• Borislav Petkov's avatar
    x86/kvm/pmu: Set AMD's virt PMU version to 1 · a80c4ec1
    Borislav Petkov authored
    After commit:
    
      672ff6cf ("KVM: x86: Raise #GP when guest vCPU do not support PMU")
    
    my AMD guests started #GPing like this:
    
      general protection fault: 0000 [#1] PREEMPT SMP
      CPU: 1 PID: 4355 Comm: bash Not tainted 5.1.0-rc6+ #3
      Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
      RIP: 0010:x86_perf_event_update+0x3b/0xa0
    
    with Code: pointing to RDPMC. It is RDPMC because the guest has the
    hardware watchdog CONFIG_HARDLOCKUP_DETECTOR_PERF enabled which uses
    perf. Instrumenting kvm_pmu_rdpmc() some, showed that it fails due to:
    
      if (!pmu->version)
      	return 1;
    
    which the above commit added. Since AMD's PMU leaves the version at 0,
    that causes the #GP injection into the guest.
    
    Set pmu->version arbitrarily to 1 and move it above the non-applicable
    struct kvm_pmu members.
    Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
    Cc: "H. Peter Anvin" <hpa@zytor.com>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Janakarajan Natarajan <Janakarajan.Natarajan@amd.com>
    Cc: kvm@vger.kernel.org
    Cc: Liran Alon <liran.alon@oracle.com>
    Cc: Mihai Carabas <mihai.carabas@oracle.com>
    Cc: Paolo Bonzini <pbonzini@redhat.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: "Radim Krčmář" <rkrcmar@redhat.com>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Tom Lendacky <thomas.lendacky@amd.com>
    Cc: x86@kernel.org
    Cc: stable@vger.kernel.org
    Fixes: 672ff6cf ("KVM: x86: Raise #GP when guest vCPU do not support PMU")
    Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
    a80c4ec1
pmu_amd.c 7.48 KB