[PATCH 5.10 041/142] KVM: arm64: Filter out v8.1+ events on v8.0 HW

Greg Kroah-Hartman
2021-02-02T20:02:35Z

From: Marc Zyngier <maz@kernel.org>

commit 9529aaa056edc76b3a41df616c71117ebe11e049 upstream.

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
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/arm64/kvm/pmu-emul.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)

--- 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 *
{
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 *
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;