From patchwork Fri Nov 18 10:36:58 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Laszlo Ersek X-Patchwork-Id: 9436185 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 8ADE960238 for ; Fri, 18 Nov 2016 10:37:42 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A68B329876 for ; Fri, 18 Nov 2016 10:37:42 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9B3062987C; Fri, 18 Nov 2016 10:37:42 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 5A73029877 for ; Fri, 18 Nov 2016 10:37:41 +0000 (UTC) Received: from localhost ([::1]:35664 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1c7gY8-0004OB-4O for patchwork-qemu-devel@patchwork.kernel.org; Fri, 18 Nov 2016 05:37:40 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45284) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1c7gXf-0004Kc-SI for qemu-devel@nongnu.org; Fri, 18 Nov 2016 05:37:13 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1c7gXe-0004UI-Gg for qemu-devel@nongnu.org; Fri, 18 Nov 2016 05:37:11 -0500 Received: from mx1.redhat.com ([209.132.183.28]:56198) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1c7gXe-0004Tb-7i for qemu-devel@nongnu.org; Fri, 18 Nov 2016 05:37:10 -0500 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4ACF980F97; Fri, 18 Nov 2016 10:37:09 +0000 (UTC) Received: from lacos-laptop-7.usersys.redhat.com (ovpn-116-70.phx2.redhat.com [10.3.116.70]) by int-mx14.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id uAIAb3PR008728; Fri, 18 Nov 2016 05:37:07 -0500 From: Laszlo Ersek To: qemu devel list Date: Fri, 18 Nov 2016 11:36:58 +0100 Message-Id: <20161118103659.10448-3-lersek@redhat.com> In-Reply-To: <20161118103659.10448-1-lersek@redhat.com> References: <20161118103659.10448-1-lersek@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.27 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Fri, 18 Nov 2016 10:37:09 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v3 for-2.9 2/3] hw/isa/lpc_ich9: add SMI feature negotiation via APM_STS X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paolo Bonzini , Kevin O'Connor , Gerd Hoffmann , "Michael S. Tsirkin" Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP Define and implement non-standard feature control for SMI handling via the APM_STS register, such that it remains compatible with SeaBIOS's current access pattern, and enables OVMF to negotiate features. Cc: "Kevin O'Connor" Cc: "Michael S. Tsirkin" Cc: Gerd Hoffmann Cc: Paolo Bonzini Signed-off-by: Laszlo Ersek --- Notes: v3: - feature negotiation is new in v3 [Paolo, Michael] docs/specs/q35-apm-sts.txt | 71 ++++++++++++++++++++++++++++++++++++++++++++++ include/hw/i386/ich9.h | 8 ++++++ hw/isa/lpc_ich9.c | 54 ++++++++++++++++++++++++++++++++++- 3 files changed, 132 insertions(+), 1 deletion(-) create mode 100644 docs/specs/q35-apm-sts.txt diff --git a/docs/specs/q35-apm-sts.txt b/docs/specs/q35-apm-sts.txt new file mode 100644 index 000000000000..cdffb6834380 --- /dev/null +++ b/docs/specs/q35-apm-sts.txt @@ -0,0 +1,71 @@ +According to the ICH9 specification, the APM_STS (Advanced Power Management +Status Port) Register, at IO Port 0xB3, is a scratchpad register for passing +data between the software agent that raises the synchronous SMI, and the SMI +handler routine in the firmware. It is not coupled to any hardware +functionality. The register is also known as SMI Data Port. + +While the ACPI FADT exposes the SMI Command Port (APM_CNT) to the OS, the Data +Port is not exposed. + +SeaBIOS uses the Data Port values 0x00 and 0x01 in its SMI handler. SeaBIOS +also relies on the original behavior of QEMU, where writing to the Command +Port (APM_CNT) would raise the SMI only on the processor writing the port. + +OVMF needs dynamically detectable and settable features for SMI behavior. We +can use the remaining bits in APM_STS for this, without disturbing SeaBIOS. + +The following describes the (non-standard) bit definitions in APM_STS. + + 7 6 5 4 3 2 1 0 + +---+---+---+---+---+---+---+---+ + | | | | | | | | | + +---+---+---+---+---+---+---+---+ + ^ ^ ^ ^ ^ ^ ^ ^ + | | | | | | | Transparent bit. Whatever bit the firmware + | | | | | | | writes in this position has no effect on + | | | | | | | hardware, and can be read back identically. + | | | | | | | + | | | | | | Feature negotiation bit. + | | | | | | + Feature bits. All reserved at the moment. + +Feature negotiation +------------------- + +Firmware that is enlightened about this feature shall write 1 to the feature +negotiation bit first (clearing all other bits), then read back the APM_STS +register. If the feature negotiation bit is set in the result, then QEMU lacks +the feature negotiation feature, and APM_STS is entirely transparent. Otherwise +(i.e., the feature negotiation bit is clear in the