Re: [Qemu-devel] [PATCH 02/17] ipmi: Add a PC ISA type structure

[Andreas Färber]

Am 08.05.2015 um 23:16 schrieb Corey Minyard:
> On 04/26/2015 03:58 AM, Michael S. Tsirkin wrote:
>> On Thu, Apr 23, 2015 at 05:57:43PM -0500, address@hidden wrote:
>>> From: Corey Minyard <address@hidden>
>>>
>>> This provides the base infrastructure to tie IPMI low-level
>>> interfaces into a PC ISA bus.
>>>
>>> Signed-off-by: Corey Minyard <address@hidden>
>>> ---
>>>  default-configs/i386-softmmu.mak   |   1 +
>>>  default-configs/x86_64-softmmu.mak |   1 +
>>>  hw/ipmi/Makefile.objs              |   1 +
>>>  hw/ipmi/isa_ipmi.c                 | 144 
>>> +++++++++++++++++++++++++++++++++++++
>>>  include/hw/nvram/fw_cfg.h          |  11 ++-
>>>  5 files changed, 157 insertions(+), 1 deletion(-)
>>>  create mode 100644 hw/ipmi/isa_ipmi.c
>>>
>>> diff --git a/default-configs/i386-softmmu.mak 
>>> b/default-configs/i386-softmmu.mak
>>> index ab1a552..1c3153b 100644
>>> --- a/default-configs/i386-softmmu.mak
>>> +++ b/default-configs/i386-softmmu.mak
>>> @@ -9,6 +9,7 @@ CONFIG_VGA_CIRRUS=y
>>>  CONFIG_VMWARE_VGA=y
>>>  CONFIG_VMMOUSE=y
>>>  CONFIG_IPMI=y
>>> +CONFIG_ISA_IPMI=y
>>>  CONFIG_SERIAL=y
>>>  CONFIG_PARALLEL=y
>>>  CONFIG_I8254=y
>>> diff --git a/default-configs/x86_64-softmmu.mak 
>>> b/default-configs/x86_64-softmmu.mak
>>> index 82bafcc..6b57430 100644
>>> --- a/default-configs/x86_64-softmmu.mak
>>> +++ b/default-configs/x86_64-softmmu.mak
>>> @@ -9,6 +9,7 @@ CONFIG_VGA_CIRRUS=y
>>>  CONFIG_VMWARE_VGA=y
>>>  CONFIG_VMMOUSE=y
>>>  CONFIG_IPMI=y
>>> +CONFIG_ISA_IPMI=y
>>>  CONFIG_SERIAL=y
>>>  CONFIG_PARALLEL=y
>>>  CONFIG_I8254=y
>>> diff --git a/hw/ipmi/Makefile.objs b/hw/ipmi/Makefile.objs
>>> index 65bde11..1518216 100644
>>> --- a/hw/ipmi/Makefile.objs
>>> +++ b/hw/ipmi/Makefile.objs
>>> @@ -1 +1,2 @@
>>> +common-obj-$(CONFIG_ISA_IPMI) += isa_ipmi.o
>>>  common-obj-$(CONFIG_IPMI) += ipmi.o
>>> diff --git a/hw/ipmi/isa_ipmi.c b/hw/ipmi/isa_ipmi.c
>>> new file mode 100644
>>> index 0000000..1c1ab8d
>>> --- /dev/null
>>> +++ b/hw/ipmi/isa_ipmi.c
>>> @@ -0,0 +1,144 @@
>>> +/*
>>> + * QEMU ISA IPMI emulation
>>> + *
>>> + * Copyright (c) 2012 Corey Minyard, MontaVista Software, LLC
>>> + *
>>> + * Permission is hereby granted, free of charge, to any person obtaining a 
>>> copy
>>> + * of this software and associated documentation files (the "Software"), 
>>> to deal
>>> + * in the Software without restriction, including without limitation the 
>>> rights
>>> + * to use, copy, modify, merge, publish, distribute, sublicense, and/or 
>>> sell
>>> + * copies of the Software, and to permit persons to whom the Software is
>>> + * furnished to do so, subject to the following conditions:
>>> + *
>>> + * The above copyright notice and this permission notice shall be included 
>>> in
>>> + * all copies or substantial portions of the Software.
>>> + *
>>> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS 
>>> OR
>>> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
>>> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
>>> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR 
>>> OTHER
>>> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
>>> FROM,
>>> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 
>>> IN
>>> + * THE SOFTWARE.
>>> + */
>>> +#include "hw/hw.h"
>>> +#include "hw/isa/isa.h"
>>> +#include "hw/i386/pc.h"
>>> +#include "qemu/timer.h"
>>> +#include "sysemu/char.h"
>>> +#include "sysemu/sysemu.h"
>>> +#include "ipmi.h"
>>> +
>>> +/* This is the type the user specifies on the -device command line */
>>> +#define TYPE_ISA_IPMI           "isa-ipmi"
>>> +#define ISA_IPMI(obj) OBJECT_CHECK(ISAIPMIDevice, (obj), TYPE_ISA_IPMI)
>>> +
>>> +typedef struct ISAIPMIDevice {
>>> +    ISADevice dev;
>>> +    char *interface;
>>> +    uint32_t iobase;
>>> +    int32 isairq;
>>> +    uint8_t slave_addr;
>>> +    CharDriverState *chr;
>>> +    IPMIInterface *intf;
>>> +} ISAIPMIDevice;
>>> +
>>> +static void ipmi_isa_realizefn(DeviceState *dev, Error **errp)
>>> +{
>>> +    ISADevice *isadev = ISA_DEVICE(dev);
>>> +    ISAIPMIDevice *ipmi = ISA_IPMI(dev);
>>> +    char typename[20];
>>> +    Object *intfobj;
>>> +    IPMIInterface *intf;
>>> +    Object *bmcobj;
>>> +    IPMIBmc *bmc;
>>> +
>>> +    if (!ipmi->interface) {
>>> +        ipmi->interface = g_strdup("kcs");
>>> +    }
>>> +
>>> +    if (ipmi->chr) {
>>> +        bmcobj = object_new(TYPE_IPMI_BMC_EXTERN);
>>> +    } else {
>>> +        bmcobj = object_new(TYPE_IPMI_BMC_SIMULATOR);
>>> +    }
>>> +    bmc = IPMI_BMC(bmcobj);
>>> +    bmc->chr = ipmi->chr;
>>> +    snprintf(typename, sizeof(typename),
>>> +             TYPE_IPMI_INTERFACE_PREFIX "%s", ipmi->interface);
>>> +    intfobj = object_new(typename);
>>
>> I wonder what Andreas thinks about this.
>> There are only 3 legal types, correct?
>> I think it would be cleaner to avoid the prefix trick,
>> and just do a plain
>>      if (!ipmi->interface)) {
>>              typename = TYPE_IPMI_INTERFACE_KCS
>>      } else if (!strcmp(ipmi->interface, "kcs")) {
>>              typename = TYPE_IPMI_INTERFACE_KCS
>>      } else if ....
>>
>>
>> etc
> 
> Well, I'm fine either way.  The way I had it seems clear enough to me,
> but I wrote it :).
> 
> If Andreas or you want it changed, not a problem.  Just say so.

