linux-kernel - Re: [PATCH] KVM: nVMX: emulate the INVVPID instruction

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Message-ID: <56026541.7030000@redhat.com>
Date:	Wed, 23 Sep 2015 10:39:29 +0200
From:	Paolo Bonzini <pbonzini@...hat.com>
To:	Wanpeng Li <wanpeng.li@...mail.com>
Cc:	Jan Kiszka <jan.kiszka@...mens.com>, Bandan Das <bsd@...hat.com>,
	Wincy Van <fanwenyi0529@...il.com>, kvm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] KVM: nVMX: emulate the INVVPID instruction



On 23/09/2015 09:59, Wanpeng Li wrote:
> Add the INVVPID instruction emulation.
> 
> Reviewed-by: Wincy Van <fanwenyi0529@...il.com>
> Signed-off-by: Wanpeng Li <wanpeng.li@...mail.com>
> ---
>  arch/x86/include/asm/vmx.h |  1 +
>  arch/x86/kvm/vmx.c         | 23 ++++++++++++++++++++++-
>  2 files changed, 23 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
> index d25f32a..69f3d71 100644
> --- a/arch/x86/include/asm/vmx.h
> +++ b/arch/x86/include/asm/vmx.h
> @@ -397,6 +397,7 @@ 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
>  
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 6ad991a..794c529 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -7189,7 +7189,28 @@ static int handle_invept(struct kvm_vcpu *vcpu)
>  
>  static int handle_invvpid(struct kvm_vcpu *vcpu)
>  {
> -	kvm_queue_exception(vcpu, UD_VECTOR);
> +	u32 vmx_instruction_info;
> +	unsigned long type;
> +
> +	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);
> +
> +	switch (type) {
> +	case VMX_VPID_EXTENT_INDIVIDUAL_ADDR:
> +	case VMX_VPID_EXTENT_SINGLE_CONTEXT:
> +	case VMX_VPID_EXTENT_ALL_CONTEXT:
> +		vmx_flush_tlb(vcpu);
> +		nested_vmx_succeed(vcpu);
> +		break;
> +	default:
> +		nested_vmx_failInvalid(vcpu);
> +		break;
> +	}
> +
> +	skip_emulated_instruction(vcpu);
>  	return 1;
>  }
>  
> 

This is not enough.  You need to add a VPID argument to
vpid_sync_vcpu_single, and inline vmx_flush_tlb in handle_invvpid so
that it can use the new VPID argument of vpid_sync_vcpu_single.

Note that the "all context" variant can be mapped to
vpid_sync_vcpu_single with vpid02 as the argument (a nice side effect of
your vpid02 design).

However, I have applied the patch to kvm/queue.  Please send the changes
separately, and I will squash them in the existing VPID patch.

Paolo
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