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Date: Tue, 27 Feb 2024 17:00:21 -0800
From: Isaku Yamahata <isaku.yamahata@linux.intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, seanjc@google.com,
	michael.roth@amd.com, aik@amd.com, isaku.yamahata@linux.intel.com,
	isaku.yamahata@intel.com
Subject: Re: [PATCH v3 13/15] KVM: SEV: define VM types for SEV and SEV-ES
Message-ID: <20240228010021.GA10568@ls.amr.corp.intel.com>
References: <20240226190344.787149-1-pbonzini@redhat.com>
 <20240226190344.787149-14-pbonzini@redhat.com>
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In-Reply-To: <20240226190344.787149-14-pbonzini@redhat.com>

On Mon, Feb 26, 2024 at 02:03:42PM -0500,
Paolo Bonzini <pbonzini@redhat.com> wrote:

> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  Documentation/virt/kvm/api.rst  |  2 ++
>  arch/x86/include/uapi/asm/kvm.h |  2 ++
>  arch/x86/kvm/svm/sev.c          | 16 +++++++++++++---
>  arch/x86/kvm/svm/svm.c          |  7 +++++++
>  arch/x86/kvm/svm/svm.h          |  1 +
>  arch/x86/kvm/x86.c              |  2 ++
>  6 files changed, 27 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
> index 0b5a33ee71ee..f0b76ff5030d 100644
> --- a/Documentation/virt/kvm/api.rst
> +++ b/Documentation/virt/kvm/api.rst
> @@ -8819,6 +8819,8 @@ means the VM type with value @n is supported.  Possible values of @n are::
>  
>    #define KVM_X86_DEFAULT_VM	0
>    #define KVM_X86_SW_PROTECTED_VM	1
> +  #define KVM_X86_SEV_VM	2
> +  #define KVM_X86_SEV_ES_VM	3
>  
>  Note, KVM_X86_SW_PROTECTED_VM is currently only for development and testing.
>  Do not use KVM_X86_SW_PROTECTED_VM for "real" VMs, and especially not in
> diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
> index d0c1b459f7e9..9d950b0b64c9 100644
> --- a/arch/x86/include/uapi/asm/kvm.h
> +++ b/arch/x86/include/uapi/asm/kvm.h
> @@ -857,5 +857,7 @@ struct kvm_hyperv_eventfd {
>  
>  #define KVM_X86_DEFAULT_VM	0
>  #define KVM_X86_SW_PROTECTED_VM	1
> +#define KVM_X86_SEV_VM		2
> +#define KVM_X86_SEV_ES_VM	3
>  
>  #endif /* _ASM_X86_KVM_H */
> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> index 2549a539a686..1248ccf433e8 100644
> --- a/arch/x86/kvm/svm/sev.c
> +++ b/arch/x86/kvm/svm/sev.c
> @@ -247,6 +247,9 @@ static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp)
>  	if (kvm->created_vcpus)
>  		return -EINVAL;
>  
> +	if (kvm->arch.vm_type != KVM_X86_DEFAULT_VM)
> +		return -EINVAL;
> +
>  	if (unlikely(sev->active))
>  		return -EINVAL;
>  
> @@ -264,6 +267,7 @@ static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp)
>  
>  	INIT_LIST_HEAD(&sev->regions_list);
>  	INIT_LIST_HEAD(&sev->mirror_vms);
> +	sev->need_init = false;
>  
>  	kvm_set_apicv_inhibit(kvm, APICV_INHIBIT_REASON_SEV);
>  
> @@ -1799,7 +1803,8 @@ int sev_vm_move_enc_context_from(struct kvm *kvm, unsigned int source_fd)
>  	if (ret)
>  		goto out_fput;
>  
> -	if (sev_guest(kvm) || !sev_guest(source_kvm)) {
> +	if (kvm->arch.vm_type != source_kvm->arch.vm_type ||
> +	    sev_guest(kvm) || !sev_guest(source_kvm)) {
>  		ret = -EINVAL;
>  		goto out_unlock;
>  	}
> @@ -2118,6 +2123,7 @@ int sev_vm_copy_enc_context_from(struct kvm *kvm, unsigned int source_fd)
>  	mirror_sev->asid = source_sev->asid;
>  	mirror_sev->fd = source_sev->fd;
>  	mirror_sev->es_active = source_sev->es_active;
> +	mirror_sev->need_init = false;
>  	mirror_sev->handle = source_sev->handle;
