Re: [Xen-devel] [PATCH for-4.9] x86/emul: Drop more redundant ctxt.event_pending checks

[Paul Durrant <Paul.Durrant@xxxxxxxxxx>]

> -----Original Message-----
> From: Andrew Cooper [mailto:andrew.cooper3@xxxxxxxxxx]
> Sent: 10 April 2017 13:15
> To: Xen-devel <xen-devel@xxxxxxxxxxxxx>
> Cc: Andrew Cooper <Andrew.Cooper3@xxxxxxxxxx>; Jan Beulich
> <JBeulich@xxxxxxxx>; Tim (Xen.org) <tim@xxxxxxx>; Paul Durrant
> <Paul.Durrant@xxxxxxxxxx>; Jun Nakajima <jun.nakajima@xxxxxxxxx>; Kevin
> Tian <kevin.tian@xxxxxxxxx>; Julien Grall <julien.grall@xxxxxxx>
> Subject: [PATCH for-4.9] x86/emul: Drop more redundant
> ctxt.event_pending checks
> 
> Since c/s 92cf67888a, x86_emulate_wrapper() asserts stricter behaviour
> about
> the relationship between X86EMUL_EXCEPTION and ctxt.event_pending.
> 
> These removals should have been included in the aforementioned
> changeset, and
> were only omitted due an oversight.
> 

As long as suitable assertions are in place...

