Re: [Xen-devel] [V1 PATCH 01/11] PVH dom0: set eflags resvd bit #1

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Fri, Nov 08, 2013 at 05:23:26PM -0800, Mukesh Rathor wrote:
> In this patch the eflags resv bit #1 is set in vmx_vmenter_helper. If
> the bit is not set, the vmlaunch/resume will fail with guest state
> invalid.

What does 'MBS' stand for? Somehow I assumed you would call
it RSV????
> 
> Signed-off-by: Mukesh Rathor <mukesh.rathor@xxxxxxxxxx>
> ---
>  xen/arch/x86/domain.c           |    2 --
>  xen/arch/x86/hvm/hvm.c          |    7 ++-----
>  xen/arch/x86/hvm/vmx/vmx.c      |    2 +-
>  xen/include/asm-x86/processor.h |    1 +
>  4 files changed, 4 insertions(+), 8 deletions(-)
> 
> diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
> index 0736a4b..e9ab6c8 100644
> --- a/xen/arch/x86/domain.c
> +++ b/xen/arch/x86/domain.c
> @@ -732,8 +732,6 @@ int arch_set_info_guest(
>      for ( i = 0; i < ARRAY_SIZE(v->arch.debugreg); ++i )
>          v->arch.debugreg[i] = c(debugreg[i]);
>  
> -    v->arch.user_regs.eflags |= 2;
> -
>      if ( !is_pv_vcpu(v) )
>      {
>          hvm_set_info_guest(v);
> diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
> index 61b5d8e..0d7ab44 100644
> --- a/xen/arch/x86/hvm/hvm.c
> +++ b/xen/arch/x86/hvm/hvm.c
> @@ -952,7 +952,7 @@ static int hvm_load_cpu_ctxt(struct domain *d, 
> hvm_domain_context_t *h)
>      v->arch.user_regs.edi = ctxt.rdi;
>      v->arch.user_regs.esp = ctxt.rsp;
>      v->arch.user_regs.eip = ctxt.rip;
> -    v->arch.user_regs.eflags = ctxt.rflags | 2;
> +    v->arch.user_regs.eflags = ctxt.rflags | X86_EFLAGS_MBS;
>      v->arch.user_regs.r8  = ctxt.r8;
>      v->arch.user_regs.r9  = ctxt.r9;
>      v->arch.user_regs.r10 = ctxt.r10;
> @@ -1133,7 +1133,6 @@ static int pvh_vcpu_initialise(struct vcpu *v)
>                           (unsigned long)v);
>  
>      v->arch.hvm_vcpu.hcall_64bit = 1;    /* PVH 32bitfixme. */
> -    v->arch.user_regs.eflags = 2;
>      v->arch.hvm_vcpu.inject_trap.vector = -1;
>  
>      if ( (rc = hvm_vcpu_cacheattr_init(v)) != 0 )
> @@ -1218,8 +1217,6 @@ int hvm_vcpu_initialise(struct vcpu *v)
>          (void(*)(unsigned long))hvm_assert_evtchn_irq,
>          (unsigned long)v);
>  
> -    v->arch.user_regs.eflags = 2;
> -
>      if ( v->vcpu_id == 0 )
>      {
>          /* NB. All these really belong in hvm_domain_initialise(). */
> @@ -3619,7 +3616,7 @@ void hvm_vcpu_reset_state(struct vcpu *v, uint16_t cs, 
> uint16_t ip)
>  
>      v->arch.vgc_flags = VGCF_online;
>      memset(&v->arch.user_regs, 0, sizeof(v->arch.user_regs));
> -    v->arch.user_regs.eflags = 2;
> +    v->arch.user_regs.eflags = X86_EFLAGS_MBS;
>      v->arch.user_regs.edx = 0x00000f00;
>      v->arch.user_regs.eip = ip;
>      memset(&v->arch.debugreg, 0, sizeof(v->arch.debugreg));
> diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
> index e93fd98..1f39220 100644
> --- a/xen/arch/x86/hvm/vmx/vmx.c
> +++ b/xen/arch/x86/hvm/vmx/vmx.c
> @@ -3033,7 +3033,7 @@ void vmx_vmenter_helper(const struct cpu_user_regs 
> *regs)
>  
>      __vmwrite(GUEST_RIP,    regs->rip);
>      __vmwrite(GUEST_RSP,    regs->rsp);
> -    __vmwrite(GUEST_RFLAGS, regs->rflags);
> +    __vmwrite(GUEST_RFLAGS, regs->rflags | X86_EFLAGS_MBS);
>  }
>  
>  /*
> diff --git a/xen/include/asm-x86/processor.h b/xen/include/asm-x86/processor.h
> index 551036d..73a3202 100644
> --- a/xen/include/asm-x86/processor.h
> +++ b/xen/include/asm-x86/processor.h
> @@ -35,6 +35,7 @@
>   * EFLAGS bits
>   */
>  #define X86_EFLAGS_CF        0x00000001 /* Carry Flag */
> +#define X86_EFLAGS_MBS       0x00000002 /* Resvd bit */
>  #define X86_EFLAGS_PF        0x00000004 /* Parity Flag */
>  #define X86_EFLAGS_AF        0x00000010 /* Auxillary carry Flag */
>  #define X86_EFLAGS_ZF        0x00000040 /* Zero Flag */
> -- 
> 1.7.2.3
> 
> 
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