I do prefer mst's suggestion. You are right that your code is clear, but
it's duplicated and thus makes refactorings harder. For clarity I would
even propose to skip bmcobj in favor of bmc. Same for the other objects.
OBJECT() is cheap, unlike other casts.

Another problem is that you're using object_new() in realize at all,
which means that it's too late for any management interface to tweak
properties on the new device. One possible solution would be to create
the object in a property setter, before realizing the object. Did you
look at how some of the other backends are implemented, such as rng?

>>> +    intf = IPMI_INTERFACE(intfobj);
>>> +    bmc->intf = intf;
>>> +    intf->bmc = bmc;
>>> +    intf->io_base = ipmi->iobase;
>>> +    intf->slave_addr = ipmi->slave_addr;
>>> +    ipmi_interface_init(intf, errp);
>>> +    if (*errp) {
>>> +        return;
>>> +    }
>>> +    ipmi_bmc_init(bmc, errp);
>>> +    if (*errp) {
>>> +        return;
>>> +    }
>>> +
>>> +    /* These may be set by the interface. */
>>> +    ipmi->iobase = intf->io_base;
>>> +    ipmi->slave_addr = intf->slave_addr;
>>> +
>>> +    if (ipmi->isairq > 0) {
>>> +        isa_init_irq(isadev, &intf->irq, ipmi->isairq);
>>> +        intf->use_irq = 1;
>>> +    }
>>> +
>>> +    ipmi->intf = intf;
>>> +    object_property_add_child(OBJECT(isadev), "intf", OBJECT(intf), errp);
>>> +    if (*errp) {
>>> +        return;
>>> +    }
>>> +    object_property_add_child(OBJECT(isadev), "bmc", OBJECT(bmc), errp);
>>> +    if (*errp) {
>>> +        return;
>>> +    }
>>> +
>> Should the created object be destroyed before return?
> 
> Returning an error from the realize here appears to result in an error
> being printed and qemu being terminated, as far as I can tell.  So it
> shouldn't matter here, right?

