The category will be used to sort the devices displayed in
the command line help.
Signed-off-by: Marcel Apfelbaum <marcel.a@redhat.com>
Message-id: 1375107465-25767-4-git-send-email-marcel.a@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
When pc-sysfw.rom_only == 0, flash memory will be
usable with kvm. In order to enable flash memory mode,
a pflash device must be created. (For example, by
using the -pflash command line parameter.)
Usage of a flash memory device with kvm requires
KVM_CAP_READONLY_MEM, and kvm will abort if
a flash device is used with an older kvm which does
not support this capability.
If a flash device is not used, then qemu/kvm will
operate in the original rom-mode.
Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1369816047-16384-5-git-send-email-jordan.l.justen@intel.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
The isapc machine with seabios currently requires the BIOS region
to be read/write memory rather than read-only memory.
KVM currently cannot support the BIOS as a ROM region, but qemu
in non-KVM mode can. Based on this, isapc machine currently only
works with KVM.
To work-around this isapc issue, this change avoids marking the
BIOS as readonly for isapc.
This change also will allow KVM to start supporting ROM mode
via KVM_CAP_READONLY_MEM.
Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1369816047-16384-2-git-send-email-jordan.l.justen@intel.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This reverts commit 9953f8822c.
While Markus's analysis is entirely correct, there are 1.6 patches
that fix the bug for real and without requiring machine type hacks.
Let's think of the children who will have to read this code, and
avoid a complicated mess of semantics that differ between <1.5,
1.5, and >1.5.
Conflicts:
hw/i386/pc_piix.c
hw/i386/pc_q35.c
include/hw/i386/pc.h
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Anthony Liguori <aliguori@us.ibm.com>
Message-id: 1368189483-7915-1-git-send-email-pbonzini@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Use of a flash memory device for the BIOS was added in series "[PATCH
v10 0/8] PC system flash support", commit 4732dca..1b89faf, v1.1.
Flash vs. ROM is a guest-visible difference. Thus, flash use had to
be suppressed for machine types pc-1.0 and older. This was
accomplished by adding a dummy device "pc-sysfw" with property
"rom_only":
* Non-zero rom_only means "use ROM". Default for pc-1.0 and older.
* Zero rom_only means "maybe use flash". Default for newer machines.
Not only is the dummy device ugly, it was also retroactively added to
the older machine types! Fortunately, it's not guest-visible (thus no
immediate guest ABI breakage), and has no vmstate (thus no immediate
migration breakage). Breakage occurs only if the user unwisely
enables flash by setting rom_only to zero. Patch review FAIL #1.
Why "maybe use flash"? Flash didn't (and still doesn't) work with
KVM. Therefore, rom_only=0 really means "use flash, except when KVM
is enabled, use ROM". This is a Bad Idea, because it makes enabling/
disabling KVM guest-visible. Patch review FAIL #2.
Aside: it also precludes migrating between KVM on and off, but that's
not possible for other reasons anyway.
Fix as follows:
1. Change the meaning of rom_only=0 to mean "use flash, no ifs, buts,
or maybes" for pc-i440fx-1.5 and pc-q35-1.5. Don't change anything
for older machines (to remain bug-compatible).
2. Change the default value from 0 to 1 for these machines.
Necessary, because 0 doesn't work with KVM. Once it does, we can flip
the default back to 0.
3. Don't revert the retroactive addition of device "pc-sysfw" to older
machine types. Seems not worth the trouble.
4. Add a TODO comment asking for device "pc-sysfw" to be dropped once
flash works with KVM.
Net effect is that you get a BIOS ROM again even when KVM is disabled,
just like for machines predating the introduction of flash.
To get flash instead, use "--global pc-sysfw.rom_only=0".
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-id: 1365780303-26398-4-git-send-email-armbru@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
