On Thu, Mar 08, 2018 at 01:46:39AM -0500, Paolo Bonzini wrote: > > >----- Original Message ----- >> From: "Sasha Levin" <Alexander.Levin@xxxxxxxxxxxxx> >> To: linux-kernel@xxxxxxxxxxxxxxx, stable@xxxxxxxxxxxxxxx >> Cc: "Paolo Bonzini" <pbonzini@xxxxxxxxxx>, "Sasha Levin" <Alexander.Levin@xxxxxxxxxxxxx> >> 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@xxxxxxxxxx> >> >> [ 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@xxxxxxxxxxx> >> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> >> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx> > >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