From nobody Sat May 18 04:30:15 2024 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2EFD715CD6D; Thu, 18 Apr 2024 12:13:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713442403; cv=none; b=DjLKcdbXYsnXO5gFfMr4SNoD5MEDLEZQnMit69ehylzxq3nuyGmlp2joVfmrFJDs/vDFqScE3sOVSP33EmT6KYcByyj4CHBO+Xe5x2DKObJcxFvtY3x5Iba5QCjKU2j3TsK78PKynTo17YMV+cuPGs5rx0OsNv7i+EPBSLcqo0U= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713442403; c=relaxed/simple; bh=t/3x9YvwBgeGmtfyzNrlEkhf5PPJrI/KNYc7npUqxro=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=c/a/0b6dlTrSUHbCSRiQCFg6YvBCtWBBnZnvySTDDmlrzpPKyet5Sk67WYWdWRBz4E+LTPQ7P4+T1sUbGaask2qW+pyqvjKEKqKLbzLsmhsERvjk1hkpPEPFWK2e5sdUGtB6XI0fnflFu8P+lxFve1A++emYTNHX+iYmXmWKJhk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b=JXgOeqo1; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="JXgOeqo1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EDC7BC2BD11; Thu, 18 Apr 2024 12:13:21 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="JXgOeqo1" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1713442400; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=WYdtdVBdKQeCcimrRJ83g62GTKmsxlDxFsEgHkC3E4w=; b=JXgOeqo1SOQWKX4vu30f/hU75KMK1tYGpPcJqrF7XwKKIhJ3UcW+WbskoOS3A2u6/xjmZW I8BVN9q72bEbghS5GsjHBUKNfTqrBYf48P22KL2tNSgUkrCtMoOpvQVyCvf4EJoPOTkuSb XWU4R3E2qcMuq3pH5N7v9ebMvWfiFGA= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id 0f0ba801 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Thu, 18 Apr 2024 12:13:19 +0000 (UTC) From: "Jason A. Donenfeld" To: tytso@mit.edu, robh@kernel.org, krzk@kernel.org, conor+dt@kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, sudanl@amazon.com, graf@amazon.com, dwmw@amazon.co.uk, krzysztof.kozlowski@linaro.org Cc: "Jason A . Donenfeld" Subject: [PATCH v7 1/3] virt: vmgenid: change implementation to use a platform driver Date: Thu, 18 Apr 2024 14:12:30 +0200 Message-ID: <20240418121249.42380-2-Jason@zx2c4.com> In-Reply-To: <20240418121249.42380-1-Jason@zx2c4.com> References: <20240418121249.42380-1-Jason@zx2c4.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Sudan Landge Re-implement vmgenid as a platform driver in preparation for adding devicetree bindings support in next commits. Signed-off-by: Sudan Landge Reviewed-by: Alexander Graf [Jason: - Small style cleanups and refactoring.] Signed-off-by: Jason A. Donenfeld --- drivers/virt/vmgenid.c | 99 +++++++++++++++++++++++++++--------------- 1 file changed, 65 insertions(+), 34 deletions(-) diff --git a/drivers/virt/vmgenid.c b/drivers/virt/vmgenid.c index a1c467a0e9f7..aebbd24512c9 100644 --- a/drivers/virt/vmgenid.c +++ b/drivers/virt/vmgenid.c @@ -7,9 +7,10 @@ * information to random.c. */ =20 +#include #include #include -#include +#include #include =20 ACPI_MODULE_NAME("vmgenid"); @@ -21,19 +22,41 @@ struct vmgenid_state { u8 this_id[VMGENID_SIZE]; }; =20 -static int vmgenid_add(struct acpi_device *device) +static void vmgenid_notify(struct device *device) +{ + struct vmgenid_state *state =3D device->driver_data; + u8 old_id[VMGENID_SIZE]; + + memcpy(old_id, state->this_id, sizeof(old_id)); + memcpy(state->this_id, state->next_id, sizeof(state->this_id)); + if (!memcmp(old_id, state->this_id, sizeof(old_id))) + return; + add_vmfork_randomness(state->this_id, sizeof(state->this_id)); +} + +static void setup_vmgenid_state(struct vmgenid_state *state, void *virt_ad= dr) { + state->next_id =3D virt_addr; + memcpy(state->this_id, state->next_id, sizeof(state->this_id)); + add_device_randomness(state->this_id, sizeof(state->this_id)); +} + +static void vmgenid_acpi_handler(acpi_handle __always_unused handle, + u32 __always_unused event, void *dev) +{ + vmgenid_notify(dev); +} + +static int vmgenid_add_acpi(struct device *dev, struct vmgenid_state *stat= e) +{ + struct acpi_device *device =3D ACPI_COMPANION(dev); struct acpi_buffer parsed =3D { ACPI_ALLOCATE_BUFFER }; - struct vmgenid_state *state; union acpi_object *obj; phys_addr_t phys_addr; acpi_status status; + void *virt_addr; int ret =3D 0; =20 - state =3D devm_kmalloc(&device->dev, sizeof(*state), GFP_KERNEL); - if (!state) - return -ENOMEM; - status =3D acpi_evaluate_object(device->handle, "ADDR", NULL, &parsed); if (ACPI_FAILURE(status)) { ACPI_EXCEPTION((AE_INFO, status, "Evaluating ADDR")); @@ -49,53 +72,61 @@ static int vmgenid_add(struct acpi_device *device) =20 phys_addr =3D (obj->package.elements[0].integer.value << 0) | (obj->package.elements[1].integer.value << 32); - state->next_id =3D devm_memremap(&device->dev, phys_addr, VMGENID_SIZE, M= EMREMAP_WB); - if (IS_ERR(state->next_id)) { - ret =3D PTR_ERR(state->next_id); + + virt_addr =3D devm_memremap(&device->dev, phys_addr, VMGENID_SIZE, MEMREM= AP_WB); + if (IS_ERR(virt_addr)) { + ret =3D PTR_ERR(virt_addr); goto out; } + setup_vmgenid_state(state, virt_addr); =20 - memcpy(state->this_id, state->next_id, sizeof(state->this_id)); - add_device_randomness(state->this_id, sizeof(state->this_id)); - - device->driver_data =3D state; + status =3D acpi_install_notify_handler(device->handle, ACPI_DEVICE_NOTIFY, + vmgenid_acpi_handler, dev); + if (ACPI_FAILURE(status)) { + ret =3D -ENODEV; + goto out; + } =20 + dev->driver_data =3D state; out: ACPI_FREE(parsed.pointer); return ret; } =20 -static void vmgenid_notify(struct acpi_device *device, u32 event) +static int vmgenid_add(struct platform_device *pdev) { - struct vmgenid_state *state =3D acpi_driver_data(device); - u8 old_id[VMGENID_SIZE]; + struct vmgenid_state *state; + struct device *dev =3D &pdev->dev; + int ret =3D 0; =20 - memcpy(old_id, state->this_id, sizeof(old_id)); - memcpy(state->this_id, state->next_id, sizeof(state->this_id)); - if (!memcmp(old_id, state->this_id, sizeof(old_id))) - return; - add_vmfork_randomness(state->this_id, sizeof(state->this_id)); + state =3D devm_kmalloc(dev, sizeof(*state), GFP_KERNEL); + if (!state) + return -ENOMEM; + + ret =3D vmgenid_add_acpi(dev, state); + + if (ret) + devm_kfree(dev, state); + return ret; } =20 -static const struct acpi_device_id vmgenid_ids[] =3D { +static const struct acpi_device_id vmgenid_acpi_ids[] =3D { { "VMGENCTR", 0 }, { "VM_GEN_COUNTER", 0 }, { } }; - -static struct acpi_driver vmgenid_driver =3D { - .name =3D "vmgenid", - .ids =3D vmgenid_ids, - .owner =3D THIS_MODULE, - .ops =3D { - .add =3D vmgenid_add, - .notify =3D vmgenid_notify - } +MODULE_DEVICE_TABLE(acpi, vmgenid_acpi_ids); + +static struct platform_driver vmgenid_plaform_driver =3D { + .probe =3D vmgenid_add, + .driver =3D { + .name =3D "vmgenid", + .acpi_match_table =3D vmgenid_acpi_ids, + }, }; =20 -module_acpi_driver(vmgenid_driver); +module_platform_driver(vmgenid_plaform_driver) =20 -MODULE_DEVICE_TABLE(acpi, vmgenid_ids); MODULE_DESCRIPTION("Virtual Machine Generation ID"); MODULE_LICENSE("GPL v2"); MODULE_AUTHOR("Jason A. Donenfeld "); --=20 2.44.0 From nobody Sat May 18 04:30:15 2024 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D73D315F418; Thu, 18 Apr 2024 12:13:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713442409; cv=none; b=F2A8V/dKwGFgKoebsLkwXyEeDiMurpO7ezqBIwK2I3N2tmBjLu1W6E8whOAb/QcglKxE9iv6aFQvSclEH33ScSTMiFMp5iJvUIdab630AiDnjku/BHJ5um6YIUYObXEoIb957Cmv32iov0VNjGEHHKlocVRm2b9LeMEZRZLL5qQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713442409; c=relaxed/simple; bh=Amq8QQQDYa44SzqqX6R4cVVx5PsYPSiIZ/0HlSgcyPI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PIR6vZ4YtO/WNeK9z41eYJPEeJyN8Etlnil5Dt+CEItnKbSUwZKF1ymGKkjjK5kD763KnIWnCvGj/sDuU+h49aU9X21X1AuZdAvDb8+tuZoyaanYCGFeV+/eavQeKX9g3Ig1I1oTXhd8ocgDRVi2zCzoJ+1nMykYbWTsiyCIwEk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b=A7sLAgGb; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="A7sLAgGb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4EE77C113CC; Thu, 18 Apr 2024 