[PATCH v3 12/14] KVM: s390: pv: module parameter to fence lazy destroy
From: Claudio Imbrenda <imbrenda@linux.ibm.com>
Date: 2021-08-04 15:41:28
Also in:
linux-s390, lkml
Subsystem:
kernel virtual machine for s390 (kvm/s390), s390 architecture, the rest · Maintainers:
Christian Borntraeger, Janosch Frank, Claudio Imbrenda, Heiko Carstens, Vasily Gorbik, Alexander Gordeev, Linus Torvalds
Add the module parameter "lazy_destroy", to allow the lazy destroy mechanism to be switched off. This might be useful for debugging purposes. The parameter is enabled by default. Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Reviewed-by: Janosch Frank <frankja@linux.ibm.com> --- arch/s390/kvm/pv.c | 13 +++++++++++++ 1 file changed, 13 insertions(+)
diff --git a/arch/s390/kvm/pv.c b/arch/s390/kvm/pv.c
index e10392a8b1ae..c570d4ce29c3 100644
--- a/arch/s390/kvm/pv.c
+++ b/arch/s390/kvm/pv.c@@ -26,6 +26,10 @@ struct deferred_priv { unsigned long stor_base; }; +static int lazy_destroy = 1; +module_param(lazy_destroy, int, 0444); +MODULE_PARM_DESC(lazy_destroy, "Deferred destroy for protected guests"); + int kvm_s390_pv_destroy_cpu(struct kvm_vcpu *vcpu, u16 *rc, u16 *rrc) { int cc = 0;
@@ -312,6 +316,9 @@ int kvm_s390_pv_deinit_vm_deferred(struct kvm *kvm, u16 *rc, u16 *rrc) { struct deferred_priv *priv; + if (!lazy_destroy) + return kvm_s390_pv_deinit_vm_now(kvm, rc, rrc); + priv = kmalloc(sizeof(*priv), GFP_KERNEL | __GFP_ZERO); if (!priv) return kvm_s390_pv_deinit_vm_now(kvm, rc, rrc);
@@ -360,6 +367,12 @@ int kvm_s390_pv_init_vm(struct kvm *kvm, u16 *rc, u16 *rrc) /* Outputs */ kvm->arch.pv.handle = uvcb.guest_handle; + if (!lazy_destroy) { + mmap_write_lock(kvm->mm); + kvm->mm->context.pv_sync_destroy = 1; + mmap_write_unlock(kvm->mm); + } + atomic_inc(&kvm->mm->context.is_protected); if (cc) { if (uvcb.header.rc & UVC_RC_NEED_DESTROY) {
--
2.31.1