From nobody Wed Dec 17 12:06:35 2025 Received: from mail-yb1-f201.google.com (mail-yb1-f201.google.com [209.85.219.201]) (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 B9B9216848B for ; Wed, 10 Jul 2024 23:42:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720654973; cv=none; b=F5QhGiEj5a8wUeGSXJjyoMRgEsMY8NjDjX5HeiU/nUnNsOItPhkiiurKq2jLbshxs9bjG9aFWRgOIMlocH0JEEkxGTTJDQiSRvVBPtMRrCUuuuiYwecW3/a6M+tfnT4pdHUUsZU0zsfLV40SoVuHn8OHV3SSHM+D18G8iDOWnNg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720654973; c=relaxed/simple; bh=bFngUTjVBtg5CbyG25RDmTc6wZ0g8Z4dE05PWolnMuA=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=EKfs7g6hLl2Up9nBkLd8UDOBmS6itvzmDOfpcmE+2K47e4ruvqDiOwEj4Lkkmxy1IcYBgzveYX1UEjk1s4kfHCsKWtJSDX///PINh7q5EYoClEHtvnanRXyfls29qE8VAFh/CP9UnKklekz70HvblFtTYHndBkmqHpnhZchR4V4= 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=NraxoE88; arc=none smtp.client-ip=209.85.219.201 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="NraxoE88" Received: by mail-yb1-f201.google.com with SMTP id 3f1490d57ef6-e032d4cf26aso518666276.3 for ; Wed, 10 Jul 2024 16:42:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1720654970; x=1721259770; 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=wAPg+uoGyE7jrnqbrfnqp+qBfKQe/ElheERXpCs/y30=; b=NraxoE884i5UGeFLgyX6LV7967m3VShM5RJlHCzHa1BM3Ym/+8c83CzC7IvyEpbJez 7udLHgCXg3ao8cBo31uGB2qPMrJE1WjFX7XI5FibKYcJ61K8Sa9qMuDgouX0kvZnFQmD qMCdCCLZciixrn7zTiTTNIfSjaKVjL8imwQEF0h1iJPrjxkJybpE+Q7yzSWS5ixF9UmG MZtuaM8JLBvfieo1nWP5Wzf2eVf9dWGUAtDEIQQSbHOUUOurd5cuj84uR2FPDCzOVo1Q nuwy7CbjpJhIkMuTCUo0jTlUUFiDE6gAcJRoM4GftShi3884dKF9Jz1RC63GHwKVSfaM 9dDA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1720654970; x=1721259770; 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=wAPg+uoGyE7jrnqbrfnqp+qBfKQe/ElheERXpCs/y30=; b=R7Ggbf2KcezbkufUvDfYjeLfWjoJakCkf40fQSPHwuhtzo/PbwcaY/5eYXSpEZ0RKM G+0P6izchbGN9e3aAdB3vwiQw8otFeZQLoyygvKX1XFeJm4EXdThnyw1bAkC5pM0CktF x5svFwbtmOpmLWxReRVYOeY3MKNz94bynNx0jutEyH6dlCXWuceWo/sKBa3w5NA5rE6z 492wUSUHabTCl5aetYOFsY3pX4BU6kymL5n85sZKrOu0KWE6LuAAFtFZglzoaaH5YL35 oMZbJQ9oZQQz2L1/KRBZz7XIUEY0CIJ/6C08t7u8bMa24cOORfKrJ2yMjIHDXW1xfY9a mycg== X-Forwarded-Encrypted: i=1; AJvYcCUrIUuMJ32AIMhqd3wViIEzaE686GU1Fw5Zw1kDZIjKG8wyyXIJEDD+85JPOl7ykHypJ7Q6+qx9L+M9FTlGOVYD/T0T926LGYVuWftv X-Gm-Message-State: AOJu0YzCHa9hrXW/ZqH3uShNbSdgU+C6c5MOxYZAZ+YqIYWz4Bh6u7wU ZgzpanZoIJKUt6iP/hOVnUOJXLwl0mlZz+HJhkeYU1eqX+6Tmpp57X7Uz464uGyQTIlvAvmsKMW pO/5rfBnUummy0asjhA== X-Google-Smtp-Source: AGHT+IEUTEcOd07Ngb0BqkggJw4ozgt7Za8itkm1dvA0VYqtERMoRdOJmQ0AmWvr6/7REaf9c4XX0hx8Il26mfc6 X-Received: from jthoughton.c.googlers.com ([fda3:e722:ac3:cc00:14:4d90:c0a8:2a4f]) (user=jthoughton job=sendgmr) by 2002:a05:6902:2101:b0:e03:31ec:8a24 with SMTP id 3f1490d57ef6-e041b17dfb5mr382800276.8.1720654969766; Wed, 10 Jul 2024 16:42:49 -0700 (PDT) Date: Wed, 10 Jul 2024 23:42:16 +0000 In-Reply-To: <20240710234222.2333120-1-jthoughton@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240710234222.2333120-1-jthoughton@google.com> X-Mailer: git-send-email 2.45.2.993.g49e7a77208-goog Message-ID: <20240710234222.2333120-13-jthoughton@google.com> Subject: [RFC