Negative, this is a property setter that has nothing to do with what its
callers do. For one, you cannot rely on errp != NULL, so you need to use
a local Error *err = NULL; and call error_propagate() when necessary.

Also keep in mind that this realized property is publicly accessible.
When set to false and re-set to true those will definitely fail as I see
no unrealize implementation ever deleting these properties. In that
case, with your guest running, terminating QEMU is not desired.

>>> +    qdev_set_legacy_instance_id(dev, intf->io_base, intf->io_length);
>>> +
>>> +    isa_register_ioport(isadev, &intf->io, intf->io_base);
>>> +}
>>> +
>>> +static void ipmi_isa_reset(DeviceState *qdev)
>>> +{
>>> +    ISAIPMIDevice *isa = ISA_IPMI(qdev);
>>> +
>>> +    ipmi_interface_reset(isa->intf);
>>> +}
>>> +
>>> +static Property ipmi_isa_properties[] = {
>>> +    DEFINE_PROP_STRING("interface", ISAIPMIDevice, interface),
>>> +    DEFINE_PROP_UINT32("iobase", ISAIPMIDevice, iobase,  0),
>>> +    DEFINE_PROP_INT32("irq",   ISAIPMIDevice, isairq,  5),
>>> +    DEFINE_PROP_UINT8("slave_addr", ISAIPMIDevice, slave_addr,  0),
>>> +    DEFINE_PROP_CHR("chardev",  ISAIPMIDevice, chr),
>>> +    DEFINE_PROP_END_OF_LIST(),
>>> +};
>>> +
>>> +static void ipmi_isa_class_initfn(ObjectClass *klass, void *data)

s/klass/oc/ preferred.

>>> +{
>>> +    DeviceClass *dc = DEVICE_CLASS(klass);
>>> +    dc->realize = ipmi_isa_realizefn;
>>> +    dc->reset = ipmi_isa_reset;
>>> +    dc->props = ipmi_isa_properties;
>>> +}
>>> +
>>> +static const TypeInfo ipmi_isa_info = {
>>> +    .name          = TYPE_ISA_IPMI,
>>> +    .parent        = TYPE_ISA_DEVICE,
>>> +    .instance_size = sizeof(ISAIPMIDevice),
>>> +    .class_init    = ipmi_isa_class_initfn,
>>> +};
>>> +
>>> +static void ipmi_register_types(void)
>>> +{
>>> +    type_register_static(&ipmi_isa_info);
>>> +}
>>> +
>>> +type_init(ipmi_register_types)
>>> diff --git a/include/hw/nvram/fw_cfg.h b/include/hw/nvram/fw_cfg.h
>>> index 6d8a8ac..cac3a34 100644
>>> --- a/include/hw/nvram/fw_cfg.h
>>> +++ b/include/hw/nvram/fw_cfg.h
>>> @@ -38,7 +38,16 @@
>>>  
>>>  #define FW_CFG_FILE_FIRST       0x20
>>>  #define FW_CFG_FILE_SLOTS       0x10
>>> -#define FW_CFG_MAX_ENTRY        (FW_CFG_FILE_FIRST+FW_CFG_FILE_SLOTS)
>>> +
>>> +#define FW_CFG_IPMI_INTERFACE   0x30
>>> +#define FW_CFG_IPMI_BASE_ADDR   0x31
>>> +#define FW_CFG_IPMI_REG_SPACE   0x32
>>> +#define FW_CFG_IPMI_REG_SPACING 0x33
>>> +#define FW_CFG_IPMI_SLAVE_ADDR  0x34
>>> +#define FW_CFG_IPMI_IRQ         0x35
>>> +#define FW_CFG_IPMI_VERSION     0x36

Do we really need all those fw_cfg entries for an optional device?

>>> +
>>> +#define FW_CFG_MAX_ENTRY        (FW_CFG_IPMI_VERSION + 1)
>>>  
>>>  #define FW_CFG_WRITE_CHANNEL    0x4000
>>>  #define FW_CFG_ARCH_LOCAL       0x8000
>>> -- 
>>> 1.8.3.1

Regards,
Andreas

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