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2022-03-16x86/sgx: Free backing memory after faulting the enclave pageJarkko Sakkinen1-9/+48
commit 08999b2489b4c9b939d7483dbd03702ee4576d96 upstream. There is a limited amount of SGX memory (EPC) on each system. When that memory is used up, SGX has its own swapping mechanism which is similar in concept but totally separate from the core mm/* code. Instead of swapping to disk, SGX swaps from EPC to normal RAM. That normal RAM comes from a shared memory pseudo-file and can itself be swapped by the core mm code. There is a hierarchy like this: EPC <-> shmem <-> disk After data is swapped back in from shmem to EPC, the shmem backing storage needs to be freed. Currently, the backing shmem is not freed. This effectively wastes the shmem while the enclave is running. The memory is recovered when the enclave is destroyed and the backing storage freed. Sort this out by freeing memory with shmem_truncate_range(), as soon as a page is faulted back to the EPC. In addition, free the memory for PCMD pages as soon as all PCMD's in a page have been marked as unused by zeroing its contents. Cc: stable@vger.kernel.org Fixes: 1728ab54b4be ("x86/sgx: Add a page reclaimer") Reported-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Link: https://lkml.kernel.org/r/20220303223859.273187-1-jarkko@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-02-16x86/sgx: Silence softlockup detection when releasing large enclavesReinette Chatre1-0/+2
commit 8795359e35bc33bf86b6d0765aa7f37431db3b9c upstream. Vijay reported that the "unclobbered_vdso_oversubscribed" selftest triggers the softlockup detector. Actual SGX systems have 128GB of enclave memory or more. The "unclobbered_vdso_oversubscribed" selftest creates one enclave which consumes all of the enclave memory on the system. Tearing down such a large enclave takes around a minute, most of it in the loop where the EREMOVE instruction is applied to each individual 4k enclave page. Spending one minute in a loop triggers the softlockup detector. Add a cond_resched() to give other tasks a chance to run and placate the softlockup detector. Cc: stable@vger.kernel.org Fixes: 1728ab54b4be ("x86/sgx: Add a page reclaimer") Reported-by: Vijay Dhanraj <vijay.dhanraj@intel.com> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Tested-by: Jarkko Sakkinen <jarkko@kernel.org> (kselftest as sanity check) Link: https://lkml.kernel.org/r/ced01cac1e75f900251b0a4ae1150aa8ebd295ec.1644345232.git.reinette.chatre@intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-25x86/sgx: Fix free page accountingReinette Chatre1-6/+6
commit ac5d272a0ad0419f52e08c91953356e32b075af7 upstream. The SGX driver maintains a single global free page counter, sgx_nr_free_pages, that reflects the number of free pages available across all NUMA nodes. Correspondingly, a list of free pages is associated with each NUMA node and sgx_nr_free_pages is updated every time a page is added or removed from any of the free page lists. The main usage of sgx_nr_free_pages is by the reclaimer that runs when it (sgx_nr_free_pages) goes below a watermark to ensure that there are always some free pages available to, for example, support efficient page faults. With sgx_nr_free_pages accessed and modified from a few places it is essential to ensure that these accesses are done safely but this is not the case. sgx_nr_free_pages is read without any protection and updated with inconsistent protection by any one of the spin locks associated with the individual NUMA nodes. For example: CPU_A CPU_B ----- ----- spin_lock(&nodeA->lock); spin_lock(&nodeB->lock); ... ... sgx_nr_free_pages--; /* NOT SAFE */ sgx_nr_free_pages--; spin_unlock(&nodeA->lock); spin_unlock(&nodeB->lock); Since sgx_nr_free_pages may be protected by different spin locks while being modified from different CPUs, the following scenario is possible: CPU_A CPU_B ----- ----- {sgx_nr_free_pages = 100} spin_lock(&nodeA->lock); spin_lock(&nodeB->lock); sgx_nr_free_pages--; sgx_nr_free_pages--; /* LOAD sgx_nr_free_pages = 100 */ /* LOAD sgx_nr_free_pages = 100 */ /* sgx_nr_free_pages-- */ /* sgx_nr_free_pages-- */ /* STORE sgx_nr_free_pages = 99 */ /* STORE sgx_nr_free_pages = 99 */ spin_unlock(&nodeA->lock); spin_unlock(&nodeB->lock); In the above scenario, sgx_nr_free_pages is decremented from two CPUs but instead of sgx_nr_free_pages ending with a value that is two less than it started with, it was only decremented by one while the number of free pages were actually reduced by two. The consequence of sgx_nr_free_pages not being protected is that its value may not accurately reflect the actual number of free pages on the system, impacting the availability of free pages in support of many flows. The problematic scenario is when the reclaimer does not run because it believes there to be sufficient free pages while any attempt to allocate a page fails because there are no free pages available. In the SGX driver the reclaimer's watermark is only 32 pages so after encountering the above example scenario 32 times a user space hang is possible when there are no more free pages because of repeated page faults caused by no free pages made available. The following flow was encountered: asm_exc_page_fault ... sgx_vma_fault() sgx_encl_load_page() sgx_encl_eldu() // Encrypted page needs to be loaded from backing // storage into newly allocated SGX memory page sgx_alloc_epc_page() // Allocate a page of SGX memory __sgx_alloc_epc_page() // Fails, no free SGX memory ... if (sgx_should_reclaim(SGX_NR_LOW_PAGES)) // Wake reclaimer wake_up(&ksgxd_waitq); return -EBUSY; // Return -EBUSY giving reclaimer time to run return -EBUSY; return -EBUSY; return VM_FAULT_NOPAGE; The reclaimer is triggered in above flow with the following code: static bool sgx_should_reclaim(unsigned long watermark) { return