PATCH 12/18] KVM: arm64: Add userfault support for steal-time From: James Houghton To: Paolo Bonzini Cc: Marc Zyngier , Oliver Upton , James Morse , Suzuki K Poulose , Zenghui Yu , Sean Christopherson , Shuah Khan , Peter Xu , Axel Rasmussen , David Matlack , James Houghton , 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-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" As part of KVM_RUN, we may need to write steal-time information to guest memory. In the case that the gfn we are writing to is userfault-enabled, we should return to userspace with fault information. With asynchronous userfaults, this change is not necessary and merely acts as an optimization. Signed-off-by: James Houghton --- arch/arm64/include/asm/kvm_host.h | 2 +- arch/arm64/kvm/arm.c | 8 ++++++-- arch/arm64/kvm/pvtime.c | 11 +++++++++-- 3 files changed, 16 insertions(+), 5 deletions(-) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm= _host.h index 36b8e97bf49e..4c7bd72ba9e8 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -1166,7 +1166,7 @@ static inline bool kvm_arch_pmi_in_guest(struct kvm_v= cpu *vcpu) =20 long kvm_hypercall_pv_features(struct kvm_vcpu *vcpu); gpa_t kvm_init_stolen_time(struct kvm_vcpu *vcpu); -void kvm_update_stolen_time(struct kvm_vcpu *vcpu); +int kvm_update_stolen_time(struct kvm_vcpu *vcpu); =20 bool kvm_arm_pvtime_supported(void); int kvm_arm_pvtime_set_attr(struct kvm_vcpu *vcpu, diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 59716789fe0f..4c7994e44217 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -974,8 +974,12 @@ static int check_vcpu_requests(struct kvm_vcpu *vcpu) */ kvm_check_request(KVM_REQ_IRQ_PENDING, vcpu); =20 - if (kvm_check_request(KVM_REQ_RECORD_STEAL, vcpu)) - kvm_update_stolen_time(vcpu); + if (kvm_check_request(KVM_REQ_RECORD_STEAL, vcpu)) { + int ret =3D kvm_update_stolen_time(vcpu); + + if (ret <=3D 0) + return ret; + } =20 if (kvm_check_request(KVM_REQ_RELOAD_GICv4, vcpu)) { /* The distributor enable bits were changed */ diff --git a/arch/arm64/kvm/pvtime.c b/arch/arm64/kvm/pvtime.c index 4ceabaa4c30b..ba0164726310 100644 --- a/arch/arm64/kvm/pvtime.c +++ b/arch/arm64/kvm/pvtime.c @@ -10,7 +10,7 @@ =20 #include =20 -void kvm_update_stolen_time(struct kvm_vcpu *vcpu) +int kvm_update_stolen_time(struct kvm_vcpu *vcpu) { struct kvm *kvm =3D vcpu->kvm; u64 base =3D vcpu->arch.steal.base; @@ -20,9 +20,14 @@ void kvm_update_stolen_time(struct kvm_vcpu *vcpu) int idx; =20 if (base =3D=3D INVALID_GPA) - return; + return 1; =20 idx =3D srcu_read_lock(&kvm->srcu); + if (gfn_to_hva(kvm, base + offset) =3D=3D KVM_HVA_ERR_USERFAULT) { + kvm_prepare_memory_fault_exit(vcpu, base + offset, PAGE_SIZE, + true, false, false, true); + return -EFAULT; + } if (!kvm_get_guest(kvm, base + offset, steal)) { steal =3D le64_to_cpu(steal); vcpu->arch.steal.last_steal =3D READ_ONCE(current->sched_info.run_delay); @@ -30,6 +35,8 @@ void kvm_update_stolen_time(struct kvm_vcpu *vcpu) kvm_put_guest(kvm, base + offset, cpu_to_le64(steal)); } srcu_read_unlock(&kvm->srcu, idx); + + return 1; } =20 long kvm_hypercall_pv_features(struct kvm_vcpu *vcpu) --=20 2.45.2.993.g49e7a77208-goog