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From: Yu Zhang <yu.c.zhang@linux.intel.com>
To: Hou Wenlong <houwenlong93@linux.alibaba.com>
Cc: kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
	Sean Christopherson <seanjc@google.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
	<x86@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
	Jan Kiszka <jan.kiszka@siemens.com>, Avi Kivity <avi@redhat.com>,
	"open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)" 
	<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 1/3] kvm: x86: Introduce hypercall x86 ops for handling hypercall not in cpl0
Date: Fri, 10 Sep 2021 00:39:01 +0800	[thread overview]
Message-ID: <20210909163901.2vvozmkuxjcgabs5@linux.intel.com> (raw)
In-Reply-To: <04a337801ad5aaa54144dc57df8ee2fc32bc9c4e.1631188011.git.houwenlong93@linux.alibaba.com>

On Thu, Sep 09, 2021 at 07:55:23PM +0800, Hou Wenlong wrote:
> Per Intel's SDM, use vmcall instruction in non VMX operation for cpl3
> it should trigger a #UD. And in VMX root operation, it should

Are you sure? IIRC, vmcall will always cause VM exit as long as CPU
is in non-root mode(regardless the CPL).

Also, could you please explain why skipping the vmcall would cause
exception in the host? Thanks!

B.R.
Yu


  reply	other threads:[~2021-09-09 16:39 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <cover.1631188011.git.houwenlong93@linux.alibaba.com>
2021-09-09 11:55 ` [PATCH v2 1/3] kvm: x86: Introduce hypercall x86 ops for handling hypercall not in cpl0 Hou Wenlong
2021-09-09 16:39   ` Yu Zhang [this message]
2021-09-09 17:09     ` Sean Christopherson
2021-09-10  1:53       ` Yu Zhang
2021-09-09 11:55 ` [PATCH v2 2/3] kvm: x86: Refactor kvm_emulate_hypercall() to no skip instruction Hou Wenlong
2021-09-09 11:55 ` [PATCH v2 3/3] kvm: x86: Emulate hypercall instead of fixing hypercall instruction Hou Wenlong
2021-09-16 16:00   ` Sean Christopherson

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