sgx_nr_free_pages < watermark && !list_empty(&sgx_active_page_list); } In the problematic scenario there were no free pages available yet the value of sgx_nr_free_pages was above the watermark. The allocation of SGX memory thus always failed because of a lack of free pages while no free pages were made available because the reclaimer is never started because of sgx_nr_free_pages' incorrect value. The consequence was that user space kept encountering VM_FAULT_NOPAGE that caused the same address to be accessed repeatedly with the same result. Change the global free page counter to an atomic type that ensures simultaneous updates are done safely. While doing so, move the updating of the variable outside of the spin lock critical section to which it does not belong. Cc: stable@vger.kernel.org Fixes: 901ddbb9ecf5 ("x86/sgx: Add a basic NUMA allocation scheme to sgx_alloc_epc_page()") Suggested-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Acked-by: Jarkko Sakkinen <jarkko@kernel.org> Link: https://lkml.kernel.org/r/a95a40743bbd3f795b465f30922dde7f1ea9e0eb.1637004094.git.reinette.chatre@intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-06-30Merge branch 'akpm' (patches from Andrew)Linus Torvalds1-2/+2
Merge misc updates from Andrew Morton: "191 patches. Subsystems affected by this patch series: kthread, ia64, scripts, ntfs, squashfs, ocfs2, kernel/watchdog, and mm (gup, pagealloc, slab, slub, kmemleak, dax, debug, pagecache, gup, swap, memcg, pagemap, mprotect, bootmem, dma, tracing, vmalloc, kasan, initialization, pagealloc, and memory-failure)" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (191 commits) mm,hwpoison: make get_hwpoison_page() call get_any_page() mm,hwpoison: send SIGBUS with error virutal address mm/page_alloc: split pcp->high across all online CPUs for cpuless nodes mm/page_alloc: allow high-order pages to be stored on the per-cpu lists mm: replace CONFIG_FLAT_NODE_MEM_MAP with CONFIG_FLATMEM mm: replace CONFIG_NEED_MULTIPLE_NODES with CONFIG_NUMA docs: remove description of DISCONTIGMEM arch, mm: remove stale mentions of DISCONIGMEM mm: remove CONFIG_DISCONTIGMEM m68k: remove support for DISCONTIGMEM arc: remove support for DISCONTIGMEM arc: update comment about HIGHMEM implementation alpha: remove DISCONTIGMEM and NUMA mm/page_alloc: move free_the_page mm/page_alloc: fix counting of managed_pages mm/page_alloc: improve memmap_pages dbg msg mm: drop SECTION_SHIFT in code comments mm/page_alloc: introduce vm.percpu_pagelist_high_fraction mm/page_alloc: limit the number of pages on PCP lists when reclaim is active mm/page_alloc: scale the number of pages that are batch freed ...
2021-06-29x86/sgx: use vma_lookup() in sgx_encl_find()Liam Howlett1-2/+2
Use vma_lookup() to find the VMA at a specific address. As vma_lookup() will return NULL if the address is not within any VMA, the start address no longer needs to be validated. Link: https://lkml.kernel.org/r/20210521174745.2219620-10-Liam.Howlett@Oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Davidlohr Bueso <dbueso@suse.de> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-28Merge tag 'x86-cleanups-2021-06-28' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 cleanups from Ingo Molnar: "Misc cleanups & removal of obsolete code" * tag 'x86-cleanups-2021-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/sgx: Correct kernel-doc's arg name in sgx_encl_release() doc: Remove references to IBM Calgary x86/setup: Document that Windows reserves the first MiB x86/crash: Remove crash_reserve_low_1M() x86/setup: Remove CONFIG_X86_RESERVE_LOW and reservelow= options x86/alternative: Align insn bytes vertically x86: Fix leftover comment typos x86/asm: Simplify __smp_mb() definition x86/alternatives: Make the x86nops[] symbol static
2021-06-15x86/sgx: Add missing xa_destroy() when virtual EPC is destroyedKai Huang1-0/+1
xa_destroy() needs to be called to destroy a virtual EPC's page array before calling kfree() to free the virtual EPC. Currently it is not called so add the missing xa_destroy(). Fixes: 540745ddbc70 ("x86/sgx: Introduce virtual EPC for use by KVM guests") Signed-off-by: Kai Huang <kai.huang@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Dave Hansen <dave.hansen@intel.com> Tested-by: Yang Zhong <yang.zhong@intel.com> Link: https://lkml.kernel.org/r/20210615101639.291929-1-kai.huang@intel.com
2021-06-11x86/sgx: Correct kernel-doc's arg name in sgx_encl_release()ChenXiaoSong1-1/+1
Fix the following kernel-doc warning: arch/x86/kernel/cpu/sgx/encl.c:392: warning: Function parameter \ or member 'ref' not described in 'sgx_encl_release' [ bp: Massage commit message. ] Signed-off-by: ChenXiaoSong <chenxiaosong2@huawei.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20210609035510.2083694-1-chenxiaosong2@huawei.com
2021-04-26Merge tag 'x86_cleanups_for_v5.13' of ↵Linus Torvalds1-2/+2
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull misc x86 cleanups from Borislav Petkov: "Trivial cleanups and fixes all over the place" * tag 'x86_cleanups_for_v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: MAINTAINERS: Remove me from IDE/ATAPI section x86/pat: Do not compile stubbed functions when X86_PAT is off x86/asm: Ensure asm/proto.h can be included stand-alone x86/platform/intel/quark: Fix incorrect kernel-doc comment syntax in files x86/msr: Make locally used functions static x86/cacheinfo: Remove unneeded dead-store initialization x86/process/64: Move cpu_current_top_of_stack out of TSS tools/turbostat: Unmark non-kernel-doc comment x86/syscalls: Fix -Wmissing-prototypes warnings from COND_SYSCALL() x86/fpu/math-emu: Fix function cast warning x86/msr: Fix wr/rdmsr_safe_regs_on_cpu() prototypes x86: Fix various typos in comments, take #2 x86: Remove unusual Unicode characters from comments x86/kaslr: Return boolean values from a function returning bool x86: Fix various typos in comments x86/setup: Remove unused RESERVE_BRK_ARRAY() stacktrace: Move documentation for arch_stack_walk_reliable() to header x86: Remove duplicate TSC DEADLINE MSR definitions
