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From: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
To: "seanjc@google.com" <seanjc@google.com>,
	"x86@kernel.org" <x86@kernel.org>,
	"kas@kernel.org" <kas@kernel.org>,
	"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
	"mingo@redhat.com" <mingo@redhat.com>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"bp@alien8.de" <bp@alien8.de>,
	"pbonzini@redhat.com" <pbonzini@redhat.com>
Cc: "Gao, Chao" <chao.gao@intel.com>,
	"Huang, Kai" <kai.huang@intel.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"Williams, Dan J" <dan.j.williams@intel.com>,
	"Hunter, Adrian" <adrian.hunter@intel.com>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"linux-coco@lists.linux.dev" <linux-coco@lists.linux.dev>,
	"xin@zytor.com" <xin@zytor.com>
Subject: Re: [RFC PATCH 2/4] KVM: x86: Extract VMXON and EFER.SVME enablement to kernel
Date: Mon, 13 Oct 2025 22:08:36 +0000	[thread overview]
Message-ID: <d75130b0a0fb9602fa8712a620cb1f7e52606ea4.camel@intel.com> (raw)
In-Reply-To: <20251010220403.987927-3-seanjc@google.com>

On Fri, 2025-10-10 at 15:04 -0700, Sean Christopherson wrote:

> +
> +int x86_virt_get_cpu(int feat)
> +{
> +	int r;
> +
> +	if (!x86_virt_initialized)
> +		return -EOPNOTSUPP;
> +
> +	if (this_cpu_inc_return(virtualization_nr_users) > 1)
> +		return 0;
> +
> +	if (x86_virt_is_vmx() && feat == X86_FEATURE_VMX)
> +		r = x86_vmx_get_cpu();
> +	else if (x86_virt_is_svm() && feat == X86_FEATURE_SVM)
> +		r = x86_svm_get_cpu();
> +	else
> +		r = -EOPNOTSUPP;
> +
> +	if (r)
> +		WARN_ON_ONCE(this_cpu_dec_return(virtualization_nr_users));
> +
> +	return r;
> +}
> +EXPORT_SYMBOL_GPL(x86_virt_get_cpu);

Not sure if I missed some previous discussion or future plans, but doing this
via X86_FEATURE_FOO seems excessive. We could just have x86_virt_get_cpu(void)
afaict? Curious if there is a plan for other things to go here?

  parent reply	other threads:[~2025-10-13 22:08 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-10-10 22:03 [RFC PATCH 0/4] KVM: x86/tdx: Have TDX handle VMXON during bringup Sean Christopherson
2025-10-10 22:03 ` [RFC PATCH 1/4] KVM: x86: Move kvm_rebooting to x86 Sean Christopherson
2025-10-10 22:04 ` [RFC PATCH 2/4] KVM: x86: Extract VMXON and EFER.SVME enablement to kernel Sean Christopherson
2025-10-13 13:20   ` Chao Gao
2025-10-13 17:49     ` Sean Christopherson
2025-10-13 22:08   ` Edgecombe, Rick P [this message]
2025-10-13 23:54     ` Sean Christopherson
2025-10-17  8:47   ` Chao Gao
2025-10-17 17:10     ` Sean Christopherson
2025-10-10 22:04 ` [RFC PATCH 3/4] KVM: x86/tdx: Do VMXON and TDX-Module initialization during tdx_init() Sean Christopherson
2025-10-13 12:49   ` Chao Gao
2025-10-13 14:23     ` Sean Christopherson
2025-10-13 19:31   ` Edgecombe, Rick P
2025-10-13 20:59     ` Sean Christopherson
2025-10-14  8:35       ` Chao Gao
2025-10-14 18:51         ` dan.j.williams
2025-10-14 19:05           ` Sean Christopherson
2025-10-14 19:44         ` Edgecombe, Rick P
2025-10-10 22:04 ` [RFC PATCH 4/4] KVM: Bury kvm_{en,dis}able_virtualization() in kvm_main.c once more Sean Christopherson
2025-10-13 22:22 ` [RFC PATCH 0/4] KVM: x86/tdx: Have TDX handle VMXON during bringup dan.j.williams
2025-10-13 23:49   ` Sean Christopherson
2025-10-14  0:18     ` dan.j.williams
2025-10-14  2:13   ` Alexey Kardashevskiy

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