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For bare-metal SGX on real hardware, the hardware provides guarantees SGX state at reboot. For instance, all pages start out uninitialized. The vepc driver provides a similar guarantee today for freshly-opened vepc instances, but guests such as Windows expect all pages to be in uninitialized state on startup, including after every guest reboot. Some userspace implementations of virtual SGX would rather avoid having to close and reopen the /dev/sgx_vepc file descriptor and re-mmap the virtual EPC. For example, they could sandbox themselves after the guest starts and forbid further calls to open(), in order to mitigate exploits from untrusted guests. Therefore, add a ioctl that does this with EREMOVE. Userspace can invoke the ioctl to bring its vEPC pages back to uninitialized state. There is a possibility that some pages fail to be removed if they are SECS pages, and the child and SECS pages could be in separate vEPC regions. Therefore, the ioctl returns the number of EREMOVE failures, telling userspace to try the ioctl again after it's done with all vEPC regions. A more verbose description of the correct usage and the possible error conditions is documented in sgx.rst. Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Link: https://lkml.kernel.org/r/20211021201155.1523989-3-pbonzini@redhat.com |
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| .. | ||
| i386 | ||
| x86_64 | ||
| amd-memory-encryption.rst | ||
| boot.rst | ||
| booting-dt.rst | ||
| buslock.rst | ||
| cpuinfo.rst | ||
| earlyprintk.rst | ||
| elf_auxvec.rst | ||
| entry_64.rst | ||
| exception-tables.rst | ||
| features.rst | ||
| index.rst | ||
| intel-iommu.rst | ||
| intel_txt.rst | ||
| kernel-stacks.rst | ||
| mds.rst | ||
| microcode.rst | ||
| mtrr.rst | ||
| orc-unwinder.rst | ||
| pat.rst | ||
| pti.rst | ||
| resctrl.rst | ||
| sgx.rst | ||
| sva.rst | ||
| tlb.rst | ||
| topology.rst | ||
| tsx_async_abort.rst | ||
| usb-legacy-support.rst | ||
| zero-page.rst | ||