2021-04-12x86/sgx: Mark sgx_vepc_vm_ops staticWei Yongjun1-1/+1
Fix the following sparse warning: arch/x86/kernel/cpu/sgx/virt.c:95:35: warning: symbol 'sgx_vepc_vm_ops' was not declared. Should it be static? This symbol is not used outside of virt.c so mark it static. [ bp: Massage commit message. ] Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20210412160023.193850-1-weiyongjun1@huawei.com
2021-04-08x86/sgx: Do not update sgx_nr_free_pages in sgx_setup_epc_section()Jarkko Sakkinen1-1/+0
The commit in Fixes: changed the SGX EPC page sanitization to end up in sgx_free_epc_page() which puts clean and sanitized pages on the free list. This was done for the reason that it is best to keep the logic to assign available-for-use EPC pages to the correct NUMA lists in a single location. sgx_nr_free_pages is also incremented by sgx_free_epc_pages() but those pages which are being added there per EPC section do not belong to the free list yet because they haven't been sanitized yet - they land on the dirty list first and the sanitization happens later when ksgxd starts massaging them. So remove that addition there and have sgx_free_epc_page() do that solely. [ bp: Sanitize commit message too. ] Fixes: 51ab30eb2ad4 ("x86/sgx: Replace section->init_laundry_list with sgx_dirty_page_list") Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20210408092924.7032-1-jarkko@kernel.org
2021-04-06x86/sgx: Move provisioning device creation out of SGX driverSean Christopherson3-32/+58
And extract sgx_set_attribute() out of sgx_ioc_enclave_provision() and export it as symbol for KVM to use. The provisioning key is sensitive. The SGX driver only allows to create an enclave which can access the provisioning key when the enclave creator has permission to open /dev/sgx_provision. It should apply to a VM as well, as the provisioning key is platform-specific, thus an unrestricted VM can also potentially compromise the provisioning key. Move the provisioning device creation out of sgx_drv_init() to sgx_init() as a preparation for adding SGX virtualization support, so that even if the SGX driver is not enabled due to flexible launch control not being available, SGX virtualization can still be enabled, and use it to restrict a VM's capability of being able to access the provisioning key. [ bp: Massage commit message. ] Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Kai Huang <kai.huang@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Acked-by: Dave Hansen <dave.hansen@intel.com> Link: https://lkml.kernel.org/r/0f4d044d621561f26d5f4ef73e8dc6cd18cc7e79.1616136308.git.kai.huang@intel.com
2021-04-06x86/sgx: Add helpers to expose ECREATE and EINIT to KVMSean Christopherson1-0/+117
The host kernel must intercept ECREATE to impose policies on guests, and intercept EINIT to be able to write guest's virtual SGX_LEPUBKEYHASH MSR values to hardware before running guest's EINIT so it can run correctly according to hardware behavior. Provide wrappers around __ecreate() and __einit() to hide the ugliness of overloading the ENCLS return value to encode multiple error formats in a single int. KVM will trap-and-execute ECREATE and EINIT as part of SGX virtualization, and reflect ENCLS execution result to guest by setting up guest's GPRs, or on an exception, injecting the correct fault based on return value of __ecreate() and __einit(). Use host userspace addresses (provided by KVM based on guest physical address of ENCLS parameters) to execute ENCLS/EINIT when possible. Accesses to both EPC and memory originating from ENCLS are subject to segmentation and paging mechanisms. It's also possible to generate kernel mappings for ENCLS parameters by resolving PFN but using __uaccess_xx() is simpler. [ bp: Return early if the __user memory accesses fail, use cpu_feature_enabled(). ] Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Kai Huang <kai.huang@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Jarkko Sakkinen <jarkko@kernel.org> Link: https://lkml.kernel.org/r/20e09daf559aa5e9e680a0b4b5fba940f1bad86e.1616136308.git.kai.huang@intel.com
2021-04-06x86/sgx: Add helper to update SGX_LEPUBKEYHASHn MSRsKai Huang3-3/+20
Add a helper to update SGX_LEPUBKEYHASHn MSRs. SGX virtualization also needs to update those MSRs based on guest's "virtual" SGX_LEPUBKEYHASHn before EINIT from guest. Signed-off-by: Kai Huang <kai.huang@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Dave Hansen <dave.hansen@intel.com> Acked-by: Jarkko Sakkinen <jarkko@kernel.org> Link: https://lkml.kernel.org/r/dfb7cd39d4dd62ea27703b64afdd8bccb579f623.1616136308.git.kai.huang@intel.com
2021-04-06x86/sgx: Add encls_faulted() helperSean Christopherson2-2/+15
Add a helper to extract the fault indicator from an encoded ENCLS return value. SGX virtualization will also need to detect ENCLS faults. Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Kai Huang <kai.huang@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Jarkko Sakkinen <jarkko@kernel.org> Acked-by: Dave Hansen <dave.hansen@intel.com> Link: https://lkml.kernel.org/r/c1f955898110de2f669da536fc6cf62e003dff88.1616136308.git.kai.huang@intel.com
2021-04-06x86/sgx: Move ENCLS leaf definitions to sgx.hSean Christopherson1-15/+0
Move the ENCLS leaf definitions to sgx.h so that they can be used by KVM. Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Kai Huang <kai.huang@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Jarkko Sakkinen <jarkko@kernel.org> Acked-by: Dave Hansen <dave.hansen@intel.com> Link: https://lkml.kernel.org/r/2e6cd7c5c1ced620cfcd292c3c6c382827fde6b2.1616136308.git.kai.huang@intel.com
2021-04-06x86/sgx: Expose SGX architectural definitions to the kernelSean Christopherson3-342/+2
