From: "Radim Krčmář" <rkrcmar@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Subject: Re: [RFC PATCH 3/4] KVM: x86: add support for emulating UMIP
Date: Thu, 14 Jul 2016 14:24:13 +0200 [thread overview]
Message-ID: <20160714122413.GG21976@potion> (raw)
In-Reply-To: <af995640-7f54-18ea-0589-f04d8ec9b054@redhat.com>
2016-07-14 09:00+0200, Paolo Bonzini:
> On 13/07/2016 22:03, Radim Krčmář wrote:
>> 2016-07-12 21:20+0200, Paolo Bonzini:
>>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>>> ---
>>> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
>>> @@ -3738,6 +3747,10 @@ static int em_lidt(struct x86_emulate_ctxt *ctxt)
>>>
>>> static int em_smsw(struct x86_emulate_ctxt *ctxt)
>>> {
>>> + if ((ctxt->ops->get_cr(ctxt, 4) & X86_CR4_UMIP) &&
>>> + ctxt->ops->cpl(ctxt) > 0)
>>
>> UMIP should #GP(0) in virtual-8086 mode too (for SMSW, SIDT, and SGDT),
>> but cpl() returns 0 in vm86.
>
> No, it returns 3.
>
> vmx->rmode.vm86_active means "there is no unrestricted guest support,
> and we're using VM86 mode to emulate real mode". The special case in
> vmx_get_cpl is needed exactly because real mode CPL is 0 but VM86 has
> CPL 3. In fact fix_rmode_seg sets DPL=3 for all segments, and CPL=SS.DPL.
Right, thanks.
next prev parent reply other threads:[~2016-07-14 12:24 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-12 19:20 [RFC PATCH 0/4] KVM: Emulate UMIP (or almost do so) Paolo Bonzini
2016-07-12 19:20 ` [RFC PATCH 1/4] x86: add UMIP feature and CR4 bit Paolo Bonzini
2016-07-12 19:20 ` [RFC PATCH 2/4] KVM: x86: emulate sldt and str Paolo Bonzini
2016-07-12 19:20 ` [RFC PATCH 3/4] KVM: x86: add support for emulating UMIP Paolo Bonzini
2016-07-13 20:03 ` Radim Krčmář
2016-07-14 7:00 ` Paolo Bonzini
2016-07-14 12:24 ` Radim Krčmář [this message]
2016-07-12 19:20 ` [RFC PATCH 4/4] KVM: vmx: " Paolo Bonzini
2016-07-13 9:21 ` Yang Zhang
2016-07-13 9:35 ` Paolo Bonzini
2016-07-13 9:54 ` Yang Zhang
2016-07-13 9:35 ` Paolo Bonzini
2016-07-13 10:02 ` Yang Zhang
2016-07-13 10:21 ` Paolo Bonzini
2016-07-13 20:30 ` Radim Krčmář
2016-07-14 8:09 ` Paolo Bonzini
2016-07-14 12:36 ` Radim Krčmář
2016-07-14 12:54 ` Paolo Bonzini
2016-07-31 2:32 ` Wanpeng Li
2016-08-01 15:01 ` Paolo Bonzini
2016-08-02 1:05 ` Wanpeng Li
2016-07-13 8:29 ` [RFC PATCH 0/4] KVM: Emulate UMIP (or almost do so) Yang Zhang
2016-07-13 9:34 ` Paolo Bonzini
2016-12-13 4:03 ` Li, Liang Z
2016-12-13 11:03 ` Paolo Bonzini
2017-03-01 9:04 ` Yu Zhang
2017-03-06 21:07 ` Paolo Bonzini
2017-03-10 8:02 ` Yu Zhang
2017-03-10 8:36 ` Paolo Bonzini
2017-03-10 9:31 ` Yu Zhang
2017-03-10 11:28 ` Yu Zhang
2017-03-10 15:00 ` Paolo Bonzini
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