KVM is not happy when starting a VM with weird RAM sizes:
# qemu-system-s390x --enable-kvm --nographic -m 1234K
qemu-system-s390x: kvm_set_user_memory_region: KVM_SET_USER_MEMORY_REGION
failed, slot=0, start=0x0, size=0x244000: Invalid argument
kvm_set_phys_mem: error registering slot: Invalid argument
Aborted (core dumped)
Let's handle that in a better way by rejecting such weird RAM sizes
right from the start:
# qemu-system-s390x --enable-kvm --nographic -m 1234K
qemu-system-s390x: ram size must be multiples of 1 MiB
Signed-off-by: David Hildenbrand <david@redhat.com>
---
hw/s390x/s390-virtio-ccw.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 18240a0fd8..e30cf0a2a1 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -180,6 +180,17 @@ static void s390_memory_init(MemoryRegion *ram)
{
MemoryRegion *sysmem = get_system_memory();
+ if (!QEMU_IS_ALIGNED(memory_region_size(ram), 1 * MiB)) {
+ /*
+ * The SCLP cannot possibly expose smaller granularity right now and KVM
+ * cannot handle smaller granularity. As we don't support NUMA, the
+ * region size directly corresponds to machine->ram_size, and the region
+ * is a single RAM memory region.
+ */
+ error_report("ram size must be multiples of 1 MiB");
+ exit(EXIT_FAILURE);
+ }
+
/* allocate RAM for core */
memory_region_add_subregion(sysmem, 0, ram);
--
2.46.0On 10.09.24 19:57, David Hildenbrand wrote:
> KVM is not happy when starting a VM with weird RAM sizes:
>
> # qemu-system-s390x --enable-kvm --nographic -m 1234K
> qemu-system-s390x: kvm_set_user_memory_region: KVM_SET_USER_MEMORY_REGION
> failed, slot=0, start=0x0, size=0x244000: Invalid argument
> kvm_set_phys_mem: error registering slot: Invalid argument
> Aborted (core dumped)
>
> Let's handle that in a better way by rejecting such weird RAM sizes
> right from the start:
>
> # qemu-system-s390x --enable-kvm --nographic -m 1234K
> qemu-system-s390x: ram size must be multiples of 1 MiB
>
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
> hw/s390x/s390-virtio-ccw.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
> index 18240a0fd8..e30cf0a2a1 100644
> --- a/hw/s390x/s390-virtio-ccw.c
> +++ b/hw/s390x/s390-virtio-ccw.c
> @@ -180,6 +180,17 @@ static void s390_memory_init(MemoryRegion *ram)
> {
> MemoryRegion *sysmem = get_system_memory();
>
> + if (!QEMU_IS_ALIGNED(memory_region_size(ram), 1 * MiB)) {
> + /*
> + * The SCLP cannot possibly expose smaller granularity right now and KVM
> + * cannot handle smaller granularity. As we don't support NUMA, the
> + * region size directly corresponds to machine->ram_size, and the region
> + * is a single RAM memory region.
> + */
> + error_report("ram size must be multiples of 1 MiB");
> + exit(EXIT_FAILURE);
> + }
I'll switch to
error_setg(&error_fatal, "ram size must be multiples of 1 MiB");
here, to avoid the manual exit().
Please someone shout if I should keep it as is.
--
Cheers,
David / dhildenb
On 23/09/2024 11.19, David Hildenbrand wrote:
> On 10.09.24 19:57, David Hildenbrand wrote:
>> KVM is not happy when starting a VM with weird RAM sizes:
>>
>> # qemu-system-s390x --enable-kvm --nographic -m 1234K
>> qemu-system-s390x: kvm_set_user_memory_region: KVM_SET_USER_MEMORY_REGION
>> failed, slot=0, start=0x0, size=0x244000: Invalid argument
>> kvm_set_phys_mem: error registering slot: Invalid argument
>> Aborted (core dumped)
>>
>> Let's handle that in a better way by rejecting such weird RAM sizes
>> right from the start:
>>
>> # qemu-system-s390x --enable-kvm --nographic -m 1234K
>> qemu-system-s390x: ram size must be multiples of 1 MiB
>>
>> Signed-off-by: David Hildenbrand <david@redhat.com>
>> ---
>> hw/s390x/s390-virtio-ccw.c | 11 +++++++++++
>> 1 file changed, 11 insertions(+)
>>
>> diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
>> index 18240a0fd8..e30cf0a2a1 100644
>> --- a/hw/s390x/s390-virtio-ccw.c
>> +++ b/hw/s390x/s390-virtio-ccw.c
>> @@ -180,6 +180,17 @@ static void s390_memory_init(MemoryRegion *ram)
>> {
>> MemoryRegion *sysmem = get_system_memory();
>> + if (!QEMU_IS_ALIGNED(memory_region_size(ram), 1 * MiB)) {
>> + /*
>> + * The SCLP cannot possibly expose smaller granularity right now
>> and KVM
>> + * cannot handle smaller granularity. As we don't support NUMA, the
>> + * region size directly corresponds to machine->ram_size, and the
>> region
>> + * is a single RAM memory region.
>> + */
>> + error_report("ram size must be multiples of 1 MiB");
>> + exit(EXIT_FAILURE);
>> + }
>
> I'll switch to
>
> error_setg(&error_fatal, "ram size must be multiples of 1 MiB");
>
> here, to avoid the manual exit().
>
> Please someone shout if I should keep it as is.
Please keep it, according to include/qapi/error.h:
* Please don't error_setg(&error_fatal, ...), use error_report() and
* exit(), because that's more obvious.
