RE: [Xen-devel] [PATCH 08/14] Nested Virtualization: efer

["Dong, Eddie" <eddie.dong@xxxxxxxxx>]

> # HG changeset patch
> # User cegger
> # Date 1281003856 -7200
> Allow guest to enable SVM in EFER
> 
> diff -r 7789f1d7d7e7 -r 8c7c597735c6 xen/arch/x86/hvm/hvm.c
> --- a/xen/arch/x86/hvm/hvm.c
> +++ b/xen/arch/x86/hvm/hvm.c
> @@ -616,6 +616,7 @@ static bool_t hvm_efer_valid(uint64_t va
>  {
>      return !((value & ~efer_validbits) ||
>               ((sizeof(long) != 8) && (value & EFER_LME)) ||
> +             (!cpu_has_svm && (value & EFER_SVME)) ||
>               (!cpu_has_nx && (value & EFER_NX)) ||
>               (!cpu_has_syscall && (value & EFER_SCE)) ||
>               (!cpu_has_lmsl && (value & EFER_LMSLE)) ||
> @@ -630,6 +631,7 @@ static int hvm_load_cpu_ctxt(struct doma
>      struct hvm_hw_cpu ctxt;
>      struct segment_register seg;
>      struct vcpu_guest_context *vc;
> +    uint64_t efer_validbits;
> 
>      /* Which vcpu is this? */
>      vcpuid = hvm_load_instance(h);
> @@ -669,9 +671,12 @@ static int hvm_load_cpu_ctxt(struct doma
>          return -EINVAL;
>      }
> 
> -    if ( !hvm_efer_valid(
> -        ctxt.msr_efer,
> -        EFER_FFXSE | EFER_LMSLE | EFER_LME | EFER_LMA | EFER_NX |
> EFER_SCE) ) +    efer_validbits = EFER_FFXSE | EFER_LMSLE | EFER_LME
> | EFER_LMA +                   | EFER_NX | EFER_SCE;
> +    if ( nestedhvm_enabled(v->domain) )
> +        efer_validbits |= EFER_SVME;

Check it is running on SVM first. 

> +
> +    if ( !hvm_efer_valid(ctxt.msr_efer, efer_validbits) )
>      {
>          gdprintk(XENLOG_ERR, "HVM restore: bad EFER 0x%"PRIx64"\n",
>                   ctxt.msr_efer);
> @@ -1081,14 +1086,18 @@ bool_t hvm_hap_nested_page_fault(unsigne
>  int hvm_set_efer(uint64_t value)
>  {
>      struct vcpu *v = current;
> +    uint64_t efer_validbits;
> 
>      value &= ~EFER_LMA;
> 
> -    if ( !hvm_efer_valid(value,
> -            EFER_FFXSE | EFER_LMSLE | EFER_LME | EFER_NX | EFER_SCE)
> ) +    efer_validbits = EFER_FFXSE | EFER_LMSLE | EFER_LME | EFER_NX
> | EFER_SCE; +    if ( nestedhvm_enabled(v->domain) )
> +        efer_validbits |= EFER_SVME;
ditto

> +
> +    if ( !hvm_efer_valid(value, efer_validbits) )
>      {
>          gdprintk(XENLOG_WARNING, "Trying to set reserved bit in "
> -                 "EFER: %"PRIx64"\n", value);
> +                 "EFER: 0x%"PRIx64"\n", value);
>          hvm_inject_exception(TRAP_gp_fault, 0, 0);
>          return X86EMUL_EXCEPTION;
>      }
> diff -r 7789f1d7d7e7 -r 8c7c597735c6 xen/include/asm-x86/cpufeature.h
> --- a/xen/include/asm-x86/cpufeature.h
> +++ b/xen/include/asm-x86/cpufeature.h
> @@ -199,6 +199,8 @@
> 
>  #define cpu_has_rdtscp          boot_cpu_has(X86_FEATURE_RDTSCP)
> 
> +#define cpu_has_svm          boot_cpu_has(X86_FEATURE_SVME)
> +
>  #endif /* __ASM_I386_CPUFEATURE_H */
> 
>  /*


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