result), the more +significant bits (the feature bits) expose the features supported by QEMU. At +the moment, no features are defined, and all feature bits read as zero. + +Once firmware confirms feature negotiation is available, it shall set (select) +a subset of the advertised feature bits, and clear the feature negotiation bit, +in a single write to the APM_STS register. In order to verify the result, the +firmware shall read back the APM_STS register. If the feature negotiation bit +is clear in the result, then the feature selection was successful. Otherwise, +the requested features either weren't a subset of the available features, or +constituted an inconsistent group of features (breaking inter-feature +dependencies, for example). Regardless of the feature negotiation bit in the +read back value, the higher order bits (i.e., the individual feature bits) are +always zero in that value. + +SeaBIOS compatibility +--------------------- + +Writing 0x00 and 0x01 to APM_STS translates to "clear all features", with the +following consequences: + +- The SMI behavior remains the original QEMU behavior, regardless of any future + features / feature bits. + +- Reading back APM_STS returns the value previously written. This is because + + - the least significant bit is transparent, + + - clearing all features is a request that always succeeds, hence the feature + negotiation bit will read as zero, + + - the feature bits always read as zero after writing zero to the feature + negotiation bit. diff --git a/include/hw/i386/ich9.h b/include/hw/i386/ich9.h index 5fd7e97d2347..8304396a487f 100644 --- a/include/hw/i386/ich9.h +++ b/include/hw/i386/ich9.h @@ -70,6 +70,9 @@ typedef struct ICH9LPCState { Notifier machine_ready; qemu_irq gsi[GSI_NUM_PINS]; + + /* SMI features negotiated via APM_STS */ + uint8_t smi_features; } ICH9LPCState; Object *ich9_lpc_find(void); @@ -208,6 +211,11 @@ Object *ich9_lpc_find(void); #define ICH9_APM_ACPI_ENABLE 0x2 #define ICH9_APM_ACPI_DISABLE 0x3 +/* non-standard bits for the APM_STS register */ +#define ICH9_APM_STS_TRANSPARENT_MASK 0x01 +#define ICH9_APM_STS_GET_SET_FEATURES 0x02 +#define ICH9_APM_STS_KNOWN_FEATURES 0x00 +#define ICH9_APM_STS_FEATURE_MASK 0xfc /* D31:F3 SMBus controller */ #define TYPE_ICH9_SMB_DEVICE "ICH9 SMB" diff --git a/hw/isa/lpc_ich9.c b/hw/isa/lpc_ich9.c index e3556c9f9eae..a50c4a15b6d1 100644 --- a/hw/isa/lpc_ich9.c +++ b/hw/isa/lpc_ich9.c @@ -390,6 +390,37 @@ static void ich9_apm_ctrl_changed(uint32_t val, void *arg) } } +static void ich9_apm_status_changed(uint32_t val, void *arg) +{ + ICH9LPCState *lpc = arg; + uint32_t new_val = 0; + + /* copy the transparent bits */ + new_val |= val & ICH9_APM_STS_TRANSPARENT_MASK; + + if (val & ICH9_APM_STS_GET_SET_FEATURES) { + /* The guest is querying features. Clearing + * ICH9_APM_STS_GET_SET_FEATURES means success. + */ + + /* provide known features */ + new_val |= ICH9_APM_STS_KNOWN_FEATURES; + } else { + /* The guest is setting features. */ + if (val & ICH9_APM_STS_FEATURE_MASK & + ~(uint32_t)ICH9_APM_STS_KNOWN_FEATURES) { + /* Unknown feature requested, report error. */ + new_val |= ICH9_APM_STS_GET_SET_FEATURES; + } else { + /* Set requested features. Clearing ICH9_APM_STS_GET_SET_FEATURES + * means success.*/ + lpc->smi_features = val & ICH9_APM_STS_KNOWN_FEATURES; + } + } + + lpc->apm.apms = new_val; +} + /* config:PMBASE */ static void ich9_lpc_pmbase_sci_update(ICH9LPCState *lpc) @@ -507,6 +538,7 @@ static void ich9_lpc_reset(DeviceState *qdev) lpc->sci_level = 0; lpc->rst_cnt = 0; + lpc->smi_features = 0; } /* root complex register block is mapped into memory space */ @@ -634,7 +666,8 @@ static void ich9_lpc_realize(PCIDevice *d, Error **errp) lpc->isa_bus = isa_bus; ich9_cc_init(lpc); - apm_init(d, &lpc->apm, ich9_apm_ctrl_changed, NULL, lpc); + apm_init(d, &lpc->apm, ich9_apm_ctrl_changed, ich9_apm_status_changed, + lpc); lpc->machine_ready.notify = ich9_lpc_machine_ready; qemu_add_machine_init_done_notifier(&lpc->machine_ready); @@ -668,6 +701,24 @@ static const VMStateDescription vmstate_ich9_rst_cnt = { } }; +static bool ich9_smi_features_needed(void *opaque) +{ + ICH9LPCState *lpc = opaque; + + return (lpc->smi_features != 0); +} + +static const VMStateDescription vmstate_ich9_smi_features = { + .name = "ICH9LPC/smi_features", + .version_id = 1, + .minimum_version_id = 1, + .needed = ich9_smi_features_needed, + .fields = (VMStateField[]) { + VMSTATE_UINT8(smi_features, ICH9LPCState), + VMSTATE_END_OF_LIST() + } +}; + static const VMStateDescription vmstate_ich9_lpc = { .name = "ICH9LPC", .version_id = 1, @@ -683,6 +734,7 @@ static const VMStateDescription vmstate_ich9_lpc = { }, .subsections = (const VMStateDescription*[]) { &vmstate_ich9_rst_cnt, + &vmstate_ich9_smi_features, NULL } };