[0/8] x86/spec-ctrl: AMD DIV fix, and VERW prerequisite bugfixes

Message

Andrew Cooper Sept. 13, 2023, 8:27 p.m. UTC

Patch 8 is the XSA-439 fix for the AMD DIV issue, disclosed insufficiently
ahead of August 8th for us to prepare a fix for the embargo.

Patches 1 thru 7 are prerequisites, identified while trying to write patch 8.

All 8 patches are for all security trees.

Andrew Cooper (8):
  x86/spec-ctrl: Fix confusion between SPEC_CTRL_EXIT_TO_XEN{,_IST}
  x86/spec-ctrl: Fold DO_SPEC_CTRL_EXIT_TO_XEN into it's single user
  x86/spec-ctrl: Turn the remaining SPEC_CTRL_{ENTRY,EXIT}_* into asm macros
  x86/spec-ctrl: Extend all SPEC_CTRL_{ENTER,EXIT}_* comments
  x86/entry: Adjust restore_all_xen to hold stack_end in %r14
  x86/entry: Track the IST-ness of an entry for the exit paths
  x86/spec-ctrl: Issue VERW during IST exit to Xen
  x86/spec-ctrl: Mitigate the Zen1 DIV leakge

 docs/misc/xen-command-line.pandoc        |   6 +-
 xen/arch/x86/hvm/svm/entry.S             |   1 +
 xen/arch/x86/include/asm/cpufeatures.h   |   2 +-
 xen/arch/x86/include/asm/spec_ctrl_asm.h | 150 ++++++++++++++++-------
 xen/arch/x86/spec_ctrl.c                 |  45 ++++++-
 xen/arch/x86/traps.c                     |  13 ++
 xen/arch/x86/x86_64/compat/entry.S       |   9 +-
 xen/arch/x86/x86_64/entry.S              |  31 +++--
 8 files changed, 198 insertions(+), 59 deletions(-)


base-commit: 6aa25c32180ab59081c73bae4c568367d9133a1f