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| author | Paolo Bonzini <pbonzini@redhat.com> | 2020-07-06 13:05:38 -0400 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-07-06 13:05:38 -0400 |
| commit | 8038a922cf9af5266eaff29ce996a0d1b788fc0d (patch) | |
| tree | f43525c33b24c53d77adc339ca4ae039c441e85a | |
| parent | fa71e9527f6a0153ae6a880031b902818af1bdaf (diff) | |
| parent | b9e10d4a6c9f5cbe6369ce2c17ebc67d2e5a4be5 (diff) | |
| download | linux-8038a922cf9af5266eaff29ce996a0d1b788fc0d.tar.gz | |
Merge tag 'kvmarm-fixes-5.8-3' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into kvm-master
KVM/arm fixes for 5.8, take #3 - Disable preemption on context-switching PMU EL0 state happening on system register trap - Don't clobber X0 when tearing down KVM via a soft reset (kexec)
| -rw-r--r-- | arch/arm64/kvm/hyp-init.S | 11 | ||||
| -rw-r--r-- | arch/arm64/kvm/pmu.c | 7 |
2 files changed, 13 insertions, 5 deletions
diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S index 6e6ed5581eed..e76c0e89d48e 100644 --- a/arch/arm64/kvm/hyp-init.S +++ b/arch/arm64/kvm/hyp-init.S @@ -136,11 +136,15 @@ SYM_CODE_START(__kvm_handle_stub_hvc) 1: cmp x0, #HVC_RESET_VECTORS b.ne 1f -reset: + /* - * Reset kvm back to the hyp stub. Do not clobber x0-x4 in - * case we coming via HVC_SOFT_RESTART. + * Set the HVC_RESET_VECTORS return code before entering the common + * path so that we do not clobber x0-x2 in case we are coming via + * HVC_SOFT_RESTART. */ + mov x0, xzr +reset: + /* Reset kvm back to the hyp stub. */ mrs x5, sctlr_el2 mov_q x6, SCTLR_ELx_FLAGS bic x5, x5, x6 // Clear SCTL_M and etc @@ -151,7 +155,6 @@ reset: /* Install stub vectors */ adr_l x5, __hyp_stub_vectors msr vbar_el2, x5 - mov x0, xzr eret 1: /* Bad stub call */ diff --git a/arch/arm64/kvm/pmu.c b/arch/arm64/kvm/pmu.c index b5ae3a5d509e..3c224162b3dd 100644 --- a/arch/arm64/kvm/pmu.c +++ b/arch/arm64/kvm/pmu.c @@ -159,7 +159,10 @@ static void kvm_vcpu_pmu_disable_el0(unsigned long events) } /* - * On VHE ensure that only guest events have EL0 counting enabled + * On VHE ensure that only guest events have EL0 counting enabled. + * This is called from both vcpu_{load,put} and the sysreg handling. + * Since the latter is preemptible, special care must be taken to + * disable preemption. */ void kvm_vcpu_pmu_restore_guest(struct kvm_vcpu *vcpu) { @@ -169,12 +172,14 @@ void kvm_vcpu_pmu_restore_guest(struct kvm_vcpu *vcpu) if (!has_vhe()) return; + preempt_disable(); host = this_cpu_ptr(&kvm_host_data); events_guest = host->pmu_events.events_guest; events_host = host->pmu_events.events_host; kvm_vcpu_pmu_enable_el0(events_guest); kvm_vcpu_pmu_disable_el0(events_host); + preempt_enable(); } /* |