From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qt1-f202.google.com (mail-qt1-f202.google.com [209.85.160.202]) (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 578A3202C31 for ; Thu, 9 Jan 2025 20:50:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736455803; cv=none; b=LTb7qyQKk+hbXd+WzhXvF94139u5V1/csgl2Ex+PgVaN6knlvBpW3TCZyHvHYqUyx1ijH61clSpSrZvSNqO/NJQTMoP7u91joavm6klN9vxgNueYl8S3M8eLpFsmLzfUYTz+/RHx4zeyKD9bjJfZxey6vbYpLV2PpMAk1IbwPcA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736455803; c=relaxed/simple; bh=Bf6Z/SdUsbkpIsqoT2JIQQkVc3cDT9ghaIOkviu+ke8=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=fl2OZPB4+BwxL86TVQnjEt48xqC/nM+sEXpIuTF3gI3eXTnzGPNnrkvp8b3gq4EsykxfCfQG6N0+1CZ3ntoIuwYgPy3NiF2CYJwQTQm0dkGKQySe9OXWCWYZElt4XNn+y0Mm4+Y/mxgbrKMY8BNeydiMAHb1JB2iTZbL43WJDUk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--jthoughton.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=GN4iOfLV; arc=none smtp.client-ip=209.85.160.202 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--jthoughton.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="GN4iOfLV" Received: by mail-qt1-f202.google.com with SMTP id d75a77b69052e-467a3c0c8f6so25378991cf.0 for ; Thu, 09 Jan 2025 12:50:01 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1736455800; x=1737060600; darn=lists.linux.dev; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=Ej4vKCsRcXi3JRFU5yXFClNg+jWCgVgQEDR3f6Axo50=; b=GN4iOfLVRAhFu3cP+nqh0K+fNrzC391B6uOCzLSG3UZl3qo6wRbpsjoVQpV2MDC+Vb ZsbVIFr8bbNzQ1TWqms3l1KWa/S4Uw8wOreSZ7dcl6+LGzxlXXOgC/7rAmSA0yEWUTLw JGxqsMVlOyJTas/Qx9KSe7tBGIkE6b0t6rwBLQ8GhyG+NktJZNN3xxdn/vx1n8MXbMxF SaXowM4IiF9SRJlQUalAENU0DjluskiHP08Yg8Os6hlDM5J1B+Q2mHU2GdFFDke5Jgmq F0GlYUd+/5OIPW0ATBRgDz48kNwLodH/UPJ2GitW0Y+h9gfb/bEkMXWO0YZnZppKm2FX XeVQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1736455800; x=1737060600; 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=Ej4vKCsRcXi3JRFU5yXFClNg+jWCgVgQEDR3f6Axo50=; b=o8NNnN3m4lAAYiCi9oEVbMP9XyK2PQNajIdBERZBxRsYGBYiaDGvkvHJK/+2SCvMza pJHtFJsQUK4y1UTm1XajFYydoB36mrLiqN+yCiuvv0Em20EZbUsBis/lj+M6t4fj84qw WjACFoXBYMyIsroM67jnPieGpLOQOnL5QVoEM+YnARn9DMBPeCihwswE3txzJkYHmjv9 xM8c5Kcdbnf2116fm+Vk5uUsjQ6rpJBUOMRYWPjTqkmGBua7/F020lzN7BEm707pQuqK K6hSMtpX48twLJQV5eUPgnKxcFXaLT3a2rGsVFxjMlgmvuUGA39xjd7Zcb6cz2tasZ44 ja3w== X-Forwarded-Encrypted: i=1; AJvYcCV3FVTq7dVSDL2W95w/h7rA5Xj0HVbVVRlZFY7Lkkjp6tkaY0gxKKyJo59OxSCawE3z+qhbGJ4=@lists.linux.dev X-Gm-Message-State: AOJu0YxFYBNJNwxFDKtEqgAVLjUJqEMouLsw2r2zCHIVgy5Nk/s1JlUz 2soisWwsnalMBcFwBxgSJ2EerYFXiZSm5XX8KuCmyzueeXzCz813GtNJtE83v2crn+p5mBI8sfG 1XKu9hVYdr6VY70Wskg== X-Google-Smtp-Source: AGHT+IEjWh1ifMEjbhq2t/4s1LokEzVaJxOMILKR5p4NmJRJSQEQbDzHfJF1YycGc5qCqnm1VGVZZj4bYy7TorUf X-Received: from qtbiw5.prod.google.com ([2002:a05:622a:6f85:b0:466:928b:3b7c]) (user=jthoughton job=prod-delivery.src-stubby-dispatcher) by 2002:a05:622a:14e:b0:467:5926:fcf2 with SMTP id d75a77b69052e-46c7107e0b4mr103936581cf.9.1736455800057; Thu, 09 Jan 2025 12:50:00 -0800 (PST) Date: Thu, 9 Jan 2025 20:49:22 +0000 In-Reply-To: <20250109204929.1106563-1-jthoughton@google.com> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250109204929.1106563-1-jthoughton@google.com> X-Mailer: