Re: [Qemu-devel] [PATCH]SVM CR8 undefined bug fix

[Alexander Graf <alex@csgraf.de>]

TeLeMan wrote:
> env->cr[8] used by SVM codes was not defined.
>
>   

As far as I remember cr8 is the very same as the TPR, so we only need to
implement one and map the other to the value we want.
My approach was to use the TPR and route the cr8 accesses to the tpr.
Even though I have to admit that this might not be consistent throughout
the code right now.

> http://www.nabble.com/file/p14921864/svm_cr8.patch svm_cr8.patch: 
>
> diff -p -u qemu.orig/target-i386/cpu.h qemu/target-i386/cpu.h
> --- qemu.orig/target-i386/cpu.h	Mon Jan 14 11:11:08 2008
> +++ qemu/target-i386/cpu.h	Thu Jan 17 23:21:22 2008
> @@ -493,7 +493,7 @@ typedef struct CPUX86State {
>      SegmentCache gdt; /* only base and limit are used */
>      SegmentCache idt; /* only base and limit are used */
>  
> -    target_ulong cr[5]; /* NOTE: cr1 is unused */
> +    target_ulong cr[9]; /* NOTE: cr1,cr5-cr7 are unused */
>      uint32_t a20_mask;
>  
>      /* FPU state */
> diff -p -u qemu.orig/target-i386/helper.c qemu/target-i386/helper.c
> --- qemu.orig/target-i386/helper.c	Mon Jan 14 11:11:08 2008
> +++ qemu/target-i386/helper.c	Thu Jan 17 23:24:04 2008
> @@ -2718,6 +2718,7 @@ void helper_movl_crN_T0(int reg)
>          break;
>      case 8:
>          cpu_set_apic_tpr(env, T0);
> +        env->cr[8] = T0;
>          break;
>      default:
>          env->cr[reg] = T0;
> @@ -4065,6 +4066,7 @@ void helper_vmrun(target_ulong addr)
>      int_ctl = ldl_phys(env->vm_vmcb + offsetof(struct vmcb,
> control.int_ctl));
>      if (int_ctl & V_INTR_MASKING_MASK) {
>          env->cr[8] = int_ctl & V_TPR_MASK;
> +	cpu_set_apic_tpr(env,env->cr[8]);
>   

This is a valid catch.

>          if (env->eflags & IF_MASK)
>              env->hflags |= HF_HIF_MASK;
>      }
> @@ -4376,8 +4378,10 @@ void vmexit(uint64_t exit_code, uint64_t
>      cpu_x86_update_cr0(env, ldq_phys(env->vm_hsave + offsetof(struct vmcb,
> save.cr0)) | CR0_PE_MASK);
>      cpu_x86_update_cr4(env, ldq_phys(env->vm_hsave + offsetof(struct vmcb,
> save.cr4)));
>      cpu_x86_update_cr3(env, ldq_phys(env->vm_hsave + offsetof(struct vmcb,
> save.cr3)));
> -    if (int_ctl & V_INTR_MASKING_MASK)
> +    if (int_ctl & V_INTR_MASKING_MASK) {
>          env->cr[8] = ldq_phys(env->vm_hsave + offsetof(struct vmcb,
>   

This too.

> save.cr8));
> +        cpu_set_apic_tpr(env,env->cr[8]);
> +    }
>      /* we need to set the efer after the crs so the hidden flags get set
> properly */
>  #ifdef TARGET_X86_64
>      env->efer  = ldq_phys(env->vm_hsave + offsetof(struct vmcb,
> save.efer));
>
>