[Qemu-devel] [PATCH] don't boot from un-selected devices

[Qemu-devel] [PATCH] don't boot from un-selected devices

[Amos Kong]

Current seabios will try to boot from selected devices first,
if they are all failed, seabios will also try to boot from
un-selected devices.

For example:
@ qemu-kvm -boot order=n,menu=on ...

Guest will boot from network first, if it's failed, guest will try to
boot from other un-selected devices (floppy, cdrom, disk) one by one.

Sometimes, user don't want to boot from some devices. This patch changes
seabios to boot only from selected devices.

If user choose first boot device from menu, then seabios will try all
the devices, even some of them are not selected.

Signed-off-by: Amos Kong <akong@redhat.com>
---
 src/boot.c |   13 ++++++++-----
 1 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/src/boot.c b/src/boot.c
index 3ca7960..ee810ac 100644
--- a/src/boot.c
+++ b/src/boot.c
@@ -424,6 +424,10 @@ interactive_bootmenu(void)
         maxmenu++;
         printf("%d. %s\n", maxmenu
                , strtcpy(desc, pos->description, ARRAY_SIZE(desc)));
+        /* If user chooses first boot device from menu, we will treat
+	    all the devices as selected. */
+        if (pos->priority == DEFAULT_PRIO)
+            pos->priority = DEFAULT_PRIO - 1;
         pos = pos->next;
     }
 
@@ -490,7 +494,10 @@ boot_prep(void)
 
     // Map drives and populate BEV list
     struct bootentry_s *pos = BootList;
-    while (pos) {
+
+    /* The priority of un-selected device is not changed,
+       we only boot from user selected devices. */
+    while (pos && pos->priority != DEFAULT_PRIO) {
         switch (pos->type) {
         case IPL_TYPE_BCV:
             call_bcv(pos->vector.seg, pos->vector.offset);
@@ -513,10 +520,6 @@ boot_prep(void)
         }
         pos = pos->next;
     }
-
-    // If nothing added a floppy/hd boot - add it manually.
-    add_bev(IPL_TYPE_FLOPPY, 0);
-    add_bev(IPL_TYPE_HARDDISK, 0);
 }
 
 
-- 
1.7.1

[Qemu-devel] [Resend][Seabios PATCH] don't boot from un-selected devices

[Amos Kong]

Current seabios will try to boot from selected devices first,
if they are all failed, seabios will also try to boot from
un-selected devices.

For example:
@ qemu-kvm -boot order=n,menu=on ...

Guest will boot from network first, if it's failed, guest will try to
boot from other un-selected devices (floppy, cdrom, disk) one by one.

Sometimes, user don't want to boot from some devices. This patch changes
seabios to boot only from selected devices.

If user choose first boot device from menu, then seabios will try all
the devices, even some of them are not selected.

Signed-off-by: Amos Kong <akong@redhat.com>
---
Resend for CCing seabios maillist.
---
 src/boot.c |   13 ++++++++-----
 1 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/src/boot.c b/src/boot.c
index 3ca7960..ee810ac 100644
--- a/src/boot.c
+++ b/src/boot.c
@@ -424,6 +424,10 @@ interactive_bootmenu(void)
         maxmenu++;
         printf("%d. %s\n", maxmenu
                , strtcpy(desc, pos->description, ARRAY_SIZE(desc)));
+        /* If user chooses first boot device from menu, we will treat
+	    all the devices as selected. */
+        if (pos->priority == DEFAULT_PRIO)
+            pos->priority = DEFAULT_PRIO - 1;
         pos = pos->next;
     }
 
@@ -490,7 +494,10 @@ boot_prep(void)
 
     // Map drives and populate BEV list
     struct bootentry_s *pos = BootList;
-    while (pos) {
+
+    /* The priority of un-selected device is not changed,
+       we only boot from user selected devices. */
+    while (pos && pos->priority != DEFAULT_PRIO) {
         switch (pos->type) {
         case IPL_TYPE_BCV:
             call_bcv(pos->vector.seg, pos->vector.offset);
@@ -513,10 +520,6 @@ boot_prep(void)
         }
         pos = pos->next;
     }
-
-    // If nothing added a floppy/hd boot - add it manually.
-    add_bev(IPL_TYPE_FLOPPY, 0);
-    add_bev(IPL_TYPE_HARDDISK, 0);
 }
 
 
-- 
1.7.1

Re: [Qemu-devel] [Resend][Seabios PATCH] don't boot from un-selected devices

[Gerd Hoffmann]

On 12/19/12 08:24, Amos Kong wrote:
> Current seabios will try to boot from selected devices first,
> if they are all failed, seabios will also try to boot from
> un-selected devices.
> 
> For example:
> @ qemu-kvm -boot order=n,menu=on ...
> 
> Guest will boot from network first, if it's failed, guest will try to
> boot from other un-selected devices (floppy, cdrom, disk) one by one.
> 
> Sometimes, user don't want to boot from some devices. This patch changes
> seabios to boot only from selected devices.

I think (i.e. I didn't test) the patch breaks booting if the user didn't
explicitly specify a boot device.

cheers,
  Gerd

Re: [Qemu-devel] [Resend][Seabios PATCH] don't boot from un-selected devices

[Amos Kong]

On Wed, Dec 19, 2012 at 08:38:13AM +0100, Gerd Hoffmann wrote:
> On 12/19/12 08:24, Amos Kong wrote:
> > Current seabios will try to boot from selected devices first,
> > if they are all failed, seabios will also try to boot from
> > un-selected devices.
> > 
> > For example:
> > @ qemu-kvm -boot order=n,menu=on ...
> > 
> > Guest will boot from network first, if it's failed, guest will try to
> > boot from other un-selected devices (floppy, cdrom, disk) one by one.
> > 
> > Sometimes, user don't want to boot from some devices. This patch changes
> > seabios to boot only from selected devices.
> 
> I think (i.e. I didn't test) the patch breaks booting if the user didn't
> explicitly specify a boot device.

