Re: [Xen-devel] [PATCH v2 15/19] x86/hvm: Reimplement hvm_copy_*_nofault() in terms of no pagefault_info

[Paul Durrant <Paul.Durrant@xxxxxxxxxx>]

> -----Original Message-----
> From: Andrew Cooper [mailto:andrew.cooper3@xxxxxxxxxx]
> Sent: 28 November 2016 11:14
> To: Xen-devel <xen-devel@xxxxxxxxxxxxx>
> Cc: Andrew Cooper <Andrew.Cooper3@xxxxxxxxxx>; Paul Durrant
> <Paul.Durrant@xxxxxxxxxx>
> Subject: [PATCH v2 15/19] x86/hvm: Reimplement hvm_copy_*_nofault() in
> terms of no pagefault_info
> 
> No functional change.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
> Acked-by: Tim Deegan <tim@xxxxxxx>
> ---
> CC: Paul Durrant <paul.durrant@xxxxxxxxxx>

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

> ---
>  xen/arch/x86/hvm/emulate.c        |  6 ++---
>  xen/arch/x86/hvm/hvm.c            | 56 
> +++++++++------------------------------
>  xen/arch/x86/mm/shadow/common.c   |  8 +++---
>  xen/include/asm-x86/hvm/support.h | 11 --------
>  4 files changed, 19 insertions(+), 62 deletions(-)
> 
> diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c
> index 6de94d4..5165bb2 100644
> --- a/xen/arch/x86/hvm/emulate.c
> +++ b/xen/arch/x86/hvm/emulate.c
> @@ -1947,9 +1947,9 @@ void hvm_emulate_init_per_insn(
>                                          hvm_access_insn_fetch,
>                                          hvmemul_ctxt->ctxt.addr_size,
>                                          &addr) &&
> -             hvm_fetch_from_guest_virt_nofault(hvmemul_ctxt->insn_buf,
> addr,
> -                                               
> sizeof(hvmemul_ctxt->insn_buf),
> -                                               pfec) == HVMCOPY_okay) ?
> +             hvm_fetch_from_guest_virt(hvmemul_ctxt->insn_buf, addr,
> +                                       sizeof(hvmemul_ctxt->insn_buf),
> +                                       pfec, NULL) == HVMCOPY_okay) ?
>              sizeof(hvmemul_ctxt->insn_buf) : 0;
>      }
>      else
> diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
> index 390f76d..5eae06a 100644
> --- a/xen/arch/x86/hvm/hvm.c
> +++ b/xen/arch/x86/hvm/hvm.c
> @@ -3066,8 +3066,6 @@ void hvm_task_switch(
> 
>  #define HVMCOPY_from_guest (0u<<0)
>  #define HVMCOPY_to_guest   (1u<<0)
> -#define HVMCOPY_no_fault   (0u<<1)
> -#define HVMCOPY_fault      (1u<<1)
>  #define HVMCOPY_phys       (0u<<2)
>  #define HVMCOPY_virt       (1u<<2)
>  static enum hvm_copy_result __hvm_copy(
> @@ -3112,13 +3110,10 @@ static enum hvm_copy_result __hvm_copy(
>                      return HVMCOPY_gfn_paged_out;
>                  if ( pfec & PFEC_page_shared )
>                      return HVMCOPY_gfn_shared;
> -                if ( flags & HVMCOPY_fault )
> +                if ( pfinfo )
>                  {
> -                    if ( pfinfo )
> -                    {
> -                        pfinfo->linear = addr;
> -                        pfinfo->ec = pfec;
> -                    }
> +                    pfinfo->linear = addr;
> +                    pfinfo->ec = pfec;
> 
>                      hvm_inject_page_fault(pfec, addr);
>                  }
> @@ -3290,16 +3285,14 @@ enum hvm_copy_result
> hvm_copy_to_guest_phys(
>      paddr_t paddr, void *buf, int size)
>  {
>      return __hvm_copy(buf, paddr, size,
> -                      HVMCOPY_to_guest | HVMCOPY_fault | HVMCOPY_phys,
> -                      0, NULL);
