On Wed, Feb 27, 2013 at 06:12:33PM -0800, H. Peter Anvin wrote:
> From: "H. Peter Anvin" <h...@zytor.com>
>
> If we touch control registers that don't exist, either read or write,
> raise the #UD exception (undefined opcode).
>
> This is useful for testing booting on old CPUs.
>
> CR4 is assumed to exist if and only if there are CPU features other
> than the FPU defined (typically at least VME).
>
> Signed-off-by: H. Peter Anvin <h...@zytor.com>
> ---
> target-i386/misc_helper.c | 25 ++++++++++++++++++++++---
> 1 file changed, 22 insertions(+), 3 deletions(-)
>
> diff --git a/target-i386/misc_helper.c b/target-i386/misc_helper.c
> index 1ff25d1..6da3f32 100644
> --- a/target-i386/misc_helper.c
> +++ b/target-i386/misc_helper.c
> @@ -154,9 +154,18 @@ target_ulong helper_read_crN(CPUX86State *env, int reg)
>
> cpu_svm_check_intercept_param(env, SVM_EXIT_READ_CR0 + reg, 0);
> switch (reg) {
> - default:
> + case 0:
> + case 2:
> + case 3:
> val = env->cr[reg];
> break;
> + case 4:
> + if (env->cpuid_features <= CPUID_FP87) {
> + raise_exception_err(env, EXCP06_ILLOP, 0);
> + } else {
> + val = env->cr[reg];
> + }
> + break;
> case 8:
> if (!(env->hflags2 & HF2_VINTR_MASK)) {
> val = cpu_get_apic_tpr(env->apic_state);
> @@ -164,6 +173,9 @@ target_ulong helper_read_crN(CPUX86State *env, int reg)
> val = env->v_tpr;
> }
> break;
> + default:
> + raise_exception_err(env, EXCP06_ILLOP, 0);
> + break;
> }
> return val;
> }
> @@ -175,11 +187,18 @@ void helper_write_crN(CPUX86State *env, int reg,
> target_ulong t0)
> case 0:
> cpu_x86_update_cr0(env, t0);
> break;
> + case 2:
> + env->cr[reg] = t0;
> + break;
> case 3:
> cpu_x86_update_cr3(env, t0);
> break;
> case 4:
> - cpu_x86_update_cr4(env, t0);
> + if (env->cpuid_features <= CPUID_FP87) {
> + raise_exception_err(env, EXCP06_ILLOP, 0);
> + } else {
> + cpu_x86_update_cr4(env, t0);
> + }
> break;
> case 8:
> if (!(env->hflags2 & HF2_VINTR_MASK)) {
> @@ -188,7 +207,7 @@ void helper_write_crN(CPUX86State *env, int reg,
> target_ulong t0)
> env->v_tpr = t0 & 0x0f;
> break;
> default:
> - env->cr[reg] = t0;
> + raise_exception_err(env, EXCP06_ILLOP, 0);
> break;
> }
> }
Reviewed-by: Aurelien Jarno <aurel...@aurel32.net>
--
Aurelien Jarno GPG: 1024D/F1BCDB73
aurel...@aurel32.net http://www.aurel32.net