Hi Gerd,

| #define DEFAULT_PRIO           9999

If we don't select some devices, their priority will always be 9999
 
| static int DefaultFloppyPrio = 101;
| static int DefaultCDPrio     = 102;
| static int DefaultHDPrio     = 103;
| static int DefaultBEVPrio    = 104;
 
The priority of selected devices will be changed to above values
first, the priority might be re-changed.

However, we can judge if device is selected or not by checking if the
priority is 9999.

. Boot guest without qemu boot option, guest will try to boot from
  network/hd/floppy/cdrom.

. If seabios ignores the order parameter of qemu, guest will also try
  to boot from network/hd/floppy/cdrom.

-- 
		Amos.

Re: [Qemu-devel] [Resend][Seabios PATCH] don't boot from un-selected devices

[Gleb Natapov]

On Wed, Dec 19, 2012 at 03:24:45PM +0800, Amos Kong wrote:
> Current seabios will try to boot from selected devices first,
> if they are all failed, seabios will also try to boot from
> un-selected devices.
> 
> For example:
> @ qemu-kvm -boot order=n,menu=on ...
> 
> Guest will boot from network first, if it's failed, guest will try to
> boot from other un-selected devices (floppy, cdrom, disk) one by one.
> 
> Sometimes, user don't want to boot from some devices. This patch changes
And sometimes he want. The patch changes behaviour unconditionally. New
behaviour should be user selectable. Something line -boot order=strict
on qemu command line.

> seabios to boot only from selected devices.
> 
> If user choose first boot device from menu, then seabios will try all
> the devices, even some of them are not selected.
> 
> Signed-off-by: Amos Kong <akong@redhat.com>
> ---
> Resend for CCing seabios maillist.
> ---
>  src/boot.c |   13 ++++++++-----
>  1 files changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/src/boot.c b/src/boot.c
> index 3ca7960..ee810ac 100644
> --- a/src/boot.c
> +++ b/src/boot.c
> @@ -424,6 +424,10 @@ interactive_bootmenu(void)
>          maxmenu++;
>          printf("%d. %s\n", maxmenu
>                 , strtcpy(desc, pos->description, ARRAY_SIZE(desc)));
> +        /* If user chooses first boot device from menu, we will treat
> +	    all the devices as selected. */
> +        if (pos->priority == DEFAULT_PRIO)
> +            pos->priority = DEFAULT_PRIO - 1;
>          pos = pos->next;
>      }
>  
> @@ -490,7 +494,10 @@ boot_prep(void)
>  
>      // Map drives and populate BEV list
>      struct bootentry_s *pos = BootList;
> -    while (pos) {
> +
> +    /* The priority of un-selected device is not changed,
> +       we only boot from user selected devices. */
> +    while (pos && pos->priority != DEFAULT_PRIO) {
>          switch (pos->type) {
>          case IPL_TYPE_BCV:
>              call_bcv(pos->vector.seg, pos->vector.offset);
> @@ -513,10 +520,6 @@ boot_prep(void)
>          }
>          pos = pos->next;
>      }
> -
> -    // If nothing added a floppy/hd boot - add it manually.
> -    add_bev(IPL_TYPE_FLOPPY, 0);
> -    add_bev(IPL_TYPE_HARDDISK, 0);
>  }
>  
>  
> -- 
> 1.7.1

--
			Gleb.

Re: [Qemu-devel] [Resend][Seabios PATCH] don't boot from un-selected devices

[Amos Kong]

On Wed, Dec 19, 2012 at 11:32:08AM +0200, Gleb Natapov wrote:
> On Wed, Dec 19, 2012 at 03:24:45PM +0800, Amos Kong wrote:
> > Current seabios will try to boot from selected devices first,
> > if they are all failed, seabios will also try to boot from
> > un-selected devices.
> > 
> > For example:
> > @ qemu-kvm -boot order=n,menu=on ...
> > 
> > Guest will boot from network first, if it's failed, guest will try to
> > boot from other un-selected devices (floppy, cdrom, disk) one by one.
> > 
> > Sometimes, user don't want to boot from some devices. This patch changes

Hi Gleb,

> And sometimes he want. The patch changes behaviour unconditionally. New
> behaviour should be user selectable. Something line -boot order=strict
> on qemu command line.

Sometimes, user don't know which devices are in boot list of seabios,
so they could not disable them through qemu cmdline.

I didn't describe the purpose clearly. Currently we can assign boot
order by "-boot order=...", if fails to boot from all devices in order
parameters, other devices in seabios's boot table will also be tried. 

The exact request should be "only boot from selected devices".

I agree to make it configurable.
eg:  qemu -boot order=nd,strict=on,menu=on
     strick: on  (only boot from selected devices)
     strick: off  (will try to boot from all devices in seabios' boot table)
     default strick should be 'off' as current behavior.
 
Thanks, Amos

> > seabios to boot only from selected devices.
> > 
> > If user choose first boot device from menu, then seabios will try all
> > the devices, even some of them are not selected.
> > 
> > Signed-off-by: Amos Kong <akong@redhat.com>
> > ---
> > Resend for CCing seabios maillist.
> > ---
> >  src/boot.c |   13 ++++++++-----
> >  1 files changed, 8 insertions(+), 5 deletions(-)
> > 
> > diff --git a/src/boot.c b/src/boot.c
> > index 3ca7960..ee810ac 100644
> > --- a/src/boot.c
> > +++ b/src/boot.c
> > @@ -424,6 +424,10 @@ interactive_bootmenu(void)
> >          maxmenu++;
> >          printf("%d. %s\n", maxmenu
> >                 , strtcpy(desc, pos->description, ARRAY_SIZE(desc)));
> > +        /* If user chooses first boot device from menu, we will treat
> > +	    all the devices as selected. */
> > +        if (pos->priority == DEFAULT_PRIO)
> > +            pos->priority = DEFAULT_PRIO - 1;
> >          pos = pos->next;
> >      }
> >  
> > @@ -490,7 +494,10 @@ boot_prep(void)
> >  
> >      // Map drives and populate BEV list
> >      struct bootentry_s *pos = BootList;
> > -    while (pos) {
> > +
> > +    /* The priority of un-selected device is not changed,
> > +       we only boot from user selected devices. */
> > +    while (pos && pos->priority != DEFAULT_PRIO) {
> >          switch (pos->type) {
> >          case IPL_TYPE_BCV:
> >              call_bcv(pos->vector.seg, pos->vector.offset);
> > @@ -513,10 +520,6 @@ boot_prep(void)
> >          }
> >          pos = pos->next;
> >      }
> > -
> > -    // If nothing added a floppy/hd boot - add it manually.
> > -    add_bev(IPL_TYPE_FLOPPY, 0);
> > -    add_bev(IPL_TYPE_HARDDISK, 0);

