From: Borislav Petkov bp@suse.de
commit a80c4ec10ed9632c44c829452dc40a0443ff4e85 upstream.
After commit:
672ff6cff80c ("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: 672ff6cff80c ("KVM: x86: Raise #GP when guest vCPU do not support PMU") Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/kvm/pmu_amd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/kvm/pmu_amd.c +++ b/arch/x86/kvm/pmu_amd.c @@ -269,10 +269,10 @@ static void amd_pmu_refresh(struct kvm_v
pmu->counter_bitmask[KVM_PMC_GP] = ((u64)1 << 48) - 1; pmu->reserved_bits = 0xffffffff00200000ull; + pmu->version = 1; /* not applicable to AMD; but clean them to prevent any fall out */ pmu->counter_bitmask[KVM_PMC_FIXED] = 0; pmu->nr_arch_fixed_counters = 0; - pmu->version = 0; pmu->global_status = 0; }