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: Borislav 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: Paolo Bonzini <pbonzini@redhat.com>