Re: [Qemu-devel] [Resend][Seabios PATCH] don't boot from un-selected devices

[Gleb Natapov]

On Tue, Dec 25, 2012 at 11:58:08AM +0800, Amos Kong wrote:
> On Wed, Dec 19, 2012 at 11:32:08AM +0200, Gleb Natapov wrote:
> > On Wed, Dec 19, 2012 at 03:24:45PM +0800, Amos Kong wrote:
> > > Current seabios will try to boot from selected devices first,
> > > if they are all failed, seabios will also try to boot from
> > > un-selected devices.
> > > 
> > > For example:
> > > @ qemu-kvm -boot order=n,menu=on ...
> > > 
> > > Guest will boot from network first, if it's failed, guest will try to
> > > boot from other un-selected devices (floppy, cdrom, disk) one by one.
> > > 
> > > Sometimes, user don't want to boot from some devices. This patch changes
> 
> Hi Gleb,
> 
> > And sometimes he want. The patch changes behaviour unconditionally. New
> > behaviour should be user selectable. Something line -boot order=strict
> > on qemu command line.
> 
> Sometimes, user don't know which devices are in boot list of seabios,
> so they could not disable them through qemu cmdline.
> 
This is not what I suggested though. And currently we do not have a way
to remove one device from the boot process. This is separate issue and
requires separate patch.

> I didn't describe the purpose clearly. Currently we can assign boot
> order by "-boot order=...", if fails to boot from all devices in order
> parameters, other devices in seabios's boot table will also be tried. 
order= is an old style. Use bootindex instead.

> 
> The exact request should be "only boot from selected devices".
You described the purpose clearly first time. This is how I understood
it :)

> 
> I agree to make it configurable.
> eg:  qemu -boot order=nd,strict=on,menu=on
>      strick: on  (only boot from selected devices)
>      strick: off  (will try to boot from all devices in seabios' boot table)
>      default strick should be 'off' as current behavior.
>  
Yes, this is my suggestion.

> Thanks, Amos
> 
> > > seabios to boot only from selected devices.
> > > 
> > > If user choose first boot device from menu, then seabios will try all
> > > the devices, even some of them are not selected.
> > > 
> > > Signed-off-by: Amos Kong <akong@redhat.com>
> > > ---
> > > Resend for CCing seabios maillist.
> > > ---
> > >  src/boot.c |   13 ++++++++-----
> > >  1 files changed, 8 insertions(+), 5 deletions(-)
> > > 
> > > diff --git a/src/boot.c b/src/boot.c
> > > index 3ca7960..ee810ac 100644
> > > --- a/src/boot.c
> > > +++ b/src/boot.c
> > > @@ -424,6 +424,10 @@ interactive_bootmenu(void)
> > >          maxmenu++;
> > >          printf("%d. %s\n", maxmenu
> > >                 , strtcpy(desc, pos->description, ARRAY_SIZE(desc)));
> > > +        /* If user chooses first boot device from menu, we will treat
> > > +	    all the devices as selected. */
> > > +        if (pos->priority == DEFAULT_PRIO)
> > > +            pos->priority = DEFAULT_PRIO - 1;
> > >          pos = pos->next;
> > >      }
> > >  
> > > @@ -490,7 +494,10 @@ boot_prep(void)
> > >  
> > >      // Map drives and populate BEV list
> > >      struct bootentry_s *pos = BootList;
> > > -    while (pos) {
> > > +
> > > +    /* The priority of un-selected device is not changed,
> > > +       we only boot from user selected devices. */
> > > +    while (pos && pos->priority != DEFAULT_PRIO) {
> > >          switch (pos->type) {
> > >          case IPL_TYPE_BCV:
> > >              call_bcv(pos->vector.seg, pos->vector.offset);
> > > @@ -513,10 +520,6 @@ boot_prep(void)
> > >          }
> > >          pos = pos->next;
> > >      }
> > > -
> > > -    // If nothing added a floppy/hd boot - add it manually.
> > > -    add_bev(IPL_TYPE_FLOPPY, 0);
> > > -    add_bev(IPL_TYPE_HARDDISK, 0);

--
			Gleb.

Re: [Qemu-devel] [Resend][Seabios PATCH] don't boot from un-selected devices

[Amos Kong]

On Tue, Dec 25, 2012 at 08:37:07AM +0200, Gleb Natapov wrote:
> On Tue, Dec 25, 2012 at 11:58:08AM +0800, Amos Kong wrote:
> > On Wed, Dec 19, 2012 at 11:32:08AM +0200, Gleb Natapov wrote:
> > > On Wed, Dec 19, 2012 at 03:24:45PM +0800, Amos Kong wrote:
> > > > Current seabios will try to boot from selected devices first,
> > > > if they are all failed, seabios will also try to boot from
> > > > un-selected devices.
> > > > 
> > > > For example:
> > > > @ qemu-kvm -boot order=n,menu=on ...
> > > > 
> > > > Guest will boot from network first, if it's failed, guest will try to
> > > > boot from other un-selected devices (floppy, cdrom, disk) one by one.
> > > > 
> > > > Sometimes, user don't want to boot from some devices. This patch changes
> > 
> > Hi Gleb,
> > 
> > > And sometimes he want. The patch changes behaviour unconditionally. New
> > > behaviour should be user selectable. Something line -boot order=strict
> > > on qemu command line.
> > 
> > Sometimes, user don't know which devices are in boot list of seabios,
> > so they could not disable them through qemu cmdline.

