* Re: [PATCH] target/s390x: Make container ids in SysIB_15x 1-based
2026-05-11 13:49 [PATCH] target/s390x: Make container ids in SysIB_15x 1-based Alexandra Winter
@ 2026-05-12 10:17 ` Gautam Gala
2026-05-12 11:05 ` Christian Borntraeger
2026-05-12 14:35 ` Hendrik Brueckner
2 siblings, 0 replies; 4+ messages in thread
From: Gautam Gala @ 2026-05-12 10:17 UTC (permalink / raw)
To: Alexandra Winter
Cc: Heiko Carstens, Christian Borntraeger, Hendrik Brueckner,
Halil Pasic, Vasily Gorbik, Alexander Gordeev, Sven Schnelle,
Eric Farman, Matthew Rosato, Ilya Leoshkevich, Thomas Richter,
Shrikanth Hegde, Mete Durlu, linux390-list, Richard Henderson,
David Hildenbrand, Cornelia Huck, qemu-stable, qemu-devel,
qemu-trivial, qemu-s390x
On Mon, May 11, 2026 at 03:49:09PM +0200, Alexandra Winter wrote:
> The Container Id in a container-type TLE of SysIB_15x is defined as 8-bit
> unsigned nonzero integer. Make stsi fc 15 emulation architecture compliant,
> by starting the container ids at 1 for the lowest numbered container.
>
> The qemu misbehaviour without this patch becomes obvious due to a recently
> proposed kernel fix. Older linux kernels pass the container ids from stsi
> fc15 unchanged to sysfs, i.e. starting at 1 on s390 hardware. This resulted
> in off-by-one values when compared to the values from HMC. A Linux kernel
> fix is being proposed to correct the sysfs topology ids by -1, so they
> start at 0, e.g. when displayed by 'lscpu -ye'. In case a KVM guest with a
> fixed kernel runs on a host with a qemu without this fix, this can result
> in container ids erroneously being shown as 255.
> Example (Fixed guest on unfixed qemu):
> $ lscpu -ye
> CPU NODE DRAWER BOOK SOCKET CORE L1d:L1i:L2 ONLINE CONFIGURED POLARIZATION ADDRESS
> 0 0 255 255 255 0 0:0:0 yes yes vert-medium 0
> 1 0 255 255 0 1 1:1:1 yes yes vert-medium 1
> After this fix:
> $ lscpu -ye
> CPU NODE DRAWER BOOK SOCKET CORE L1d:L1i:L2 ONLINE CONFIGURED POLARIZATION ADDRESS
> 0 0 0 0 0 0 0:0:0 yes yes vert-medium 0
> 1 0 0 0 1 1 1:1:1 yes yes vert-medium 1
>
> Fixes: f4f54b582f ("target/s390x/cpu topology: handle STSI(15) and build the SYSIB")
> Signed-off-by: Alexandra Winter <wintera@linux.ibm.com>
> ---
> target/s390x/kvm/stsi-topology.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/target/s390x/kvm/stsi-topology.c b/target/s390x/kvm/stsi-topology.c
> index 301d41b68d..afd00da0e6 100644
> --- a/target/s390x/kvm/stsi-topology.c
> +++ b/target/s390x/kvm/stsi-topology.c
> @@ -90,9 +90,9 @@ static int stsi_topology_fill_sysib(S390TopologyList *topology_list,
> int last_drawer = -1;
> int last_book = -1;
> int last_socket = -1;
> - int drawer_id = 0;
> - int book_id = 0;
> - int socket_id = 0;
> + int drawer_id = 1;
> + int book_id = 1;
> + int socket_id = 1;
> int n = sizeof(SysIB_151x);
>
> QTAILQ_FOREACH(entry, topology_list, next) {
> @@ -103,12 +103,12 @@ static int stsi_topology_fill_sysib(S390TopologyList *topology_list,
> if (level > 3 && drawer_change) {
> SYSIB_GUARD(n, sizeof(SYSIBContainerListEntry));
> p = fill_container(p, 3, drawer_id++);
> - book_id = 0;
> + book_id = 1;
> }
> if (level > 2 && book_change) {
> SYSIB_GUARD(n, sizeof(SYSIBContainerListEntry));
> p = fill_container(p, 2, book_id++);
> - socket_id = 0;
> + socket_id = 1;
> }
> if (socket_change) {
> SYSIB_GUARD(n, sizeof(SYSIBContainerListEntry));
> --
> 2.39.5 (Apple Git-154)
>
Thanks, this looks correct.
