Re: [PATCH 1/2] KVM: x86: Add kvm_x86_ops.get_exit_reason

From: David Matlack <dmatlack@google.com>
To: David Edmondson <david.edmondson@oracle.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	Borislav Petkov <bp@alien8.de>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Joerg Roedel <joro@8bytes.org>, Ingo Molnar <mingo@redhat.com>,
	Sean Christopherson <seanjc@google.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	x86@kernel.org
Subject: Re: [PATCH 1/2] KVM: x86: Add kvm_x86_ops.get_exit_reason
Date: Wed, 30 Jun 2021 16:36:05 +0000	[thread overview]
Message-ID: <YNyddfOnfIMfakwI@google.com> (raw)
In-Reply-To: <20210628173152.2062988-2-david.edmondson@oracle.com>

On Mon, Jun 28, 2021 at 06:31:51PM +0100, David Edmondson wrote:
> For later use.

Please add more context to the commit message.

> 
> Signed-off-by: David Edmondson <david.edmondson@oracle.com>
> ---
>  arch/x86/include/asm/kvm-x86-ops.h | 1 +
>  arch/x86/include/asm/kvm_host.h    | 1 +
>  arch/x86/kvm/svm/svm.c             | 6 ++++++
>  arch/x86/kvm/vmx/vmx.c             | 6 ++++++
>  4 files changed, 14 insertions(+)
> 
> diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
> index a12a4987154e..afb0917497c1 100644
> --- a/arch/x86/include/asm/kvm-x86-ops.h
> +++ b/arch/x86/include/asm/kvm-x86-ops.h
> @@ -85,6 +85,7 @@ KVM_X86_OP_NULL(sync_pir_to_irr)
>  KVM_X86_OP(set_tss_addr)
>  KVM_X86_OP(set_identity_map_addr)
>  KVM_X86_OP(get_mt_mask)
> +KVM_X86_OP(get_exit_reason)
>  KVM_X86_OP(load_mmu_pgd)
>  KVM_X86_OP_NULL(has_wbinvd_exit)
>  KVM_X86_OP(get_l2_tsc_offset)
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 974cbfb1eefe..0ee580c68839 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -1365,6 +1365,7 @@ struct kvm_x86_ops {
>  	int (*set_tss_addr)(struct kvm *kvm, unsigned int addr);
>  	int (*set_identity_map_addr)(struct kvm *kvm, u64 ident_addr);
>  	u64 (*get_mt_mask)(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio);
> +	u64 (*get_exit_reason)(struct kvm_vcpu *vcpu);
>  
>  	void (*load_mmu_pgd)(struct kvm_vcpu *vcpu, hpa_t root_hpa,
>  			     int root_level);
> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> index 616b9679ddcc..408c854b4ac9 100644
> --- a/arch/x86/kvm/svm/svm.c
> +++ b/arch/x86/kvm/svm/svm.c
> @@ -4009,6 +4009,11 @@ static u64 svm_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio)
>  	return 0;
>  }
>  
> +static u64 svm_get_exit_reason(struct kvm_vcpu *vcpu)
> +{
> +	return to_svm(vcpu)->vmcb->control.exit_code;
> +}
> +
>  static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
>  {
>  	struct vcpu_svm *svm = to_svm(vcpu);
> @@ -4573,6 +4578,7 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
>  	.set_tss_addr = svm_set_tss_addr,
>  	.set_identity_map_addr = svm_set_identity_map_addr,
>  	.get_mt_mask = svm_get_mt_mask,
> +	.get_exit_reason = svm_get_exit_reason,
>  
>  	.get_exit_info = svm_get_exit_info,
>  
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index 927a552393b9..a19b006c287a 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -6997,6 +6997,11 @@ static u64 vmx_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio)
>  	return (cache << VMX_EPT_MT_EPTE_SHIFT) | ipat;
>  }
>  
> +static u64 vmx_get_exit_reason(struct kvm_vcpu *vcpu)
> +{
> +	return to_vmx(vcpu)->exit_reason.basic;

Why not the full exit reason?

> +}
> +
>  static void vmcs_set_secondary_exec_control(struct vcpu_vmx *vmx)
>  {
>  	/*
> @@ -7613,6 +7618,7 @@ static struct kvm_x86_ops vmx_x86_ops __initdata = {
>  	.set_tss_addr = vmx_set_tss_addr,
>  	.set_identity_map_addr = vmx_set_identity_map_addr,
>  	.get_mt_mask = vmx_get_mt_mask,
> +	.get_exit_reason = vmx_get_exit_reason,
>  
>  	.get_exit_info = vmx_get_exit_info,
>  
> -- 
> 2.30.2
> 