@vger.kernel.org \ --cc=linux-mm@kvack.org \ --cc=luto@kernel.org \ --cc=mingo@redhat.com \ --cc=pbonzini@redhat.com \ --cc=qemu-devel@nongnu.org \ --cc=seanjc@google.com \ --cc=steven.price@arm.com \ --cc=tglx@linutronix.de \ --cc=vkuznets@redhat.com \ --cc=wanpengli@tencent.com \ --cc=x86@kernel.org \ --cc=yu.c.zhang@linux.intel.com \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.