Received-SPF: pass (google.com: domain of linux-kernel+bounces-102974-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.80.249 as permitted sender) client-ip=147.75.80.249;
Date: Thu, 14 Mar 2024 16:32:20 +0800
From: Chao Gao <chao.gao@intel.com>
To: <isaku.yamahata@intel.com>
CC: <kvm@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<isaku.yamahata@gmail.com>, Paolo Bonzini <pbonzini@redhat.com>,
	<erdemaktas@google.com>, Sean Christopherson <seanjc@google.com>, Sagi Shahar
	<sagis@google.com>, Kai Huang <kai.huang@intel.com>, <chen.bo@intel.com>,
	<hang.yuan@intel.com>, <tina.zhang@intel.com>
Subject: Re: [PATCH v19 019/130] KVM: x86: Add is_vm_type_supported callback
Message-ID: <ZfK2FCApVeB0xbAk@chao-email>
References: <cover.1708933498.git.isaku.yamahata@intel.com>
 <6712a8a18abb033b1c32b9b6579ac297e3b00ab6.1708933498.git.isaku.yamahata@intel.com>
Content-Type: text/plain; charset="us-ascii"
Content-Disposition: inline
In-Reply-To: <6712a8a18abb033b1c32b9b6579ac297e3b00ab6.1708933498.git.isaku.yamahata@intel.com>
Precedence: bulk
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?Oei7QqfvptkZy0lFE0E+A5g6D4Sq/7eQsEmOSDQLssAIdVC0VdiUdfE2CUNe?=
 =?us-ascii?Q?9T/y4nV0d3KeBv2Y7ZkJ+vjjUMRiD9pMTPm8xaDynakB43KpJa5m6kytDj0B?=
 =?us-ascii?Q?3V6W1L9QE8kKOYmmNlRGtdP/PN1id9zZhXnVqpKxZv57rxLfkNSJ4YZEfa2L?=
 =?us-ascii?Q?RaflC4KNu+/HOn/W6nTt6UI2LFMsWk/aCqVhTvI4FwXetJIqBfnZC/IYyKIz?=
 =?us-ascii?Q?+APTgzK/rVjTRM8BN0zB/oYNxRF8bzz88yUlmn66UQP+HRqv3WcRV6BiiCh/?=
 =?us-ascii?Q?uLwpXYoNQCmciLPSGmKOXxK1z8kY3n1Rp0oDakvw3nMzClXaBiSst9J63pJT?=
 =?us-ascii?Q?QkzVCsCj0CqdfkxY/zMMGH464un0Z2aixkgOqHmZhGpzReDOFKJTsPJxzQYI?=
 =?us-ascii?Q?fj+5y4h4QH/PiXy66OpsbTACnemFADCn/s/jgw9921U7tePwPjbQmxmjh6RO?=
 =?us-ascii?Q?9yr4KbhRzHKrS2ERcI39TTzAhjgH6UsfPv759rZ3bldXNZrgomespOlQRbNi?=
 =?us-ascii?Q?O9uD7ph5oO7OZ0eABLdK67quRzQWwAtAMlJcRqm/5HpZs4iYeTir8nwkhQUS?=
 =?us-ascii?Q?rgHaKb9/+S1cC2XGd4sX/QpMmw5cvLAoWagIXgB99s+KBSvp1fGwOAdtHflp?=
 =?us-ascii?Q?OUj8ILPcYGeiO395AeuxFW+iJa+Mkxvy0lbmSK3RPp55lZABsWESRexN1cO5?=
 =?us-ascii?Q?ymzITmqy0DisASirxVoPHKF94BfuThiZgvvCkfG/33lCYwSwSyMIUjkaWA5n?=
 =?us-ascii?Q?lrsKBSJ8Aai3SPIUH9tPPpdwahHH50scs39CVU7ZpM4xPm0N2AqkF7r7/iXz?=
 =?us-ascii?Q?MSOPaPS5QNQHGCjko6lBlmie1aO3iSzCVYGYUZ6h8euLkGyydn8V473k0zHj?=
 =?us-ascii?Q?fDoNoykGLOKL4kzAXdthPKbka87b1NGoc1pnPUKUnakNg1DBXCyokIdkdrmk?=
 =?us-ascii?Q?amINoMn24lU8hr2Y+aopBdhhadU/elCQgplT1ogRHp1dSakLFCqCHICQHhRg?=
 =?us-ascii?Q?QsOYxXWrSBqRBlGumM+Ccz9kB+ZLqN0iN7OjpvhnuIKCoeTRyrRsUZraxgVA?=
 =?us-ascii?Q?cINhyHYbjsXEcqBYY/kARkQ3/XcA5hTf+/w23da2oXk65wKjXG41CNV6Cg8f?=
 =?us-ascii?Q?qp5HO3EQOALzK+z/PTRaKA1UfFFs9xMzO0ryQuEB5DypkAs87zyfiSw6Nc9D?=
 =?us-ascii?Q?7BaFlOZl+gmn8C/fPWvVVZUCBa7bEu/apTsN9y7sTzxTZq97jvrUNB1v0aAC?=
 =?us-ascii?Q?ayuGfGvrI7j4VPn0m8gYEDOcsoiYj0HJebznZyGOJdCZnC4o8Eg+DQFgVeIj?=
 =?us-ascii?Q?hJ1B3XtPpR+J7h11VUcTQC3QZoAFK2Dbl5l0vxus6Asm0Pqag40NxmYT83oP?=
 =?us-ascii?Q?mAJvd8NpbFQEQeF5qOWjg07BB7+yj8Gw1+XGRBq5jVy72T7nHQVsY4kFhGzL?=
 =?us-ascii?Q?7QtgOUBpQxC+hcKGC9V2f8tOeTwONXDZpjmLjQBZlocSsE4BlBrIeWyMWke8?=
 =?us-ascii?Q?VwH31xlz+CoNboD2CqsWk71URjdGqBTJvGBp2BuqBr9QK+8OrvKU6ijB0zjq?=
 =?us-ascii?Q?U5BP4dDbQJH9igWr/WdRl5l60WRbeeVp8/5PEotS?=
X-MS-Exchange-CrossTenant-Network-Message-Id: 71c68b89-0471-4f56-0e75-08dc440149a3
X-MS-Exchange-CrossTenant-AuthSource: CH3PR11MB8660.namprd11.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 14 Mar 2024 08:32:30.2335
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: XDTM2LSK92xTefp3dr7FtrViELvnxPrtIqgxmRpTIewN19QRTzU14cNfNDDRWs3tfW6fxovEUuwi5erfnHuP3w==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: SN7PR11MB7512
X-OriginatorOrg: intel.com