12:13:28 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="A7sLAgGb" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1713442406; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=7gsorX/0HQ5s+ktgRAadAV+5SRctARQllFusL+M6cyE=; b=A7sLAgGbzIHH3b48pvtyBzSksVK30qrf+KChuiYNq+5V1ViTvvrRdJuw386U+quDa7RGJs TskpmyVFyinCJY9QkeaoHf4ioTV1yXjCpRoZPNPxlXCYJql5PMGCINloGFRd+0SHy8i16G sfIR0DO2dB3QdcwGU4plIdIVafbtrqo= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id c261e6bf (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Thu, 18 Apr 2024 12:13:25 +0000 (UTC) From: "Jason A. Donenfeld" To: tytso@mit.edu, robh@kernel.org, krzk@kernel.org, conor+dt@kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, sudanl@amazon.com, graf@amazon.com, dwmw@amazon.co.uk, krzysztof.kozlowski@linaro.org Cc: "Jason A . Donenfeld" Subject: [PATCH v7 2/3] dt-bindings: rng: Add vmgenid support Date: Thu, 18 Apr 2024 14:12:31 +0200 Message-ID: <20240418121249.42380-3-Jason@zx2c4.com> In-Reply-To: <20240418121249.42380-1-Jason@zx2c4.com> References: <20240418121249.42380-1-Jason@zx2c4.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Sudan Landge Virtual Machine Generation ID driver was introduced in commit af6b54e2b5ba ("virt: vmgenid: notify RNG of VM fork and supply generation ID"), as an ACPI only device. VMGenID specification http://go.microsoft.com/fwlink/?LinkId=3D260709 defines a mechanism for the BIOS/hypervisors to communicate to the virtual machine that it is executed with a different configuration (e.g. snapshot execution or creation from a template). The guest operating system can use the notification for various purposes such as re-initializing its random number generator etc. As per the specs, hypervisor should provide a globally unique identified, or GUID via ACPI. This patch tries to mimic the mechanism to provide the same functionality which is for a hypervisor/BIOS to notify the virtual machine when it is executed with a different configuration. As part of this support the devicetree bindings requires the hypervisors or BIOS to provide a memory address which holds the GUID and an IRQ which is used to notify when there is a change in the GUID. The memory exposed in the DT should follow the rules defined in the vmgenid spec mentioned above. Reason for this change: Chosing ACPI or devicetree is an intrinsic part of an hypervisor design. Without going into details of why a hypervisor would chose DT over ACPI, we would like to highlight that the hypervisors that have chose devicetree and now want to make use of the vmgenid functionality cannot do so today because vmgenid is an ACPI only device. This forces these hypervisors to change their design which could have undesirable impacts on their use-cases, test-scenarios etc. The point of vmgenid is to provide a mechanism to discover a GUID when the execution state of a virtual machine changes and the simplest way to do it is pass a memory location and an interrupt via devicetree. It would complicate things unnecessarily if instead of using devicetree, we try to implement a new protocol or modify other protocols to somehow provide the same functionility. We believe that adding a devicetree binding for vmgenid is a simpler, better alternative to provide the same functionality and will allow such hypervisors as mentioned above to continue using devicetree. More references to the vmgenid specs are found below. Signed-off-by: Sudan Landge Reviewed-by: Rob Herring Reviewed-by: Alexander Graf Link: https://www.qemu.org/docs/master/specs/vmgenid.html Link: https://learn.microsoft.com/en-us/windows/win32/hyperv_v2/virtual-mac= hine-generation-identifier Signed-off-by: Jason A. Donenfeld --- .../bindings/rng/microsoft,vmgenid.yaml | 49 +++++++++++++++++++ MAINTAINERS | 1 + 2 files changed, 50 insertions(+) create mode 100644 Documentation/devicetree/bindings/rng/microsoft,vmgenid= .yaml diff --git a/Documentation/devicetree/bindings/rng/microsoft,vmgenid.yaml b= /Documentation/devicetree/bindings/rng/microsoft,vmgenid.yaml new file mode 100644 index 000000000000..8f20dee93e7e --- /dev/null +++ b/Documentation/devicetree/bindings/rng/microsoft,vmgenid.yaml @@ -0,0 +1,49 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/rng/microsoft,vmgenid.