Reviewed-by: Gautam Gala <ggala@linux.ibm.com>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] target/s390x: Make container ids in SysIB_15x 1-based
2026-05-11 13:49 [PATCH] target/s390x: Make container ids in SysIB_15x 1-based Alexandra Winter
2026-05-12 10:17 ` Gautam Gala
@ 2026-05-12 11:05 ` Christian Borntraeger
2026-05-12 14:35 ` Hendrik Brueckner
2 siblings, 0 replies; 4+ messages in thread
From: Christian Borntraeger @ 2026-05-12 11:05 UTC (permalink / raw)
To: Alexandra Winter, Heiko Carstens, Hendrik Brueckner
Cc: Halil Pasic, Vasily Gorbik, Alexander Gordeev, Sven Schnelle,
Gautam Gala, Eric Farman, Matthew Rosato, Ilya Leoshkevich,
Thomas Richter, Shrikanth Hegde, Mete Durlu, Richard Henderson,
David Hildenbrand, Cornelia Huck, qemu-stable, qemu-devel,
qemu-trivial, qemu-s390x
Am 11.05.26 um 15:49 schrieb Alexandra Winter:
> The Container Id in a container-type TLE of SysIB_15x is defined as 8-bit
> unsigned nonzero integer. Make stsi fc 15 emulation architecture compliant,
> by starting the container ids at 1 for the lowest numbered container.
>
> The qemu misbehaviour without this patch becomes obvious due to a recently
> proposed kernel fix. Older linux kernels pass the container ids from stsi
> fc15 unchanged to sysfs, i.e. starting at 1 on s390 hardware. This resulted
> in off-by-one values when compared to the values from HMC. A Linux kernel
> fix is being proposed to correct the sysfs topology ids by -1, so they
> start at 0, e.g. when displayed by 'lscpu -ye'. In case a KVM guest with a
> fixed kernel runs on a host with a qemu without this fix, this can result
> in container ids erroneously being shown as 255.
> Example (Fixed guest on unfixed qemu):
> $ lscpu -ye
> CPU NODE DRAWER BOOK SOCKET CORE L1d:L1i:L2 ONLINE CONFIGURED POLARIZATION ADDRESS
> 0 0 255 255 255 0 0:0:0 yes yes vert-medium 0
> 1 0 255 255 0 1 1:1:1 yes yes vert-medium 1
> After this fix:
> $ lscpu -ye
> CPU NODE DRAWER BOOK SOCKET CORE L1d:L1i:L2 ONLINE CONFIGURED POLARIZATION ADDRESS
> 0 0 0 0 0 0 0:0:0 yes yes vert-medium 0
> 1 0 0 0 1 1 1:1:1 yes yes vert-medium 1
>
> Fixes: f4f54b582f ("target/s390x/cpu topology: handle STSI(15) and build the SYSIB")
> Signed-off-by: Alexandra Winter <wintera@linux.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@linux.ibm.com>
I guess this should go via Connys s390 tree.
