| Message ID | 20231027182217.3615211-4-seanjc@google.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | KVM: guest_memfd() and per-page attributes | expand |
On 10/27/23 20:21, Sean Christopherson wrote: > From: Chao Peng <chao.p.peng@linux.intel.com> Currently in mmu_notifier > invalidate path, hva range is recorded and then checked against by > mmu_notifier_retry_hva() in the page fault handling path. However, for > the to be introduced private memory, a page fault may not have a hva > associated, checking gfn(gpa) makes more sense. For existing hva based > shared memory, gfn is expected to also work. The only downside is when > aliasing multiple gfns to a single hva, the current algorithm of > checking multiple ranges could result in a much larger range being > rejected. Such aliasing should be uncommon, so the impact is expected > small. Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Paolo
On 2023-10-27 11:21 AM, Sean Christopherson wrote: > From: Chao Peng <chao.p.peng@linux.intel.com> > > Currently in mmu_notifier invalidate path, hva range is recorded and > then checked against by mmu_notifier_retry_hva() in the page fault > handling path. However, for the to be introduced private memory, a page ^^^^^^^^^^^^^^^^^^^^^^^^ Is there a missing word here? > fault may not have a hva associated, checking gfn(gpa) makes more sense. > > For existing hva based shared memory, gfn is expected to also work. The > only downside is when aliasing multiple gfns to a single hva, the > current algorithm of checking multiple ranges could result in a much > larger range being rejected. Such aliasing should be uncommon, so the > impact is expected small. > > Suggested-by: Sean Christopherson <seanjc@google.com> > Cc: Xu Yilun <yilun.xu@intel.com> > Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com> > Reviewed-by: Fuad Tabba <tabba@google.com> > Tested-by: Fuad Tabba <tabba@google.com> > [sean: convert vmx_set_apic_access_page_addr() to gfn-based API] > Signed-off-by: Sean Christopherson <seanjc@google.com> > --- > arch/x86/kvm/mmu/mmu.c | 10 ++++++---- > arch/x86/kvm/vmx/vmx.c | 11 +++++------ > include/linux/kvm_host.h | 33 ++++++++++++++++++++------------ > virt/kvm/kvm_main.c | 41 +++++++++++++++++++++++++++++++--------- > 4 files changed, 64 insertions(+), 31 deletions(-) > > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > index f7901cb4d2fa..d33657d61d80 100644 > --- a/arch/x86/kvm/mmu/mmu.c > +++ b/arch/x86/kvm/mmu/mmu.c > @@ -3056,7 +3056,7 @@ static void direct_pte_prefetch(struct kvm_vcpu *vcpu, u64 *sptep) > * > * There are several ways to safely use this helper: > * > - * - Check mmu_invalidate_retry_hva() after grabbing the mapping level, before > + * - Check mmu_invalidate_retry_gfn() after grabbing the mapping level, before > * consuming it. In this case, mmu_lock doesn't need to be held during the > * lookup, but it does need to be held while checking the MMU notifier. > * > @@ -4358,7 +4358,7 @@ static bool is_page_fault_stale(struct kvm_vcpu *vcpu, > return true; > > return fault->slot && > - mmu_invalidate_retry_hva(vcpu->kvm, fault->mmu_seq, fault->hva); > + mmu_invalidate_retry_gfn(vcpu->kvm, fault->mmu_seq, fault->gfn); > } > > static int direct_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault) > @@ -6245,7 +6245,9 @@ void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end) > > write_lock(&kvm->mmu_lock); > > - kvm_mmu_invalidate_begin(kvm, 0, -1ul); > + kvm_mmu_invalidate_begin(kvm); > + > + kvm_mmu_invalidate_range_add(kvm, gfn_start, gfn_end); > > flush = kvm_rmap_zap_gfn_range(kvm, gfn_start, gfn_end); > > @@ -6255,7 +6257,7 @@ void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end) > if (flush) > kvm_flush_remote_tlbs_range(kvm, gfn_start, gfn_end - gfn_start); > > - kvm_mmu_invalidate_end(kvm, 0, -1ul); > + kvm_mmu_invalidate_end(kvm); > > write_unlock(&kvm->mmu_lock); > } > diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c > index 72e3943f3693..6e502ba93141 100644 > --- a/arch/x86/kvm/vmx/vmx.c > +++ b/arch/x86/kvm/vmx/vmx.c > @@ -6757,10 +6757,10 @@ static void vmx_set_apic_access_page_addr(struct kvm_vcpu *vcpu) > return; > > /* > - * Grab the memslot so that the hva lookup for the mmu_notifier retry > - * is guaranteed to use the same memslot as the pfn lookup, i.e. rely > - * on the pfn lookup's validation of the memslot to ensure a valid hva > - * is used for the retry check. > + * Explicitly grab the memslot using KVM's internal slot ID to ensure > + * KVM doesn't unintentionally grab a userspace memslot. It _should_ > + * be impossible for userspace to create a memslot for the APIC when > + * APICv is enabled, but paranoia won't hurt in this case. > */ > slot = id_to_memslot(slots, APIC_ACCESS_PAGE_PRIVATE_MEMSLOT); > if (!slot || slot->flags & KVM_MEMSLOT_INVALID) > @@ -6785,8 +6785,7 @@ static void vmx_set_apic_access_page_addr(struct kvm_vcpu *vcpu) > return; > > read_lock(&vcpu->kvm->mmu_lock); > - if (mmu_invalidate_retry_hva(kvm, mmu_seq, > - gfn_to_hva_memslot(slot, gfn))) { > + if (mmu_invalidate_retry_gfn(kvm, mmu_seq, gfn)) { > kvm_make_request(KVM_REQ_APIC_PAGE_RELOAD, vcpu); > read_unlock(&vcpu->kvm->mmu_lock); > goto out; > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index fb6c6109fdca..11d091688346 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -787,8 +787,8 @@ struct kvm { > struct mmu_notifier mmu_notifier; > unsigned long mmu_invalidate_seq; > long mmu_invalidate_in_progress; > - unsigned long mmu_invalidate_range_start; > - unsigned long mmu_invalidate_range_end; > + gfn_t mmu_invalidate_range_start; > + gfn_t mmu_invalidate_range_end; > #endif > struct list_head devices; > u64 manual_dirty_log_protect; > @@ -1392,10 +1392,9 @@ 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_mmu_invalidate_begin(struct kvm *kvm, unsigned long start, > - unsigned long end); > -void kvm_mmu_invalidate_end(struct kvm *kvm, unsigned long start, > - unsigned long end); > +void kvm_mmu_invalidate_begin(struct kvm *kvm); > +void kvm_mmu_invalidate_range_add(struct kvm *kvm, gfn_t start, gfn_t end); What is the reason to separate range_add() from begin()? > +void kvm_mmu_invalidate_end(struct kvm *kvm); > > long kvm_arch_dev_ioctl(struct file *filp, > unsigned int ioctl, unsigned long arg); > @@ -1970,9 +1969,9 @@ static inline int mmu_invalidate_retry(struct kvm *kvm, unsigned long mmu_seq) > return 0; > } > > -static inline int mmu_invalidate_retry_hva(struct kvm *kvm, > +static inline int mmu_invalidate_retry_gfn(struct kvm *kvm, > unsigned long mmu_seq, > - unsigned long hva) > + gfn_t gfn) > { > lockdep_assert_held(&kvm->mmu_lock); > /* > @@ -1981,10 +1980,20 @@ static inline int mmu_invalidate_retry_hva(struct kvm *kvm, > * that might be being invalidated. Note that it may include some false > * positives, due to shortcuts when handing concurrent invalidations. > */ > - if (unlikely(kvm->mmu_invalidate_in_progress) && > - hva >= kvm->mmu_invalidate_range_start && > - hva < kvm->mmu_invalidate_range_end) > - return 1; > + if (unlikely(kvm->mmu_invalidate_in_progress)) { > + /* > + * Dropping mmu_lock after bumping mmu_invalidate_in_progress > + * but before updating the range is a KVM bug. > + */ > + if (WARN_ON_ONCE(kvm->mmu_invalidate_range_start == INVALID_GPA || > + kvm->mmu_invalidate_range_end == INVALID_GPA)) > + return 1; > + > + if (gfn >= kvm->mmu_invalidate_range_start && > + gfn < kvm->mmu_invalidate_range_end) > + return 1; > + } > + > if (kvm->mmu_invalidate_seq != mmu_seq) > return 1; > return 0; > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index 5a97e6c7d9c2..1a577a25de47 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -543,9 +543,7 @@ static inline struct kvm *mmu_notifier_to_kvm(struct mmu_notifier *mn) > > typedef bool (*gfn_handler_t)(struct kvm *kvm, struct kvm_gfn_range *range); > > -typedef void (*on_lock_fn_t)(struct kvm *kvm, unsigned long start, > - unsigned long end); > - > +typedef void (*on_lock_fn_t)(struct kvm *kvm); > typedef void (*on_unlock_fn_t)(struct kvm *kvm); > > struct kvm_mmu_notifier_range { > @@ -637,7 +635,8 @@ static __always_inline int __kvm_handle_hva_range(struct kvm *kvm, > locked = true; > KVM_MMU_LOCK(kvm); > if (!IS_KVM_NULL_FN(range->on_lock)) > - range->on_lock(kvm, range->start, range->end); > + range->on_lock(kvm); > + > if (IS_KVM_NULL_FN(range->handler)) > break; > } > @@ -742,16 +741,29 @@ static void kvm_mmu_notifier_change_pte(struct mmu_notifier *mn, > kvm_handle_hva_range(mn, address, address + 1, arg, kvm_change_spte_gfn); > } > > -void kvm_mmu_invalidate_begin(struct kvm *kvm, unsigned long start, > - unsigned long end) > +void kvm_mmu_invalidate_begin(struct kvm *kvm) > { > + lockdep_assert_held_write(&kvm->mmu_lock); > /* > * The count increase must become visible at unlock time as no > * spte can be established without taking the mmu_lock and > * count is also read inside the mmu_lock critical section. > */ > kvm->mmu_invalidate_in_progress++; > + > if (likely(kvm->mmu_invalidate_in_progress == 1)) { > + kvm->mmu_invalidate_range_start = INVALID_GPA; > + kvm->mmu_invalidate_range_end = INVALID_GPA; I don't think this is incorrect, but I was a little suprised to see this here rather than in end() when mmu_invalidate_in_progress decrements to 0. > + } > +} > + > +void kvm_mmu_invalidate_range_add(struct kvm *kvm, gfn_t start, gfn_t end) > +{ > + lockdep_assert_held_write(&kvm->mmu_lock); Does this compile/function on KVM architectures with !KVM_HAVE_MMU_RWLOCK? I assumed we would get an email from the buildbot if it didn't compile but I don't know if buildbot builds with lockdep enabled. On this topic, I wonder if we should just bit the bullet and convert all architectures to a rwlock_t. > + > + WARN_ON_ONCE(!kvm->mmu_invalidate_in_progress); > + > + if (likely(kvm->mmu_invalidate_range_start == INVALID_GPA)) { > kvm->mmu_invalidate_range_start = start; > kvm->mmu_invalidate_range_end = end; > } else { > @@ -771,6 +783,12 @@ void kvm_mmu_invalidate_begin(struct kvm *kvm, unsigned long start, > } > } > > +static bool kvm_mmu_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range) > +{ > + kvm_mmu_invalidate_range_add(kvm, range->start, range->end); > + return kvm_unmap_gfn_range(kvm, range); > +} > + > static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn, > const struct mmu_notifier_range *range) > { > @@ -778,7 +796,7 @@ static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn, > const struct kvm_mmu_notifier_range hva_range = { > .start = range->start, > .end = range->end, > - .handler = kvm_unmap_gfn_range, > + .handler = kvm_mmu_unmap_gfn_range, > .on_lock = kvm_mmu_invalidate_begin, > .on_unlock = kvm_arch_guest_memory_reclaimed, > .flush_on_ret = true, > @@ -817,8 +835,7 @@ static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn, > return 0; > } > > -void kvm_mmu_invalidate_end(struct kvm *kvm, unsigned long start, > - unsigned long end) > +void kvm_mmu_invalidate_end(struct kvm *kvm) > { > /* > * This sequence increase will notify the kvm page fault that > @@ -834,6 +851,12 @@ void kvm_mmu_invalidate_end(struct kvm *kvm, unsigned long start, Let's add a lockdep_assert_held_write(&kvm->mmu_lock) here too while we're at it? > */ > kvm->mmu_invalidate_in_progress--; > KVM_BUG_ON(kvm->mmu_invalidate_in_progress < 0, kvm); > + > + /* > + * Assert that at least one range was added between start() and end(). > + * Not adding a range isn't fatal, but it is a KVM bug. > + */ > + WARN_ON_ONCE(kvm->mmu_invalidate_range_start == INVALID_GPA); > } > > static void kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn, > -- > 2.42.0.820.g83a721a137-goog >