>-static bool kvm_is_vm_type_supported(unsigned long type)
>+bool __kvm_is_vm_type_supported(unsigned long type)
> {
> 	return type == KVM_X86_DEFAULT_VM ||
> 	       (type == KVM_X86_SW_PROTECTED_VM &&
> 		IS_ENABLED(CONFIG_KVM_SW_PROTECTED_VM) && tdp_enabled);

maybe just do:
	switch (type) {
	case KVM_X86_DEFAULT_VM:
		return true;
	case KVM_X86_SW_PROTECTED_VM:
		return IS_ENABLED(CONFIG_KVM_SW_PROTECTED_VM) && tdp_enabled;
	default:
		return static_call(kvm_x86_is_vm_type_supported)(type);
	}

There are two benefits
1) switch/case improves readability a little.
2) no need to expose __kvm_is_vm_type_supported()


> }
>+EXPORT_SYMBOL_GPL(__kvm_is_vm_type_supported);

>+
>+static bool kvm_is_vm_type_supported(unsigned long type)
>+{
>+	return static_call(kvm_x86_is_vm_type_supported)(type);
>+}
> 
> int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
> {
>@@ -4784,6 +4790,10 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
> 		r = BIT(KVM_X86_DEFAULT_VM);
> 		if (kvm_is_vm_type_supported(KVM_X86_SW_PROTECTED_VM))
> 			r |= BIT(KVM_X86_SW_PROTECTED_VM);
>+		if (kvm_is_vm_type_supported(KVM_X86_TDX_VM))
>+			r |= BIT(KVM_X86_TDX_VM);
>+		if (kvm_is_vm_type_supported(KVM_X86_SNP_VM))
>+			r |= BIT(KVM_X86_SNP_VM);

maybe use a for-loop?