Hi Gleb, Kevin

> This is not what I suggested though. And currently we do not have a way
> to remove one device from the boot process. This is separate issue and
> requires separate patch.

issue 1: add a qemu parameter to tell seabios don't boot from unselected device
issue 2: add the ability to seabios to ignore unselected device

right?
 
> > I didn't describe the purpose clearly. Currently we can assign boot
> > order by "-boot order=...", if fails to boot from all devices in order
> > parameters, other devices in seabios's boot table will also be tried. 
> order= is an old style. Use bootindex instead.
 

(I'm trying to describe the old/new principles, correct me if sth is
wrong, thanks)

+ Old style: order=...

There are two registers in Bochs/qemu's CMOS map, which are used for
boot sequence.
(number of boot devices <= 3)
-------------------------------------------------------
0x38 S    eltorito boot sequence + boot signature check
     bits
     0    floppy boot signature check (1: disabled, 0: enabled)
     7-4  boot drive #3 (0: unused, 1: fd, 2: hd, 3:cd, else: fd)

0x3d S    eltorito boot sequence (see above)
     bits
     3-0  boot drive #1
     7-4  boot drive #2

==> set order in qemu:
hw/pc.c: set_boot_dev(ISADevice *s, const char *boot_device, ..) {
    ...
    rtc_set_memory(s, 0x3d, (bds[1] << 4) | bds[0]);
    rtc_set_memory(s, 0x38, (bds[2] << 4) | (fd_bootchk ? 0x0 : 0x1));
}

==> process order in seabios:
seabios/src/boot.c: boot_setup():
        u32 bootorder = (inb_cmos(CMOS_BIOS_BOOTFLAG2)
              | ((inb_cmos(CMOS_BIOS_BOOTFLAG1) & 0xf0) << 4));
        DefaultFloppyPrio = DefaultCDPrio = DefaultHDPrio
            = DefaultBEVPrio = DEFAULT_PRIO;

^^^ device priority will be set to 9999 before processing
        int i;
        for (i=101; i<104; i++) {
            u32 val = bootorder & 0x0f;
            bootorder >>= 4;
            switch (val) {
            case 1: DefaultFloppyPrio = i; break;
            case 2: DefaultHDPrio = i;     break;
            case 3: DefaultCDPrio = i;     break;
            case 4: DefaultBEVPrio = i;    break;

^^^ if one device is selected in cmos register, its priority will be
set to 10*, the priority of un-selected devices are still 9999.
            }
        }


+ New style: bootindex
  a bootorder string which contains the descriptions of boot devices.
  (eg. /pci@i0cf8/ethernet@3/ethernet-phy@0\n...)
  it's loaded through 'bootorder' file in rom by seabios.
  So 'selected' device can be found in this string.
  seabios will use the table index as the priority of selected devices.

  Seabios uses boot_add_{floppy,floppy,hd,bcv,cd,cbfs} to add devices
  to boot entry list. the priority will be processed at this point by:
    defPrio(prio, Default...Prio)

  'prio' is got when init the device, two conditions:
      -1: unselected
      index of bootorder table: selected in bootorder rom file.

  So after processing, priority of unselected devices will be re-set to 9999.

Based on this, we can judge if device is selected or not by checking
if priority is 9999. The only problem should be legacy FD/HD.

However, it's better to add a flag ('selected') in struct bev_s. If
qemu tells seabios to ignore unselected devices, we can ignore them in
do_boot().

// Determine next boot method and attempt a boot using it.
static void do_boot(int seq_nr) {
    ....
    // Boot the given BEV type. 
    struct bev_s *ie = &BEV[seq_nr];
    if (!ie->selected)
        boot_fail();
    ...

> > The exact request should be "only boot from selected devices".
> You described the purpose clearly first time. This is how I understood
> it :)
> 
> > 
> > I agree to make it configurable.
> > eg:  qemu -boot order=nd,strict=on,menu=on
> >      strick: on  (only boot from selected devices)
> >      strick: off  (will try to boot from all devices in seabios' boot table)
> >      default strick should be 'off' as current behavior.
> >  
> Yes, this is my suggestion.
> 
> > Thanks, Amos
> > 
> > > > seabios to boot only from selected devices.
> > > > 
> > > > If user choose first boot device from menu, then seabios will try all
> > > > the devices, even some of them are not selected.
> > >

Hi Kevin,

> > > The BIOS Boot Specification (BBS) is quite complex and your patch
> > > changes SeaBIOS' behavior in subtle ways that I'm not convinced is
> > > safe.  (For example, by not always adding an FD/HD entry it may no
> > > longer be possible to boot from a legacy option rom which emulates
> > > an
> > > FD.)

Yes, not easy as my solution.

> > > Instead of altering the core algorithm for this feature, a different
> > > approach would be to add a new "boot device" (eg, IPL_TYPE_HALT)
> > > that
> > > is only registered if found in the bootorder file and just calls
> > > boot_fail() when attempted.

But how to know if device is seleted or not? Bios processes the
bootorder complexly. But I find the priority is a clew.

