On 08/10/2015 07:57, Wanpeng Li wrote:
> Add the INVVPID instruction emulation.
> 
> Reviewed-by: Wincy Van <[email protected]>
> Signed-off-by: Wanpeng Li <[email protected]>
> ---
>  arch/x86/include/asm/vmx.h |  3 +++
>  arch/x86/kvm/vmx.c         | 49 
> +++++++++++++++++++++++++++++++++++++++++++++-
>  2 files changed, 51 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
> index 448b7ca..af5fdaf 100644
> --- a/arch/x86/include/asm/vmx.h
> +++ b/arch/x86/include/asm/vmx.h
> @@ -397,8 +397,10 @@ enum vmcs_field {
>  #define IDENTITY_PAGETABLE_PRIVATE_MEMSLOT   (KVM_USER_MEM_SLOTS + 2)
>  
>  #define VMX_NR_VPIDS                         (1 << 16)
> +#define VMX_VPID_EXTENT_INDIVIDUAL_ADDR      0
>  #define VMX_VPID_EXTENT_SINGLE_CONTEXT               1
>  #define VMX_VPID_EXTENT_ALL_CONTEXT          2
> +#define VMX_VPID_EXTENT_SHIFT                        40

This is not used.

Comparing handle_invept with handle_invvpid, some differences are 
apparent:

>  static int handle_invvpid(struct kvm_vcpu *vcpu)
>  {
> -     kvm_queue_exception(vcpu, UD_VECTOR);
> +     struct vcpu_vmx *vmx = to_vmx(vcpu);
> +     u32 vmx_instruction_info;
> +     unsigned long type;
> +     gva_t gva;
> +     struct x86_exception e;
> +     int vpid;
> +
> +     if (!(vmx->nested.nested_vmx_secondary_ctls_high &
> +           SECONDARY_EXEC_ENABLE_VPID)) {

This lacks a check against VMX_VPID_INVVPID_BIT.

> +             kvm_queue_exception(vcpu, UD_VECTOR);
> +             return 1;
> +     }
> +
> +     if (!nested_vmx_check_permission(vcpu))
> +             return 1;
> +
> +     vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO);
> +     type = kvm_register_readl(vcpu, (vmx_instruction_info >> 28) & 0xf);

This is missing the equivalent of this invept code:

        types = (vmx->nested.nested_vmx_ept_caps >> VMX_EPT_EXTENT_SHIFT) & 6;

        if (!(types & (1UL << type))) {
                nested_vmx_failValid(vcpu,
                                VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID);
                return 1;
        }

> +     /* according to the intel vmx instruction reference, the memory
> +      * operand is read even if it isn't needed (e.g., for type==global)
> +      */
> +     if (get_vmx_mem_address(vcpu, vmcs_readl(EXIT_QUALIFICATION),
> +                     vmx_instruction_info, false, &gva))
> +             return 1;
> +     if (kvm_read_guest_virt(&vcpu->arch.emulate_ctxt, gva, &vpid,
> +                             sizeof(u32), &e)) {
> +             kvm_inject_page_fault(vcpu, &e);
> +             return 1;
> +     }
> +
> +     switch (type) {
> +     case VMX_VPID_EXTENT_ALL_CONTEXT:
> +             if (get_vmcs12(vcpu)->virtual_processor_id == 0) {
> +                     nested_vmx_failValid(vcpu,
> +                             VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID);
> +                     return 1;
> +             }
> +             vmx_flush_tlb(vcpu);
> +             nested_vmx_succeed(vcpu);
> +             break;
> +     default:
> +             /* Trap single context invalidation invvpid calls */
> +             BUG_ON(1);

... which means that this BUG_ON(1) is guest triggerable.

Unit tests would have caught this... :)

Paolo

> +             break;
> +     }
> +
> +     skip_emulated_instruction(vcpu);
>       return 1;
>  }
>  
> 
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