Expose SGX architectural structures, as KVM will use many of the architectural constants and structs to virtualize SGX. Name the new header file as asm/sgx.h, rather than asm/sgx_arch.h, to have single header to provide SGX facilities to share with other kernel componments. Also update MAINTAINERS to include asm/sgx.h. Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Co-developed-by: Kai Huang <kai.huang@intel.com> Signed-off-by: Kai Huang <kai.huang@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Jarkko Sakkinen <jarkko@kernel.org> Acked-by: Dave Hansen <dave.hansen@intel.com> Link: https://lkml.kernel.org/r/6bf47acd91ab4d709e66ad1692c7803e4c9063a0.1616136308.git.kai.huang@intel.com
2021-04-06x86/sgx: Initialize virtual EPC driver even when SGX driver is disabledKai Huang1-1/+10
Modify sgx_init() to always try to initialize the virtual EPC driver, even if the SGX driver is disabled. The SGX driver might be disabled if SGX Launch Control is in locked mode, or not supported in the hardware at all. This allows (non-Linux) guests that support non-LC configurations to use SGX. [ bp: De-silli-fy the test. ] Signed-off-by: Kai Huang <kai.huang@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Sean Christopherson <seanjc@google.com> Acked-by: Jarkko Sakkinen <jarkko@kernel.org> Acked-by: Dave Hansen <dave.hansen@intel.com> Link: https://lkml.kernel.org/r/d35d17a02bbf8feef83a536cec8b43746d4ea557.1616136308.git.kai.huang@intel.com
2021-04-06x86/sgx: Introduce virtual EPC for use by KVM guestsSean Christopherson3-0/+269
Add a misc device /dev/sgx_vepc to allow userspace to allocate "raw" Enclave Page Cache (EPC) without an associated enclave. The intended and only known use case for raw EPC allocation is to expose EPC to a KVM guest, hence the 'vepc' moniker, virt.{c,h} files and X86_SGX_KVM Kconfig. The SGX driver uses the misc device /dev/sgx_enclave to support userspace in creating an enclave. Each file descriptor returned from opening /dev/sgx_enclave represents an enclave. Unlike the SGX driver, KVM doesn't control how the guest uses the EPC, therefore EPC allocated to a KVM guest is not associated with an enclave, and /dev/sgx_enclave is not suitable for allocating EPC for a KVM guest. Having separate device nodes for the SGX driver and KVM virtual EPC also allows separate permission control for running host SGX enclaves and KVM SGX guests. To use /dev/sgx_vepc to allocate a virtual EPC instance with particular size, the hypervisor opens /dev/sgx_vepc, and uses mmap() with the intended size to get an address range of virtual EPC. Then it may use the address range to create one KVM memory slot as virtual EPC for a guest. Implement the "raw" EPC allocation in the x86 core-SGX subsystem via /dev/sgx_vepc rather than in KVM. Doing so has two major advantages: - Does not require changes to KVM's uAPI, e.g. EPC gets handled as just another memory backend for guests. - EPC management is wholly contained in the SGX subsystem, e.g. SGX does not have to export any symbols, changes to reclaim flows don't need to be routed through KVM, SGX's dirty laundry doesn't have to get aired out for the world to see, and so on and so forth. The virtual EPC pages allocated to guests are currently not reclaimable. Reclaiming an EPC page used by enclave requires a special reclaim mechanism separate from normal page reclaim, and that mechanism is not supported for virutal EPC pages. Due to the complications of handling reclaim conflicts between guest and host, reclaiming virtual EPC pages is significantly more complex than basic support for SGX virtualization. [ bp: - Massage commit message and comments - use cpu_feature_enabled() - vertically align struct members init - massage Virtual EPC clarification text - move Kconfig prompt to Virtualization ] Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Co-developed-by: Kai Huang <kai.huang@intel.com> Signed-off-by: Kai Huang <kai.huang@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Dave Hansen <dave.hansen@intel.com> Acked-by: Jarkko Sakkinen <jarkko@kernel.org> Link: https://lkml.kernel.org/r/0c38ced8c8e5a69872db4d6a1c0dabd01e07cad7.1616136308.git.kai.huang@intel.com
2021-03-27x86/sgx: Add SGX_CHILD_PRESENT hardware error codeSean Christopherson1-0/+2
SGX driver can accurately track how enclave pages are used. This enables SECS to be specifically targeted and EREMOVE'd only after all child pages have been EREMOVE'd. This ensures that SGX driver will never encounter SGX_CHILD_PRESENT in normal operation. Virtual EPC is different. The host does not track how EPC pages are used by the guest, so it cannot guarantee EREMOVE success. It might, for instance, encounter a SECS with a non-zero child count. Add a definition of SGX_CHILD_PRESENT. It will be used exclusively by the SGX virtualization driver to handle recoverable EREMOVE errors when saniziting EPC pages after they are freed. Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Kai Huang <kai.huang@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Dave Hansen <dave.hansen@intel.com> Acked-by: Jarkko Sakkinen <jarkko@kernel.org> Link: https://lkml.kernel.org/r/050b198e882afde7e6eba8e6a0d4da39161dbb5a.1616136308.git.kai.huang@intel.com
2021-03-27x86/sgx: Wipe out EREMOVE from sgx_free_epc_page()Kai Huang5-17/+39
