[PATCH 00/11] KVM: x86: Clean up kvm__{read,write}() mess

Sean Christopherson
2026-04-09T23:56:27Z

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.

Sean Christopherson (11):
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: Move kvm_<reg>_{read,write}() definitions to x86.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

arch/x86/kvm/cpuid.c | 12 ++--
arch/x86/kvm/hyperv.c | 24 +++----
arch/x86/kvm/hyperv.h | 4 +-
arch/x86/kvm/kvm_cache_regs.h | 34 ---------
arch/x86/kvm/svm/nested.c | 8 +--
arch/x86/kvm/svm/svm.c | 17 ++---
arch/x86/kvm/vmx/nested.c | 8 +--
arch/x86/kvm/vmx/sgx.c | 4 +-
arch/x86/kvm/vmx/tdx.c | 18 ++---
arch/x86/kvm/x86.c | 125 +++++++++++++++++-----------------
arch/x86/kvm/x86.h | 69 +++++++++++++++++--
arch/x86/kvm/xen.c | 39 ++++++-----
12 files changed, 193 insertions(+), 169 deletions(-)

base-commit: b89df297a47e641581ee67793592e5c6ae0428f4
--
2.53.0.1213.gd9a14994de-goog