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AJvYcCV+Ub6hoWqdj3QeXcmJLrbWib/B+SklKge78hgtkEF8TAdQentcjhh6SoBHOsAyG/Dui7p6ogXsvg==@kvack.org X-Gm-Message-State: AOJu0YwyyWuf7IR2iTtJdBcY8ci9QQFGYWQiN5oFCSlMs/6UF9WOKTYS 5Y+h63l7P2XPp1ll+a+T079NhNAIddH3xbjfTGqc45ijT68JhREmerboXBCBAWjF5aXlA05WJg= = X-Google-Smtp-Source: AGHT+IH5o8XkmQE16RpA7JAnMr7kPBXwGpQkyy1fEQJArMIbsDhiWMuAir53k+JzjSmedSowM4jfKUSd+w== X-Received: from wmbay1.prod.google.com ([2002:a05:600c:1e01:b0:43d:9f1:31a9]) (user=tabba job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:4e52:b0:43c:fc04:6d34 with SMTP id 5b1f17b1804b1-43d9489777emr25843765e9.20.1743175906450; Fri, 28 Mar 2025 08:31:46 -0700 (PDT) Date: Fri, 28 Mar 2025 15:31:32 +0000 In-Reply-To: <20250328153133.3504118-1-tabba@google.com> Mime-Version: 1.0 References: <20250328153133.3504118-1-tabba@google.com> X-Mailer: git-send-email 2.49.0.472.ge94155a9ec-goog Message-ID: <20250328153133.3504118-7-tabba@google.com> Subject: [PATCH v7 6/7] KVM: guest_memfd: Handle invalidation of shared memory From: Fuad Tabba To: kvm@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-mm@kvack.org Cc: pbonzini@redhat.com, chenhuacai@kernel.org, mpe@ellerman.id.au, anup@brainfault.org, paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, seanjc@google.com, viro@zeniv.linux.org.uk, brauner@kernel.org, willy@infradead.org, akpm@linux-foundation.org, xiaoyao.li@intel.com, yilun.xu@intel.com, chao.p.peng@linux.intel.com, jarkko@kernel.org, amoorthy@google.com, dmatlack@google.com, isaku.yamahata@intel.com, mic@digikod.net, vbabka@suse.cz, vannapurve@google.com, ackerleytng@google.com, mail@maciej.szmigiero.name, david@redhat.com, michael.roth@amd.com, wei.w.wang@intel.com, liam.merwick@oracle.com, isaku.yamahata@gmail.com, kirill.shutemov@linux.intel.com, suzuki.poulose@arm.com, steven.price@arm.com, quic_eberman@quicinc.com, quic_mnalajal@quicinc.com, quic_tsoni@quicinc.com, quic_svaddagi@quicinc.com, quic_cvanscha@quicinc.com, quic_pderrin@quicinc.com, quic_pheragu@quicinc.com, catalin.marinas@arm.com, james.morse@arm.com, yuzenghui@huawei.com, oliver.upton@linux.dev, maz@kernel.org, will@kernel.org, qperret@google.com, keirf@google.com, roypat@amazon.co.uk, shuah@kernel.org, hch@infradead.org, jgg@nvidia.com, rientjes@google.com, jhubbard@nvidia.com, fvdl@google.com, hughd@google.com, jthoughton@google.com, peterx@redhat.com, pankaj.gupta@amd.com, tabba@google.com X-Stat-Signature: zh9brcyjwjmiu8jm5wktyyd7s9h1nwuy X-Rspam-User: X-Rspamd-Queue-Id: 0E0C4180008 X-Rspamd-Server: rspam08 X-HE-Tag: 1743175907-216675 X-HE-Meta: U2FsdGVkX1/QZpNS1LD1xDPeaY2SFxaEJsw+KZbrpx1qJ/7M/R978wL2KfohSVOX13PjwMLVKX7iqkfPkz8DhrWgvBgfFIhj8N+mky/Bl3JmOzRU3aCX5wRw8M8PsnZdc3e9n68oEmkv2N8WC3OkMvUAk5lGqiV2w3TJYveD7roKC2g2FDuvWcHhLRa6u9WPBRhrRuGLyJ15tqwyyfIPDTYgXQBEaqsdnKr+/fUFdzaMSIQD4dhYbmKEciqS3bLrXcfFG+XTj5Dp6zmDC09taLIs4MisO2sZNeJYjOpVh5eob85rWkmvlFUdg4oxrw3lKNho1jE6bH+xQz19p/ZqFLg55CLGhSsHSOuKD1QXIJ3yFKIY9dc3/EhToWPngODVqfB086SVjoib7eaAuyvoYbV45sVFKIv5bVbZPbe1nL9JgXcs2DgUCy77d/kzH0vyVTj6a+L6decblQnnomruiFuLgoJdsIwfzzr32J/apBRKME1sk3XpwpkZXKGiwKKXjKF+LzQ9YdvcGR1g7jfXEMCFNKL9yuJDzcK+pe3npZtWlIZ6Ut5ZDNGBQnGEn64gJNUrMqwz+NgRCWt9xt4v2JbvcP8oddJOkl1hYO+eO1fk2TQRU+Cg0wegQsjZozRmhlRBMxppfvur6Fd/RgfVco1H9JaihAEWWsWkxg2IwdaCQ2Gjfq/XhSB6rNgVbS/TNWbw6hESaaOJek84PM4/LVFC/sATE1QiJzshEoGCPnuvhWpKLL1tfvmKalGk0YqVzmT2aAGUIcovoOazeop7P1frTD3xsoUQmjkwEuj3peX3l9g1dZNVAUkNy+zzlpHzHqAXZBJLsNAVTNd85pl6ERkYiCOi2CsfJTcRiEDD4V4I7eYP133TrUDXedsgX1WebvAr1W3Ka9ThLvOOlkjLQKalucGnJClOti5K9LqupIH3YD6RKHFqSBDNwws+D9AmrdNgl00WKTmaSDInV37 