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Date: Fri, 10 May 2024 10:47:37 +1200
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Subject: Re: [PATCH v19 037/130] KVM: TDX: Make KVM_CAP_MAX_VCPUS backend
 specific
From: "Huang, Kai" <kai.huang@intel.com>
To: Sean Christopherson <seanjc@google.com>, <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>, Sagi Shahar <sagis@google.com>, <chen.bo@intel.com>,
	<hang.yuan@intel.com>, <tina.zhang@intel.com>
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> 
> Implement the callback for TDX guest to check whether the maximum vCPUs
> passed from usrspace can be supported by TDX, and if it can, override
> Accordingly, in the KVM_CHECK_EXTENSION IOCTL(), change to return the
> 'struct kvm::max_vcpus' for a given VM for the KVM_CAP_MAX_VCPUS.

Sorry some error during copy/paste.  The above should be:

Implement the callback for TDX guest to check whether the maximum vCPUs
passed from usrspace can be supported by TDX, and if it can, override
the 'struct kvm::max_vcpus'.  Leave VMX guests and all AMD guests
unsupported to avoid any side-effect for those VMs.

Accordingly, in the KVM_CHECK_EXTENSION IOCTL(), change to return the
'struct kvm::max_vcpus' for a given VM for the KVM_CAP_MAX_VCPUS.