Re: SVSM: Updated Linux and QEMU branches available for testing

[Liam Merwick <liam.merwick@oracle.com>]

On 01/09/2026 01:58, Liam Merwick wrote:
> Hi Jörg, On 31/08/2026 16: 24, Jörg Rödel wrote: > Hi Liam, On Mon, Aug 
> 31, 2026 at 09: 41: 13AM +0100, Liam Merwick wrote: > > > On 27/08/2026 
> 17: 17, Jörg Rödel wrote: > > Hi, I just pushed out > new branches for 
> COCONUT-SVSMs
> 
> Hi Jörg,
> 
> On 31/08/2026 16:24, Jörg Rödel wrote:
>> Hi Liam, On Mon, Aug 31, 2026 at 09: 41: 13AM +0100, Liam Merwick wrote: 
>>  > > On 27/08/2026 17: 17, Jörg Rödel wrote: > > Hi, I just pushed out 
>> new branches for COCONUT-SVSMs downstream Linux > > and QEMU changes. 
>> The new branches
>> 
>> Hi Liam,
>> 
>> On Mon, Aug 31, 2026 at 09:41:13AM +0100, Liam Merwick wrote:
>>> 
>>> On 27/08/2026 17:17, Jörg Rödel wrote:
>>> > Hi, I just pushed out new branches for COCONUT-SVSMs downstream Linux
>>> > and QEMU changes. The new branches need to be used together, as there
>>> > have been rebases which changed parts of the user-space interface. For
>>> > Linux the branch is:
>>> > https: //github. com/coconut-svsm/linux/tree/svsm-v7. 2
>>> > 
>>> 
>>> 
>>> On a system that was running the 7.1 branches, I've upgraded the host
>>> kernel and qemu to the 7.2 branches and am now getting CPU stalls in
>>> the guest (and eventual boot hang).
>>> 
>>> I'm using ./scripts/launch_guest.sh (and 2026.08-devel)
>>> 
>>> One thing I've noticed with kvm_stat is that the top host functions are
>>> 
>>>  Event                                         Total %Total CurAvg/s
>>>  kvm_set_irq                                 2304824   22.2     2095
>>>  kvm_ioapic_set_irq                          2304824   22.2     2095
>>>  kvm_pic_set_irq                             2304768   22.2     2095
>>>  kvm_exit                                     626814    6.0      159
>>>  kvm_entry                                    626814    6.0      159
>>>  kvm_vmgexit_exit                             299778    2.9      105
>>>  kvm_vmgexit_enter                            299777    2.9      105
>>>  (...)
>> 
>> Thanks for testing the new branches. Can you please share your exact
>> launch_guest.sh command line? Also, what type of guest image are you running,
>> something I can download as well?

Another data point. The machine I encountered this issue is a Genoa
machine. I did a fresh install on a Turin and another Genoa and those
do not reproduce the issue - the latest SVSM branches work on those.

On the problematic Genoa, switching back to the 7.1 based kernel/qemu
combo works. This machine has been running SNP/SVSM for a while so not
a fully clean config - it could have accumulated some setting that is
incompatible but I don't see anything yet in /proc/cmdline, etc.

Regards,
Liam


>> 
> In a svsm repo, at tag v2026.08-devel where I've built svsm with
> FW_FILE pointing to the svsm edk2 repo at tag
> db97fa0a4b29 ("OvmfPkg/PlatformPei: Initialize
> PcdConfidentialComputingGuestAttr early")
> [ I tried both DEBUG and RELEASE builds ] and qemu is built from
> the svsm-v7.2 branch.
> 
> 
> ./scripts/launch_guest.sh --qemu
> /root/src/coconut/qemu/build/qemu-system-x86_64 -i bin/coconut-qemu.igvm
> --image ./resolute-server-cloudimg-amd64.img
> 
> Initially I was using OL9 in the guest but I reproduced it with an
> unmodified Ubuntu 26.04 [1]
> 
> Regards,
> Liam
> 
> [1]
> https://cloud-images.ubuntu.com/resolute/current/resolute-server-cloudimg-amd64.img
> 
>