Messages in this thread | | | From | Sasha Levin <> | Subject | Re: [PATCH AUTOSEL for 4.14 12/67] KVM: x86: add support for emulating UMIP | Date | Mon, 19 Mar 2018 15:22:47 +0000 |
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On Thu, Mar 08, 2018 at 01:46:39AM -0500, Paolo Bonzini wrote: > > >----- Original Message ----- >> From: "Sasha Levin" <Alexander.Levin@microsoft.com> >> To: linux-kernel@vger.kernel.org, stable@vger.kernel.org >> Cc: "Paolo Bonzini" <pbonzini@redhat.com>, "Sasha Levin" <Alexander.Levin@microsoft.com> >> Sent: Thursday, March 8, 2018 5:57:36 AM >> Subject: [PATCH AUTOSEL for 4.14 12/67] KVM: x86: add support for emulating UMIP >> >> From: Paolo Bonzini <pbonzini@redhat.com> >> >> [ Upstream commit 66336cab3531d3325ebde36a04725dddd0c42cb5 ] >> >> The User-Mode Instruction Prevention feature present in recent Intel >> processor prevents a group of instructions (sgdt, sidt, sldt, smsw, and >> str) from being executed with CPL > 0. Otherwise, a general protection >> fault is issued. >> >> UMIP instructions in general are also able to trigger vmexits, so we can >> actually emulate UMIP on older processors. This commit sets up the >> infrastructure so that kvm-intel.ko and kvm-amd.ko can set the UMIP >> feature bit for CPUID even if the feature is not actually available >> in hardware. >> >> Reviewed-by: Wanpeng Li <wanpeng.li@hotmail.com> >> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> >> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> > >This is not enough (there were a couple bugs, plus you have not >added the changes needed to the handle SLDT, STR, etc. in the >emulator). But since this is a feature, why is it being backported >to 4.14, especially without any testing??
Hi Paolo,
They were proposed for stable as part of the automatic patch selection process. I'll drop this patch.
--
Thanks, Sasha
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