> +                      HVMCOPY_to_guest | HVMCOPY_phys, 0, NULL);
>  }
> 
>  enum hvm_copy_result hvm_copy_from_guest_phys(
>      void *buf, paddr_t paddr, int size)
>  {
>      return __hvm_copy(buf, paddr, size,
> -                      HVMCOPY_from_guest | HVMCOPY_fault | HVMCOPY_phys,
> -                      0, NULL);
> +                      HVMCOPY_from_guest | HVMCOPY_phys, 0, NULL);
>  }
> 
>  enum hvm_copy_result hvm_copy_to_guest_virt(
> @@ -3307,7 +3300,7 @@ enum hvm_copy_result hvm_copy_to_guest_virt(
>      pagefault_info_t *pfinfo)
>  {
>      return __hvm_copy(buf, vaddr, size,
> -                      HVMCOPY_to_guest | HVMCOPY_fault | HVMCOPY_virt,
> +                      HVMCOPY_to_guest | HVMCOPY_virt,
>                        PFEC_page_present | PFEC_write_access | pfec, pfinfo);
>  }
> 
> @@ -3316,7 +3309,7 @@ enum hvm_copy_result
> hvm_copy_from_guest_virt(
>      pagefault_info_t *pfinfo)
>  {
>      return __hvm_copy(buf, vaddr, size,
> -                      HVMCOPY_from_guest | HVMCOPY_fault | HVMCOPY_virt,
> +                      HVMCOPY_from_guest | HVMCOPY_virt,
>                        PFEC_page_present | pfec, pfinfo);
>  }
> 
> @@ -3325,34 +3318,10 @@ enum hvm_copy_result
> hvm_fetch_from_guest_virt(
>      pagefault_info_t *pfinfo)
>  {
>      return __hvm_copy(buf, vaddr, size,
> -                      HVMCOPY_from_guest | HVMCOPY_fault | HVMCOPY_virt,
> +                      HVMCOPY_from_guest | HVMCOPY_virt,
>                        PFEC_page_present | PFEC_insn_fetch | pfec, pfinfo);
>  }
> 
> -enum hvm_copy_result hvm_copy_to_guest_virt_nofault(
> -    unsigned long vaddr, void *buf, int size, uint32_t pfec)
> -{
> -    return __hvm_copy(buf, vaddr, size,
> -                      HVMCOPY_to_guest | HVMCOPY_no_fault | HVMCOPY_virt,
> -                      PFEC_page_present | PFEC_write_access | pfec, NULL);
> -}
> -
> -enum hvm_copy_result hvm_copy_from_guest_virt_nofault(
> -    void *buf, unsigned long vaddr, int size, uint32_t pfec)
> -{
> -    return __hvm_copy(buf, vaddr, size,
> -                      HVMCOPY_from_guest | HVMCOPY_no_fault | HVMCOPY_virt,
> -                      PFEC_page_present | pfec, NULL);
> -}
> -
> -enum hvm_copy_result hvm_fetch_from_guest_virt_nofault(
> -    void *buf, unsigned long vaddr, int size, uint32_t pfec)
> -{
> -    return __hvm_copy(buf, vaddr, size,
> -                      HVMCOPY_from_guest | HVMCOPY_no_fault | HVMCOPY_virt,
> -                      PFEC_page_present | PFEC_insn_fetch | pfec, NULL);
> -}
> -
>  unsigned long copy_to_user_hvm(void *to, const void *from, unsigned int
> len)
>  {
>      int rc;
> @@ -3364,8 +3333,7 @@ unsigned long copy_to_user_hvm(void *to, const
> void *from, unsigned int len)
>          return 0;
>      }
> 
> -    rc = hvm_copy_to_guest_virt_nofault((unsigned long)to, (void *)from,
> -                                        len, 0);
> +    rc = hvm_copy_to_guest_virt((unsigned long)to, (void *)from, len, 0,
> NULL);
>      return rc ? len : 0; /* fake a copy_to_user() return code */
>  }
> 
> @@ -3395,7 +3363,7 @@ unsigned long copy_from_user_hvm(void *to,
> const void *from, unsigned len)
>          return 0;
>      }
> 
> -    rc = hvm_copy_from_guest_virt_nofault(to, (unsigned long)from, len, 0);
> +    rc = hvm_copy_from_guest_virt(to, (unsigned long)from, len, 0, NULL);