EREMOVE takes a page and removes any association between that page and an enclave. It must be run on a page before it can be added into another enclave. Currently, EREMOVE is run as part of pages being freed into the SGX page allocator. It is not expected to fail, as it would indicate a use-after-free of EPC pages. Rather than add the page back to the pool of available EPC pages, the kernel intentionally leaks the page to avoid additional errors in the future. However, KVM does not track how guest pages are used, which means that SGX virtualization use of EREMOVE might fail. Specifically, it is legitimate that EREMOVE returns SGX_CHILD_PRESENT for EPC assigned to KVM guest, because KVM/kernel doesn't track SECS pages. To allow SGX/KVM to introduce a more permissive EREMOVE helper and to let the SGX virtualization code use the allocator directly, break out the EREMOVE call from the SGX page allocator. Rename the original sgx_free_epc_page() to sgx_encl_free_epc_page(), indicating that it is used to free an EPC page assigned to a host enclave. Replace sgx_free_epc_page() with sgx_encl_free_epc_page() in all call sites so there's no functional change. At the same time, improve the error message when EREMOVE fails, and add documentation to explain to the user what that failure means and to suggest to the user what to do when this bug happens in the case it happens. [ bp: Massage commit message, fix typos and sanitize text, simplify. ] Signed-off-by: Kai Huang <kai.huang@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Link: https://lkml.kernel.org/r/20210325093057.122834-1-kai.huang@intel.com
2021-03-25x86/sgx: Remove unnecessary kmap() from sgx_ioc_enclave_init()Ira Weiny1-6/+8
kmap() is inefficient and is being replaced by kmap_local_page(), if possible. There is no readily apparent reason why initp_page needs to be allocated and kmap'ed() except that 'sigstruct' needs to be page-aligned and 'token' 512 byte-aligned. Rather than change it to kmap_local_page(), use kmalloc() instead because kmalloc() can give this alignment when allocating PAGE_SIZE bytes. Remove the alloc_page()/kmap() and replace with kmalloc(PAGE_SIZE, ...) to get a page aligned kernel address. In addition, add a comment to document the alignment requirements so that others don't attempt to 'fix' this again. [ bp: Massage commit message. ] Signed-off-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20210324182246.2484875-1-ira.weiny@intel.com
2021-03-19x86/sgx: Add a basic NUMA allocation scheme to sgx_alloc_epc_page()Jarkko Sakkinen2-48/+87
Background ========== SGX enclave memory is enumerated by the processor in contiguous physical ranges called Enclave Page Cache (EPC) sections. Currently, there is a free list per section, but allocations simply target the lowest-numbered sections. This is functional, but has no NUMA awareness. Fortunately, EPC sections are covered by entries in the ACPI SRAT table. These entries allow each EPC section to be associated with a NUMA node, just like normal RAM. Solution ======== Implement a NUMA-aware enclave page allocator. Mirror the buddy allocator and maintain a list of enclave pages for each NUMA node. Attempt to allocate enclave memory first from local nodes, then fall back to other nodes. Note that the fallback is not as sophisticated as the buddy allocator and is itself not aware of NUMA distances. When a node's free list is empty, it searches for the next-highest node with enclave pages (and will wrap if necessary). This could be improved in the future. Other ===== NUMA_KEEP_MEMINFO dependency is required for phys_to_target_node(). [ Kai Huang: Do not return NULL from __sgx_alloc_epc_page() because callers do not expect that and that leads to a NULL ptr deref. ] [ dhansen: Fix an uninitialized 'nid' variable in __sgx_alloc_epc_page() as Reported-by: kernel test robot <lkp@intel.com> to avoid any potential allocations from the wrong NUMA node or even premature allocation failures. ] Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Kai Huang <kai.huang@intel.com> Signed-off-by: Dave Hansen <dave.hansen@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Link: https://lore.kernel.org/lkml/158188326978.894464.217282995221175417.stgit@dwillia2-desk3.amr.corp.intel.com/ Link: https://lkml.kernel.org/r/20210319040602.178558-1-kai.huang@intel.com Link: https://lkml.kernel.org/r/20210318214933.29341-1-dave.hansen@intel.com Link: https://lkml.kernel.org/r/20210317235332.362001-2-jarkko.sakkinen@intel.com
2021-03-18x86/sgx: Replace section->init_laundry_list with sgx_dirty_page_listJarkko Sakkinen2-36/+25
During normal runtime, the "ksgxd" daemon behaves like a version of kswapd just for SGX. But, before it starts acting like kswapd, its first job is to initialize enclave memory. Currently, the SGX boot code places each enclave page on a epc_section->init_laundry_list. Once it starts up, the ksgxd code walks over that list and populates the actual SGX page allocator. However, the per-section structures are going away to make way for the SGX NUMA allocator. There's also little need to have a per-section structure; the enclave pages are all treated identically, and they can be placed on the correct allocator list from metadata stored in the enclave page (struct sgx_epc_page) itself. Modify sgx_sanitize_section() to take a single page list instead of taking a section and deriving the list from there. Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Link: https://lkml.kernel.org/r/20210317235332.362001-1-jarkko.sakkinen@intel.com
2021-03-18x86: Fix various typos in commentsIngo Molnar2-3/+3
Fix ~144 single-word typos in arch/x86/ code comments. Doing this in a single commit should reduce the churn. Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: linux-kernel@vger.kernel.org
2021-02-21Merge tag 'x86_sgx_for_v5.12' of ↵Linus Torvalds2-13/+9
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 SGX fixes from Borislav Petkov: "Random small fixes which missed the initial SGX submission. Also, some procedural clarifications" * tag 'x86_sgx_for_v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: MAINTAINERS: Add Dave Hansen as reviewer for INTEL SGX x86/sgx: Drop racy follow_pfn() check MAINTAINERS: Fix the tree location for INTEL SGX patches x86/sgx: Fix the return type of sgx_init()
2021-02-08x86/sgx: Maintain encl->refcount for each encl->mm_list entryJarkko Sakkinen2-0/+8