On Mon, Oct 30, 2023 at 5:53 PM David Matlack <dmatlack@google.com> wrote: > > On 2023-10-27 11:21 AM, Sean Christopherson wrote: > > From: Chao Peng <chao.p.peng@linux.intel.com> > > > > Currently in mmu_notifier invalidate path, hva range is recorded and > > then checked against by mmu_notifier_retry_hva() in the page fault > > handling path. However, for the to be introduced private memory, a page > ^^^^^^^^^^^^^^^^^^^^^^^^ > > Is there a missing word here? No but there could be missing hyphens ("for the to-be-introduced private memory"); possibly a "soon" could help parsing and that is what you were talking about? > > if (likely(kvm->mmu_invalidate_in_progress == 1)) { > > + kvm->mmu_invalidate_range_start = INVALID_GPA; > > + kvm->mmu_invalidate_range_end = INVALID_GPA; > > I don't think this is incorrect, but I was a little suprised to see this > here rather than in end() when mmu_invalidate_in_progress decrements to > 0. I think that would be incorrect on the very first start? > > + } > > +} > > + > > +void kvm_mmu_invalidate_range_add(struct kvm *kvm, gfn_t start, gfn_t end) > > +{ > > + lockdep_assert_held_write(&kvm->mmu_lock); > > Does this compile/function on KVM architectures with > !KVM_HAVE_MMU_RWLOCK? Yes: #define lockdep_assert_held_write(l) \ lockdep_assert(lockdep_is_held_type(l, 0)) where 0 is the lock-held type used by lock_acquire_exclusive. In turn is what you get for a spinlock or mutex, in addition to a rwlock or rwsem that is taken for write. Instead, lockdep_assert_held() asserts that the lock is taken without asserting a particular lock-held type. > > @@ -834,6 +851,12 @@ void kvm_mmu_invalidate_end(struct kvm *kvm, unsigned long start, > > Let's add a lockdep_assert_held_write(&kvm->mmu_lock) here too while > we're at it? Yes, good idea. Paolo
On Mon, Oct 30, 2023 at 9:53 AM David Matlack <dmatlack@google.com> wrote: > > On 2023-10-27 11:21 AM, Sean Christopherson wrote: > > From: Chao Peng <chao.p.peng@linux.intel.com> > > > > +void kvm_mmu_invalidate_range_add(struct kvm *kvm, gfn_t start, gfn_t end); > > What is the reason to separate range_add() from begin()? Nevermind, I see how it's needed in kvm_mmu_unmap_gfn_range().
On Mon, Oct 30, 2023 at 10:01 AM Paolo Bonzini <pbonzini@redhat.com> wrote: > > On Mon, Oct 30, 2023 at 5:53 PM David Matlack <dmatlack@google.com> wrote: > > > > On 2023-10-27 11:21 AM, Sean Christopherson wrote: > > > From: Chao Peng <chao.p.peng@linux.intel.com> > > > > > > Currently in mmu_notifier invalidate path, hva range is recorded and > > > then checked against by mmu_notifier_retry_hva() in the page fault > > > handling path. However, for the to be introduced private memory, a page > > ^^^^^^^^^^^^^^^^^^^^^^^^ > > > > Is there a missing word here? > > No but there could be missing hyphens ("for the to-be-introduced > private memory"); possibly a "soon" could help parsing and that is > what you were talking about? Ah that explains it :) > > > > if (likely(kvm->mmu_invalidate_in_progress == 1)) { > > > + kvm->mmu_invalidate_range_start = INVALID_GPA; > > > + kvm->mmu_invalidate_range_end = INVALID_GPA; > > > > I don't think this is incorrect, but I was a little suprised to see this > > here rather than in end() when mmu_invalidate_in_progress decrements to > > 0. > > I think that would be incorrect on the very first start? Good point. KVM could initialize start/end before registering notifiers, but that's extra code.
