KVM: arm64: Filter out v8.1+ events on v8.0 HW

When running on v8.0 HW, make sure we don't try to advertise
events in the 0x4000-0x403f range.

Cc: stable@vger.kernel.org
Fixes: 88865beca9062 ("KVM: arm64: Mask out filtered events in PCMEID{0,1}_EL1")
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210121105636.1478491-1-maz@kernel.org

diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c
index 4ad66a532e38b37007fd75610e15a426b7123bd8..247422ac78a9e5c01e543146076428d81db061fc 100644 (file)
--- a/arch/arm64/kvm/pmu-emul.c
+++ b/arch/arm64/kvm/pmu-emul.c
@@ -788,7 +788,7 @@ u64 kvm_pmu_get_pmceid(struct kvm_vcpu *vcpu, bool pmceid1)
 {
        unsigned long *bmap = vcpu->kvm->arch.pmu_filter;
        u64 val, mask = 0;
-       int base, i;
+       int base, i, nr_events;
 
        if (!pmceid1) {
                val = read_sysreg(pmceid0_el0);
@@ -801,13 +801,17 @@ u64 kvm_pmu_get_pmceid(struct kvm_vcpu *vcpu, bool pmceid1)
        if (!bmap)
                return val;
 
+       nr_events = kvm_pmu_event_mask(vcpu->kvm) + 1;
+
        for (i = 0; i < 32; i += 8) {
                u64 byte;
 
                byte = bitmap_get_value8(bmap, base + i);
                mask |= byte << i;
-               byte = bitmap_get_value8(bmap, 0x4000 + base + i);
-               mask |= byte << (32 + i);
+               if (nr_events >= (0x4000 + base + 32)) {
+                       byte = bitmap_get_value8(bmap, 0x4000 + base + i);
+                       mask |= byte << (32 + i);
+               }
        }
 
        return val & mask;