| Message ID | 20220330122605.247613-11-imbrenda@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: s390: pv: implement lazy destroy for reboot | expand |
On 3/30/22 14:25, Claudio Imbrenda wrote: > Add an mmu_notifier for protected VMs. The callback function is > triggered when the mm is torn down, and will attempt to convert all > protected vCPUs to non-protected. This allows the mm teardown to use > the destroy page UVC instead of export. > > Also make KVM select CONFIG_MMU_NOTIFIER, needed to use mmu_notifiers. > > Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Acked-by: Janosch Frank <frankja@linux.ibm.com> > --- > arch/s390/include/asm/kvm_host.h | 2 ++ > arch/s390/kvm/Kconfig | 1 + > arch/s390/kvm/kvm-s390.c | 5 ++++- > arch/s390/kvm/pv.c | 26 ++++++++++++++++++++++++++ > 4 files changed, 33 insertions(+), 1 deletion(-) > > diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h > index a22c9266ea05..1bccb8561ba9 100644 > --- a/arch/s390/include/asm/kvm_host.h > +++ b/arch/s390/include/asm/kvm_host.h > @@ -19,6 +19,7 @@ > #include <linux/kvm.h> > #include <linux/seqlock.h> > #include <linux/module.h> > +#include <linux/mmu_notifier.h> > #include <asm/debug.h> > #include <asm/cpu.h> > #include <asm/fpu/api.h> > @@ -921,6 +922,7 @@ struct kvm_s390_pv { > u64 guest_len; > unsigned long stor_base; > void *stor_var; > + struct mmu_notifier mmu_notifier; > }; > > struct kvm_arch{ > diff --git a/arch/s390/kvm/Kconfig b/arch/s390/kvm/Kconfig > index 2e84d3922f7c..33f4ff909476 100644 > --- a/arch/s390/kvm/Kconfig > +++ b/arch/s390/kvm/Kconfig > @@ -34,6 +34,7 @@ config KVM > select SRCU > select KVM_VFIO > select INTERVAL_TREE > + select MMU_NOTIFIER > help > Support hosting paravirtualized guest machines using the SIE > virtualization capability on the mainframe. This should work > diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c > index 21fcca09e9bf..446f89db93a1 100644 > --- a/arch/s390/kvm/kvm-s390.c > +++ b/arch/s390/kvm/kvm-s390.c > @@ -32,6 +32,7 @@ > #include <linux/sched/signal.h> > #include <linux/string.h> > #include <linux/pgtable.h> > +#include <linux/mmu_notifier.h> > > #include <asm/asm-offsets.h> > #include <asm/lowcore.h> > @@ -2833,8 +2834,10 @@ void kvm_arch_destroy_vm(struct kvm *kvm) > * can mess with the pv state. To avoid lockdep_assert_held from > * complaining we do not use kvm_s390_pv_is_protected. > */ > - if (kvm_s390_pv_get_handle(kvm)) > + if (kvm_s390_pv_get_handle(kvm)) { > kvm_s390_pv_deinit_vm(kvm, &rc, &rrc); > + mmu_notifier_unregister(&kvm->arch.pv.mmu_notifier, kvm->mm); > + } > debug_unregister(kvm->arch.dbf); > free_page((unsigned long)kvm->arch.sie_page2); > if (!kvm_is_ucontrol(kvm)) > diff --git a/arch/s390/kvm/pv.c b/arch/s390/kvm/pv.c > index 76ef33a277d3..788b96b36931 100644 > --- a/arch/s390/kvm/pv.c > +++ b/arch/s390/kvm/pv.c > @@ -14,6 +14,7 @@ > #include <asm/mman.h> > #include <linux/pagewalk.h> > #include <linux/sched/mm.h> > +#include <linux/mmu_notifier.h> > #include "kvm-s390.h" > > static void kvm_s390_clear_pv_state(struct kvm *kvm) > @@ -192,6 +193,26 @@ int kvm_s390_pv_deinit_vm(struct kvm *kvm, u16 *rc, u16 *rrc) > return -EIO; > } > > +static void kvm_s390_pv_mmu_notifier_release(struct mmu_notifier *subscription, > + struct mm_struct *mm) > +{ > + struct kvm *kvm = container_of(subscription, struct kvm, arch.pv.mmu_notifier); > + u16 dummy; > + > + /* > + * No locking is needed since this is the last thread of the last user of this > + * struct mm. > + * When the struct kvm gets deinitialized, this notifier is also > + * unregistered. This means that if this notifier runs, then the > + * struct kvm is still valid. > + */ > + kvm_s390_cpus_from_pv(kvm, &dummy, &dummy); > +} > + > +static const struct mmu_notifier_ops kvm_s390_pv_mmu_notifier_ops = { > + .release = kvm_s390_pv_mmu_notifier_release, > +}; > + > int kvm_s390_pv_init_vm(struct kvm *kvm, u16 *rc, u16 *rrc) > { > struct uv_cb_cgc uvcb = { > @@ -233,6 +254,11 @@ int kvm_s390_pv_init_vm(struct kvm *kvm, u16 *rc, u16 *rrc) > return -EIO; > } > kvm->arch.gmap->guest_handle = uvcb.guest_handle; > + /* Add the notifier only once. No races because we hold kvm->lock */ > + if (kvm->arch.pv.mmu_notifier.ops != &kvm_s390_pv_mmu_notifier_ops) { > + kvm->arch.pv.mmu_notifier.ops = &kvm_s390_pv_mmu_notifier_ops; > + mmu_notifier_register(&kvm->arch.pv.mmu_notifier, kvm->mm); > + } > return 0; > } >
