mirror of https://gitee.com/openkylin/linux.git
arm64: KVM: pmu: Reset PMSELR_EL0.SEL to a sane value before entering the guest
The ARMv8 architecture allows the cycle counter to be configured by setting PMSELR_EL0.SEL==0x1f and then accessing PMXEVTYPER_EL0, hence accessing PMCCFILTR_EL0. But it disallows the use of PMSELR_EL0.SEL==0x1f to access the cycle counter itself through PMXEVCNTR_EL0. Linux itself doesn't violate this rule, but we may end up with PMSELR_EL0.SEL being set to 0x1f when we enter a guest. If that guest accesses PMXEVCNTR_EL0, the access may UNDEF at EL1, despite the guest not having done anything wrong. In order to avoid this unfortunate course of events (haha!), let's sanitize PMSELR_EL0 on guest entry. This ensures that the guest won't explode unexpectedly. Cc: stable@vger.kernel.org #4.6+ Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
This commit is contained in:
parent
8e1a0476f8
commit
21cbe3cc8a
|
@ -85,7 +85,13 @@ static void __hyp_text __activate_traps(struct kvm_vcpu *vcpu)
|
|||
write_sysreg(val, hcr_el2);
|
||||
/* Trap on AArch32 cp15 c15 accesses (EL1 or EL0) */
|
||||
write_sysreg(1 << 15, hstr_el2);
|
||||
/* Make sure we trap PMU access from EL0 to EL2 */
|
||||
/*
|
||||
* Make sure we trap PMU access from EL0 to EL2. Also sanitize
|
||||
* PMSELR_EL0 to make sure it never contains the cycle
|
||||
* counter, which could make a PMXEVCNTR_EL0 access UNDEF at
|
||||
* EL1 instead of being trapped to EL2.
|
||||
*/
|
||||
write_sysreg(0, pmselr_el0);
|
||||
write_sysreg(ARMV8_PMU_USERENR_MASK, pmuserenr_el0);
|
||||
write_sysreg(vcpu->arch.mdcr_el2, mdcr_el2);
|
||||
__activate_traps_arch()();
|
||||
|
|
Loading…
Reference in New Issue