[0/9] x86/spec-ctrl: AMD DIV fix, and VERW prerequisite bugfixes

Message

Andrew Cooper Sept. 15, 2023, 3 p.m. UTC

Patch 9 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 8 are prerequisites, identified while trying to write patch 9.

All 9 patches are for all security trees.

Andrew Cooper (9):
  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: Improve 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/amd: Introduce is_zen{1,2}_uarch() predicates
  x86/spec-ctrl: Mitigate the Zen1 DIV leakge

 docs/misc/xen-command-line.pandoc        |   6 +-
 xen/arch/x86/cpu/amd.c                   |  18 +--
 xen/arch/x86/hvm/svm/entry.S             |   1 +
 xen/arch/x86/include/asm/amd.h           |  11 ++
 xen/arch/x86/include/asm/cpufeatures.h   |   2 +-
 xen/arch/x86/include/asm/spec_ctrl_asm.h | 152 ++++++++++++++++-------
 xen/arch/x86/spec_ctrl.c                 |  49 +++++++-
 xen/arch/x86/traps.c                     |  13 ++
 xen/arch/x86/x86_64/compat/entry.S       |   9 +-
 xen/arch/x86/x86_64/entry.S              |  30 ++++-
 10 files changed, 220 insertions(+), 71 deletions(-)