[kvm-unit-tests,v2,00/10] Add #VC exception handling for AMD SEV-ES

Message

Varad Gautam Feb. 9, 2022, 4:44 p.m. UTC

For AMD SEV-ES, kvm-unit-tests currently rely on UEFI to set up a
#VC exception handler. This leads to the following problems:

1) The test's page table needs to map the firmware and the shared
   GHCB used by the firmware.
2) The firmware needs to keep its #VC handler in the current IDT
   so that kvm-unit-tests can copy the #VC entry into its own IDT.
3) The firmware #VC handler might use state which is not available
   anymore after ExitBootServices.
4) After ExitBootServices, the firmware needs to get the GHCB address
   from the GHCB MSR if it needs to use the kvm-unit-test GHCB. This
   requires keeping an identity mapping, and the GHCB address must be
   in the MSR at all times where a #VC could happen.

Problems 1) and 2) were temporarily mitigated via commits b114aa57ab
("x86 AMD SEV-ES: Set up GHCB page") and 706ede1833 ("x86 AMD SEV-ES:
Copy UEFI #VC IDT entry") respectively.

However, to make kvm-unit-tests reliable against 3) and 4), the tests
must supply their own #VC handler [1][2].

This series adds #VC exception processing from Linux into kvm-unit-tests,
and makes it the default way of handling #VC exceptions.

If --amdsev-efi-vc is passed during ./configure, the tests will continue
using the UEFI #VC handler.

[1] https://lore.kernel.org/all/[e-mail]/
[2] https://lore.kernel.org/all/[e-mail]/

v2:
- Drop #VC processing code for RDTSC/RDTSCP and WBINVD (seanjc). KVM does
  not trap RDTSC/RDTSCP, and the tests do not produce a WBINVD exit to be
  handled.
- Clarify the rationale for tests needing their own #VC handler (marcorr).

Varad Gautam (10):
  x86: AMD SEV-ES: Setup #VC exception handler for AMD SEV-ES
  x86: Move svm.h to lib/x86/
  lib: x86: Import insn decoder from Linux
  x86: AMD SEV-ES: Pull related GHCB definitions and helpers from Linux
  x86: AMD SEV-ES: Prepare for #VC processing
  lib/x86: Move xsave helpers to lib/
  x86: AMD SEV-ES: Handle CPUID #VC
  x86: AMD SEV-ES: Handle MSR #VC
  x86: AMD SEV-ES: Handle IOIO #VC
  x86: AMD SEV-ES: Handle string IO for IOIO #VC

 Makefile                   |    3 +
 configure                  |   21 +
 lib/x86/amd_sev.c          |   13 +-
 lib/x86/amd_sev.h          |  107 +++
 lib/x86/amd_sev_vc.c       |  468 +++++++++++
 lib/x86/desc.c             |   15 +
 lib/x86/desc.h             |    1 +
 lib/x86/insn/inat-tables.c | 1566 ++++++++++++++++++++++++++++++++++++
 lib/x86/insn/inat.c        |   86 ++
 lib/x86/insn/inat.h        |  233 ++++++
 lib/x86/insn/inat_types.h  |   18 +
 lib/x86/insn/insn.c        |  778 ++++++++++++++++++
 lib/x86/insn/insn.h        |  280 +++++++
 lib/x86/setup.c            |    8 +
 {x86 => lib/x86}/svm.h     |   37 +
 lib/x86/xsave.c            |   37 +
 lib/x86/xsave.h            |   16 +
 x86/Makefile.common        |    4 +
 x86/Makefile.x86_64        |    1 +
 x86/svm.c                  |    2 +-
 x86/svm_tests.c            |    2 +-
 x86/xsave.c                |   43 +-
 22 files changed, 3687 insertions(+), 52 deletions(-)
 create mode 100644 lib/x86/amd_sev_vc.c
 create mode 100644 lib/x86/insn/inat-tables.c
 create mode 100644 lib/x86/insn/inat.c
 create mode 100644 lib/x86/insn/inat.h
 create mode 100644 lib/x86/insn/inat_types.h
 create mode 100644 lib/x86/insn/insn.c
 create mode 100644 lib/x86/insn/insn.h
 rename {x86 => lib/x86}/svm.h (93%)
 create mode 100644 lib/x86/xsave.c
 create mode 100644 lib/x86/xsave.h