Qemu vs Qemu-KVM

Qemu vs Qemu-KVM

[Mikolaj Kucharski]

Hi all,

Qemu and Qemu-KVM, are they the same projects with the same developers
behind of those projects or not? Are those projects trying to converge
at some stage, or is this just RedHat's convention to create from kvm's
sources package named qemu?

I have an issue with qemu from Fedora 12, and I've send email[#ref1] to
qemu-devel mailing list, but after looking again closer to 0.12.1
release from qemu.org and kvm.sf.net sources are not the same.

I have personal interest in resolving RedHat's bz #508801, unfortunately
I cannot do that myself, so I wanted to ask on the list for help, but now
I'm confused where should I go.



References
 1. http://marc.info/?l=qemu-devel&m=126132150719852&w=2
 2. https://bugzilla.redhat.com/show_bug.cgi?id=508801


-- 
best regards
q#

Re: Qemu vs Qemu-KVM

[Gleb Natapov]

On Sun, Dec 20, 2009 at 11:10:24PM +0000, Mikolaj Kucharski wrote:
> Hi all,
> 
> Qemu and Qemu-KVM, are they the same projects with the same developers
> behind of those projects or not? Are those projects trying to converge
> at some stage, or is this just RedHat's convention to create from kvm's
> sources package named qemu?
> 
Trying to converge.

> I have an issue with qemu from Fedora 12, and I've send email[#ref1] to
> qemu-devel mailing list, but after looking again closer to 0.12.1
> release from qemu.org and kvm.sf.net sources are not the same.
> 
> I have personal interest in resolving RedHat's bz #508801, unfortunately
> I cannot do that myself, so I wanted to ask on the list for help, but now
> I'm confused where should I go.
> 
Can you try kvm modules from latest kvm.git please? It looks like emulation of
"push %ds" fails and it was added after 2.6.32.

--
			Gleb.

Re: Qemu vs Qemu-KVM

[Avi Kivity]

On 12/21/2009 09:22 AM, Gleb Natapov wrote:
>
> Can you try kvm modules from latest kvm.git please? It looks like emulation of
> "push %ds" fails and it was added after 2.6.32.
>
>    

We shouldn't be emulating 'push %ds' at all.  It's not used either for 
mmio or for updating page tables.  Something went wrong earlier.

-- 
error compiling committee.c: too many arguments to function

Re: Qemu vs Qemu-KVM

[Mikolaj Kucharski]

On Mon, Dec 21, 2009 at 09:22:52AM +0200, Gleb Natapov wrote:
> > I have personal interest in resolving RedHat's bz #508801, unfortunately
> > I cannot do that myself, so I wanted to ask on the list for help, but now
> > I'm confused where should I go.
> > 
> Can you try kvm modules from latest kvm.git please? It looks like emulation of
> "push %ds" fails and it was added after 2.6.32.

Having following GIT repositories:

git://git.kernel.org/pub/scm/virt/kvm/kvm.git
git://git.kernel.org/pub/scm/virt/kvm/kvm-kmod.git

Which one I should use to build my modules from? I would like to keep my
system (Fedora 12) consistent and I don't want to have any parts built
outside of rpm. I would like to contribute/help for RedHat's bz #508801
resolution, but I need some directions.

Is kvm.git whole Linux kernel?

-- 
best regards
q#

Re: Qemu vs Qemu-KVM

[Gleb Natapov]

On Mon, Dec 21, 2009 at 10:21:14PM +0000, Mikolaj Kucharski wrote:
> On Mon, Dec 21, 2009 at 09:22:52AM +0200, Gleb Natapov wrote:
> > > I have personal interest in resolving RedHat's bz #508801, unfortunately
> > > I cannot do that myself, so I wanted to ask on the list for help, but now
> > > I'm confused where should I go.
> > > 
> > Can you try kvm modules from latest kvm.git please? It looks like emulation of
> > "push %ds" fails and it was added after 2.6.32.
> 
> Having following GIT repositories:
> 
> git://git.kernel.org/pub/scm/virt/kvm/kvm.git
> git://git.kernel.org/pub/scm/virt/kvm/kvm-kmod.git
> 
> Which one I should use to build my modules from? I would like to keep my
> system (Fedora 12) consistent and I don't want to have any parts built
> outside of rpm. I would like to contribute/help for RedHat's bz #508801
> resolution, but I need some directions.
> 
> Is kvm.git whole Linux kernel?
> 
Don't bother, I already tested upstream with OpenBSD and, as Avi said,
the problem is somewhere else.

