From: Peter Zijlstra <peterz@infradead.org>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
x86@kernel.org, Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Borislav Petkov <bp@alien8.de>,
Andy Lutomirski <luto@amacapital.net>,
David Howells <dhowells@redhat.com>,
Kees Cook <keescook@chromium.org>,
Dave Hansen <dave.hansen@intel.com>,
Kai Huang <kai.huang@linux.intel.com>,
Jacob Pan <jacob.jun.pan@linux.intel.com>,
Alison Schofield <alison.schofield@intel.com>,
linux-mm@kvack.org, kvm@vger.kernel.org,
keyrings@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH, RFC 46/62] x86/mm: Keep reference counts on encrypted VMAs for MKTME
Date: Fri, 14 Jun 2019 13:54:24 +0200 [thread overview]
Message-ID: <20190614115424.GG3436@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20190508144422.13171-47-kirill.shutemov@linux.intel.com>
On Wed, May 08, 2019 at 05:44:06PM +0300, Kirill A. Shutemov wrote:
> From: Alison Schofield <alison.schofield@intel.com>
>
> The MKTME (Multi-Key Total Memory Encryption) Key Service needs
> a reference count on encrypted VMAs. This reference count is used
> to determine when a hardware encryption KeyID is no longer in use
> and can be freed and reassigned to another Userspace Key.
>
> The MKTME Key service does the percpu_ref_init and _kill, so
> these gets/puts on encrypted VMA's can be considered the
> intermediaries in the lifetime of the key.
>
> Increment/decrement the reference count during encrypt_mprotect()
> system call for initial or updated encryption on a VMA.
>
> Piggy back on the vm_area_dup/free() helpers. If the VMAs being
> duplicated, or freed are encrypted, adjust the reference count.
That all talks about VMAs, but...
> @@ -102,6 +115,22 @@ void __prep_encrypted_page(struct page *page, int order, int keyid, bool zero)
>
> page++;
> }
> +
> + /*
> + * Make sure the KeyID cannot be freed until the last page that
> + * uses the KeyID is gone.
> + *
> + * This is required because the page may live longer than VMA it
> + * is mapped into (i.e. in get_user_pages() case) and having
> + * refcounting per-VMA is not enough.
> + *
> + * Taking a reference per-4K helps in case if the page will be
> + * split after the allocation. free_encrypted_page() will balance
> + * out the refcount even if the page was split and freed as bunch
> + * of 4K pages.
> + */
> +
> + percpu_ref_get_many(&encrypt_count[keyid], 1 << order);
> }
>
> /*
> @@ -110,7 +139,9 @@ void __prep_encrypted_page(struct page *page, int order, int keyid, bool zero)
> */
> void free_encrypted_page(struct page *page, int order)
> {
> - int i;
> + int i, keyid;
> +
> + keyid = page_keyid(page);
>
> /*
> * The hardware/CPU does not enforce coherency between mappings
> @@ -125,6 +156,8 @@ void free_encrypted_page(struct page *page, int order)
> lookup_page_ext(page)->keyid = 0;
> page++;
> }
> +
> + percpu_ref_put_many(&encrypt_count[keyid], 1 << order);
> }
counts pages, what gives?
next prev parent reply other threads:[~2019-06-14 11:54 UTC|newest]
Thread overview: 153+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-08 14:43 [PATCH, RFC 00/62] Intel MKTME enabling Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 01/62] mm: Do no merge VMAs with different encryption KeyIDs Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 02/62] mm: Add helpers to setup zero page mappings Kirill A. Shutemov
2019-05-29 7:21 ` Mike Rapoport
2019-05-08 14:43 ` [PATCH, RFC 03/62] mm/ksm: Do not merge pages with different KeyIDs Kirill A. Shutemov
2019-05-10 18:07 ` Dave Hansen
2019-05-13 14:27 ` Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 04/62] mm/page_alloc: Unify alloc_hugepage_vma() Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 05/62] mm/page_alloc: Handle allocation for encrypted memory Kirill A. Shutemov
2019-05-29 7:21 ` Mike Rapoport
2019-05-29 12:47 ` Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 06/62] mm/khugepaged: Handle encrypted pages Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 07/62] x86/mm: Mask out KeyID bits from page table entry pfn Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 08/62] x86/mm: Introduce variables to store number, shift and mask of KeyIDs Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 09/62] x86/mm: Preserve KeyID on pte_modify() and pgprot_modify() Kirill A. Shutemov
2019-06-14 9:15 ` Peter Zijlstra
