From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f74.google.com (mail-wm1-f74.google.com [209.85.128.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 43A051DA11B for ; Fri, 28 Mar 2025 15:31:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.74 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743175909; cv=none; b=l9bJfTid2hE6bPWPiFeANyRsM3pf40WBzpPDWI1+cL45/0kkzYYcE6Vn/vzwBMgfrEtqYB2uRP1re+FsJ15sxtd3NWNsc1zX/DXxw48JYRkSH/X/ZgmCgFg7u8lKgLj1g2w6GeJKe1+IWDIuBp8ByMN3yco5EUKQsC+oush7u/M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743175909; c=relaxed/simple; bh=ywIBAiOIC5j43YjmiU9xRCcK2knCGG5rRQ+rKgEbt1M=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=cc5XvyfFKisZWGfOcy2ixeS68GTfwBO8H88xGD7LhefmJmLVCQXBOfs2Q/xdH5lQbMiDX+zF8yqQzSexQNVpa9jGLRaE80xtl5qY+XrmGYJplyo9fgsCGvwMvo+dfnVl+r4ZNSq74hHaoGuzfouEXSKsguuwtX2u5JYYQhUbTpM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--tabba.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=FL12P20F; arc=none smtp.client-ip=209.85.128.74 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--tabba.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="FL12P20F" Received: by mail-wm1-f74.google.com with SMTP id 5b1f17b1804b1-43ce8f82e66so14195625e9.3 for ; Fri, 28 Mar 2025 08:31:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1743175907; x=1743780707; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=R3RfnojiUTVQNcoqz4Ca2o/3ssUHr85YnTpv1JDxiLk=; b=FL12P20F7u8xMJE7WrwcNxU9Z8rGvw4Yqdre3DgDqWwXXApSqQEsW+Ry5YSzqoEgOw lk5mqm5i/vwzJPG3Qqw/BkmvJZQIXu7KMbgm6DPkF6+sVFkZh/QkF3OgMWy2NjXEAaTc lx7QWxaptoaAraNat7foWWC6YFKLb8QLMBivdQBo5qNi8iKO5wT8EuXuxxYbS/nbV7Ad 744Ovc/urM3yRLTpsR60FK/gKR4v/9HJqJkVtDvfeZuqCqDwY/kS/qZtIlKjI7G+zazx uiW+vjEkZmVhmo8WHq9M1dqjrHf6avT4m3Y8xJlZ1tOJEjOiXYsg7Grgd38BjvDmB+Pl zl5w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1743175907; x=1743780707; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=R3RfnojiUTVQNcoqz4Ca2o/3ssUHr85YnTpv1JDxiLk=; b=hvCFaImGo8uBgfs6KANbbu39YbeMpWbHigI9Cu6HoY1JulQC+Rpi9u0lNr9Cx2xRjJ UvnilufWZEC/E1xNue9JOl/IbQMeihT6LDxNXx0UwnfhnhDafElusFCQkCowsytg38Ep 1+Fv8Qag1Ng8ZKsmF4njx0Gy5D9+QWfo9oOBbBmuQaqa78/Gf/sWo8tCofzdMhUefOZZ avlqGT/Fo03ghoMLOn3/+UHwbEtfHjUWfUEoqoOK5q+0v21eF7XLuGfp14LQuk94jPEQ 1ryq9slJuWZnbixRKXyGMLd72Tb1+yQdf9oI/NMsGotNLMKVnt3kCzRs2j+/JWFEkV5i 28Uw== X-Gm-Message-State: AOJu0YwU2SMc3byrDbAOFO5XiKW0A+OHXgNA2iK5krNt3Xh84/G+N2RI IJcHJoyMIRRdaaZnOIFRuDxmSs6SLlaxncXeS1iYLtN5g7abRzew9mHXOc3ylxy0g3kzYCs/gtE v4V/bSxZZm8wUpYFoAc+zvfN+Nd2gwi7aDzEueMi+63dZQXEVwd6/5qs+iADGfzezTlzt494uvw CZOz6uf/AqcP299D2oauqYrf0= 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> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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 Content-Type: text/plain; charset="UTF-8" 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 -- 2.49.0.472.ge94155a9ec-goog