• Andrew Jones's avatar
    arm/pmu: fix probe on AArch64 · 098add54
    Andrew Jones authored
    The spec for ID_DFR0_EL1 says "In an AArch64-only implementation,
    this register is UNKNOWN." Indeed ThunderX just returns zero when
    that register is read. This means we can't rely on a non-zero
    value to determine if we can test the PMU. For AArch64 we need to
    read ID_AA64DFR0_EL1. This patch has the side effect of no longer
    running PMU tests on TCG for AArch64. That's actually another fix,
    though, as TCG chooses not to implement a PMU for AArch64 at this
    time. The only way it worked before was probing the wrong register
    and proceeding even though the version was 2, which is not a valid
    version for AArch64. When TCG eventually implements a PMU things
    should "just work".
    Reviewed-by: default avatarWei Huang <wei@redhat.com>
    Signed-off-by: Andrew Jones's avatarAndrew Jones <drjones@redhat.com>