KVM: arm64: PMU: Fix PMCR_EL0 reset value

ARMV8_PMU_PMCR_N_MASK is an unshifted value which results in the wrong
reset value for PMCR_EL0, so shift it to fix it.

This fixes the following error when running qemu:

  $ qemu-system-aarch64 -cpu host -machine type=virt,accel=kvm -kernel ...

  target/arm/helper.c:1813: pmevcntr_rawwrite: Assertion `counter < pmu_num_counters(env)' failed.

Fixes: 292e8f149476 ("KVM: arm64: PMU: Simplify PMCR_EL0 reset handling")
Signed-off-by: James Clark <james.clark@arm.com>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221209164446.1972014-2-james.clark@arm.com

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index d5ee52d..c6cbfe6 100644 (file)
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -646,7 +646,7 @@ static void reset_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
                return;
 
        /* Only preserve PMCR_EL0.N, and reset the rest to 0 */
-       pmcr = read_sysreg(pmcr_el0) & ARMV8_PMU_PMCR_N_MASK;
+       pmcr = read_sysreg(pmcr_el0) & (ARMV8_PMU_PMCR_N_MASK << ARMV8_PMU_PMCR_N_SHIFT);
        if (!kvm_supports_32bit_el0())
                pmcr |= ARMV8_PMU_PMCR_LC;