From: Paolo Bonzini <pbonzini@redhat.com>
To: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Cc: Li Wang <liwang@redhat.com>,
tglx@linutronix.de, kernellwp@gmail.com, ricardo.neri@intel.com,
pengfei.xu@intel.com, LTP List <ltp@lists.linux.it>,
linux-kernel <linux-kernel@vger.kernel.org>,
Ping Fang <pifang@redhat.com>
Subject: Re: [Kernel BUG?] SMSW operation get success on UMIP KVM guest
Date: Mon, 1 Jul 2019 19:30:50 +0200 [thread overview]
Message-ID: <cde7f924-10c9-7ffc-d323-b786240244b3@redhat.com> (raw)
In-Reply-To: <20190701145308.GA19368@ranerica-svr.sc.intel.com>
On 01/07/19 16:53, Ricardo Neri wrote:
>>
>> (*) before the x86 people jump at me, this won't happen unless you
>> explicitly pass an option to QEMU, such as "-cpu host,+umip". :) The
>> incorrect emulation of SMSW when CR4.UMIP=1 is why.
> Paolo, what do you mean by the incorrect emulation of SMSW?
When KVM tries to emulate UMIP on a system that doesn't have it, SMSW
won't cause a #GP. The processor is simply not able to trap to the
hypervisor on SMSW (unlike SGDT/SIDT/SLDT/STR), so it's impossible to do
better.
Paolo
next prev parent reply other threads:[~2019-07-01 17:30 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CAEemH2cg01cdz=amrCWU00Xof9+cxmfR_DqCBaQe36QoGsakmA@mail.gmail.com>
2019-07-01 8:03 ` Thomas Gleixner
2019-07-01 12:02 ` Paolo Bonzini
2019-07-01 14:53 ` Ricardo Neri
2019-07-01 17:30 ` Paolo Bonzini [this message]
[not found] ` <CAEemH2fqMpoiBo+asyawHsOWgdXy-ggV0mwQs9A9EJ1kh=uhAA@mail.gmail.com>
2019-07-01 16:03 ` Ricardo Neri
[not found] ` <CAEemH2fR98TBHaOM37aGmzbgdZ_XPokJeUNN6dU1r=1WhOSmEw@mail.gmail.com>
2019-07-02 8:40 ` Pengfei Xu
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