v0Q6hbA5 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: When guest_memfd backed memory is invalidated, e.g., on punching holes, releasing, ensure that the sharing states are updated and that any folios in a transient state are restored to an appropriate state. Signed-off-by: Fuad Tabba --- virt/kvm/guest_memfd.c | 57 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c index ce19bd6c2031..eec9d5e09f09 100644 --- a/virt/kvm/guest_memfd.c +++ b/virt/kvm/guest_memfd.c @@ -118,6 +118,16 @@ static struct folio *kvm_gmem_get_folio(struct inode *inode, pgoff_t index) return filemap_grab_folio(inode->i_mapping, index); } +#ifdef CONFIG_KVM_GMEM_SHARED_MEM +static void kvm_gmem_offset_range_invalidate_shared(struct inode *inode, + pgoff_t start, pgoff_t end); +#else +static inline void kvm_gmem_offset_range_invalidate_shared(struct inode *inode, + pgoff_t start, pgoff_t end) +{ +} +#endif + static void kvm_gmem_invalidate_begin(struct kvm_gmem *gmem, pgoff_t start, pgoff_t end) { @@ -127,6 +137,7 @@ static void kvm_gmem_invalidate_begin(struct kvm_gmem *gmem, pgoff_t start, unsigned long index; xa_for_each_range(&gmem->bindings, index, slot, start, end - 1) { + struct file *file = READ_ONCE(slot->gmem.file); pgoff_t pgoff = slot->gmem.pgoff; struct kvm_gfn_range gfn_range = { @@ -146,6 +157,16 @@ static void kvm_gmem_invalidate_begin(struct kvm_gmem *gmem, pgoff_t start, } flush |= kvm_mmu_unmap_gfn_range(kvm, &gfn_range); + + /* + * If this gets called after kvm_gmem_unbind() it means that all + * in-flight operations are gone, and the file has been closed. + */ + if (file) { + kvm_gmem_offset_range_invalidate_shared(file_inode(file), + gfn_range.start, + gfn_range.end); + } } if (flush) @@ -512,6 +533,42 @@ static int kvm_gmem_offset_clear_shared(struct inode *inode, pgoff_t index) return r; } +/* + * Callback when invalidating memory that is potentially shared. + * + * Must be called with the offsets_lock write lock held. + */ +static void kvm_gmem_offset_range_invalidate_shared(struct inode *inode, + pgoff_t start, pgoff_t end) +{ + struct xarray *shared_offsets = &kvm_gmem_private(inode)->shared_offsets; + rwlock_t *offsets_lock = &kvm_gmem_private(inode)->offsets_lock; + pgoff_t i; + + lockdep_assert_held_write(offsets_lock); + + for (i = start; i < end; i++) { + /* + * If the folio is NONE_SHARED, it indicates that it's + * transitioning to private (GUEST_SHARED). Transition it to + * shared (ALL_SHARED) and remove the callback. + */ + if (xa_to_value(xa_load(shared_offsets, i)) == KVM_GMEM_NONE_SHARED) { + struct folio *folio = filemap_lock_folio(inode->i_mapping, i); + + if (!WARN_ON_ONCE(IS_ERR(folio))) { + if (folio_test_guestmem(folio)) + kvm_gmem_restore_pending_folio(folio, inode); + + folio_unlock(folio); + folio_put(folio); + } + } + + xa_erase(shared_offsets, i); + } +} + /* * Marks the range [start, end) as not shared with the host. If the host doesn't * have any references to a particular folio, then that folio is marked as