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Virtual Machine Generation ID + +maintainers: + - Jason A. Donenfeld + +description: + Firmwares or hypervisors can use this devicetree to describe an + interrupt and a shared resource to inject a Virtual Machine Generation I= D. + Virtual Machine Generation ID is a globally unique identifier (GUID) and + the devicetree binding follows VMGenID specification defined in + http://go.microsoft.com/fwlink/?LinkId=3D260709. + +properties: + compatible: + const: microsoft,vmgenid + + reg: + description: + Specifies a 16-byte VMGenID in endianness-agnostic hexadecimal forma= t. + maxItems: 1 + + interrupts: + description: + Interrupt used to notify that a new VMGenID is available. + maxItems: 1 + +required: + - compatible + - reg + - interrupts + +additionalProperties: false + +examples: + - | + #include + rng@80000000 { + compatible =3D "microsoft,vmgenid"; + reg =3D <0x80000000 0x1000>; + interrupts =3D ; + }; + +... diff --git a/MAINTAINERS b/MAINTAINERS index aa3b947fb080..c84ac9258a48 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -18463,6 +18463,7 @@ M: "Theodore Ts'o" M: Jason A. Donenfeld S: Maintained T: git https://git.kernel.org/pub/scm/linux/kernel/git/crng/random.git +F: Documentation/devicetree/bindings/rng/microsoft,vmgenid.yaml F: drivers/char/random.c F: drivers/virt/vmgenid.c =20 --=20 2.44.0 From nobody Sat May 18 04:30:15 2024 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 35C9215FA76; Thu, 18 Apr 2024 12:13:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713442416; cv=none; b=ni8+qd2W3oU1vCcKxoTaNLFEcU4fPkW8Opys+RHzoyONj+j65NEeRckQw8AEd3S6wuZegithRQe/Z2NQ9gb3pH1ZkaSVOQ3/pUEmT4Jvf9YkBdsAYNs/a++qvNELAAI8Wa8Wip1hRcw6J/2pm7zwPKpcOriwI1/3KjWjO08PaEk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713442416; c=relaxed/simple; bh=VQUJGeeRWUloAWWB1Hyejv1PGZzE7T5/iKqrDFVIZDo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=D56dhTwmbySM8wMF2qOLkmFdxUL/FS83wGAYs8ynkTZFdmNgcYVml7jo24ckJmzABvrcwO45gJam1B0pgAJL7f1JjEPgKUk5oL+JB1AerXctqGDK+KmYGgDOdctqKAE8I5+GLCEuOreA5hcNtlbeEJVNgSS0rZ7LJ+D/gtFHmgU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b=edwjgr6E; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="edwjgr6E" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A7BE6C2BD11; Thu, 18 Apr 2024 12:13:34 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="edwjgr6E" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1713442413; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=aq6JxSnWT2dRtETeeOa/f63j90uhZ8kS0pFZ3RGL2y8=; b=edwjgr6EnEXfAJpSfhxKoISY47u6S9LNTNfxb7wqGAHku9KcROKgQty+HaL2+s5GqU7R5j OwO7vmerWfA+m5BQAX/n7leXDYH4JdcHWUAB9jj5blEJNGF/KfG3S4qsbcjvuP6jTVN1Tg Ok1fW9K6R/BZmkDK199QbBwZv00h+HE= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id 81429b10 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Thu, 18 Apr 2024 12:13:33 +0000 (UTC) From: "Jason A. Donenfeld" To: tytso@mit.edu, robh@kernel.org, krzk@kernel.org, conor+dt@kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, sudanl@amazon.com, graf@amazon.com, dwmw@amazon.co.uk, krzysztof.kozlowski@linaro.org Cc: "Jason A . Donenfeld" Subject: [PATCH v7 3/3] virt: vmgenid: add support for devicetree bindings Date: Thu, 18 Apr 2024 14:12:32 +0200 Message-ID: <20240418121249.42380-4-Jason@zx2c4.com> In-Reply-To: <20240418121249.42380-1-Jason@zx2c4.com> References: <20240418121249.42380-1-Jason@zx2c4.