2019-06-14 13:03 ` Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 10/62] x86/mm: Detect MKTME early Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 11/62] x86/mm: Add a helper to retrieve KeyID for a page Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 12/62] x86/mm: Add a helper to retrieve KeyID for a VMA Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 13/62] x86/mm: Add hooks to allocate and free encrypted pages Kirill A. Shutemov
2019-06-14 9:34 ` Peter Zijlstra
2019-06-14 11:04 ` Peter Zijlstra
2019-06-14 13:28 ` Kirill A. Shutemov
2019-06-14 13:43 ` Peter Zijlstra
2019-06-14 22:41 ` Kirill A. Shutemov
2019-06-17 9:25 ` Peter Zijlstra
2019-06-14 13:14 ` Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 14/62] x86/mm: Map zero pages into encrypted mappings correctly Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 15/62] x86/mm: Rename CONFIG_RANDOMIZE_MEMORY_PHYSICAL_PADDING Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 16/62] x86/mm: Allow to disable MKTME after enumeration Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 17/62] x86/mm: Calculate direct mapping size Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 18/62] x86/mm: Implement syncing per-KeyID direct mappings Kirill A. Shutemov
2019-06-14 9:51 ` Peter Zijlstra
2019-06-14 22:43 ` Kirill A. Shutemov
2019-06-17 9:27 ` Peter Zijlstra
2019-06-17 14:43 ` Kirill A. Shutemov
2019-06-17 14:51 ` Peter Zijlstra
2019-06-17 15:17 ` Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 19/62] x86/mm: Handle encrypted memory in page_to_virt() and __pa() Kirill A. Shutemov
2019-06-14 11:10 ` Peter Zijlstra
2019-05-08 14:43 ` [PATCH, RFC 20/62] mm/page_ext: Export lookup_page_ext() symbol Kirill A. Shutemov
2019-06-14 11:12 ` Peter Zijlstra
2019-06-14 22:44 ` Kirill A. Shutemov
2019-06-17 9:30 ` Peter Zijlstra
2019-06-17 11:01 ` Kai Huang
2019-06-17 11:13 ` Huang, Kai
2019-05-08 14:43 ` [PATCH, RFC 21/62] mm/rmap: Clear vma->anon_vma on unlink_anon_vmas() Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 22/62] x86/pconfig: Set a valid encryption algorithm for all MKTME commands Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 23/62] keys/mktme: Introduce a Kernel Key Service for MKTME Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 24/62] keys/mktme: Preparse the MKTME key payload Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 25/62] keys/mktme: Instantiate and destroy MKTME keys Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 26/62] keys/mktme: Move the MKTME payload into a cache aligned structure Kirill A. Shutemov
2019-06-14 11:35 ` Peter Zijlstra
2019-06-14 17:10 ` Alison Schofield
2019-05-08 14:43 ` [PATCH, RFC 27/62] keys/mktme: Strengthen the entropy of CPU generated MKTME keys Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 28/62] keys/mktme: Set up PCONFIG programming targets for " Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 29/62] keys/mktme: Program MKTME keys into the platform hardware Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 30/62] keys/mktme: Set up a percpu_ref_count for MKTME keys Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 31/62] keys/mktme: Require CAP_SYS_RESOURCE capability " Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 32/62] keys/mktme: Store MKTME payloads if cmdline parameter allows Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 33/62] acpi: Remove __init from acpi table parsing functions Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 34/62] acpi/hmat: Determine existence of an ACPI HMAT Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 35/62] keys/mktme: Require ACPI HMAT to register the MKTME Key Service Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 36/62] acpi/hmat: Evaluate topology presented in ACPI HMAT for MKTME Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 37/62] keys/mktme: Do not allow key creation in unsafe topologies Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 38/62] keys/mktme: Support CPU hotplug for MKTME key service Kirill A. Shutemov
2019-05-08 14:43 ` [PATCH, RFC 39/62] keys/mktme: Find new PCONFIG targets during memory hotplug Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 40/62] keys/mktme: Program new PCONFIG targets with MKTME keys Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 41/62] keys/mktme: Support memory hotplug for " Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 42/62] mm: Generalize the mprotect implementation to support extensions Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 43/62] syscall/x86: Wire up a system call for MKTME encryption keys Kirill A. Shutemov