Thanks, Amos

>   That way users get the default
> > > behaviour
> > > unless they explicitly request a halt in boot at a given priority.
> > > 
> > > -Kevin

> > > > Signed-off-by: Amos Kong <akong@redhat.com>
> > > > ---
> > > > Resend for CCing seabios maillist.
> > > > ---
> > > >  src/boot.c |   13 ++++++++-----
> > > >  1 files changed, 8 insertions(+), 5 deletions(-)
> > > > 
> > > > diff --git a/src/boot.c b/src/boot.c
> > > > index 3ca7960..ee810ac 100644
> > > > --- a/src/boot.c
> > > > +++ b/src/boot.c
> > > > @@ -424,6 +424,10 @@ interactive_bootmenu(void)
> > > >          maxmenu++;
> > > >          printf("%d. %s\n", maxmenu
> > > >                 , strtcpy(desc, pos->description, ARRAY_SIZE(desc)));
> > > > +        /* If user chooses first boot device from menu, we will treat
> > > > +	    all the devices as selected. */
> > > > +        if (pos->priority == DEFAULT_PRIO)
> > > > +            pos->priority = DEFAULT_PRIO - 1;
> > > >          pos = pos->next;
> > > >      }
> > > >  
> > > > @@ -490,7 +494,10 @@ boot_prep(void)
> > > >  
> > > >      // Map drives and populate BEV list
> > > >      struct bootentry_s *pos = BootList;
> > > > -    while (pos) {
> > > > +
> > > > +    /* The priority of un-selected device is not changed,
> > > > +       we only boot from user selected devices. */
> > > > +    while (pos && pos->priority != DEFAULT_PRIO) {
> > > >          switch (pos->type) {
> > > >          case IPL_TYPE_BCV:
> > > >              call_bcv(pos->vector.seg, pos->vector.offset);
> > > > @@ -513,10 +520,6 @@ boot_prep(void)
> > > >          }
> > > >          pos = pos->next;
> > > >      }
> > > > -
> > > > -    // If nothing added a floppy/hd boot - add it manually.
> > > > -    add_bev(IPL_TYPE_FLOPPY, 0);
> > > > -    add_bev(IPL_TYPE_HARDDISK, 0);

[Qemu-devel] [SeaBIOS PATCH v2] boot: support strict boot and make it configurable

[Amos Kong]

Current seabios will try to boot from selected devices first,
if they are all failed, seabios will also try to boot from
un-selected devices.

For example:
@ qemu-kvm -boot order=n,menu=on ...

Guest will boot from network first, if it's failed, guest will try to
boot from other un-selected devices (floppy, cdrom, disk) one by one.

We need to make it configurable, seabios user can config it by a rom
file('etc/boot-strict'). 'strict boot' means only boot from user
selected devices.

I added some comments in this patch to explain why we can judge if
device is selected or not by DEFAULT_PRIO(9999). I also added 'selected'
flag in struct bootentry_s and struct bev_s to make it clearer.

If this patch is accepted, I will add a boot option (-boot strict=on)
for qemu.

Signed-off-by: Amos Kong <akong@redhat.com>
---
 src/boot.c |   31 ++++++++++++++++++++++++-------
 1 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/src/boot.c b/src/boot.c
index c67cc7f..99ac791 100644
--- a/src/boot.c
+++ b/src/boot.c
@@ -92,6 +92,7 @@ find_prio(const char *glob)
     int i;
     for (i = 0; i < BootorderCount; i++)
         if (glob_prefix(glob, Bootorder[i]))
+            // device exists in the Bootorder list loaded from rom file
             return i+1;
     return -1;
 }
@@ -249,12 +250,14 @@ boot_setup(void)
             CheckFloppySig = 0;
         u32 bootorder = (inb_cmos(CMOS_BIOS_BOOTFLAG2)
                          | ((inb_cmos(CMOS_BIOS_BOOTFLAG1) & 0xf0) << 4));
+        // reset device priority to default DEFAULT_PRIO(9999)
         DefaultFloppyPrio = DefaultCDPrio = DefaultHDPrio
             = DefaultBEVPrio = DEFAULT_PRIO;
         int i;
         for (i=101; i<104; i++) {
             u32 val = bootorder & 0x0f;
             bootorder >>= 4;
+            // priority of devices selected in bootorder will be changed
             switch (val) {
             case 1: DefaultFloppyPrio = i; break;
             case 2: DefaultHDPrio = i;     break;
@@ -280,6 +283,7 @@ struct bootentry_s {
         struct drive_s *drive;
     };
     int priority;
+    int selected;
     const char *description;
     struct bootentry_s *next;
 };
@@ -304,6 +308,9 @@ bootentry_add(int type, int prio, u32 data, const char *desc)
     }
     be->type = type;
     be->priority = prio;
+    // set 'selected' flag according to the priority
+    if (prio != DEFAULT_PRIO)
+        be->selected = 1;
     be->data = data;
     be->description = desc ?: "?";
     dprintf(3, "Registering bootable: %s (type:%d prio:%d data:%x)\n"
@@ -332,6 +339,8 @@ bootentry_add(int type, int prio, u32 data, const char *desc)
 }
 
 // Return the given priority if it's set - defaultprio otherwise.
+// This function is called by boot_add_*(), it will only pass
+// DEFAULT_PRIO(9999) for unselected devices as the boot-entry priority.
 static inline int defPrio(int priority, int defaultprio) {
     return (priority < 0) ? defaultprio : priority;
 }
@@ -454,13 +463,14 @@ interactive_bootmenu(void)
 struct bev_s {
     int type;
     u32 vector;
+    int selected;
 };
 static struct bev_s BEV[20];
 static int BEVCount;
 static int HaveHDBoot, HaveFDBoot;
 
 static void
-add_bev(int type, u32 vector)
+add_bev(int type, u32 vector, int selected)
 {
     if (type == IPL_TYPE_HARDDISK && HaveHDBoot++)
         return;
@@ -471,6 +481,7 @@ add_bev(int type, u32 vector)
     struct bev_s *bev = &BEV[BEVCount++];
     bev->type = type;
     bev->vector = vector;
+    bev->selected = selected;
 }
 
