Re: [Qemu-devel] [RFC PATCH 1/5] bootindex: add *_boot_device_path function

[Amos Kong <akong@redhat.com>]

On Tue, Jul 08, 2014 at 01:22:53PM +0000, Gonglei (Arei) wrote:
> > -----Original Message-----
> > From: chenliang (T)
> > Sent: Tuesday, July 08, 2014 7:03 PM
> > To: Amos Kong
> > Cc: Gonglei (Arei); qemu-devel@nongnu.org; afaerber@suse.de;
> > agraf@suse.de; stefanha@redhat.com; aik@ozlabs.ru;
> > alex.williamson@redhat.com; armbru@redhat.com; eblake@redhat.com;
> > kwolf@redhat.com; peter.maydell@linaro.org; lcapitulino@redhat.com;
> > mst@redhat.com; pbonzini@redhat.com; lersek@redhat.com;
> > kraxel@redhat.com; imammedo@redhat.com; dmitry@daynix.com;
> > marcel.a@redhat.com; peter.crosthwaite@xilinx.com; rth@twiddle.net;
> > somlo@cmu.edu; Huangweidong (C); Luonengjun; Huangpeng (Peter)
> > Subject: Re: [RFC PATCH 1/5] bootindex: add *_boot_device_path function
> > 
> > On 2014/7/8 16:33, Amos Kong wrote:
> > 
> > > On Mon, Jul 07, 2014 at 05:10:57PM +0800, arei.gonglei@huawei.com
> > wrote:
> > >> From: Chenliang <chenliang88@huawei.com>
> > >>
> > >> Add del_boot_device_path and modify_boot_device_path. Device should
> > >> be removed from boot device list  by del_boot_device_path when device
> > >> hotplug. modify_boot_device_path is used to modify deviceboot order.
> > >
> > > s/hotplug/is unhotplugged/
> > >
> > > same issue in commitlog of patch 3/5
> > >
> 
> Yep, thanks!
> 
> > >> Signed-off-by: Chenliang <chenliang88@huawei.com>
> > >> Signed-off-by: Gonglei <arei.gonglei@huawei.com>
> > >> ---
> > >>  include/sysemu/sysemu.h |  4 ++++
> > >>  vl.c                    | 55
> > +++++++++++++++++++++++++++++++++++++++++++++++++
> > >>  2 files changed, 59 insertions(+)
> > >>
> > >> diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
> > >> index 285c45b..38ef1cd 100644
> > >> --- a/include/sysemu/sysemu.h
> > >> +++ b/include/sysemu/sysemu.h
> > >> @@ -204,6 +204,10 @@ void usb_info(Monitor *mon, const QDict *qdict);
> > >>
> > >>  void add_boot_device_path(int32_t bootindex, DeviceState *dev,
> > >>                            const char *suffix);
> > >> +void del_boot_device_path(int32_t bootindex, DeviceState *dev,
> > >> +                          const char *suffix);
> > >> +void modify_boot_device_path(int32_t bootindex, DeviceState *dev,
> > >> +                             const char *suffix);
> > >>  char *get_boot_devices_list(size_t *size, bool ignore_suffixes);
> > >>
> > >>  DeviceState *get_boot_device(uint32_t position);
> > >> diff --git a/vl.c b/vl.c
> > >> index a1686ef..6264e11 100644
> > >> --- a/vl.c
> > >> +++ b/vl.c
> > >> @@ -1247,6 +1247,61 @@ void add_boot_device_path(int32_t bootindex,
> > DeviceState *dev,
> > >>      QTAILQ_INSERT_TAIL(&fw_boot_order, node, link);
> > >>  }
> > >>
> > >> +static bool is_same_fw_dev_path(DeviceState *src, DeviceState *target)
> > >> +{
> > >> +    bool ret = false;
> > >> +    char *devpath_src = qdev_get_fw_dev_path(src);
> > >> +    char *devpath_target = qdev_get_fw_dev_path(target);
> > >> +
> > >> +    if (!strcmp(devpath_src, devpath_target)) {
> > >> +        ret = true;
> > >> +    }
> > >> +
> > >> +    g_free(devpath_src);
> > >> +    g_free(devpath_target);
> > >> +    return ret;
> > >> +}
> > >> +
> > >> +void del_boot_device_path(int32_t bootindex, DeviceState *dev,
> > >> +                          const char *suffix)
> > >> +{
> > >> +    FWBootEntry *i;
> > >> +
> > >> +    assert(dev != NULL);
> > >> +
> > >
> > > assert(booindex >= 0 || suffix != NULL);
> > >
> 
> suffix call be NULL. 
> 
> > >> +    QTAILQ_FOREACH(i, &fw_boot_order, link) {
> > >> +        if (is_same_fw_dev_path(i->dev, dev)) {
> > >
> > >                if (!suffix) {
> > >                    break;
> > >                }

If suffix is NULL, at least we should do nothing in the loop.

> > >
> > >> +            if (suffix && i->suffix && strcmp(i->suffix, suffix)) {
> > >> +                continue;
> > >> +            }

How about this one?

                   if (!suffix) {
                        break;
                   } else (i->suffix && strcmp(i->suffix, suffix)) {
                        continue;
                   }


> > >
> > > If suffix is NULL, then all the entries will be removed?
> 
> If suffix is NULL, the entry will be checked by the bootindex as below
> QTAILQ_FOREACH loop. If suffix and bootindex are all not match,
> no entry will not be deleted from the global fw_boot_order list.

This is why I added "assert(booindex >= 0 || suffix != NULL);" on
above.
                                         ^^^^
> > 
> > 
> > yes, it will be if caller don't give suffix.
> > 
> > >
> > >> +            QTAILQ_REMOVE(&fw_boot_order, i, link);
> > >> +            g_free(i->suffix);
> > >> +            g_free(i);
> > >> +            break;
> > >> +        }
> > >> +    }
> > >> +
> > >> +    if (bootindex == -1) {
> > >
> > >    if (bootindex < 0) {
> > 
> > 
> > acked
> > 
> > >
> > >> +        return;
> > >> +    }
> > >> +
> > >> +    QTAILQ_FOREACH(i, &fw_boot_order, link) {
> > >> +        if (i->bootindex == bootindex) {
> > >> +            QTAILQ_REMOVE(&fw_boot_order, i, link);
> > >> +            g_free(i->suffix);
> > >> +            g_free(i);
> > >> +            break;
> > >> +        }
> > >> +    }
> > >> +}
> > >> +
> > >> +void modify_boot_device_path(int32_t bootindex, DeviceState *dev,
> > >> +                             const char *suffix)
> > >> +{
> > >> +    del_boot_device_path(bootindex, dev, suffix);
> > >> +    add_boot_device_path(bootindex, dev, suffix);
> > >
> > > Why do you directly modify existed entry?
> > 
> > 
> > Sometimes, in old boot device list:
> > 
> > device_id      bootindex
> > net0           1
> > net1           2
> > net2           3
> > 
> > we want to make vm reboot from net2, we can do it like this:
> > 
> > modify_boot_device_path(bootindex=1, DeviceState=net2, suffix=NULL), the
> > new boot device list will like this:
> > 
> > device_id     bootindex
> > net2          1
> > net1          2
> > 
> 
> Yes. 
> the visual bootindex of net0 will be deleted, and then we can look 
> it as default value.
> 
> Best regards,
> -Gonglei

-- 
			Amos.