2019-05-29 7:21 ` Mike Rapoport
2019-05-29 18:12 ` Alison Schofield
2019-05-08 14:44 ` [PATCH, RFC 44/62] x86/mm: Set KeyIDs in encrypted VMAs for MKTME Kirill A. Shutemov
2019-06-14 11:44 ` Peter Zijlstra
2019-06-14 17:33 ` Alison Schofield
2019-06-14 18:26 ` Dave Hansen
2019-06-14 18:46 ` Alison Schofield
2019-06-14 19:11 ` Dave Hansen
2019-06-17 9:10 ` Peter Zijlstra
2019-05-08 14:44 ` [PATCH, RFC 45/62] mm: Add the encrypt_mprotect() system call " Kirill A. Shutemov
2019-06-14 11:47 ` Peter Zijlstra
2019-06-14 17:35 ` Alison Schofield
2019-06-14 11:51 ` Peter Zijlstra
2019-06-15 0:32 ` Alison Schofield
2019-06-17 9:08 ` Peter Zijlstra
2019-06-17 15:07 ` Andy Lutomirski
2019-06-17 15:28 ` Dave Hansen
2019-06-17 15:46 ` Andy Lutomirski
2019-06-17 18:27 ` Dave Hansen
2019-06-17 19:12 ` Andy Lutomirski
2019-06-17 21:36 ` Dave Hansen
2019-06-18 0:48 ` Kai Huang
2019-06-18 1:50 ` Andy Lutomirski
2019-06-18 2:11 ` Kai Huang
2019-06-18 4:24 ` Andy Lutomirski
2019-06-18 14:19 ` Dave Hansen
2019-06-18 0:05 ` Kai Huang
2019-06-18 0:15 ` Andy Lutomirski
2019-06-18 1:35 ` Kai Huang
2019-06-18 1:43 ` Andy Lutomirski
2019-06-18 2:23 ` Kai Huang
2019-06-18 9:12 ` Peter Zijlstra
2019-06-18 14:09 ` Dave Hansen
2019-06-18 16:15 ` Kirill A. Shutemov
2019-06-18 16:22 ` Dave Hansen
2019-06-18 16:36 ` Andy Lutomirski
2019-06-18 16:48 ` Dave Hansen
2019-06-18 14:13 ` Dave Hansen
2019-06-17 23:59 ` Kai Huang
2019-06-18 1:34 ` Lendacky, Thomas
2019-06-18 1:40 ` Andy Lutomirski
2019-06-18 2:02 ` Lendacky, Thomas
2019-06-18 4:19 ` Andy Lutomirski
2019-05-08 14:44 ` [PATCH, RFC 46/62] x86/mm: Keep reference counts on encrypted VMAs " Kirill A. Shutemov
2019-06-14 11:54 ` Peter Zijlstra [this message]
2019-06-14 18:39 ` Alison Schofield
2019-05-08 14:44 ` [PATCH, RFC 47/62] mm: Restrict MKTME memory encryption to anonymous VMAs Kirill A. Shutemov
2019-06-14 11:55 ` Peter Zijlstra
2019-06-15 0:07 ` Alison Schofield
2019-05-08 14:44 ` [PATCH, RFC 48/62] selftests/x86/mktme: Test the MKTME APIs Kirill A. Shutemov
2019-05-08 17:09 ` Alison Schofield
2019-05-08 14:44 ` [PATCH, RFC 49/62] mm, x86: export several MKTME variables Kirill A. Shutemov
2019-06-14 11:56 ` Peter Zijlstra
2019-06-17 3:14 ` Kai Huang
2019-06-17 7:46 ` Peter Zijlstra
2019-06-17 8:39 ` Kai Huang
2019-06-17 11:25 ` Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 50/62] kvm, x86, mmu: setup MKTME keyID to spte for given PFN Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 51/62] iommu/vt-d: Support MKTME in DMA remapping Kirill A. Shutemov
2019-06-14 12:04 ` Peter Zijlstra
2019-05-08 14:44 ` [PATCH, RFC 52/62] x86/mm: introduce common code for mem encryption Kirill A. Shutemov
2019-05-08 16:58 ` Christoph Hellwig
2019-05-08 20:52 ` Jacob Pan
2019-05-08 21:21 ` Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 53/62] x86/mm: Use common code for DMA memory encryption Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 54/62] x86/mm: Disable MKTME on incompatible platform configurations Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 55/62] x86/mm: Disable MKTME if not all system memory supports encryption Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 56/62] x86: Introduce CONFIG_X86_INTEL_MKTME Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 57/62] x86/mktme: Overview of Multi-Key Total Memory Encryption Kirill A. Shutemov
2019-05-29 7:21 ` Mike Rapoport
2019-05-29 18:13 ` Alison Schofield
2019-07-14 18:16 ` Randy Dunlap
2019-07-15 9:02 ` Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 58/62] x86/mktme: Document the MKTME provided security mitigations Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 59/62] x86/mktme: Document the MKTME kernel configuration requirements Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 60/62] x86/mktme: Document the MKTME Key Service API Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 61/62] x86/mktme: Document the MKTME API for anonymous memory encryption Kirill A. Shutemov
2019-05-08 14:44 ` [PATCH, RFC 62/62] x86/mktme: Demonstration program using the MKTME APIs Kirill A. Shutemov
2019-05-29 7:30 ` [PATCH, RFC 00/62] Intel MKTME enabling Mike Rapoport
2019-05-29 18:20 ` Alison Schofield
2019-06-14 12:15 ` Peter Zijlstra
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