 // Prepare for boot - show menu and run bcvs.
@@ -494,29 +505,29 @@ boot_prep(void)
         switch (pos->type) {
         case IPL_TYPE_BCV:
             call_bcv(pos->vector.seg, pos->vector.offset);
-            add_bev(IPL_TYPE_HARDDISK, 0);
+            add_bev(IPL_TYPE_HARDDISK, 0, pos->selected);
             break;
         case IPL_TYPE_FLOPPY:
             map_floppy_drive(pos->drive);
-            add_bev(IPL_TYPE_FLOPPY, 0);
+            add_bev(IPL_TYPE_FLOPPY, 0, pos->selected);
             break;
         case IPL_TYPE_HARDDISK:
             map_hd_drive(pos->drive);
-            add_bev(IPL_TYPE_HARDDISK, 0);
+            add_bev(IPL_TYPE_HARDDISK, 0, pos->selected);
             break;
         case IPL_TYPE_CDROM:
             map_cd_drive(pos->drive);
             // NO BREAK
         default:
-            add_bev(pos->type, pos->data);
+		add_bev(pos->type, pos->data, pos->selected);
             break;
         }
         pos = pos->next;
     }
 
     // If nothing added a floppy/hd boot - add it manually.
-    add_bev(IPL_TYPE_FLOPPY, 0);
-    add_bev(IPL_TYPE_HARDDISK, 0);
+    add_bev(IPL_TYPE_FLOPPY, 0, 0);
+    add_bev(IPL_TYPE_HARDDISK, 0, 0);
 }
 
 
@@ -654,6 +665,12 @@ do_boot(int seq_nr)
 
     // Boot the given BEV type.
     struct bev_s *ie = &BEV[seq_nr];
+
+    int strict = romfile_loadint("etc/boot-strict", 0);
+    // do strict boot, only boot from user selected devices
+    if (strict && !ie->selected)
+        boot_fail();
+
     switch (ie->type) {
     case IPL_TYPE_FLOPPY:
         printf("Booting from Floppy...\n");
-- 
1.7.1

Re: [Qemu-devel] [SeaBIOS PATCH v2] boot: support strict boot and make it configurable

[Kevin O'Connor]

On Wed, Dec 26, 2012 at 08:55:40AM +0800, Amos Kong wrote:
> Current seabios will try to boot from selected devices first,
> if they are all failed, seabios will also try to boot from
> un-selected devices.
> 
> For example:
> @ qemu-kvm -boot order=n,menu=on ...
> 
> Guest will boot from network first, if it's failed, guest will try to
> boot from other un-selected devices (floppy, cdrom, disk) one by one.
> 
> We need to make it configurable, seabios user can config it by a rom
> file('etc/boot-strict'). 'strict boot' means only boot from user
> selected devices.
> 
> I added some comments in this patch to explain why we can judge if
> device is selected or not by DEFAULT_PRIO(9999). I also added 'selected'
> flag in struct bootentry_s and struct bev_s to make it clearer.
> 
> If this patch is accepted, I will add a boot option (-boot strict=on)
> for qemu.

I think it would be simpler to use the existing bootorder file instead
of introducing a new "boot-strict" file.  Something like the below
(untested).

-Kevin


diff --git a/src/boot.c b/src/boot.c
index c67cc7f..56843e3 100644
--- a/src/boot.c
+++ b/src/boot.c
@@ -291,6 +291,7 @@ static struct bootentry_s *BootList;
 #define IPL_TYPE_CBFS        0x20
 #define IPL_TYPE_BEV         0x80
 #define IPL_TYPE_BCV         0x81
+#define IPL_TYPE_HALT        0xf0
 
 static void
 bootentry_add(int type, int prio, u32 data, const char *desc)
@@ -488,6 +489,10 @@ boot_prep(void)
     interactive_bootmenu();
     wait_threads();
 
+    int haltprio = find_prio("HALT");
+    if (haltprio >= 0)
+        bootentry_add(IPL_TYPE_HALT, haltprio, 0, "HALT");
+
     // Map drives and populate BEV list
     struct bootentry_s *pos = BootList;
     while (pos) {
@@ -672,6 +677,9 @@ do_boot(int seq_nr)
     case IPL_TYPE_BEV:
         boot_rom(ie->vector);
         break;
+    case IPL_TYPE_HALT:
+        boot_fail();
+        break;
     }
 
     // Boot failed: invoke the boot recovery function

Re: [Qemu-devel] [SeaBIOS PATCH v2] boot: support strict boot and make it configurable

[Amos Kong]

On Tue, Jan 08, 2013 at 11:00:42PM -0500, Kevin O'Connor wrote:
> On Wed, Dec 26, 2012 at 08:55:40AM +0800, Amos Kong wrote:
> > Current seabios will try to boot from selected devices first,
> > if they are all failed, seabios will also try to boot from
> > un-selected devices.
> > 
> > For example:
> > @ qemu-kvm -boot order=n,menu=on ...
> > 
> > Guest will boot from network first, if it's failed, guest will try to
> > boot from other un-selected devices (floppy, cdrom, disk) one by one.
> > 
> > We need to make it configurable, seabios user can config it by a rom
> > file('etc/boot-strict'). 'strict boot' means only boot from user
> > selected devices.
> > 
> > I added some comments in this patch to explain why we can judge if
> > device is selected or not by DEFAULT_PRIO(9999). I also added 'selected'
> > flag in struct bootentry_s and struct bev_s to make it clearer.
> > 
> > If this patch is accepted, I will add a boot option (-boot strict=on)
> > for qemu.
> 
> I think it would be simpler to use the existing bootorder file instead
> of introducing a new "boot-strict" file.  Something like the below
> (untested).

Thanks for your patch. It's good. I thought you suggest me to add a
new type, and bootentry_add unselected devices to HALT type.

I did a simple test, patch works. I will re-post this patch and change
qemu code to use this new type.

Amos
 
> -Kevin
> 
> 
> diff --git a/src/boot.c b/src/boot.c
> index c67cc7f..56843e3 100644
> --- a/src/boot.c
> +++ b/src/boot.c
> @@ -291,6 +291,7 @@ static struct bootentry_s *BootList;
>  #define IPL_TYPE_CBFS        0x20
>  #define IPL_TYPE_BEV         0x80
>  #define IPL_TYPE_BCV         0x81
> +#define IPL_TYPE_HALT        0xf0
>  
>  static void
>  bootentry_add(int type, int prio, u32 data, const char *desc)
> @@ -488,6 +489,10 @@ boot_prep(void)
>      interactive_bootmenu();
>      wait_threads();
>  
> +    int haltprio = find_prio("HALT");
> +    if (haltprio >= 0)
> +        bootentry_add(IPL_TYPE_HALT, haltprio, 0, "HALT");
> +
>      // Map drives and populate BEV list
>      struct bootentry_s *pos = BootList;
>      while (pos) {
> @@ -672,6 +677,9 @@ do_boot(int seq_nr)
>      case IPL_TYPE_BEV:
>          boot_rom(ie->vector);
>          break;
> +    case IPL_TYPE_HALT:
> +        boot_fail();
> +        break;
>      }
>  
>      // Boot failed: invoke the boot recovery function

Re: [Qemu-devel] [SeaBIOS PATCH v2] boot: support strict boot and make it configurable

[Kevin O'Connor]

On Wed, Jan 09, 2013 at 01:03:37PM +0800, Amos Kong wrote:
> On Tue, Jan 08, 2013 at 11:00:42PM -0500, Kevin O'Connor wrote:
> > On Wed, Dec 26, 2012 at 08:55:40AM +0800, Amos Kong wrote:
> > > Current seabios will try to boot from selected devices first,
> > > if they are all failed, seabios will also try to boot from
> > > un-selected devices.
[...]
> > I think it would be simpler to use the existing bootorder file instead
> > of introducing a new "boot-strict" file.  Something like the below
> > (untested).
> 
> Thanks for your patch. It's good. I thought you suggest me to add a
> new type, and bootentry_add unselected devices to HALT type.
> 
> I did a simple test, patch works. I will re-post this patch and change
> qemu code to use this new type.

Thanks.  I committed my patch.

-Kevin

[Qemu-devel] [SeaBIOS PATCH v3] boot: add a new type to halt booting

[Amos Kong]

Current seabios will try to boot from selected devices first,
if they are all failed, seabios will also try to boot from
un-selected devices.

For example:
@ qemu-kvm -boot order=n,menu=on ...

Guest will boot from network first, if it's failed, guest will try to
boot from other un-selected devices (floppy, cdrom, disk) one by one.

We need to make it configurable. This patch added a new type, qemu can
add "HALT" at the end of bootindex string, then seabios will halt
booting after trying to boot from selected devices.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Signed-off-by: Amos Kong <akong@redhat.com>
---
v3: add a new type to halt booting (Kevin)
___
 src/boot.c |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/src/boot.c b/src/boot.c
index c67cc7f..eea2354 100644
--- a/src/boot.c
+++ b/src/boot.c
@@ -291,6 +291,7 @@ static struct bootentry_s *BootList;
 #define IPL_TYPE_CBFS        0x20
 #define IPL_TYPE_BEV         0x80
 #define IPL_TYPE_BCV         0x81
+#define IPL_TYPE_HALT        0xf0
 
 static void
 bootentry_add(int type, int prio, u32 data, const char *desc)
@@ -488,6 +489,11 @@ boot_prep(void)
     interactive_bootmenu();
     wait_threads();
 
+    int haltprio = find_prio("HALT");
+
+    if (haltprio >= 0)
+        bootentry_add(IPL_TYPE_HALT, haltprio, 0, "HALT");
+
     // Map drives and populate BEV list
     struct bootentry_s *pos = BootList;
     while (pos) {
@@ -672,6 +678,9 @@ do_boot(int seq_nr)
     case IPL_TYPE_BEV:
         boot_rom(ie->vector);
         break;
+    case IPL_TYPE_HALT:
+        boot_fail();
+        break;
     }
 
     // Boot failed: invoke the boot recovery function
-- 
1.7.1

Re: [Qemu-devel] [Resend][Seabios PATCH] don't boot from un-selected devices

[Ronen Hod]

On 12/19/2012 11:32 AM, Gleb Natapov wrote:
> On Wed, Dec 19, 2012 at 03:24:45PM +0800, Amos Kong wrote:
>> Current seabios will try to boot from selected devices first,
>> if they are all failed, seabios will also try to boot from
>> un-selected devices.
>>
>> For example:
>> @ qemu-kvm -boot order=n,menu=on ...
>>
>> Guest will boot from network first, if it's failed, guest will try to
>> boot from other un-selected devices (floppy, cdrom, disk) one by one.
>>
>> Sometimes, user don't want to boot from some devices. This patch changes
> And sometimes he want. The patch changes behaviour unconditionally. New
> behaviour should be user selectable. Something line -boot order=strict
> on qemu command line.

Another option would be to add a "terminator" symbol, say "T" (I couldn't find a good terminator), so that order=ndT, would mean strict "nd".

Ronen.

>
>> seabios to boot only from selected devices.
>>
>> If user choose first boot device from menu, then seabios will try all
>> the devices, even some of them are not selected.
>>
>> Signed-off-by: Amos Kong <akong@redhat.com>
>> ---
>> Resend for CCing seabios maillist.
>> ---
>>   src/boot.c |   13 ++++++++-----
>>   1 files changed, 8 insertions(+), 5 deletions(-)
>>
>> diff --git a/src/boot.c b/src/boot.c
>> index 3ca7960..ee810ac 100644
>> --- a/src/boot.c
>> +++ b/src/boot.c
>> @@ -424,6 +424,10 @@ interactive_bootmenu(void)
>>           maxmenu++;
>>           printf("%d. %s\n", maxmenu
>>                  , strtcpy(desc, pos->description, ARRAY_SIZE(desc)));
>> +        /* If user chooses first boot device from menu, we will treat
>> +	    all the devices as selected. */
>> +        if (pos->priority == DEFAULT_PRIO)
>> +            pos->priority = DEFAULT_PRIO - 1;
>>           pos = pos->next;
>>       }
>>   
>> @@ -490,7 +494,10 @@ boot_prep(void)
>>   
>>       // Map drives and populate BEV list
>>       struct bootentry_s *pos = BootList;
>> -    while (pos) {
>> +
>> +    /* The priority of un-selected device is not changed,
>> +       we only boot from user selected devices. */
>> +    while (pos && pos->priority != DEFAULT_PRIO) {
>>           switch (pos->type) {
>>           case IPL_TYPE_BCV:
>>               call_bcv(pos->vector.seg, pos->vector.offset);
>> @@ -513,10 +520,6 @@ boot_prep(void)
>>           }
>>           pos = pos->next;
>>       }
>> -
>> -    // If nothing added a floppy/hd boot - add it manually.
>> -    add_bev(IPL_TYPE_FLOPPY, 0);
>> -    add_bev(IPL_TYPE_HARDDISK, 0);
>>   }
>>   
>>   
>> -- 
>> 1.7.1
> --
> 			Gleb.
>

Re: [Qemu-devel] [Resend][Seabios PATCH] don't boot from un-selected devices

[Gleb Natapov]

On Tue, Dec 25, 2012 at 05:59:04PM +0200, Ronen Hod wrote:
> On 12/19/2012 11:32 AM, Gleb Natapov wrote:
> >On Wed, Dec 19, 2012 at 03:24:45PM +0800, Amos Kong wrote:
> >>Current seabios will try to boot from selected devices first,
> >>if they are all failed, seabios will also try to boot from
> >>un-selected devices.
> >>
> >>For example:
> >>@ qemu-kvm -boot order=n,menu=on ...
> >>
> >>Guest will boot from network first, if it's failed, guest will try to
> >>boot from other un-selected devices (floppy, cdrom, disk) one by one.
> >>
> >>Sometimes, user don't want to boot from some devices. This patch changes
> >And sometimes he want. The patch changes behaviour unconditionally. New
> >behaviour should be user selectable. Something line -boot order=strict
> >on qemu command line.
> 
> Another option would be to add a "terminator" symbol, say "T" (I couldn't find a good terminator), so that order=ndT, would mean strict "nd".
> 
Not very helpful if the order is specified with bootindex like it
should.

> Ronen.
> 
> >
> >>seabios to boot only from selected devices.
> >>
> >>If user choose first boot device from menu, then seabios will try all
> >>the devices, even some of them are not selected.
> >>
> >>Signed-off-by: Amos Kong <akong@redhat.com>
> >>---
> >>Resend for CCing seabios maillist.
> >>---
> >>  src/boot.c |   13 ++++++++-----
> >>  1 files changed, 8 insertions(+), 5 deletions(-)
> >>
> >>diff --git a/src/boot.c b/src/boot.c
> >>index 3ca7960..ee810ac 100644
> >>--- a/src/boot.c
> >>+++ b/src/boot.c
> >>@@ -424,6 +424,10 @@ interactive_bootmenu(void)
> >>          maxmenu++;
> >>          printf("%d. %s\n", maxmenu
> >>                 , strtcpy(desc, pos->description, ARRAY_SIZE(desc)));
> >>+        /* If user chooses first boot device from menu, we will treat
> >>+	    all the devices as selected. */
> >>+        if (pos->priority == DEFAULT_PRIO)
> >>+            pos->priority = DEFAULT_PRIO - 1;
> >>          pos = pos->next;
> >>      }
> >>@@ -490,7 +494,10 @@ boot_prep(void)
> >>      // Map drives and populate BEV list
> >>      struct bootentry_s *pos = BootList;
> >>-    while (pos) {
> >>+
> >>+    /* The priority of un-selected device is not changed,
> >>+       we only boot from user selected devices. */
> >>+    while (pos && pos->priority != DEFAULT_PRIO) {
> >>          switch (pos->type) {
> >>          case IPL_TYPE_BCV:
> >>              call_bcv(pos->vector.seg, pos->vector.offset);
> >>@@ -513,10 +520,6 @@ boot_prep(void)
> >>          }
> >>          pos = pos->next;
> >>      }
> >>-
> >>-    // If nothing added a floppy/hd boot - add it manually.
> >>-    add_bev(IPL_TYPE_FLOPPY, 0);
> >>-    add_bev(IPL_TYPE_HARDDISK, 0);
> >>  }
> >>-- 
> >>1.7.1
> >--
> >			Gleb.
> >

--
			Gleb.

Re: [Qemu-devel] [Resend][Seabios PATCH] don't boot from un-selected devices

[Kevin O'Connor]

On Wed, Dec 19, 2012 at 03:24:45PM +0800, Amos Kong wrote:
> Current seabios will try to boot from selected devices first,
> if they are all failed, seabios will also try to boot from
> un-selected devices.
> 
> For example:
> @ qemu-kvm -boot order=n,menu=on ...
> 
> Guest will boot from network first, if it's failed, guest will try to
> boot from other un-selected devices (floppy, cdrom, disk) one by one.
> 
> Sometimes, user don't want to boot from some devices. This patch changes
> seabios to boot only from selected devices.
> 
> If user choose first boot device from menu, then seabios will try all
> the devices, even some of them are not selected.

The BIOS Boot Specification (BBS) is quite complex and your patch
changes SeaBIOS' behavior in subtle ways that I'm not convinced is
safe.  (For example, by not always adding an FD/HD entry it may no
longer be possible to boot from a legacy option rom which emulates an
FD.)

Instead of altering the core algorithm for this feature, a different
approach would be to add a new "boot device" (eg, IPL_TYPE_HALT) that
is only registered if found in the bootorder file and just calls
boot_fail() when attempted.  That way users get the default behaviour
unless they explicitly request a halt in boot at a given priority.

-Kevin