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authorPaolo Bonzini <pbonzini@redhat.com>2020-07-06 13:05:38 -0400
committerPaolo Bonzini <pbonzini@redhat.com>2020-07-06 13:05:38 -0400
commit8038a922cf9af5266eaff29ce996a0d1b788fc0d (patch)
treef43525c33b24c53d77adc339ca4ae039c441e85a
parentfa71e9527f6a0153ae6a880031b902818af1bdaf (diff)
parentb9e10d4a6c9f5cbe6369ce2c17ebc67d2e5a4be5 (diff)
downloadlinux-stericsson-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.S11
-rw-r--r--arch/arm64/kvm/pmu.c7
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();
}
/*