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Re: [Xen-devel] [PATCH v2 05/10] nEPT: Try to enable EPT paging for L2 guest.



Minor comments below.

On Wed, Dec 19, 2012 at 11:44 AM, Xiantao Zhang <xiantao.zhang@xxxxxxxxx> wrote:
> From: Zhang Xiantao <xiantao.zhang@xxxxxxxxx>
>
> Once found EPT is enabled by L1 VMM, enabled nested EPT support
> for L2 guest.
>
> Signed-off-by: Zhang Xiantao <xiantao.zhang@xxxxxxxxx>
> ---
>  xen/arch/x86/hvm/vmx/vmx.c         |   16 +++++++++--
>  xen/arch/x86/hvm/vmx/vvmx.c        |   48 +++++++++++++++++++++++++++--------
>  xen/include/asm-x86/hvm/vmx/vvmx.h |    5 +++-
>  3 files changed, 54 insertions(+), 15 deletions(-)
>
> diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
> index d74aae0..e5be5a2 100644
> --- a/xen/arch/x86/hvm/vmx/vmx.c
> +++ b/xen/arch/x86/hvm/vmx/vmx.c
> @@ -1461,6 +1461,7 @@ static struct hvm_function_table __read_mostly 
> vmx_function_table = {
>      .nhvm_vcpu_guestcr3   = nvmx_vcpu_guestcr3,
>      .nhvm_vcpu_p2m_base   = nvmx_vcpu_eptp_base,
>      .nhvm_vcpu_asid       = nvmx_vcpu_asid,
> +    .nhvm_vmcx_hap_enabled = nvmx_ept_enabled,
>      .nhvm_vmcx_guest_intercepts_trap = nvmx_intercepts_exception,
>      .nhvm_vcpu_vmexit_trap = nvmx_vmexit_trap,
>      .nhvm_intr_blocked    = nvmx_intr_blocked,
> @@ -2003,6 +2004,7 @@ static void ept_handle_violation(unsigned long 
> qualification, paddr_t gpa)
>      unsigned long gla, gfn = gpa >> PAGE_SHIFT;
>      mfn_t mfn;
>      p2m_type_t p2mt;
> +    int ret;
>      struct domain *d = current->domain;
>
>      if ( tb_init_done )
> @@ -2017,18 +2019,26 @@ static void ept_handle_violation(unsigned long 
> qualification, paddr_t gpa)
>          _d.gpa = gpa;
>          _d.qualification = qualification;
>          _d.mfn = mfn_x(get_gfn_query_unlocked(d, gfn, &_d.p2mt));
> -
> +
>          __trace_var(TRC_HVM_NPF, 0, sizeof(_d), &_d);
>      }
>
> -    if ( hvm_hap_nested_page_fault(gpa,
> +    ret = hvm_hap_nested_page_fault(gpa,
>                                     qualification & EPT_GLA_VALID       ? 1 : 
> 0,
>                                     qualification & EPT_GLA_VALID
>                                       ? __vmread(GUEST_LINEAR_ADDRESS) : 
> ~0ull,
>                                     qualification & EPT_READ_VIOLATION  ? 1 : 
> 0,
>                                     qualification & EPT_WRITE_VIOLATION ? 1 : 
> 0,
> -                                   qualification & EPT_EXEC_VIOLATION  ? 1 : 
> 0) )
> +                                   qualification & EPT_EXEC_VIOLATION  ? 1 : 
> 0);
> +    switch ( ret ) {
> +    case 0:
> +        break;
> +    case 1:
>          return;
> +    case -1:
> +        vcpu_nestedhvm(current).nv_vmexit_pending = 1;

I think we should add some comments for this case (e.g. what it means,
what to do).