On Fri, Oct 27, 2023 at 11:21:45AM -0700, Sean Christopherson wrote: > From: Chao Peng <chao.p.peng@linux.intel.com> > > Currently in mmu_notifier invalidate path, hva range is recorded and > then checked against by mmu_notifier_retry_hva() in the page fault ^ should be mmu_invalidate_retry_hva(). Besides this, Reviewed-by: Xu Yilun <yilun.xu@linux.intel.com> Thanks
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index f7901cb4d2fa..d33657d61d80 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -3056,7 +3056,7 @@ static void direct_pte_prefetch(struct kvm_vcpu *vcpu, u64 *sptep) * * There are several ways to safely use this helper: * - * - Check mmu_invalidate_retry_hva() after grabbing the mapping level, before + * - Check mmu_invalidate_retry_gfn() after grabbing the mapping level, before * consuming it. In this case, mmu_lock doesn't need to be held during the * lookup, but it does need to be held while checking the MMU notifier. * @@ -4358,7 +4358,7 @@ static bool is_page_fault_stale(struct kvm_vcpu *vcpu, return true; return fault->slot && - mmu_invalidate_retry_hva(vcpu->kvm, fault->mmu_seq, fault->hva); + mmu_invalidate_retry_gfn(vcpu->kvm, fault->mmu_seq, fault->gfn); } static int direct_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault) @@ -6245,7 +6245,9 @@ void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end) write_lock(&kvm->mmu_lock); - kvm_mmu_invalidate_begin(kvm, 0, -1ul); + kvm_mmu_invalidate_begin(kvm); + + kvm_mmu_invalidate_range_add(kvm, gfn_start, gfn_end); flush = kvm_rmap_zap_gfn_range(kvm, gfn_start, gfn_end); @@ -6255,7 +6257,7 @@ void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end) if (flush) kvm_flush_remote_tlbs_range(kvm, gfn_start, gfn_end - gfn_start); - kvm_mmu_invalidate_end(kvm, 0, -1ul); + kvm_mmu_invalidate_end(kvm); write_unlock(&kvm->mmu_lock); } diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 72e3943f3693..6e502ba93141 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -6757,10 +6757,10 @@ static void vmx_set_apic_access_page_addr(struct kvm_vcpu *vcpu) return; /* - * Grab the memslot so that the hva lookup for the mmu_notifier retry - * is guaranteed to use the same memslot as the pfn lookup, i.e. rely - * on the pfn lookup's validation of the memslot to ensure a valid hva - * is used for the retry check. + * Explicitly grab the memslot using KVM's internal slot ID to ensure + * KVM doesn't unintentionally grab a userspace memslot. It _should_ + * be impossible for userspace to create a memslot for the APIC when + * APICv is enabled, but paranoia won't hurt in this case. */ slot = id_to_memslot(slots, APIC_ACCESS_PAGE_PRIVATE_MEMSLOT); if (!slot || slot->flags & KVM_MEMSLOT_INVALID) @@ -6785,8 +6785,7 @@ static void vmx_set_apic_access_page_addr(struct kvm_vcpu *vcpu) return; read_lock(&vcpu->kvm->mmu_lock); - if (mmu_invalidate_retry_hva(kvm, mmu_seq, - gfn_to_hva_memslot(slot, gfn))) { + if (mmu_invalidate_retry_gfn(kvm, mmu_seq, gfn)) { kvm_make_request(KVM_REQ_APIC_PAGE_RELOAD, vcpu); read_unlock(&vcpu->kvm->mmu_lock); goto out; diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index fb6c6109fdca..11d091688346 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -787,8 +787,8 @@ struct kvm { struct mmu_notifier mmu_notifier; unsigned long mmu_invalidate_seq; long mmu_invalidate_in_progress; - unsigned long mmu_invalidate_range_start; - unsigned long mmu_invalidate_range_end; + gfn_t mmu_invalidate_range_start; + gfn_t mmu_invalidate_range_end; #endif struct list_head devices; u64 manual_dirty_log_protect; @@ -1392,10 +1392,9 @@ 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_mmu_invalidate_begin(struct kvm *kvm, unsigned long start, - unsigned long end); -void kvm_mmu_invalidate_end(struct kvm *kvm, unsigned long start, - unsigned long end); +void kvm_mmu_invalidate_begin(struct kvm *kvm); +void kvm_mmu_invalidate_range_add(struct kvm *kvm, gfn_t start, gfn_t end); +void kvm_mmu_invalidate_end(struct kvm *kvm); long kvm_arch_dev_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg); @@ -1970,9 +1969,9 @@ static inline int mmu_invalidate_retry(struct kvm *kvm, unsigned long mmu_seq) return 0; } -static inline int mmu_invalidate_retry_hva(struct kvm *kvm, +static inline int mmu_invalidate_retry_gfn(struct kvm *kvm, unsigned long mmu_seq, - unsigned long hva) + gfn_t gfn) { lockdep_assert_held(&kvm->mmu_lock); /* @@ -1981,10 +1980,20 @@ static inline int mmu_invalidate_retry_hva(struct kvm *kvm, * that might be being invalidated. Note that it may include some false * positives, due to shortcuts when handing concurrent invalidations. */ - if (unlikely(kvm->mmu_invalidate_in_progress) && - hva >= kvm->mmu_invalidate_range_start && - hva < kvm->mmu_invalidate_range_end) - return 1; + if (unlikely(kvm->mmu_invalidate_in_progress)) { + /* + * Dropping mmu_lock after bumping mmu_invalidate_in_progress + * but before updating the range is a KVM bug. + */ + if (WARN_ON_ONCE(kvm->mmu_invalidate_range_start == INVALID_GPA || + kvm->mmu_invalidate_range_end == INVALID_GPA)) + return 1; + + if (gfn >= kvm->mmu_invalidate_range_start && + gfn < kvm->mmu_invalidate_range_end) + return 1; + } + if (kvm->mmu_invalidate_seq != mmu_seq) return 1; return 0; diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 5a97e6c7d9c2..1a577a25de47 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -543,9 +543,7 @@ static inline struct kvm *mmu_notifier_to_kvm(struct mmu_notifier *mn) typedef bool (*gfn_handler_t)(struct kvm *kvm, struct kvm_gfn_range *range); -typedef void (*on_lock_fn_t)(struct kvm *kvm, unsigned long start, - unsigned long end); - +typedef void (*on_lock_fn_t)(struct kvm *kvm); typedef void (*on_unlock_fn_t)(struct kvm *kvm); struct kvm_mmu_notifier_range { @@ -637,7 +635,8 @@ static __always_inline int __kvm_handle_hva_range(struct kvm *kvm, locked = true; KVM_MMU_LOCK(kvm); if (!IS_KVM_NULL_FN(range->on_lock)) - range->on_lock(kvm, range->start, range->end); + range->on_lock(kvm); + if (IS_KVM_NULL_FN(range->handler)) break; } @@ -742,16 +741,29 @@ static void kvm_mmu_notifier_change_pte(struct mmu_notifier *mn, kvm_handle_hva_range(mn, address, address + 1, arg, kvm_change_spte_gfn); } -void kvm_mmu_invalidate_begin(struct kvm *kvm, unsigned long start, - unsigned long end) +void kvm_mmu_invalidate_begin(struct kvm *kvm) { + lockdep_assert_held_write(&kvm->mmu_lock); /* * The count increase must become visible at unlock time as no * spte can be established without taking the mmu_lock and * count is also read inside the mmu_lock critical section. */ kvm->mmu_invalidate_in_progress++; + if (likely(kvm->mmu_invalidate_in_progress == 1)) { + kvm->mmu_invalidate_range_start = INVALID_GPA; + kvm->mmu_invalidate_range_end = INVALID_GPA; + } +} + +void kvm_mmu_invalidate_range_add(struct kvm *kvm, gfn_t start, gfn_t end) +{ + lockdep_assert_held_write(&kvm->mmu_lock); + + WARN_ON_ONCE(!kvm->mmu_invalidate_in_progress); + + if (likely(kvm->mmu_invalidate_range_start == INVALID_GPA)) { kvm->mmu_invalidate_range_start = start; kvm->mmu_invalidate_range_end = end; } else { @@ -771,6 +783,12 @@ void kvm_mmu_invalidate_begin(struct kvm *kvm, unsigned long start, } } +static bool kvm_mmu_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range) +{ + kvm_mmu_invalidate_range_add(kvm, range->start, range->end); + return kvm_unmap_gfn_range(kvm, range); +} + static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn, const struct mmu_notifier_range *range) { @@ -778,7 +796,7 @@ static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn, const struct kvm_mmu_notifier_range hva_range = { .start = range->start, .end = range->end, - .handler = kvm_unmap_gfn_range, + .handler = kvm_mmu_unmap_gfn_range, .on_lock = kvm_mmu_invalidate_begin, .on_unlock = kvm_arch_guest_memory_reclaimed, .flush_on_ret = true, @@ -817,8 +835,7 @@ static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn, return 0; } -void kvm_mmu_invalidate_end(struct kvm *kvm, unsigned long start, - unsigned long end) +void kvm_mmu_invalidate_end(struct kvm *kvm) { /* * This sequence increase will notify the kvm page fault that @@ -834,6 +851,12 @@ void kvm_mmu_invalidate_end(struct kvm *kvm, unsigned long start, */ kvm->mmu_invalidate_in_progress--; KVM_BUG_ON(kvm->mmu_invalidate_in_progress < 0, kvm); + + /* + * Assert that at least one range was added between start() and end(). + * Not adding a range isn't fatal, but it is a KVM bug. + */ + WARN_ON_ONCE(kvm->mmu_invalidate_range_start == INVALID_GPA); } static void kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn,