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From: Sean Christopherson <seanjc@google.com>
To: Hou Wenlong <houwenlong.hwl@antgroup.com>
Cc: kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.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>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	Marcelo Tosatti <mtosatti@redhat.com>,
	Gleb Natapov <gleb@redhat.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] KVM: x86/emulator: Defer not-present segment check in __load_segment_descriptor()
Date: Mon, 7 Feb 2022 19:21:19 +0000	[thread overview]
Message-ID: <YgFxL1uTKPCUpokQ@google.com> (raw)
In-Reply-To: <117283244eab58e94d589af58a5f2b245b8c0025.1642669684.git.houwenlong.hwl@antgroup.com>

On Thu, Jan 20, 2022, Hou Wenlong wrote:
> Per Intel's SDM on the "Instruction Set Reference", when
> loading segment descriptor, not-present segment check should
> be after all type and privilege checks. But the emulator checks
> it first, then #NP is triggered instead of #GP if privilege fails
> and segment is not present. Put not-present segment check after
> type and privilege checks in __load_segment_descriptor().

For posterity, KVM doesn't support CALL GATES or TASK GATES, so the "early" #NP
check for those is missing.

> Fixes: 38ba30ba51a00 (KVM: x86 emulator: Emulate task switch in emulator.c)
> Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com>
> ---

Reviewed-by: Sean Christopherson <seanjc@google.com>

  reply	other threads:[~2022-02-07 19:24 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <cover.1642669684.git.houwenlong.hwl@antgroup.com>
2022-01-20  9:33 ` [PATCH 1/2] KVM: x86/emulator: Defer not-present segment check in __load_segment_descriptor() Hou Wenlong
2022-02-07 19:21   ` Sean Christopherson [this message]
2022-01-20  9:33 ` [PATCH 2/2] KVM: x86: Fix wrong privilege check for code segment " Hou Wenlong
2022-02-07 19:51   ` Sean Christopherson

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