[PATCH v2 00/15] KVM: x86: Clean up kvm_<reg>_{read,write}() mess

[Sean Christopherson <seanjc@google.com>]

Add proper, explicit "raw" versions of kvm_<reg>_{read,write}(), along
with "e" versions (for hardcoded 32-bit accesses), and convert the
existing kvm_<reg>_{read,write}() APIs into mode-aware variants.

This was prompted by commit 435741a4e766 ("KVM: SVM: Properly check RAX
on #GP intercept of SVM instructions"), where using kvm_rax_read() to
get EAX/RAX would have (*very* surprisingly) been wrong as it's actually
a "raw" variant that doesn't truncate accesses when the guest is in 32-bit
mode.

Aside from my dislike of inconsistent APIs, I really want to avoid carrying
code that's subtly relying on using kvm_register_read(...) when accessing a
hardcoded register.

Fix a handful of minor warts along the way.

Oh, and introduce regs.{c,h}, which just a "minor" addendum.  Yosry pointed
out that moving _more_ code into x86.h was rather gross (especially since the
code split was super arbitrary), and it turns out that create regs.{c,h} isn't
all that hard.  In the future, I think we can also add msr.{c,h}, so I very
deliberately didn't include that functionality in regs.{c,h}.

v2:
 - Collect tags. [Yosry, Kai
 - Fix some truly egregious goofs. [Binbin]
 - Rename kvm_cache_regs.h => regs.h, add regs.c. [Yosry, though he'll
   probably yell at me for saying this was his suggestion :-) ]
 - Drop superfluous casting/masking of e*x() usage. [Kai]

v1: https://lore.kernel.org/all/20260409235622.2052730-1-seanjc@google.com

Sean Christopherson (15):
  KVM: SVM: Truncate INVLPGA address in compatibility mode
  KVM: x86/xen: Bug the VM if 32-bit KVM observes a 64-bit mode
    hypercall
  KVM: x86/xen: Don't truncate RAX when handling hypercall from
    protected guest
  KVM: VMX: Read 32-bit GPR values for ENCLS instructions outside of
    64-bit mode
  KVM: x86: Trace hypercall register *after* truncating values for
    32-bit
  KVM: x86: Rename kvm_cache_regs.h => regs.h
  KVM: x86: Move inlined CR and DR helpers from x86.h to regs.h
  KVM: x86: Add mode-aware versions of kvm_<reg>_{read,write}() helpers
  KVM: x86: Drop non-raw kvm_<reg>_write() helpers
  KVM: nSVM: Use kvm_rax_read() now that it's mode-aware
  Revert "KVM: VMX: Read 32-bit GPR values for ENCLS instructions
    outside of 64-bit mode"
  KVM: x86: Harden is_64_bit_hypercall() against bugs on 32-bit kernels
  KVM: x86: Move update_cr8_intercept() to lapic.c
  KVM: x86: Move kvm_pv_async_pf_enabled() to x86.h (as an inline)
  KVM: x86: Move the bulk of register specific code from x86.c to regs.c

 arch/x86/include/asm/kvm_host.h           |   2 -
 arch/x86/kvm/Makefile                     |   4 +-
 arch/x86/kvm/cpuid.c                      |  12 +-
 arch/x86/kvm/emulate.c                    |   2 +-
 arch/x86/kvm/hyperv.c                     |  21 +-
 arch/x86/kvm/hyperv.h                     |   4 +-
 arch/x86/kvm/lapic.c                      |  28 +-
 arch/x86/kvm/lapic.h                      |   1 +
 arch/x86/kvm/mmu.h                        |   2 +-
 arch/x86/kvm/mmu/mmu.c                    |   2 +-
 arch/x86/kvm/regs.c                       | 829 +++++++++++++++++++
 arch/x86/kvm/{kvm_cache_regs.h => regs.h} | 203 ++++-
 arch/x86/kvm/smm.c                        |   2 +-
 arch/x86/kvm/svm/nested.c                 |   8 +-
 arch/x86/kvm/svm/svm.c                    |  19 +-
 arch/x86/kvm/svm/svm.h                    |   2 +-
 arch/x86/kvm/vmx/nested.c                 |   8 +-
 arch/x86/kvm/vmx/nested.h                 |   2 +-
 arch/x86/kvm/vmx/sgx.c                    |   6 +-
 arch/x86/kvm/vmx/tdx.c                    |  18 +-
 arch/x86/kvm/vmx/vmx.c                    |   2 +-
 arch/x86/kvm/vmx/vmx.h                    |   2 +-
 arch/x86/kvm/x86.c                        | 935 +---------------------
 arch/x86/kvm/x86.h                        | 116 +--
 arch/x86/kvm/xen.c                        |  39 +-
 25 files changed, 1162 insertions(+), 1107 deletions(-)
 create mode 100644 arch/x86/kvm/regs.c
 rename arch/x86/kvm/{kvm_cache_regs.h => regs.h} (58%)


base-commit: a9512a611bd030088f13477258d1f8103cceaa40
-- 
2.54.0.563.g4f69b47b94-goog