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h index a22c9266ea05..1bccb8561ba9 100644 --- a/arch/s390/include/asm/kvm_host.h +++ b/arch/s390/include/asm/kvm_host.h @@ -19,6 +19,7 @@ #include <linux/kvm.h> #include <linux/seqlock.h> #include <linux/module.h> +#include <linux/mmu_notifier.h> #include <asm/debug.h> #include <asm/cpu.h> #include <asm/fpu/api.h> @@ -921,6 +922,7 @@ struct kvm_s390_pv { u64 guest_len; unsigned long stor_base; void *stor_var; + struct mmu_notifier mmu_notifier; }; struct kvm_arch{ diff --git a/arch/s390/kvm/Kconfig b/arch/s390/kvm/Kconfig index 2e84d3922f7c..33f4ff909476 100644 --- a/arch/s390/kvm/Kconfig +++ b/arch/s390/kvm/Kconfig @@ -34,6 +34,7 @@ config KVM select SRCU select KVM_VFIO select INTERVAL_TREE + select MMU_NOTIFIER help Support hosting paravirtualized guest machines using the SIE virtualization capability on the mainframe. This should work diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 21fcca09e9bf..446f89db93a1 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -32,6 +32,7 @@ #include <linux/sched/signal.h> #include <linux/string.h> #include <linux/pgtable.h> +#include <linux/mmu_notifier.h> #include <asm/asm-offsets.h> #include <asm/lowcore.h> @@ -2833,8 +2834,10 @@ void kvm_arch_destroy_vm(struct kvm *kvm) * can mess with the pv state. To avoid lockdep_assert_held from * complaining we do not use kvm_s390_pv_is_protected. */ - if (kvm_s390_pv_get_handle(kvm)) + if (kvm_s390_pv_get_handle(kvm)) { kvm_s390_pv_deinit_vm(kvm, &rc, &rrc); + mmu_notifier_unregister(&kvm->arch.pv.mmu_notifier, kvm->mm); + } debug_unregister(kvm->arch.dbf); free_page((unsigned long)kvm->arch.sie_page2); if (!kvm_is_ucontrol(kvm)) diff --git a/arch/s390/kvm/pv.c b/arch/s390/kvm/pv.c index 76ef33a277d3..788b96b36931 100644 --- a/arch/s390/kvm/pv.c +++ b/arch/s390/kvm/pv.c @@ -14,6 +14,7 @@ #include <asm/mman.h> #include <linux/pagewalk.h> #include <linux/sched/mm.h> +#include <linux/mmu_notifier.h> #include "kvm-s390.h" static void kvm_s390_clear_pv_state(struct kvm *kvm) @@ -192,6 +193,26 @@ int kvm_s390_pv_deinit_vm(struct kvm *kvm, u16 *rc, u16 *rrc) return -EIO; } +static void kvm_s390_pv_mmu_notifier_release(struct mmu_notifier *subscription, + struct mm_struct *mm) +{ + struct kvm *kvm = container_of(subscription, struct kvm, arch.pv.mmu_notifier); + u16 dummy; + + /* + * No locking is needed since this is the last thread of the last user of this + * struct mm. + * When the struct kvm gets deinitialized, this notifier is also + * unregistered. This means that if this notifier runs, then the + * struct kvm is still valid. + */ + kvm_s390_cpus_from_pv(kvm, &dummy, &dummy); +} + +static const struct mmu_notifier_ops kvm_s390_pv_mmu_notifier_ops = { + .release = kvm_s390_pv_mmu_notifier_release, +}; + int kvm_s390_pv_init_vm(struct kvm *kvm, u16 *rc, u16 *rrc) { struct uv_cb_cgc uvcb = { @@ -233,6 +254,11 @@ int kvm_s390_pv_init_vm(struct kvm *kvm, u16 *rc, u16 *rrc) return -EIO; } kvm->arch.gmap->guest_handle = uvcb.guest_handle; + /* Add the notifier only once. No races because we hold kvm->lock */ + if (kvm->arch.pv.mmu_notifier.ops != &kvm_s390_pv_mmu_notifier_ops) { + kvm->arch.pv.mmu_notifier.ops = &kvm_s390_pv_mmu_notifier_ops; + mmu_notifier_register(&kvm->arch.pv.mmu_notifier, kvm->mm); + } return 0; }
Add an mmu_notifier for protected VMs. The callback function is triggered when the mm is torn down, and will attempt to convert all protected vCPUs to non-protected. This allows the mm teardown to use the destroy page UVC instead of export. Also make KVM select CONFIG_MMU_NOTIFIER, needed to use mmu_notifiers. Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com> --- arch/s390/include/asm/kvm_host.h | 2 ++ arch/s390/kvm/Kconfig | 1 + arch/s390/kvm/kvm-s390.c | 5 ++++- arch/s390/kvm/pv.c | 26 ++++++++++++++++++++++++++ 4 files changed, 33 insertions(+), 1 deletion(-)