This has been shown in tests: [ +0.000008] WARNING: CPU: 3 PID: 7620 at kernel/rcu/srcutree.c:374 cleanup_srcu_struct+0xed/0x100 This is essentially a use-after free, although SRCU notices it as an SRCU cleanup in an invalid context. == Background == SGX has a data structure (struct sgx_encl_mm) which keeps per-mm SGX metadata. This is separate from struct sgx_encl because, in theory, an enclave can be mapped from more than one mm. sgx_encl_mm includes a pointer back to the sgx_encl. This means that sgx_encl must have a longer lifetime than all of the sgx_encl_mm's that point to it. That's usually the case: sgx_encl_mm is freed only after the mmu_notifier is unregistered in sgx_release(). However, there's a race. If the process is exiting, sgx_mmu_notifier_release() can be called in parallel with sgx_release() instead of being called *by* it. The mmu_notifier path keeps encl_mm alive past when sgx_encl can be freed. This inverts the lifetime rules and means that sgx_mmu_notifier_release() can access a freed sgx_encl. == Fix == Increase encl->refcount when encl_mm->encl is established. Release this reference when encl_mm is freed. This ensures that encl outlives encl_mm. [ bp: Massage commit message. ] Fixes: 1728ab54b4be ("x86/sgx: Add a page reclaimer") Reported-by: Haitao Huang <haitao.huang@linux.intel.com> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Link: https://lkml.kernel.org/r/20210207221401.29933-1-jarkko@kernel.org
2021-02-05x86/sgx: Drop racy follow_pfn() checkDaniel Vetter1-8/+0
PTE insertion is fundamentally racy, and this check doesn't do anything useful. Quoting Sean: "Yeah, it can be whacked. The original, never-upstreamed code asserted that the resolved PFN matched the PFN being installed by the fault handler as a sanity check on the SGX driver's EPC management. The WARN assertion got dropped for whatever reason, leaving that useless chunk." Jason stumbled over this as a new user of follow_pfn(), and I'm trying to get rid of unsafe callers of that function so it can be locked down further. This is independent prep work for the referenced patch series: https://lore.kernel.org/dri-devel/20201127164131.2244124-1-daniel.vetter@ffwll.ch/ Fixes: 947c6e11fa43 ("x86/sgx: Add ptrace() support for the SGX driver") Reported-by: Jason Gunthorpe <jgg@ziepe.ca> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Link: https://lkml.kernel.org/r/20210204184519.2809313-1-daniel.vetter@ffwll.ch
2021-01-21x86/sgx: Fix the return type of sgx_init()Sami Tolvanen1-5/+9
device_initcall() expects a function of type initcall_t, which returns an integer. Change the signature of sgx_init() to match. Fixes: e7e0545299d8c ("x86/sgx: Initialize metadata for Enclave Page Cache (EPC) sections") Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Darren Kenny <darren.kenny@oracle.com> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Link: https://lkml.kernel.org/r/20210113232311.277302-1-samitolvanen@google.com
2020-12-03x86/sgx: Return -EINVAL on a zero length buffer in sgx_ioc_enclave_add_pages()Jarkko Sakkinen1-1/+1
The sgx_enclave_add_pages.length field is documented as * @length: length of the data (multiple of the page size) Fail with -EINVAL, when the caller gives a zero length buffer of data to be added as pages to an enclave. Right now 'ret' is returned as uninitialized in that case. [ bp: Flesh out commit message. ] Fixes: c6d26d370767 ("x86/sgx: Add SGX_IOC_ENCLAVE_ADD_PAGES") Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/linux-sgx/X8ehQssnslm194ld@mwanda/ Link: https://lkml.kernel.org/r/20201203183527.139317-1-jarkko@kernel.org
2020-11-24x86/sgx: Fix sgx_ioc_enclave_provision() kernel-doc commentBorislav Petkov1-1/+1
Fix ./arch/x86/kernel/cpu/sgx/ioctl.c:666: warning: Function parameter or member \ 'encl' not described in 'sgx_ioc_enclave_provision' ./arch/x86/kernel/cpu/sgx/ioctl.c:666: warning: Excess function parameter \ 'enclave' description in 'sgx_ioc_enclave_provision' Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20201123181922.0c009406@canb.auug.org.au
2020-11-19x86/sgx: Return -ERESTARTSYS in sgx_ioc_enclave_add_pages()Jarkko Sakkinen1-1/+1
Return -ERESTARTSYS instead of -EINTR in sgx_ioc_enclave_add_pages() when interrupted before any pages have been processed. At this point ioctl can be obviously safely restarted. Reported-by: Haitao Huang <haitao.huang@intel.com> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20201118213932.63341-1-jarkko@kernel.org
2020-11-18x86/sgx: Clarify 'laundry_list' lockingDave Hansen2-9/+20
Short Version: The SGX section->laundry_list structure is effectively thread-local, but declared next to some shared structures. Its semantics are clear as mud. Fix that. No functional changes. Compile tested only. Long Version: The SGX hardware keeps per-page metadata. This can provide things like permissions, integrity and replay protection. It also prevents things like having an enclave page mapped multiple times or shared between enclaves. But, that presents a problem for kexec()'d kernels (or any other kernel that does not run immediately after a hardware reset). This is because the last kernel may have been rude and forgotten to reset pages, which would trigger the "shared page" sanity check. To fix this, the SGX code "launders" the pages by running the EREMOVE instruction on all pages at boot. This is slow and can take a long time, so it is performed off in the SGX-specific ksgxd instead of being synchronous at boot. The init code hands the list of pages to launder in a per-SGX-section list: ->laundry_list. The only code to touch this list is the init code and ksgxd. This means that no locking is necessary for ->laundry_list. However, a lock is required for section->page_list, which is accessed while creating enclaves and by ksgxd. This lock (section->lock) is acquired by ksgxd while also processing ->laundry_list. It is easy to confuse the purpose of the locking as being for ->laundry_list and ->page_list. Rename ->laundry_list to ->init_laundry_list to make it clear that this is not normally used at runtime. Also add some comments clarifying the locking, and reorganize 'sgx_epc_section' to put 'lock' near the things it protects. Note: init_laundry_list is 128 bytes of wasted space at runtime. It could theoretically be dynamically allocated and then freed after the laundering process. But it would take nearly 128 bytes of extra instructions to do that. Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20201116222531.4834-1-dave.hansen@intel.com