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Sudan Landge Extend the vmgenid platform driver to support devicetree bindings. With this support, hypervisors can send vmgenid notifications to the virtual machine without the need to enable ACPI. The bindings are located at: Documentation/devicetree/bindings/rng/microsoft,vmgenid.yaml Since this makes the driver work for both ACPI and devicetree, adjust the Kconfig to include `|| OF`, which in turn means accounting for !CONFIG_ACPI in the code with a short ifdef. Signed-off-by: Sudan Landge Reviewed-by: Alexander Graf [Jason: - Small style cleanups and refactoring. - Fold in Kconfig OF dependency and ACPI conditionalization. ] Signed-off-by: Jason A. Donenfeld --- drivers/virt/Kconfig | 2 +- drivers/virt/vmgenid.c | 53 ++++++++++++++++++++++++++++++++++++++++-- 2 files changed, 52 insertions(+), 3 deletions(-) diff --git a/drivers/virt/Kconfig b/drivers/virt/Kconfig index 40129b6f0eca..017d6c38c3ba 100644 --- a/drivers/virt/Kconfig +++ b/drivers/virt/Kconfig @@ -16,7 +16,7 @@ if VIRT_DRIVERS config VMGENID tristate "Virtual Machine Generation ID driver" default y - depends on ACPI + depends on ACPI || OF help Say Y here to use the hypervisor-provided Virtual Machine Generation ID to reseed the RNG when the VM is cloned. This is highly recommended if diff --git a/drivers/virt/vmgenid.c b/drivers/virt/vmgenid.c index aebbd24512c9..7f2d1e5656df 100644 --- a/drivers/virt/vmgenid.c +++ b/drivers/virt/vmgenid.c @@ -2,12 +2,13 @@ /* * Copyright (C) 2022 Jason A. Donenfeld . All Rights Res= erved. * - * The "Virtual Machine Generation ID" is exposed via ACPI and changes whe= n a + * The "Virtual Machine Generation ID" is exposed via ACPI or DT and chang= es when a * virtual machine forks or is cloned. This driver exists for shepherding = that * information to random.c. */ =20 #include +#include #include #include #include @@ -41,6 +42,7 @@ static void setup_vmgenid_state(struct vmgenid_state *sta= te, void *virt_addr) add_device_randomness(state->this_id, sizeof(state->this_id)); } =20 +#ifdef CONFIG_ACPI static void vmgenid_acpi_handler(acpi_handle __always_unused handle, u32 __always_unused event, void *dev) { @@ -92,6 +94,43 @@ static int vmgenid_add_acpi(struct device *dev, struct v= mgenid_state *state) ACPI_FREE(parsed.pointer); return ret; } +#else +static int vmgenid_add_acpi(struct device *dev, struct vmgenid_state *stat= e) +{ + return -EINVAL; +} +#endif + +static irqreturn_t vmgenid_of_irq_handler(int __always_unused irq, void *d= ev) +{ + vmgenid_notify(dev); + return IRQ_HANDLED; +} + +static int vmgenid_add_of(struct platform_device *pdev, + struct vmgenid_state *state) +{ + void *virt_addr; + int ret; + + virt_addr =3D devm_platform_get_and_ioremap_resource(pdev, 0, NULL); + if (IS_ERR(virt_addr)) + return PTR_ERR(virt_addr); + + setup_vmgenid_state(state, virt_addr); + + ret =3D platform_get_irq(pdev, 0); + if (ret) + return ret; + + ret =3D devm_request_irq(&pdev->dev, ret, vmgenid_of_irq_handler, + IRQF_SHARED, "vmgenid", &pdev->dev); + if (ret) + return ret; + + pdev->dev.driver_data =3D state; + return 0; +} =20 static int vmgenid_add(struct platform_device *pdev) { @@ -103,13 +142,22 @@ static int vmgenid_add(struct platform_device *pdev) if (!state) return -ENOMEM; =20 - ret =3D vmgenid_add_acpi(dev, state); + if (dev->of_node) + ret =3D vmgenid_add_of(pdev, state); + else + ret =3D vmgenid_add_acpi(dev, state); =20 if (ret) devm_kfree(dev, state); return ret; } =20 +static const struct of_device_id vmgenid_of_ids[] =3D { + { .compatible =3D "microsoft,vmgenid", }, + { }, +}; +MODULE_DEVICE_TABLE(of, vmgenid_of_ids); + static const struct acpi_device_id vmgenid_acpi_ids[] =3D { { "VMGENCTR", 0 }, { "VM_GEN_COUNTER", 0 }, @@ -122,6 +170,7 @@ static struct platform_driver vmgenid_plaform_driver = =3D { .driver =3D { .name =3D "vmgenid", .acpi_match_table =3D vmgenid_acpi_ids, + .of_match_table =3D vmgenid_of_ids, }, }; =20 --=20 2.44.0