> +        return;
> +    }
>
>      /* Everything else is an error. */
>      mfn = get_gfn_query_unlocked(d, gfn, &p2mt);
> diff --git a/xen/arch/x86/hvm/vmx/vvmx.c b/xen/arch/x86/hvm/vmx/vvmx.c
> index 76cf757..c100730 100644
> --- a/xen/arch/x86/hvm/vmx/vvmx.c
> +++ b/xen/arch/x86/hvm/vmx/vvmx.c
> @@ -41,6 +41,7 @@ int nvmx_vcpu_initialise(struct vcpu *v)
>          gdprintk(XENLOG_ERR, "nest: allocation for shadow vmcs failed\n");
>         goto out;
>      }
> +    nvmx->ept.enabled = 0;
>      nvmx->vmxon_region_pa = 0;
>      nvcpu->nv_vvmcx = NULL;
>      nvcpu->nv_vvmcxaddr = VMCX_EADDR;
> @@ -96,9 +97,11 @@ uint64_t nvmx_vcpu_guestcr3(struct vcpu *v)
>
>  uint64_t nvmx_vcpu_eptp_base(struct vcpu *v)
>  {
> -    /* TODO */
> -    ASSERT(0);
> -    return 0;
> +    uint64_t eptp_base;
> +    struct nestedvcpu *nvcpu = &vcpu_nestedhvm(v);
> +
> +    eptp_base = __get_vvmcs(nvcpu->nv_vvmcx, EPT_POINTER);
> +    return eptp_base & PAGE_MASK;
>  }
>
>  uint32_t nvmx_vcpu_asid(struct vcpu *v)
> @@ -108,6 +111,13 @@ uint32_t nvmx_vcpu_asid(struct vcpu *v)
>      return 0;
>  }
>
> +bool_t nvmx_ept_enabled(struct vcpu *v)
> +{
> +    struct nestedvmx *nvmx = &vcpu_2_nvmx(v);
> +
> +    return !!(nvmx->ept.enabled);
> +}
> +
>  static const enum x86_segment sreg_to_index[] = {
>      [VMX_SREG_ES] = x86_seg_es,
>      [VMX_SREG_CS] = x86_seg_cs,
> @@ -503,14 +513,16 @@ void nvmx_update_exec_control(struct vcpu *v, u32 
> host_cntrl)
>  }
>
>  void nvmx_update_secondary_exec_control(struct vcpu *v,
> -                                            unsigned long value)
> +                                            unsigned long host_cntrl)
>  {
>      u32 shadow_cntrl;
>      struct nestedvcpu *nvcpu = &vcpu_nestedhvm(v);
> +    struct nestedvmx *nvmx = &vcpu_2_nvmx(v);
>
>      shadow_cntrl = __get_vvmcs(nvcpu->nv_vvmcx, SECONDARY_VM_EXEC_CONTROL);
> -    shadow_cntrl |= value;
> -    set_shadow_control(v, SECONDARY_VM_EXEC_CONTROL, shadow_cntrl);
> +    nvmx->ept.enabled = !!(shadow_cntrl & SECONDARY_EXEC_ENABLE_EPT);
> +    shadow_cntrl |= host_cntrl;
> +    __vmwrite(SECONDARY_VM_EXEC_CONTROL, shadow_cntrl);
>  }
>
>  static void nvmx_update_pin_control(struct vcpu *v, unsigned long host_cntrl)
> @@ -818,6 +830,17 @@ static void load_shadow_guest_state(struct vcpu *v)
>      /* TODO: CR3 target control */
>  }
>
> +
> +static uint64_t get_shadow_eptp(struct vcpu *v)
> +{
> +    uint64_t np2m_base = nvmx_vcpu_eptp_base(v);
> +    struct p2m_domain *p2m = p2m_get_nestedp2m(v, np2m_base);
> +    struct ept_data *ept = &p2m->ept;
> +
> +    ept->asr = pagetable_get_pfn(p2m_get_pagetable(p2m));
> +    return ept_get_eptp(ept);
> +}
> +
>  static void virtual_vmentry(struct cpu_user_regs *regs)
>  {
>      struct vcpu *v = current;
> @@ -862,7 +885,10 @@ static void virtual_vmentry(struct cpu_user_regs *regs)
>      /* updating host cr0 to sync TS bit */
>      __vmwrite(HOST_CR0, v->arch.hvm_vmx.host_cr0);
>
> -    /* TODO: EPT_POINTER */
> +    /* Setup virtual ETP for L2 guest*/
> +    if ( nestedhvm_paging_mode_hap(v) )
> +        __vmwrite(EPT_POINTER, get_shadow_eptp(v));
> +
>  }
>
>  static void sync_vvmcs_guest_state(struct vcpu *v, struct cpu_user_regs 
> *regs)
> @@ -915,8 +941,8 @@ static void sync_vvmcs_ro(struct vcpu *v)
>      /* Adjust exit_reason/exit_qualifciation for violation case */
>      if ( __get_vvmcs(vvmcs, VM_EXIT_REASON) ==
>                  EXIT_REASON_EPT_VIOLATION ) {
> -        __set_vvmcs(vvmcs, EXIT_QUALIFICATION, nvmx->ept_exit.exit_qual);
> -        __set_vvmcs(vvmcs, VM_EXIT_REASON, nvmx->ept_exit.exit_reason);
> +        __set_vvmcs(vvmcs, EXIT_QUALIFICATION, nvmx->ept.exit_qual);
> +        __set_vvmcs(vvmcs, VM_EXIT_REASON, nvmx->ept.exit_reason);
>      }
>  }
>
> @@ -1480,8 +1506,8 @@ nvmx_hap_walk_L1_p2m(struct vcpu *v, paddr_t L2_gpa, 
> paddr_t *L1_gpa,
>          case EPT_TRANSLATE_VIOLATION:
>          case EPT_TRANSLATE_MISCONFIG:
>              rc = NESTEDHVM_PAGEFAULT_INJECT;
> -            nvmx->ept_exit.exit_reason = exit_reason;
> -            nvmx->ept_exit.exit_qual = exit_qual;
> +            nvmx->ept.exit_reason = exit_reason;
> +            nvmx->ept.exit_qual = exit_qual;
>              break;
>          case EPT_TRANSLATE_RETRY:
>              rc = NESTEDHVM_PAGEFAULT_RETRY;
> diff --git a/xen/include/asm-x86/hvm/vmx/vvmx.h 
> b/xen/include/asm-x86/hvm/vmx/vvmx.h
> index 8eb377b..661cd8a 100644
> --- a/xen/include/asm-x86/hvm/vmx/vvmx.h
> +++ b/xen/include/asm-x86/hvm/vmx/vvmx.h
> @@ -33,9 +33,10 @@ struct nestedvmx {
>          u32           error_code;
>      } intr;
>      struct {
> +        char     enabled;

I think we should use boot_t not char.

>          uint32_t exit_reason;
>          uint32_t exit_qual;
> -    } ept_exit;
> +    } ept;
>  };
>
>  #define vcpu_2_nvmx(v) (vcpu_nestedhvm(v).u.nvmx)
> @@ -110,6 +111,8 @@ int nvmx_intercepts_exception(struct vcpu *v,
>                                unsigned int trap, int error_code);
>  void nvmx_domain_relinquish_resources(struct domain *d);
>
> +bool_t nvmx_ept_enabled(struct vcpu *v);
> +
>  int nvmx_handle_vmxon(struct cpu_user_regs *regs);
>  int nvmx_handle_vmxoff(struct cpu_user_regs *regs);
>
> --
> 1.7.1
>



-- 
Jun
Intel Open Source Technology Center

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