>  	INIT_LIST_HEAD(&mirror_sev->regions_list);
>  	INIT_LIST_HEAD(&mirror_sev->mirror_vms);
> @@ -2183,10 +2189,14 @@ void sev_vm_destroy(struct kvm *kvm)
>  
>  void __init sev_set_cpu_caps(void)
>  {
> -	if (sev_enabled)
> +	if (sev_enabled) {
>  		kvm_cpu_cap_set(X86_FEATURE_SEV);
> -	if (sev_es_enabled)
> +		kvm_caps.supported_vm_types |= BIT(KVM_X86_SEV_VM);
> +	}
> +	if (sev_es_enabled) {
>  		kvm_cpu_cap_set(X86_FEATURE_SEV_ES);
> +		kvm_caps.supported_vm_types |= BIT(KVM_X86_SEV_ES_VM);
> +	}
>  }
>  
>  void __init sev_hardware_setup(void)
> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> index 1cf9e5f1fd02..f4a750426b24 100644
> --- a/arch/x86/kvm/svm/svm.c
> +++ b/arch/x86/kvm/svm/svm.c
> @@ -4089,6 +4089,9 @@ static void svm_cancel_injection(struct kvm_vcpu *vcpu)
>  
>  static int svm_vcpu_pre_run(struct kvm_vcpu *vcpu)
>  {
> +	if (to_kvm_sev_info(vcpu->kvm)->need_init)
> +		return -EINVAL;
> +
>  	return 1;
>  }
>  
> @@ -4890,6 +4893,10 @@ static void svm_vm_destroy(struct kvm *kvm)
>  
>  static int svm_vm_init(struct kvm *kvm)
>  {
> +	if (kvm->arch.vm_type != KVM_X86_DEFAULT_VM &&
> +	    kvm->arch.vm_type != KVM_X86_SW_PROTECTED_VM)
> +		to_kvm_sev_info(kvm)->need_init = true;
> +
>  	if (!pause_filter_count || !pause_filter_thresh)
>  		kvm->arch.pause_in_guest = true;
>  
> diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
> index ebf2160bf0c6..7a921acc534f 100644
> --- a/arch/x86/kvm/svm/svm.h
> +++ b/arch/x86/kvm/svm/svm.h
> @@ -79,6 +79,7 @@ enum {
>  struct kvm_sev_info {
>  	bool active;		/* SEV enabled guest */
>  	bool es_active;		/* SEV-ES enabled guest */
> +	bool need_init;		/* waiting for SEV_INIT2 */
>  	unsigned int asid;	/* ASID used for this guest */
>  	unsigned int handle;	/* SEV firmware handle */
>  	int fd;			/* SEV device fd */
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 3b87e65904ae..b9dfe3179332 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -12576,6 +12576,8 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
>  	kvm->arch.vm_type = type;
>  	kvm->arch.has_private_mem =
>  		(type == KVM_X86_SW_PROTECTED_VM);
> +	kvm->arch.has_protected_state =
> +		(type == KVM_X86_SEV_ES_VM);

Can we push it down into init_vm() op? I hesitate to add TDX check here.
kvm_page_track_init() and kvm_mmu_init_vm() wouldn't depend on it.


diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index f4a750426b24..a083873b9057 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -4893,6 +4893,9 @@ static void svm_vm_destroy(struct kvm *kvm)
 
 static int svm_vm_init(struct kvm *kvm)
 {
+       if (kvm->arch.vm_type == KVM_X86_SEV_ES_VM)
+               kvm->arch.has_protected_state = true;
+
        if (kvm->arch.vm_type != KVM_X86_DEFAULT_VM &&
            kvm->arch.vm_type != KVM_X86_SW_PROTECTED_VM)
                to_kvm_sev_info(kvm)->need_init = true;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index b9dfe3179332..3b87e65904ae 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -12576,8 +12576,6 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
        kvm->arch.vm_type = type;
        kvm->arch.has_private_mem =
                (type == KVM_X86_SW_PROTECTED_VM);
-       kvm->arch.has_protected_state =
-               (type == KVM_X86_SEV_ES_VM);
 
        ret = kvm_page_track_init(kvm);
        if (ret)

-- 
Isaku Yamahata <isaku.yamahata@linux.intel.com>