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* [PATCH v2 00/15] KVM: x86: Clean up kvm_<reg>_{read,write}() mess
@ 2026-05-14 21:53 Sean Christopherson
  2026-05-14 21:53 ` [PATCH v2 01/15] KVM: SVM: Truncate INVLPGA address in compatibility mode Sean Christopherson
                   ` (15 more replies)
  0 siblings, 16 replies; 31+ messages in thread
From: Sean Christopherson @ 2026-05-14 21:53 UTC (permalink / raw)
  To: Sean Christopherson, Paolo Bonzini, Vitaly Kuznetsov,
	Kiryl Shutsemau, David Woodhouse, Paul Durrant
  Cc: Dave Hansen, Rick Edgecombe, kvm, x86, linux-coco, linux-kernel,
	Yosry Ahmed, Kai Huang, Binbin Wu

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


^ permalink raw reply	[flat|nested] 31+ messages in thread

end of thread, other threads:[~2026-05-15 12:55 UTC | newest]

Thread overview: 31+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-05-14 21:53 [PATCH v2 00/15] KVM: x86: Clean up kvm_<reg>_{read,write}() mess Sean Christopherson
2026-05-14 21:53 ` [PATCH v2 01/15] KVM: SVM: Truncate INVLPGA address in compatibility mode Sean Christopherson
2026-05-15  6:36   ` Binbin Wu
2026-05-14 21:53 ` [PATCH v2 02/15] KVM: x86/xen: Bug the VM if 32-bit KVM observes a 64-bit mode hypercall Sean Christopherson
2026-05-15  6:46   ` Binbin Wu
2026-05-14 21:53 ` [PATCH v2 03/15] KVM: x86/xen: Don't truncate RAX when handling hypercall from protected guest Sean Christopherson
2026-05-15  7:21   ` Binbin Wu
2026-05-15 12:55     ` Sean Christopherson
2026-05-14 21:53 ` [PATCH v2 04/15] KVM: VMX: Read 32-bit GPR values for ENCLS instructions outside of 64-bit mode Sean Christopherson
2026-05-15  7:26   ` Binbin Wu
2026-05-14 21:53 ` [PATCH v2 05/15] KVM: x86: Trace hypercall register *after* truncating values for 32-bit Sean Christopherson
2026-05-15  7:32   ` Binbin Wu
2026-05-14 21:53 ` [PATCH v2 06/15] KVM: x86: Rename kvm_cache_regs.h => regs.h Sean Christopherson
2026-05-14 22:28   ` Yosry Ahmed
2026-05-15  7:45   ` Binbin Wu
2026-05-14 21:53 ` [PATCH v2 07/15] KVM: x86: Move inlined CR and DR helpers from x86.h to regs.h Sean Christopherson
2026-05-14 22:30   ` Yosry Ahmed
2026-05-15  8:07   ` Binbin Wu
2026-05-14 21:53 ` [PATCH v2 08/15] KVM: x86: Add mode-aware versions of kvm_<reg>_{read,write}() helpers Sean Christopherson
2026-05-15  8:46   ` Binbin Wu
2026-05-14 21:53 ` [PATCH v2 09/15] KVM: x86: Drop non-raw kvm_<reg>_write() helpers Sean Christopherson
2026-05-15  9:11   ` Binbin Wu
2026-05-14 21:53 ` [PATCH v2 10/15] KVM: nSVM: Use kvm_rax_read() now that it's mode-aware Sean Christopherson
2026-05-14 21:53 ` [PATCH v2 11/15] Revert "KVM: VMX: Read 32-bit GPR values for ENCLS instructions outside of 64-bit mode" Sean Christopherson
2026-05-15  9:26   ` Binbin Wu
2026-05-14 21:53 ` [PATCH v2 12/15] KVM: x86: Harden is_64_bit_hypercall() against bugs on 32-bit kernels Sean Christopherson
2026-05-15  9:31   ` Binbin Wu
2026-05-14 21:53 ` [PATCH v2 13/15] KVM: x86: Move update_cr8_intercept() to lapic.c Sean Christopherson
2026-05-14 21:53 ` [PATCH v2 14/15] KVM: x86: Move kvm_pv_async_pf_enabled() to x86.h (as an inline) Sean Christopherson
2026-05-14 21:53 ` [PATCH v2 15/15] KVM: x86: Move the bulk of register specific code from x86.c to regs.c Sean Christopherson
2026-05-14 22:31 ` [PATCH v2 00/15] KVM: x86: Clean up kvm_<reg>_{read,write}() mess Yosry Ahmed

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