Reviewed-by: Paul Durrant <paul.durrant@xxxxxxxxxx>

> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> ---
> CC: Jan Beulich <JBeulich@xxxxxxxx>
> CC: Tim Deegan <tim@xxxxxxx>
> CC: Paul Durrant <paul.durrant@xxxxxxxxxx>
> CC: Jun Nakajima <jun.nakajima@xxxxxxxxx>
> CC: Kevin Tian <kevin.tian@xxxxxxxxx>
> CC: Julien Grall <julien.grall@xxxxxxx>
> ---
>  xen/arch/x86/hvm/emulate.c      |  6 ++----
>  xen/arch/x86/hvm/hvm.c          |  3 +--
>  xen/arch/x86/hvm/io.c           |  3 +--
>  xen/arch/x86/hvm/vmx/realmode.c | 15 ---------------
>  xen/arch/x86/mm/shadow/multi.c  |  2 +-
>  xen/arch/x86/traps.c            |  9 ---------
>  6 files changed, 5 insertions(+), 33 deletions(-)
> 
> diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c
> index 06b8f1b..91e269f 100644
> --- a/xen/arch/x86/hvm/emulate.c
> +++ b/xen/arch/x86/hvm/emulate.c
> @@ -2035,8 +2035,7 @@ int hvm_emulate_one_mmio(unsigned long mfn,
> unsigned long gla)
>          hvm_dump_emulation_state(XENLOG_G_WARNING "MMCFG", &ctxt);
>          break;
>      case X86EMUL_EXCEPTION:
> -        if ( ctxt.ctxt.event_pending )
> -            hvm_inject_event(&ctxt.ctxt.event);
> +        hvm_inject_event(&ctxt.ctxt.event);
>          /* fallthrough */
>      default:
>          hvm_emulate_writeback(&ctxt);
> @@ -2095,8 +2094,7 @@ void hvm_emulate_one_vm_event(enum
> emul_kind kind, unsigned int trapnr,
>          hvm_inject_hw_exception(trapnr, errcode);
>          break;
>      case X86EMUL_EXCEPTION:
> -        if ( ctx.ctxt.event_pending )
> -            hvm_inject_event(&ctx.ctxt.event);
> +        hvm_inject_event(&ctx.ctxt.event);
>          break;
>      }
> 
> diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
> index f50d15f..9ffe702 100644
> --- a/xen/arch/x86/hvm/hvm.c
> +++ b/xen/arch/x86/hvm/hvm.c
> @@ -3696,8 +3696,7 @@ void hvm_ud_intercept(struct cpu_user_regs
> *regs)
>          hvm_inject_hw_exception(TRAP_invalid_op, X86_EVENT_NO_EC);
>          break;
>      case X86EMUL_EXCEPTION:
> -        if ( ctxt.ctxt.event_pending )
> -            hvm_inject_event(&ctxt.ctxt.event);
> +        hvm_inject_event(&ctxt.ctxt.event);
>          /* fall through */
>      default:
>          hvm_emulate_writeback(&ctxt);
> diff --git a/xen/arch/x86/hvm/io.c b/xen/arch/x86/hvm/io.c
> index 9e00409..67528d9 100644
> --- a/xen/arch/x86/hvm/io.c
> +++ b/xen/arch/x86/hvm/io.c
> @@ -100,8 +100,7 @@ bool
> hvm_emulate_one_insn(hvm_emulate_validate_t *validate)
>          return false;
> 
>      case X86EMUL_EXCEPTION:
> -        if ( ctxt.ctxt.event_pending )
> -            hvm_inject_event(&ctxt.ctxt.event);
> +        hvm_inject_event(&ctxt.ctxt.event);
>          break;
>      }
> 
> diff --git a/xen/arch/x86/hvm/vmx/realmode.c
> b/xen/arch/x86/hvm/vmx/realmode.c
> index 7b908c7..4eb4232 100644
> --- a/xen/arch/x86/hvm/vmx/realmode.c
> +++ b/xen/arch/x86/hvm/vmx/realmode.c
> @@ -114,21 +114,6 @@ void vmx_realmode_emulate_one(struct
> hvm_emulate_ctxt *hvmemul_ctxt)
> 
>      if ( rc == X86EMUL_EXCEPTION )
>      {
> -        if ( !hvmemul_ctxt->ctxt.event_pending )
> -        {
> -            unsigned long intr_info;
> -
> -            __vmread(VM_ENTRY_INTR_INFO, &intr_info);
> -            __vmwrite(VM_ENTRY_INTR_INFO, 0);
> -            if ( !(intr_info & INTR_INFO_VALID_MASK) )
> -            {
> -                gdprintk(XENLOG_ERR, "Exception pending but no info.\n");
> -                goto fail;
> -            }
> -            hvmemul_ctxt->ctxt.event.vector = (uint8_t)intr_info;
> -            hvmemul_ctxt->ctxt.event.insn_len = 0;
> -        }
> -
>          if ( unlikely(curr->domain->debugger_attached) &&
>               ((hvmemul_ctxt->ctxt.event.vector == TRAP_debug) ||
>                (hvmemul_ctxt->ctxt.event.vector == TRAP_int3)) )
> diff --git a/xen/arch/x86/mm/shadow/multi.c
> b/xen/arch/x86/mm/shadow/multi.c
> index 5195d61..2fb0125 100644
> --- a/xen/arch/x86/mm/shadow/multi.c
> +++ b/xen/arch/x86/mm/shadow/multi.c
> @@ -3457,7 +3457,7 @@ static int sh_page_fault(struct vcpu *v,
> 
>      r = x86_emulate(&emul_ctxt.ctxt, emul_ops);
> 
> -    if ( r == X86EMUL_EXCEPTION && emul_ctxt.ctxt.event_pending )
> +    if ( r == X86EMUL_EXCEPTION )
>      {
>          /*
>           * This emulation covers writes to shadow pagetables.  We tolerate 
> #PF
> diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
> index d69769f..ca0a04a 100644
> --- a/xen/arch/x86/traps.c
> +++ b/xen/arch/x86/traps.c
> @@ -3185,15 +3185,9 @@ static void emulate_gate_op(struct cpu_user_regs
> *regs)
>      if ( IS_ERR_OR_NULL(state) )
>      {
>          if ( PTR_ERR(state) == -X86EMUL_EXCEPTION )
> -        {
> -            ASSERT(ctxt.ctxt.event_pending);
>              pv_inject_event(&ctxt.ctxt.event);
> -        }
>          else
> -        {
> -            ASSERT(!ctxt.ctxt.event_pending);
>              do_guest_trap(TRAP_gp_fault, regs);
> -        }
>          return;
>      }
> 
> @@ -3234,13 +3228,10 @@ static void emulate_gate_op(struct
> cpu_user_regs *regs)
> 
>      if ( rc == X86EMUL_EXCEPTION )
>      {
> -        ASSERT(ctxt.ctxt.event_pending);
>          pv_inject_event(&ctxt.ctxt.event);
>          return;
>      }
> 
> -    ASSERT(!ctxt.ctxt.event_pending);
> -
>      if ( rc != X86EMUL_OKAY ||
>           jump < 0 ||
>           (opnd_sel & ~3) != regs->error_code ||
> --
> 2.1.4


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel