diff options
| author | Sean Christopherson <seanjc@google.com> | 2022-05-26 23:08:14 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-06-10 16:01:31 +0200 |
| commit | b443183a25ab61840a12de92f8822849e017b9c8 (patch) | |
| tree | b3f1773c38494a32c798eb5f93e037c2833938b0 /arch/x86/kvm/kvm_emulate.h | |
| parent | KVM: x86: Use 16-bit fields to track dirty/valid emulator GPRs (diff) | |
| download | linux-b443183a25ab61840a12de92f8822849e017b9c8.tar.xz linux-b443183a25ab61840a12de92f8822849e017b9c8.zip | |
KVM: x86: Reduce the number of emulator GPRs to '8' for 32-bit KVM
Reduce the number of GPRs emulated by 32-bit KVM from 16 to 8. KVM does
not support emulating 64-bit mode on 32-bit host kernels, and so should
never generate accesses to R8-15.
Opportunistically use NR_EMULATOR_GPRS in rsm_load_state_{32,64}() now
that it is precise and accurate for both flavors.
Wrap the definition with full #ifdef ugliness; sadly, IS_ENABLED()
doesn't guarantee a compile-time constant as far as BUILD_BUG_ON() is
concerned.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Message-Id: <20220526210817.3428868-6-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/kvm_emulate.h')
| -rw-r--r-- | arch/x86/kvm/kvm_emulate.h | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/arch/x86/kvm/kvm_emulate.h b/arch/x86/kvm/kvm_emulate.h index 3a65d6ea7fe6..034c845b3c63 100644 --- a/arch/x86/kvm/kvm_emulate.h +++ b/arch/x86/kvm/kvm_emulate.h @@ -306,11 +306,12 @@ typedef void (*fastop_t)(struct fastop *); * tracked/accessed via _eip, and except for RIP relative addressing, which * also uses _eip, RIP cannot be a register operand nor can it be an operand in * a ModRM or SIB byte. - * - * TODO: this is technically wrong for 32-bit KVM, which only supports 8 GPRs; - * R8-R15 don't exist. */ +#ifdef CONFIG_X86_64 #define NR_EMULATOR_GPRS 16 +#else +#define NR_EMULATOR_GPRS 8 +#endif struct x86_emulate_ctxt { void *vcpu; |