diff options
author | Dave Airlie <airlied@redhat.com> | 2022-11-24 04:05:43 +0300 |
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committer | Dave Airlie <airlied@redhat.com> | 2022-11-24 04:05:43 +0300 |
commit | d47f9580839eb6fe568e38b2084d94887fbf5ce0 (patch) | |
tree | 2493555057f8e5c850590d7438fdbf4472666201 /virt/kvm/pfncache.c | |
parent | 3d335a523b938a445a674be24d1dd5c7a4c86fb6 (diff) | |
parent | eb7081409f94a9a8608593d0fb63a1aa3d6f95d8 (diff) | |
download | linux-d47f9580839eb6fe568e38b2084d94887fbf5ce0.tar.xz |
Backmerge tag 'v6.1-rc6' into drm-next
Linux 6.1-rc6
This is needed for drm-misc-next and tegra.
Signed-off-by: Dave Airlie <airlied@redhat.com>
Diffstat (limited to 'virt/kvm/pfncache.c')
-rw-r--r-- | virt/kvm/pfncache.c | 62 |
1 files changed, 46 insertions, 16 deletions
diff --git a/virt/kvm/pfncache.c b/virt/kvm/pfncache.c index 68ff41d39545..346e47f15572 100644 --- a/virt/kvm/pfncache.c +++ b/virt/kvm/pfncache.c @@ -81,6 +81,9 @@ bool kvm_gfn_to_pfn_cache_check(struct kvm *kvm, struct gfn_to_pfn_cache *gpc, { struct kvm_memslots *slots = kvm_memslots(kvm); + if (!gpc->active) + return false; + if ((gpa & ~PAGE_MASK) + len > PAGE_SIZE) return false; @@ -240,10 +243,11 @@ int kvm_gfn_to_pfn_cache_refresh(struct kvm *kvm, struct gfn_to_pfn_cache *gpc, { struct kvm_memslots *slots = kvm_memslots(kvm); unsigned long page_offset = gpa & ~PAGE_MASK; - kvm_pfn_t old_pfn, new_pfn; + bool unmap_old = false; unsigned long old_uhva; + kvm_pfn_t old_pfn; void *old_khva; - int ret = 0; + int ret; /* * If must fit within a single page. The 'len' argument is @@ -261,6 +265,11 @@ int kvm_gfn_to_pfn_cache_refresh(struct kvm *kvm, struct gfn_to_pfn_cache *gpc, write_lock_irq(&gpc->lock); + if (!gpc->active) { + ret = -EINVAL; + goto out_unlock; + } + old_pfn = gpc->pfn; old_khva = gpc->khva - offset_in_page(gpc->khva); old_uhva = gpc->uhva; @@ -291,6 +300,7 @@ int kvm_gfn_to_pfn_cache_refresh(struct kvm *kvm, struct gfn_to_pfn_cache *gpc, /* If the HVA→PFN mapping was already valid, don't unmap it. */ old_pfn = KVM_PFN_ERR_FAULT; old_khva = NULL; + ret = 0; } out: @@ -305,14 +315,15 @@ int kvm_gfn_to_pfn_cache_refresh(struct kvm *kvm, struct gfn_to_pfn_cache *gpc, gpc->khva = NULL; } - /* Snapshot the new pfn before dropping the lock! */ - new_pfn = gpc->pfn; + /* Detect a pfn change before dropping the lock! */ + unmap_old = (old_pfn != gpc->pfn); +out_unlock: write_unlock_irq(&gpc->lock); mutex_unlock(&gpc->refresh_lock); - if (old_pfn != new_pfn) + if (unmap_old) gpc_unmap_khva(kvm, old_pfn, old_khva); return ret; @@ -346,42 +357,61 @@ void kvm_gfn_to_pfn_cache_unmap(struct kvm *kvm, struct gfn_to_pfn_cache *gpc) } EXPORT_SYMBOL_GPL(kvm_gfn_to_pfn_cache_unmap); +void kvm_gpc_init(struct gfn_to_pfn_cache *gpc) +{ + rwlock_init(&gpc->lock); + mutex_init(&gpc->refresh_lock); +} +EXPORT_SYMBOL_GPL(kvm_gpc_init); -int kvm_gfn_to_pfn_cache_init(struct kvm *kvm, struct gfn_to_pfn_cache *gpc, - struct kvm_vcpu *vcpu, enum pfn_cache_usage usage, - gpa_t gpa, unsigned long len) +int kvm_gpc_activate(struct kvm *kvm, struct gfn_to_pfn_cache *gpc, + struct kvm_vcpu *vcpu, enum pfn_cache_usage usage, + gpa_t gpa, unsigned long len) { WARN_ON_ONCE(!usage || (usage & KVM_GUEST_AND_HOST_USE_PFN) != usage); if (!gpc->active) { - rwlock_init(&gpc->lock); - mutex_init(&gpc->refresh_lock); - gpc->khva = NULL; gpc->pfn = KVM_PFN_ERR_FAULT; gpc->uhva = KVM_HVA_ERR_BAD; gpc->vcpu = vcpu; gpc->usage = usage; gpc->valid = false; - gpc->active = true; spin_lock(&kvm->gpc_lock); list_add(&gpc->list, &kvm->gpc_list); spin_unlock(&kvm->gpc_lock); + + /* + * Activate the cache after adding it to the list, a concurrent + * refresh must not establish a mapping until the cache is + * reachable by mmu_notifier events. + */ + write_lock_irq(&gpc->lock); + gpc->active = true; + write_unlock_irq(&gpc->lock); } return kvm_gfn_to_pfn_cache_refresh(kvm, gpc, gpa, len); } -EXPORT_SYMBOL_GPL(kvm_gfn_to_pfn_cache_init); +EXPORT_SYMBOL_GPL(kvm_gpc_activate); -void kvm_gfn_to_pfn_cache_destroy(struct kvm *kvm, struct gfn_to_pfn_cache *gpc) +void kvm_gpc_deactivate(struct kvm *kvm, struct gfn_to_pfn_cache *gpc) { if (gpc->active) { + /* + * Deactivate the cache before removing it from the list, KVM + * must stall mmu_notifier events until all users go away, i.e. + * until gpc->lock is dropped and refresh is guaranteed to fail. + */ + write_lock_irq(&gpc->lock); + gpc->active = false; + write_unlock_irq(&gpc->lock); + spin_lock(&kvm->gpc_lock); list_del(&gpc->list); spin_unlock(&kvm->gpc_lock); kvm_gfn_to_pfn_cache_unmap(kvm, gpc); - gpc->active = false; } } -EXPORT_SYMBOL_GPL(kvm_gfn_to_pfn_cache_destroy); +EXPORT_SYMBOL_GPL(kvm_gpc_deactivate); |