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Linus Torvalds da9803dfd3 This feature enhances the current guest memory encryption support
called SEV by also encrypting the guest register state, making the
 registers inaccessible to the hypervisor by en-/decrypting them on world
 switches. Thus, it adds additional protection to Linux guests against
 exfiltration, control flow and rollback attacks.
 
 With SEV-ES, the guest is in full control of what registers the
 hypervisor can access. This is provided by a guest-host exchange
 mechanism based on a new exception vector called VMM Communication
 Exception (#VC), a new instruction called VMGEXIT and a shared
 Guest-Host Communication Block which is a decrypted page shared between
 the guest and the hypervisor.
 
 Intercepts to the hypervisor become #VC exceptions in an SEV-ES guest so
 in order for that exception mechanism to work, the early x86 init code
 needed to be made able to handle exceptions, which, in itself, brings
 a bunch of very nice cleanups and improvements to the early boot code
 like an early page fault handler, allowing for on-demand building of the
 identity mapping. With that, !KASLR configurations do not use the EFI
 page table anymore but switch to a kernel-controlled one.
 
 The main part of this series adds the support for that new exchange
 mechanism. The goal has been to keep this as much as possibly
 separate from the core x86 code by concentrating the machinery in two
 SEV-ES-specific files:
 
  arch/x86/kernel/sev-es-shared.c
  arch/x86/kernel/sev-es.c
 
 Other interaction with core x86 code has been kept at minimum and behind
 static keys to minimize the performance impact on !SEV-ES setups.
 
 Work by Joerg Roedel and Thomas Lendacky and others.
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Merge tag 'x86_seves_for_v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 SEV-ES support from Borislav Petkov:
 "SEV-ES enhances the current guest memory encryption support called SEV
  by also encrypting the guest register state, making the registers
  inaccessible to the hypervisor by en-/decrypting them on world
  switches. Thus, it adds additional protection to Linux guests against
  exfiltration, control flow and rollback attacks.

  With SEV-ES, the guest is in full control of what registers the
  hypervisor can access. This is provided by a guest-host exchange
  mechanism based on a new exception vector called VMM Communication
  Exception (#VC), a new instruction called VMGEXIT and a shared
  Guest-Host Communication Block which is a decrypted page shared
  between the guest and the hypervisor.

  Intercepts to the hypervisor become #VC exceptions in an SEV-ES guest
  so in order for that exception mechanism to work, the early x86 init
  code needed to be made able to handle exceptions, which, in itself,
  brings a bunch of very nice cleanups and improvements to the early
  boot code like an early page fault handler, allowing for on-demand
  building of the identity mapping. With that, !KASLR configurations do
  not use the EFI page table anymore but switch to a kernel-controlled
  one.

  The main part of this series adds the support for that new exchange
  mechanism. The goal has been to keep this as much as possibly separate
  from the core x86 code by concentrating the machinery in two
  SEV-ES-specific files:

    arch/x86/kernel/sev-es-shared.c
    arch/x86/kernel/sev-es.c

  Other interaction with core x86 code has been kept at minimum and
  behind static keys to minimize the performance impact on !SEV-ES
  setups.

  Work by Joerg Roedel and Thomas Lendacky and others"

* tag 'x86_seves_for_v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (73 commits)
  x86/sev-es: Use GHCB accessor for setting the MMIO scratch buffer
  x86/sev-es: Check required CPU features for SEV-ES
  x86/efi: Add GHCB mappings when SEV-ES is active
  x86/sev-es: Handle NMI State
  x86/sev-es: Support CPU offline/online
  x86/head/64: Don't call verify_cpu() on starting APs
  x86/smpboot: Load TSS and getcpu GDT entry before loading IDT
  x86/realmode: Setup AP jump table
  x86/realmode: Add SEV-ES specific trampoline entry point
  x86/vmware: Add VMware-specific handling for VMMCALL under SEV-ES
  x86/kvm: Add KVM-specific VMMCALL handling under SEV-ES
  x86/paravirt: Allow hypervisor-specific VMMCALL handling under SEV-ES
  x86/sev-es: Handle #DB Events
  x86/sev-es: Handle #AC Events
  x86/sev-es: Handle VMMCALL Events
  x86/sev-es: Handle MWAIT/MWAITX Events
  x86/sev-es: Handle MONITOR/MONITORX Events
  x86/sev-es: Handle INVD Events
  x86/sev-es: Handle RDPMC Events
  x86/sev-es: Handle RDTSC(P) Events
  ...
2020-10-14 10:21:34 -07:00
arch This feature enhances the current guest memory encryption support 2020-10-14 10:21:34 -07:00
block drivers-5.10-2020-10-12 2020-10-13 13:04:41 -07:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto drivers-5.10-2020-10-12 2020-10-13 13:04:41 -07:00
Documentation Merge branch 'akpm' (patches from Andrew) 2020-10-14 09:57:24 -07:00
drivers objtool changes for v5.10: 2020-10-14 10:13:37 -07:00
fs mm, oom_adj: don't loop through tasks in __set_oom_adj when not necessary 2020-10-13 18:38:35 -07:00
include objtool changes for v5.10: 2020-10-14 10:13:37 -07:00
init printk changes for 5.10 2020-10-13 15:58:10 -07:00
ipc ipc: adjust proc_ipc_sem_dointvec definition to match prototype 2020-09-05 12:14:29 -07:00
kernel objtool changes for v5.10: 2020-10-14 10:13:37 -07:00
lib mm/page_alloc.c: fix freeing non-compound pages 2020-10-13 18:38:33 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm/migrate: remove obsolete comment about device public 2020-10-13 18:38:36 -07:00
net io_uring-5.10-2020-10-12 2020-10-13 12:36:21 -07:00
samples mm,kmemleak-test.c: move kmemleak-test.c to samples dir 2020-10-13 18:38:27 -07:00
scripts Merge branch 'akpm' (patches from Andrew) 2020-10-14 09:57:24 -07:00
security selinux/stable-5.10 PR 20201012 2020-10-13 16:29:55 -07:00
sound sound fixes for 5.9-rc7 2020-09-24 09:00:05 -07:00
tools This feature enhances the current guest memory encryption support 2020-10-14 10:21:34 -07:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt KVM: fix memory leak in kvm_io_bus_unregister_dev() 2020-09-11 13:15:11 -04:00
.clang-format memblock: use separate iterators for memory and reserved regions 2020-10-13 18:38:35 -07:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: docs: ignore sphinx_*/ directories 2020-09-10 10:44:31 -06:00
.mailmap As hoped, things calmed down for docs this cycle; fewer changes and almost 2020-10-12 16:21:29 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS CREDITS: Replace HTTP links with HTTPS ones 2020-07-23 14:53:58 -06:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS objtool changes for v5.10: 2020-10-14 10:13:37 -07:00
Makefile Revert "kbuild: disable clang's default use of -fmerge-all-constants" 2020-10-13 18:38:26 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.