--
			Gleb.

Re: Qemu vs Qemu-KVM

[Avi Kivity]

On 12/22/2009 12:21 AM, Mikolaj Kucharski wrote:
> On Mon, Dec 21, 2009 at 09:22:52AM +0200, Gleb Natapov wrote:
>    
>>> I have personal interest in resolving RedHat's bz #508801, unfortunately
>>> I cannot do that myself, so I wanted to ask on the list for help, but now
>>> I'm confused where should I go.
>>>
>>>        
>> Can you try kvm modules from latest kvm.git please? It looks like emulation of
>> "push %ds" fails and it was added after 2.6.32.
>>      
> Having following GIT repositories:
>
> git://git.kernel.org/pub/scm/virt/kvm/kvm.git
> git://git.kernel.org/pub/scm/virt/kvm/kvm-kmod.git
>
> Which one I should use to build my modules from? I would like to keep my
> system (Fedora 12) consistent and I don't want to have any parts built
> outside of rpm. I would like to contribute/help for RedHat's bz #508801
> resolution, but I need some directions.
>
>    

git clone git://git.kernel.org/pub/scm/virt/kvm/kvm-kmod.git

git submodule init
git submodule update
./configure
make sync
make
make install

> Is kvm.git whole Linux kernel

Yes.  kvm-kmod downloads it (via git submodule) and extracts the kvm 
bits (via make sync).

-- 
error compiling committee.c: too many arguments to function

Re: Qemu vs Qemu-KVM

[Gleb Natapov]

On Tue, Dec 22, 2009 at 09:15:57AM +0200, Gleb Natapov wrote:
> On Mon, Dec 21, 2009 at 10:21:14PM +0000, Mikolaj Kucharski wrote:
> > On Mon, Dec 21, 2009 at 09:22:52AM +0200, Gleb Natapov wrote:
> > > > I have personal interest in resolving RedHat's bz #508801, unfortunately
> > > > I cannot do that myself, so I wanted to ask on the list for help, but now
> > > > I'm confused where should I go.
> > > > 
> > > Can you try kvm modules from latest kvm.git please? It looks like emulation of
> > > "push %ds" fails and it was added after 2.6.32.
> > 
> > Having following GIT repositories:
> > 
> > git://git.kernel.org/pub/scm/virt/kvm/kvm.git
> > git://git.kernel.org/pub/scm/virt/kvm/kvm-kmod.git
> > 
> > Which one I should use to build my modules from? I would like to keep my
> > system (Fedora 12) consistent and I don't want to have any parts built
> > outside of rpm. I would like to contribute/help for RedHat's bz #508801
> > resolution, but I need some directions.
> > 
> > Is kvm.git whole Linux kernel?
> > 
> Don't bother, I already tested upstream with OpenBSD and, as Avi said,
> the problem is somewhere else.
> 
For some strange reason openbsd configures gsi 4 (com0) and gsi 12
(i8042) to be level triggered active high in ioapic. That causes KVM
to send endless stream of interrupts into the guest, so guest's stack
overflows into framebuffer area. At this point KVM start to emulate
instructions and fails. I don't know why openbsd configures those
interrupts incorrectly. It also ignores my attempts to override interrupt
polarity/type with ACPI tables. Somebody knowledgeable in openbsd should
look into why it configures interrupt controller incorrectly. If I
override wrong settings inside KVM like in the patch below openbsd boots,
but I doubt com port is usable. 


diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
index 38a2d20..fc37eac 100644
--- a/virt/kvm/ioapic.c
+++ b/virt/kvm/ioapic.c
@@ -121,6 +121,8 @@ static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
 	default:
 		index = (ioapic->ioregsel - 0x10) >> 1;
 
+		if (!(ioapic->ioregsel & 1))
+			val &= ~0xa000;
 		ioapic_debug("change redir index %x val %x\n", index, val);
 		if (index >= IOAPIC_NUM_PINS)
 			return;
--
			Gleb.