On 21/03/2017 05:18, Wanpeng Li wrote:
> From: Wanpeng Li <wanpeng...@hotmail.com>
> 
> This can be reproduced by running kvm-unit-tests/vmx.flat on L0 w/ vpid 
> disabled.
> 
> Test suite: VPID
> Unhandled exception 6 #UD at ip 00000000004051a6
> error_code=0000      rflags=00010047      cs=00000008
> rax=0000000000000000 rcx=0000000000000001 rdx=0000000000000047 
> rbx=0000000000402f79
> rbp=0000000000456240 rsi=0000000000000001 rdi=0000000000000000
> r8=000000000000000a  r9=00000000000003f8 r10=0000000080010011 
> r11=0000000000000000
> r12=0000000000000003 r13=0000000000000708 r14=0000000000000000 
> r15=0000000000000000
> cr0=0000000080010031 cr2=0000000000000000 cr3=0000000007fff000 
> cr4=0000000000002020
> cr8=0000000000000000
> STACK: @4051a6 40523e 400f7f 402059 40028f
> 
> We should hide and forbid VPID in L1 if it is disabled on L0. However, nested 
> VPID
> enable bit is set unconditionally during setup nested vmx exec controls 
> though VPID 
> is not exposed through nested VMX capablity. This patch fixes it by don't set 
> nested 
> VPID enable bit if it is disabled on L0.
> 
> Cc: Paolo Bonzini <pbonz...@redhat.com>
> Cc: Radim Krčmář <rkrc...@redhat.com>
> Fixes: 5c614b3583e (KVM: nVMX: nested VPID emulation)
> Signed-off-by: Wanpeng Li <wanpeng...@hotmail.com>
> ---
>  arch/x86/kvm/vmx.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 98e82ee..8795a70 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -2753,7 +2753,6 @@ static void nested_vmx_setup_ctls_msrs(struct vcpu_vmx 
> *vmx)
>               SECONDARY_EXEC_RDTSCP |
>               SECONDARY_EXEC_DESC |
>               SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE |
> -             SECONDARY_EXEC_ENABLE_VPID |
>               SECONDARY_EXEC_APIC_REGISTER_VIRT |
>               SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY |
>               SECONDARY_EXEC_WBINVD_EXITING |
> @@ -2781,10 +2780,12 @@ static void nested_vmx_setup_ctls_msrs(struct 
> vcpu_vmx *vmx)
>        * though it is treated as global context.  The alternative is
>        * not failing the single-context invvpid, and it is worse.
>        */
> -     if (enable_vpid)
> +     if (enable_vpid) {
> +             vmx->nested.nested_vmx_secondary_ctls_high |=
> +                     SECONDARY_EXEC_ENABLE_VPID;
>               vmx->nested.nested_vmx_vpid_caps = VMX_VPID_INVVPID_BIT |
>                       VMX_VPID_EXTENT_SUPPORTED_MASK;
> -     else
> +     } else
>               vmx->nested.nested_vmx_vpid_caps = 0;
>  
>       if (enable_unrestricted_guest)
> 

Applied patch 1 and 3 to kvm/master (well, locally for now).

Paolo

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