https://bugzilla.kernel.org/show_bug.cgi?id=203543 --- Comment #10 from moi@xxxxxxxxxxxxx --- Reverting both commits solves this problem: f93f7ede087f2edcc18e4b02310df5749a6b5a61 e51bfdb68725dc052d16241ace40ea3140f938aa On 2019-05-21 8:57 a.m., bugzilla-daemon@xxxxxxxxxxxxxxxxxxx wrote: > https://bugzilla.kernel.org/show_bug.cgi?id=203543 > > --- Comment #9 from dhill@xxxxxxxxxx --- > Hi guys, > > I justed tested kernel 5.2.1-rc1 which contains the following commit > reverting the previously mentionned commit but... the problem is still > there: > > > [root@wolfe linux-stable]# su - jenkins -s /bin/bash > [jenkins@wolfe ~]$ ssh root@192.168.122.2 > Activate the web console with: systemctl enable --now cockpit.socket > > Last login: Tue May 21 08:53:28 2019 from 192.168.122.1 > [root@undercloud-0-rhosp15 ~]# modprobe kvm_intel > modprobe: ERROR: could not insert 'kvm_intel': Input/output error > [root@undercloud-0-rhosp15 ~]# logout > Connection to 192.168.122.2 closed. > [jenkins@wolfe ~]$ uname -a > Linux wolfe.orion 5.2.0-20190521081919+ #6 SMP Tue May 21 08:25:14 EDT > 2019 x86_64 x86_64 x86_64 GNU/Linux > > > I'll try reverting the commit and then reverting only the commit that > causes issues. > > commit f93f7ede087f2edcc18e4b02310df5749a6b5a61 > Author: Sean Christopherson <sean.j.christopherson@xxxxxxxxx> > Date: Wed May 8 09:08:19 2019 -0700 > > Revert "KVM: nVMX: Expose RDPMC-exiting only when guest supports PMU" > > The RDPMC-exiting control is dependent on the existence of the RDPMC > instruction itself, i.e. is not tied to the "Architectural Performance > Monitoring" feature. For all intents and purposes, the control exists > on all CPUs with VMX support since RDPMC also exists on all VCPUs with > VMX supported. Per Intel's SDM: > > The RDPMC instruction was introduced into the IA-32 Architecture in > the Pentium Pro processor and the Pentium processor with MMX > technology. > The earlier Pentium processors have performance-monitoring > counters, but > they must be read with the RDMSR instruction. > > Because RDPMC-exiting always exists, KVM requires the control and > refuses > to load if it's not available. As a result, hiding the PMU from a > guest > breaks nested virtualization if the guest attemts to use KVM. > > While it's not explicitly stated in the RDPMC pseudocode, the VM-Exit > check for RDPMC-exiting follows standard fault vs. VM-Exit > prioritization > for privileged instructions, e.g. occurs after the CPL/CR0.PE/CR4.PCE > checks, but before the counter referenced in ECX is checked for > validity. > > In other words, the original KVM behavior of injecting a #GP was > correct, > and the KVM unit test needs to be adjusted accordingly, e.g. eat > the #GP > when the unit test guest (L3 in this case) executes RDPMC without > RDPMC-exiting set in the unit test host (L2). > > This reverts commit e51bfdb68725dc052d16241ace40ea3140f938aa. > > Fixes: e51bfdb68725 ("KVM: nVMX: Expose RDPMC-exiting only when > guest supports PMU") > Reported-by: David Hill <hilld@xxxxxxxxxxxxxxx> > Cc: Saar Amar <saaramar@xxxxxxxxxxxxx> > Cc: Mihai Carabas <mihai.carabas@xxxxxxxxxx> > Cc: Jim Mattson <jmattson@xxxxxxxxxx> > Cc: Liran Alon <liran.alon@xxxxxxxxxx> > Cc: stable@xxxxxxxxxxxxxxx > Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx> > Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> > > > On 2019-05-08 6:14 p.m., bugzilla-daemon@xxxxxxxxxxxxxxxxxxx wrote: >> https://bugzilla.kernel.org/show_bug.cgi?id=203543 >> >> --- Comment #8 from Liran Alon (liran.alon@xxxxxxxxxx) --- >> +Paolo >> >> What are your thoughts on this? >> What is the reason that KVM relies on CPU_BASED_RDPMC_EXITING to be exposed >> from underlying CPU? How is it critical for it’s functionality? >> If it’s because we want to make sure that we hide host PMCs, we should >> condition this to be a min requirement of kvm_intel only in case underlying >> CPU >> exposes PMU to begin with. >> Do you agree? If yes, I can create the patch to fix this. >> >> -Liran >> >>> On 8 May 2019, at 16:51, bugzilla-daemon@xxxxxxxxxxxxxxxxxxx wrote: >>> >>> >>> >>> >>> https://urldefense.proofpoint.com/v2/url?u=https-3A__bugzilla.kernel.org_show-5Fbug.cgi-3Fid-3D203543&d=DwIDaQ&c=RoP1YumCXCgaWHvlZYR8PZh8Bv7qIrMUB65eapI_JnE&r=Jk6Q8nNzkQ6LJ6g42qARkg6ryIDGQr-yKXPNGZbpTx0&m=7TirfLMNxYI-3Ygxm3kjDUB49Jwmk8bqD7671wy0hi8&s=Z_L1UqH19zon0ohDrCMU91ixA-Wn_vO7d-fO8s2G3PI&e= >>> >>> --- Comment #5 from David Hill (hilld@xxxxxxxxxxxxxxx) --- >>> I can confirm that reverting that commit solves the problem: >>> >>> e51bfdb68725 ("KVM: nVMX: Expose RDPMC-exiting only when guest supports >>> PMU”) >>> >>> -- >>> You are receiving this mail because: >>> You are watching the assignee of the bug. -- You are receiving this mail because: You are watching the assignee of the bug.