2020-11-18x86/sgx: Add ptrace() support for the SGX driverJarkko Sakkinen1-0/+111
Enclave memory is normally inaccessible from outside the enclave. This makes enclaves hard to debug. However, enclaves can be put in a debug mode when they are being built. In that mode, enclave data *can* be read and/or written by using the ENCLS[EDBGRD] and ENCLS[EDBGWR] functions. This is obviously only for debugging and destroys all the protections present with normal enclaves. But, enclaves know their own debug status and can adjust their behavior appropriately. Add a vm_ops->access() implementation which can be used to read and write memory inside debug enclaves. This is typically used via ptrace() APIs. [ bp: Massage. ] Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Tested-by: Jethro Beekman <jethro@fortanix.com> Link: https://lkml.kernel.org/r/20201112220135.165028-23-jarkko@kernel.org
2020-11-18x86/sgx: Add a page reclaimerJarkko Sakkinen6-27/+1134
Just like normal RAM, there is a limited amount of enclave memory available and overcommitting it is a very valuable tool to reduce resource use. Introduce a simple reclaim mechanism for enclave pages. In contrast to normal page reclaim, the kernel cannot directly access enclave memory. To get around this, the SGX architecture provides a set of functions to help. Among other things, these functions copy enclave memory to and from normal memory, encrypting it and protecting its integrity in the process. Implement a page reclaimer by using these functions. Picks victim pages in LRU fashion from all the enclaves running in the system. A new kernel thread (ksgxswapd) reclaims pages in the background based on watermarks, similar to normal kswapd. All enclave pages can be reclaimed, architecturally. But, there are some limits to this, such as the special SECS metadata page which must be reclaimed last. The page version array (used to mitigate replaying old reclaimed pages) is also architecturally reclaimable, but not yet implemented. The end result is that the vast majority of enclave pages are currently reclaimable. Co-developed-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Jethro Beekman <jethro@fortanix.com> Link: https://lkml.kernel.org/r/20201112220135.165028-22-jarkko@kernel.org
2020-11-18x86/sgx: Add SGX_IOC_ENCLAVE_PROVISIONJarkko Sakkinen3-1/+62
The whole point of SGX is to create a hardware protected place to do “stuff”. But, before someone is willing to hand over the keys to the castle , an enclave must often prove that it is running on an SGX-protected processor. Provisioning enclaves play a key role in providing proof. There are actually three different enclaves in play in order to make this happen: 1. The application enclave. The familiar one we know and love that runs the actual code that’s doing real work. There can be many of these on a single system, or even in a single application. 2. The quoting enclave (QE). The QE is mentioned in lots of silly whitepapers, but, for the purposes of kernel enabling, just pretend they do not exist. 3. The provisioning enclave. There is typically only one of these enclaves per system. Provisioning enclaves have access to a special hardware key. They can use this key to help to generate certificates which serve as proof that enclaves are running on trusted SGX hardware. These certificates can be passed around without revealing the special key. Any user who can create a provisioning enclave can access the processor-unique Provisioning Certificate Key which has privacy and fingerprinting implications. Even if a user is permitted to create normal application enclaves (via /dev/sgx_enclave), they should not be able to create provisioning enclaves. That means a separate permissions scheme is needed to control provisioning enclave privileges. Implement a separate device file (/dev/sgx_provision) which allows creating provisioning enclaves. This device will typically have more strict permissions than the plain enclave device. The actual device “driver” is an empty stub. Open file descriptors for this device will represent a token which allows provisioning enclave duty. This file descriptor can be passed around and ultimately given as an argument to the /dev/sgx_enclave driver ioctl(). [ bp: Touchups. ] Suggested-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: linux-security-module@vger.kernel.org Link: https://lkml.kernel.org/r/20201112220135.165028-16-jarkko@kernel.org
2020-11-18x86/sgx: Add SGX_IOC_ENCLAVE_INITJarkko Sakkinen4-1/+230
Enclaves have two basic states. They are either being built and are malleable and can be modified by doing things like adding pages. Or, they are locked down and not accepting changes. They can only be run after they have been locked down. The ENCLS[EINIT] function induces the transition from being malleable to locked-down. Add an ioctl() that performs ENCLS[EINIT]. After this, new pages can no longer be added with ENCLS[EADD]. This is also the time where the enclave can be measured to verify its integrity. Co-developed-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Tested-by: Jethro Beekman <jethro@fortanix.com> Link: https://lkml.kernel.org/r/20201112220135.165028-15-jarkko@kernel.org