git-send-email 2.47.1.613.gc27f4b7a9f-goog Message-ID: <20250109204929.1106563-7-jthoughton@google.com> Subject: [PATCH v2 06/13] KVM: arm64: Add support for KVM_MEM_USERFAULT From: James Houghton To: Paolo Bonzini , Sean Christopherson Cc: Jonathan Corbet , Marc Zyngier , Oliver Upton , Yan Zhao , James Houghton , Nikita Kalyazin , Anish Moorthy , Peter Gonda , Peter Xu , David Matlack , wei.w.wang@intel.com, kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev Content-Type: text/plain; charset="UTF-8" Adhering to the requirements of KVM Userfault: 1. When it is toggled on, zap the second stage with kvm_arch_flush_shadow_memslot(). This is to respect userfault-ness. 2. When KVM_MEM_USERFAULT is enabled, restrict new second-stage mappings to be PAGE_SIZE, just like when dirty logging is enabled. Do not zap the second stage when KVM_MEM_USERFAULT is disabled to remain consistent with the behavior when dirty logging is disabled. Signed-off-by: James Houghton --- arch/arm64/kvm/Kconfig | 1 + arch/arm64/kvm/mmu.c | 26 +++++++++++++++++++++++++- 2 files changed, 26 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig index ead632ad01b4..d89b4088b580 100644 --- a/arch/arm64/kvm/Kconfig +++ b/arch/arm64/kvm/Kconfig @@ -38,6 +38,7 @@ menuconfig KVM select HAVE_KVM_VCPU_RUN_PID_CHANGE select SCHED_INFO select GUEST_PERF_EVENTS if PERF_EVENTS + select HAVE_KVM_USERFAULT help Support hosting virtualized guest machines. diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index c9d46ad57e52..e099bdcfac42 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -1493,7 +1493,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, * logging_active is guaranteed to never be true for VM_PFNMAP * memslots. */ - if (logging_active) { + if (logging_active || kvm_memslot_userfault(memslot)) { force_pte = true; vma_shift = PAGE_SHIFT; } else { @@ -1582,6 +1582,13 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, mmu_seq = vcpu->kvm->mmu_invalidate_seq; mmap_read_unlock(current->mm); + if (kvm_gfn_userfault(kvm, memslot, gfn)) { + kvm_prepare_memory_fault_exit(vcpu, gfn << PAGE_SHIFT, + PAGE_SIZE, write_fault, + exec_fault, false, true); + return -EFAULT; + } + pfn = __kvm_faultin_pfn(memslot, gfn, write_fault ? FOLL_WRITE : 0, &writable, &page); if (pfn == KVM_PFN_ERR_HWPOISON) { @@ -2073,6 +2080,23 @@ void kvm_arch_commit_memory_region(struct kvm *kvm, enum kvm_mr_change change) { bool log_dirty_pages = new && new->flags & KVM_MEM_LOG_DIRTY_PAGES; + u32 new_flags = new ? new->flags : 0; + u32 changed_flags = (new_flags) ^ (old ? old->flags : 0); + + /* + * If KVM_MEM_USERFAULT has been enabled, drop all the stage-2 mappings + * so that we can respect userfault-ness. + */ + if ((changed_flags & KVM_MEM_USERFAULT) && + (new_flags & KVM_MEM_USERFAULT) && + change == KVM_MR_FLAGS_ONLY) + kvm_arch_flush_shadow_memslot(kvm, old); + + /* + * Nothing left to do if not toggling dirty logging. + */ + if (!(changed_flags & KVM_MEM_LOG_DIRTY_PAGES)) + return; /* * At this point memslot has been committed and there is an -- 2.47.1.613.gc27f4b7a9f-goog