| Message ID | 20210802183329.2309921-3-mlevitsk@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | My AVIC patch queue | expand |
On 02/08/21 20:33, Maxim Levitsky wrote: > This together with previous patch, ensures that > kvm_zap_gfn_range doesn't race with page fault > running on another vcpu, and will make this page fault code > retry instead. > > This is based on a patch suggested by Sean Christopherson: > https://lkml.org/lkml/2021/7/22/1025 > > Suggested-by: Sean Christopherson <seanjc@google.com> > Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> > --- > arch/x86/kvm/mmu/mmu.c | 4 ++++ > include/linux/kvm_host.h | 5 +++++ > virt/kvm/kvm_main.c | 7 +++++-- > 3 files changed, 14 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > index 9d78cb1c0f35..9da635e383c2 100644 > --- a/arch/x86/kvm/mmu/mmu.c > +++ b/arch/x86/kvm/mmu/mmu.c > @@ -5640,6 +5640,8 @@ void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end) > > write_lock(&kvm->mmu_lock); > > + kvm_inc_notifier_count(kvm, gfn_start, gfn_end); > + > if (kvm_memslots_have_rmaps(kvm)) { > for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { > slots = __kvm_memslots(kvm, i); > @@ -5671,6 +5673,8 @@ void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end) > if (flush) > kvm_flush_remote_tlbs_with_address(kvm, gfn_start, gfn_end); > > + kvm_dec_notifier_count(kvm, gfn_start, gfn_end); > + > write_unlock(&kvm->mmu_lock); > } > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index 9d6b4ad407b8..962e11a73e8e 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -985,6 +985,11 @@ void kvm_mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc); > void *kvm_mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc); > #endif > > +void kvm_inc_notifier_count(struct kvm *kvm, unsigned long start, > + unsigned long end); > +void kvm_dec_notifier_count(struct kvm *kvm, unsigned long start, > + unsigned long end); > + > long kvm_arch_dev_ioctl(struct file *filp, > unsigned int ioctl, unsigned long arg); > long kvm_arch_vcpu_ioctl(struct file *filp, > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index a96cbe24c688..71042cd807b3 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -608,7 +608,7 @@ static void kvm_mmu_notifier_change_pte(struct mmu_notifier *mn, > kvm_handle_hva_range(mn, address, address + 1, pte, kvm_set_spte_gfn); > } > > -static void kvm_inc_notifier_count(struct kvm *kvm, unsigned long start, > +void kvm_inc_notifier_count(struct kvm *kvm, unsigned long start, > unsigned long end) > { > /* > @@ -636,6 +636,7 @@ static void kvm_inc_notifier_count(struct kvm *kvm, unsigned long start, > max(kvm->mmu_notifier_range_end, end); > } > } > +EXPORT_SYMBOL_GPL(kvm_inc_notifier_count); > > static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn, > const struct mmu_notifier_range *range) > @@ -670,7 +671,7 @@ static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn, > return 0; > } > > -static void kvm_dec_notifier_count(struct kvm *kvm, unsigned long start, > +void kvm_dec_notifier_count(struct kvm *kvm, unsigned long start, > unsigned long end) > { > /* > @@ -687,6 +688,8 @@ static void kvm_dec_notifier_count(struct kvm *kvm, unsigned long start, > */ > kvm->mmu_notifier_count--; > } > +EXPORT_SYMBOL_GPL(kvm_dec_notifier_count); > + > > static void kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn, > const struct mmu_notifier_range *range) > Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 9d78cb1c0f35..9da635e383c2 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -5640,6 +5640,8 @@ void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end) write_lock(&kvm->mmu_lock); + kvm_inc_notifier_count(kvm, gfn_start, gfn_end); + if (kvm_memslots_have_rmaps(kvm)) { for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { slots = __kvm_memslots(kvm, i); @@ -5671,6 +5673,8 @@ void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end) if (flush) kvm_flush_remote_tlbs_with_address(kvm, gfn_start, gfn_end); + kvm_dec_notifier_count(kvm, gfn_start, gfn_end); + write_unlock(&kvm->mmu_lock); } diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 9d6b4ad407b8..962e11a73e8e 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -985,6 +985,11 @@ void kvm_mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc); void *kvm_mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc); #endif +void kvm_inc_notifier_count(struct kvm *kvm, unsigned long start, + unsigned long end); +void kvm_dec_notifier_count(struct kvm *kvm, unsigned long start, + unsigned long end); + long kvm_arch_dev_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg); long kvm_arch_vcpu_ioctl(struct file *filp, diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index a96cbe24c688..71042cd807b3 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -608,7 +608,7 @@ static void kvm_mmu_notifier_change_pte(struct mmu_notifier *mn, kvm_handle_hva_range(mn, address, address + 1, pte, kvm_set_spte_gfn); } -static void kvm_inc_notifier_count(struct kvm *kvm, unsigned long start, +void kvm_inc_notifier_count(struct kvm *kvm, unsigned long start, unsigned long end) { /* @@ -636,6 +636,7 @@ static void kvm_inc_notifier_count(struct kvm *kvm, unsigned long start, max(kvm->mmu_notifier_range_end, end); } } +EXPORT_SYMBOL_GPL(kvm_inc_notifier_count); static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn, const struct mmu_notifier_range *range) @@ -670,7 +671,7 @@ static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn, return 0; } -static void kvm_dec_notifier_count(struct kvm *kvm, unsigned long start, +void kvm_dec_notifier_count(struct kvm *kvm, unsigned long start, unsigned long end) { /* @@ -687,6 +688,8 @@ static void kvm_dec_notifier_count(struct kvm *kvm, unsigned long start, */ kvm->mmu_notifier_count--; } +EXPORT_SYMBOL_GPL(kvm_dec_notifier_count); + static void kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn, const struct mmu_notifier_range *range)
This together with previous patch, ensures that kvm_zap_gfn_range doesn't race with page fault running on another vcpu, and will make this page fault code retry instead. This is based on a patch suggested by Sean Christopherson: https://lkml.org/lkml/2021/7/22/1025 Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> --- arch/x86/kvm/mmu/mmu.c | 4 ++++ include/linux/kvm_host.h | 5 +++++ virt/kvm/kvm_main.c | 7 +++++-- 3 files changed, 14 insertions(+), 2 deletions(-)