2020-11-18x86/sgx: Add SGX_IOC_ENCLAVE_ADD_PAGESJarkko Sakkinen2-0/+285
SGX enclave pages are inaccessible to normal software. They must be populated with data by copying from normal memory with the help of the EADD and EEXTEND functions of the ENCLS instruction. Add an ioctl() which performs EADD that adds new data to an enclave, and optionally EEXTEND functions that hash the page contents and use the hash as part of enclave “measurement” to ensure enclave integrity. The enclave author gets to decide which pages will be included in the enclave measurement with EEXTEND. Measurement is very slow and has sometimes has very little value. For instance, an enclave _could_ measure every page of data and code, but would be slow to initialize. Or, it might just measure its code and then trust that code to initialize the bulk of its data after it starts running. Co-developed-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Tested-by: Jethro Beekman <jethro@fortanix.com> Link: https://lkml.kernel.org/r/20201112220135.165028-14-jarkko@kernel.org
2020-11-18x86/sgx: Add SGX_IOC_ENCLAVE_CREATEJarkko Sakkinen6-0/+154
Add an ioctl() that performs the ECREATE function of the ENCLS instruction, which creates an SGX Enclave Control Structure (SECS). Although the SECS is an in-memory data structure, it is present in enclave memory and is not directly accessible by software. Co-developed-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Tested-by: Jethro Beekman <jethro@fortanix.com> Link: https://lkml.kernel.org/r/20201112220135.165028-13-jarkko@kernel.org
2020-11-18x86/sgx: Add an SGX misc driver interfaceJarkko Sakkinen6-1/+345
Intel(R) SGX is a new hardware functionality that can be used by applications to set aside private regions of code and data called enclaves. New hardware protects enclave code and data from outside access and modification. Add a driver that presents a device file and ioctl API to build and manage enclaves. [ bp: Small touchups, remove unused encl variable in sgx_encl_find() as Reported-by: kernel test robot <lkp@intel.com> ] Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> Co-developed-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Tested-by: Jethro Beekman <jethro@fortanix.com> Link: https://lkml.kernel.org/r/20201112220135.165028-12-jarkko@kernel.org
2020-11-17x86/sgx: Add SGX page allocator functionsJarkko Sakkinen2-0/+68
Add functions for runtime allocation and free. This allocator and its algorithms are as simple as it gets. They do a linear search across all EPC sections and find the first free page. They are not NUMA-aware and only hand out individual pages. The SGX hardware does not support large pages, so something more complicated like a buddy allocator is unwarranted. The free function (sgx_free_epc_page()) implicitly calls ENCLS[EREMOVE], which returns the page to the uninitialized state. This ensures that the page is ready for use at the next allocation. Co-developed-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Jethro Beekman <jethro@fortanix.com> Link: https://lkml.kernel.org/r/20201112220135.165028-10-jarkko@kernel.org
2020-11-17x86/sgx: Initialize metadata for Enclave Page Cache (EPC) sectionsSean Christopherson3-0/+252
Although carved out of normal DRAM, enclave memory is marked in the system memory map as reserved and is not managed by the core mm. There may be several regions spread across the system. Each contiguous region is called an Enclave Page Cache (EPC) section. EPC sections are enumerated via CPUID Enclave pages can only be accessed when they are mapped as part of an enclave, by a hardware thread running inside the enclave. Parse CPUID data, create metadata for EPC pages and populate a simple EPC page allocator. Although much smaller, ‘struct sgx_epc_page’ metadata is the SGX analog of the core mm ‘struct page’. Similar to how the core mm’s page->flags encode zone and NUMA information, embed the EPC section index to the first eight bits of sgx_epc_page->desc. This allows a quick reverse lookup from EPC page to EPC section. Existing client hardware supports only a single section, while upcoming server hardware will support at most eight sections. Thus, eight bits should be enough for long term needs. Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Co-developed-by: Serge Ayoun <serge.ayoun@intel.com> Signed-off-by: Serge Ayoun <serge.ayoun@intel.com> Co-developed-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Jethro Beekman <jethro@fortanix.com> Link: https://lkml.kernel.org/r/20201112220135.165028-6-jarkko@kernel.org
2020-11-17x86/sgx: Add wrappers for ENCLS functionsJarkko Sakkinen1-0/+231
ENCLS is the userspace instruction which wraps virtually all unprivileged SGX functionality for managing enclaves. It is essentially the ioctl() of instructions with each function implementing different SGX-related functionality. Add macros to wrap the ENCLS functionality. There are two main groups, one for functions which do not return error codes and a “ret_” set for those that do. ENCLS functions are documented in Intel SDM section 36.6. Co-developed-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Jethro Beekman <jethro@fortanix.com> Link: https://lkml.kernel.org/r/20201112220135.165028-3-jarkko@kernel.org
2020-11-17x86/sgx: Add SGX architectural data structuresJarkko Sakkinen1-0/+338
Define the SGX architectural data structures used by various SGX functions. This is not an exhaustive representation of all SGX data structures but only those needed by the kernel. The goal is to sequester hardware structures in "sgx/arch.h" and keep them separate from kernel-internal or uapi structures. The data structures are described in Intel SDM section 37.6. Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Jethro Beekman <jethro@fortanix.com> Link: https://lkml.kernel.org/r/20201112220135.165028-2-jarkko@kernel.org