> ---
> target/s390x/kvm/stsi-topology.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/target/s390x/kvm/stsi-topology.c b/target/s390x/kvm/stsi-topology.c
> index 301d41b68d..afd00da0e6 100644
> --- a/target/s390x/kvm/stsi-topology.c
> +++ b/target/s390x/kvm/stsi-topology.c
> @@ -90,9 +90,9 @@ static int stsi_topology_fill_sysib(S390TopologyList *topology_list,
> int last_drawer = -1;
> int last_book = -1;
> int last_socket = -1;
> - int drawer_id = 0;
> - int book_id = 0;
> - int socket_id = 0;
> + int drawer_id = 1;
> + int book_id = 1;
> + int socket_id = 1;
> int n = sizeof(SysIB_151x);
>
> QTAILQ_FOREACH(entry, topology_list, next) {
> @@ -103,12 +103,12 @@ static int stsi_topology_fill_sysib(S390TopologyList *topology_list,
> if (level > 3 && drawer_change) {
> SYSIB_GUARD(n, sizeof(SYSIBContainerListEntry));
> p = fill_container(p, 3, drawer_id++);
> - book_id = 0;
> + book_id = 1;
> }
> if (level > 2 && book_change) {
> SYSIB_GUARD(n, sizeof(SYSIBContainerListEntry));
> p = fill_container(p, 2, book_id++);
> - socket_id = 0;
> + socket_id = 1;
> }
> if (socket_change) {
> SYSIB_GUARD(n, sizeof(SYSIBContainerListEntry));
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] target/s390x: Make container ids in SysIB_15x 1-based
2026-05-11 13:49 [PATCH] target/s390x: Make container ids in SysIB_15x 1-based Alexandra Winter
2026-05-12 10:17 ` Gautam Gala
2026-05-12 11:05 ` Christian Borntraeger
@ 2026-05-12 14:35 ` Hendrik Brueckner
2 siblings, 0 replies; 4+ messages in thread
From: Hendrik Brueckner @ 2026-05-12 14:35 UTC (permalink / raw)
To: Alexandra Winter
Cc: Heiko Carstens, Christian Borntraeger, Hendrik Brueckner,
Halil Pasic, Vasily Gorbik, Alexander Gordeev, Sven Schnelle,
Gautam Gala, Eric Farman, Matthew Rosato, Ilya Leoshkevich,
Thomas Richter, Shrikanth Hegde, Mete Durlu, linux390-list,
Richard Henderson, David Hildenbrand, Cornelia Huck, qemu-stable,
qemu-devel, qemu-trivial, qemu-s390x
On Mon, May 11, 2026 at 03:49:09PM +0200, Alexandra Winter wrote:
> The Container Id in a container-type TLE of SysIB_15x is defined as 8-bit
> unsigned nonzero integer. Make stsi fc 15 emulation architecture compliant,
> by starting the container ids at 1 for the lowest numbered container.
>
> The qemu misbehaviour without this patch becomes obvious due to a recently
> proposed kernel fix. Older linux kernels pass the container ids from stsi
> fc15 unchanged to sysfs, i.e. starting at 1 on s390 hardware. This resulted
> in off-by-one values when compared to the values from HMC. A Linux kernel
> fix is being proposed to correct the sysfs topology ids by -1, so they
> start at 0, e.g. when displayed by 'lscpu -ye'. In case a KVM guest with a
> fixed kernel runs on a host with a qemu without this fix, this can result
> in container ids erroneously being shown as 255.
> Example (Fixed guest on unfixed qemu):
> $ lscpu -ye
> CPU NODE DRAWER BOOK SOCKET CORE L1d:L1i:L2 ONLINE CONFIGURED POLARIZATION ADDRESS
> 0 0 255 255 255 0 0:0:0 yes yes vert-medium 0
> 1 0 255 255 0 1 1:1:1 yes yes vert-medium 1
> After this fix:
> $ lscpu -ye
> CPU NODE DRAWER BOOK SOCKET CORE L1d:L1i:L2 ONLINE CONFIGURED POLARIZATION ADDRESS
> 0 0 0 0 0 0 0:0:0 yes yes vert-medium 0
> 1 0 0 0 1 1 1:1:1 yes yes vert-medium 1
>
> Fixes: f4f54b582f ("target/s390x/cpu topology: handle STSI(15) and build the SYSIB")
> Signed-off-by: Alexandra Winter <wintera@linux.ibm.com>
Acked-by: Hendrik Brueckner <brueckner@linux.ibm.com>
^ permalink raw reply [flat|nested] 4+ messages in thread