| Message ID | 20230311002258.852397-24-seanjc@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/i915/gvt: KVM: KVMGT fixes and page-track cleanups | expand |
Tested-by: Yan Zhao <yan.y.zhao@intel.com> On Fri, Mar 10, 2023 at 04:22:54PM -0800, Sean Christopherson wrote: > When adding/removing gfns to/from write-tracking, assert that mmu_lock > is held for write, and that either slots_lock or kvm->srcu is held. > mmu_lock must be held for write to protect gfn_write_track's refcount, > and SRCU or slots_lock must be held to protect the memslot itself. > > Signed-off-by: Sean Christopherson <seanjc@google.com> > --- > arch/x86/kvm/mmu/page_track.c | 17 +++++++++++------ > 1 file changed, 11 insertions(+), 6 deletions(-) > > diff --git a/arch/x86/kvm/mmu/page_track.c b/arch/x86/kvm/mmu/page_track.c > index 1993db4578e5..ffcd7ac66f9e 100644 > --- a/arch/x86/kvm/mmu/page_track.c > +++ b/arch/x86/kvm/mmu/page_track.c > @@ -12,6 +12,7 @@ > */ > #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt > > +#include <linux/lockdep.h> > #include <linux/kvm_host.h> > #include <linux/rculist.h> > > @@ -77,9 +78,6 @@ static void update_gfn_write_track(struct kvm_memory_slot *slot, gfn_t gfn, > * add guest page to the tracking pool so that corresponding access on that > * page will be intercepted. > * > - * It should be called under the protection both of mmu-lock and kvm->srcu > - * or kvm->slots_lock. > - * > * @kvm: the guest instance we are interested in. > * @slot: the @gfn belongs to. > * @gfn: the guest page. > @@ -87,6 +85,11 @@ static void update_gfn_write_track(struct kvm_memory_slot *slot, gfn_t gfn, > void kvm_write_track_add_gfn(struct kvm *kvm, struct kvm_memory_slot *slot, > gfn_t gfn) > { > + lockdep_assert_held_write(&kvm->mmu_lock); > + > + lockdep_assert_once(lockdep_is_held(&kvm->slots_lock) || > + srcu_read_lock_held(&kvm->srcu)); > + > if (WARN_ON(!kvm_page_track_write_tracking_enabled(kvm))) > return; > > @@ -107,9 +110,6 @@ EXPORT_SYMBOL_GPL(kvm_write_track_add_gfn); > * remove the guest page from the tracking pool which stops the interception > * of corresponding access on that page. > * > - * It should be called under the protection both of mmu-lock and kvm->srcu > - * or kvm->slots_lock. > - * > * @kvm: the guest instance we are interested in. > * @slot: the @gfn belongs to. > * @gfn: the guest page. > @@ -117,6 +117,11 @@ EXPORT_SYMBOL_GPL(kvm_write_track_add_gfn); > void kvm_write_track_remove_gfn(struct kvm *kvm, > struct kvm_memory_slot *slot, gfn_t gfn) > { > + lockdep_assert_held_write(&kvm->mmu_lock); > + > + lockdep_assert_once(lockdep_is_held(&kvm->slots_lock) || > + srcu_read_lock_held(&kvm->srcu)); > + > if (WARN_ON(!kvm_page_track_write_tracking_enabled(kvm))) > return; > > -- > 2.40.0.rc1.284.g88254d51c5-goog >
diff --git a/arch/x86/kvm/mmu/page_track.c b/arch/x86/kvm/mmu/page_track.c index 1993db4578e5..ffcd7ac66f9e 100644 --- a/arch/x86/kvm/mmu/page_track.c +++ b/arch/x86/kvm/mmu/page_track.c @@ -12,6 +12,7 @@ */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include <linux/lockdep.h> #include <linux/kvm_host.h> #include <linux/rculist.h> @@ -77,9 +78,6 @@ static void update_gfn_write_track(struct kvm_memory_slot *slot, gfn_t gfn, * add guest page to the tracking pool so that corresponding access on that * page will be intercepted. * - * It should be called under the protection both of mmu-lock and kvm->srcu - * or kvm->slots_lock. - * * @kvm: the guest instance we are interested in. * @slot: the @gfn belongs to. * @gfn: the guest page. @@ -87,6 +85,11 @@ static void update_gfn_write_track(struct kvm_memory_slot *slot, gfn_t gfn, void kvm_write_track_add_gfn(struct kvm *kvm, struct kvm_memory_slot *slot, gfn_t gfn) { + lockdep_assert_held_write(&kvm->mmu_lock); + + lockdep_assert_once(lockdep_is_held(&kvm->slots_lock) || + srcu_read_lock_held(&kvm->srcu)); + if (WARN_ON(!kvm_page_track_write_tracking_enabled(kvm))) return; @@ -107,9 +110,6 @@ EXPORT_SYMBOL_GPL(kvm_write_track_add_gfn); * remove the guest page from the tracking pool which stops the interception * of corresponding access on that page. * - * It should be called under the protection both of mmu-lock and kvm->srcu - * or kvm->slots_lock. - * * @kvm: the guest instance we are interested in. * @slot: the @gfn belongs to. * @gfn: the guest page. @@ -117,6 +117,11 @@ EXPORT_SYMBOL_GPL(kvm_write_track_add_gfn); void kvm_write_track_remove_gfn(struct kvm *kvm, struct kvm_memory_slot *slot, gfn_t gfn) { + lockdep_assert_held_write(&kvm->mmu_lock); + + lockdep_assert_once(lockdep_is_held(&kvm->slots_lock) || + srcu_read_lock_held(&kvm->srcu)); + if (WARN_ON(!kvm_page_track_write_tracking_enabled(kvm))) return;
When adding/removing gfns to/from write-tracking, assert that mmu_lock is held for write, and that either slots_lock or kvm->srcu is held. mmu_lock must be held for write to protect gfn_write_track's refcount, and SRCU or slots_lock must be held to protect the memslot itself. Signed-off-by: Sean Christopherson <seanjc@google.com> --- arch/x86/kvm/mmu/page_track.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-)