>      return rc ? len : 0; /* fake a copy_from_user() return code */
>  }
> 
> @@ -4070,8 +4038,8 @@ void hvm_ud_intercept(struct cpu_user_regs
> *regs)
>                                          (hvm_long_mode_enabled(cur) &&
>                                           cs->attr.fields.l) ? 64 :
>                                          cs->attr.fields.db ? 32 : 16, &addr) 
> &&
> -             (hvm_fetch_from_guest_virt_nofault(sig, addr, sizeof(sig),
> -                                                walk) == HVMCOPY_okay) &&
> +             (hvm_fetch_from_guest_virt(sig, addr, sizeof(sig),
> +                                        walk, NULL) == HVMCOPY_okay) &&
>               (memcmp(sig, "\xf\xbxen", sizeof(sig)) == 0) )
>          {
>              regs->eip += sizeof(sig);
> diff --git a/xen/arch/x86/mm/shadow/common.c
> b/xen/arch/x86/mm/shadow/common.c
> index e8501ce..b659324 100644
> --- a/xen/arch/x86/mm/shadow/common.c
> +++ b/xen/arch/x86/mm/shadow/common.c
> @@ -419,8 +419,8 @@ const struct x86_emulate_ops
> *shadow_init_emulation(
>          (!hvm_translate_linear_addr(
>              x86_seg_cs, regs->eip, sizeof(sh_ctxt->insn_buf),
>              hvm_access_insn_fetch, sh_ctxt, &addr) &&
> -         !hvm_fetch_from_guest_virt_nofault(
> -             sh_ctxt->insn_buf, addr, sizeof(sh_ctxt->insn_buf), 0))
> +         !hvm_fetch_from_guest_virt(
> +             sh_ctxt->insn_buf, addr, sizeof(sh_ctxt->insn_buf), 0, NULL))
>          ? sizeof(sh_ctxt->insn_buf) : 0;
> 
>      return &hvm_shadow_emulator_ops;
> @@ -447,8 +447,8 @@ void shadow_continue_emulation(struct
> sh_emulate_ctxt *sh_ctxt,
>                  (!hvm_translate_linear_addr(
>                      x86_seg_cs, regs->eip, sizeof(sh_ctxt->insn_buf),
>                      hvm_access_insn_fetch, sh_ctxt, &addr) &&
> -                 !hvm_fetch_from_guest_virt_nofault(
> -                     sh_ctxt->insn_buf, addr, sizeof(sh_ctxt->insn_buf), 0))
> +                 !hvm_fetch_from_guest_virt(
> +                     sh_ctxt->insn_buf, addr, sizeof(sh_ctxt->insn_buf), 0, 
> NULL))
>                  ? sizeof(sh_ctxt->insn_buf) : 0;
>              sh_ctxt->insn_buf_eip = regs->eip;
>          }
> diff --git a/xen/include/asm-x86/hvm/support.h b/xen/include/asm-
> x86/hvm/support.h
> index 4aa5a36..114aa04 100644
> --- a/xen/include/asm-x86/hvm/support.h
> +++ b/xen/include/asm-x86/hvm/support.h
> @@ -105,17 +105,6 @@ enum hvm_copy_result
> hvm_fetch_from_guest_virt(
>      void *buf, unsigned long vaddr, int size, uint32_t pfec,
>      pagefault_info_t *pfinfo);
> 
> -/*
> - * As above (copy to/from a guest virtual address), but no fault is generated
> - * when HVMCOPY_bad_gva_to_gfn is returned.
> - */
> -enum hvm_copy_result hvm_copy_to_guest_virt_nofault(
> -    unsigned long vaddr, void *buf, int size, uint32_t pfec);
> -enum hvm_copy_result hvm_copy_from_guest_virt_nofault(
> -    void *buf, unsigned long vaddr, int size, uint32_t pfec);
> -enum hvm_copy_result hvm_fetch_from_guest_virt_nofault(
> -    void *buf, unsigned long vaddr, int size, uint32_t pfec);
> -
>  #define HVM_HCALL_completed  0 /* hypercall completed - no further
> action */
>  #define HVM_HCALL_preempted  1 /* hypercall preempted - re-execute
> VMCALL */
>  #define HVM_HCALL_invalidate 2 /* invalidate ioemu-dm memory cache
> */
> --
> 2.1.4


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