Thanks,
Thomas
On 23.09.24 17:36, Thomas Huth wrote:
> On 23/09/2024 11.19, David Hildenbrand wrote:
>> On 10.09.24 19:57, David Hildenbrand wrote:
>>> KVM is not happy when starting a VM with weird RAM sizes:
>>>
>>> # qemu-system-s390x --enable-kvm --nographic -m 1234K
>>> qemu-system-s390x: kvm_set_user_memory_region: KVM_SET_USER_MEMORY_REGION
>>> failed, slot=0, start=0x0, size=0x244000: Invalid argument
>>> kvm_set_phys_mem: error registering slot: Invalid argument
>>> Aborted (core dumped)
>>>
>>> Let's handle that in a better way by rejecting such weird RAM sizes
>>> right from the start:
>>>
>>> # qemu-system-s390x --enable-kvm --nographic -m 1234K
>>> qemu-system-s390x: ram size must be multiples of 1 MiB
>>>
>>> Signed-off-by: David Hildenbrand <david@redhat.com>
>>> ---
>>> hw/s390x/s390-virtio-ccw.c | 11 +++++++++++
>>> 1 file changed, 11 insertions(+)
>>>
>>> diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
>>> index 18240a0fd8..e30cf0a2a1 100644
>>> --- a/hw/s390x/s390-virtio-ccw.c
>>> +++ b/hw/s390x/s390-virtio-ccw.c
>>> @@ -180,6 +180,17 @@ static void s390_memory_init(MemoryRegion *ram)
>>> {
>>> MemoryRegion *sysmem = get_system_memory();
>>> + if (!QEMU_IS_ALIGNED(memory_region_size(ram), 1 * MiB)) {
>>> + /*
>>> + * The SCLP cannot possibly expose smaller granularity right now
>>> and KVM
>>> + * cannot handle smaller granularity. As we don't support NUMA, the
>>> + * region size directly corresponds to machine->ram_size, and the
>>> region
>>> + * is a single RAM memory region.
>>> + */
>>> + error_report("ram size must be multiples of 1 MiB");
>>> + exit(EXIT_FAILURE);
>>> + }
>>
>> I'll switch to
>>
>> error_setg(&error_fatal, "ram size must be multiples of 1 MiB");
>>
>> here, to avoid the manual exit().
>>
>> Please someone shout if I should keep it as is.
>
> Please keep it, according to include/qapi/error.h:
>
> * Please don't error_setg(&error_fatal, ...), use error_report() and
> * exit(), because that's more obvious.
>
Controversial, but will do. Thanks!
--
Cheers,
David / dhildenb
On Tue, 2024-09-10 at 19:57 +0200, David Hildenbrand wrote: > KVM is not happy when starting a VM with weird RAM sizes: > > # qemu-system-s390x --enable-kvm --nographic -m 1234K > qemu-system-s390x: kvm_set_user_memory_region: KVM_SET_USER_MEMORY_REGION > failed, slot=0, start=0x0, size=0x244000: Invalid argument > kvm_set_phys_mem: error registering slot: Invalid argument > Aborted (core dumped) > > Let's handle that in a better way by rejecting such weird RAM sizes > right from the start: > > # qemu-system-s390x --enable-kvm --nographic -m 1234K > qemu-system-s390x: ram size must be multiples of 1 MiB > > Signed-off-by: David Hildenbrand <david@redhat.com> > --- > hw/s390x/s390-virtio-ccw.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) TIL. Thanks David! Reviewed-by: Eric Farman <farman@linux.ibm.com>
On 10/09/2024 19.57, David Hildenbrand wrote: > KVM is not happy when starting a VM with weird RAM sizes: > > # qemu-system-s390x --enable-kvm --nographic -m 1234K > qemu-system-s390x: kvm_set_user_memory_region: KVM_SET_USER_MEMORY_REGION > failed, slot=0, start=0x0, size=0x244000: Invalid argument > kvm_set_phys_mem: error registering slot: Invalid argument > Aborted (core dumped) > > Let's handle that in a better way by rejecting such weird RAM sizes > right from the start: > > # qemu-system-s390x --enable-kvm --nographic -m 1234K > qemu-system-s390x: ram size must be multiples of 1 MiB > > Signed-off-by: David Hildenbrand <david@redhat.com> > --- > hw/s390x/s390-virtio-ccw.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) Reviewed-by: Thomas Huth <thuth@redhat.com>
On 9/10/24 7:57 PM, David Hildenbrand wrote: > KVM is not happy when starting a VM with weird RAM sizes: > > # qemu-system-s390x --enable-kvm --nographic -m 1234K > qemu-system-s390x: kvm_set_user_memory_region: KVM_SET_USER_MEMORY_REGION > failed, slot=0, start=0x0, size=0x244000: Invalid argument > kvm_set_phys_mem: error registering slot: Invalid argument > Aborted (core dumped) > > Let's handle that in a better way by rejecting such weird RAM sizes > right from the start: > Huh, I always assumed that ram is handled in multiples of 1MB in QEMU. Acked-by: Janosch Frank <frankja@linux.ibm.com>
On 11.09.24 13:28, Janosch Frank wrote: > On 9/10/24 7:57 PM, David Hildenbrand wrote: >> KVM is not happy when starting a VM with weird RAM sizes: >> >> # qemu-system-s390x --enable-kvm --nographic -m 1234K >> qemu-system-s390x: kvm_set_user_memory_region: KVM_SET_USER_MEMORY_REGION >> failed, slot=0, start=0x0, size=0x244000: Invalid argument >> kvm_set_phys_mem: error registering slot: Invalid argument >> Aborted (core dumped) >> >> Let's handle that in a better way by rejecting such weird RAM sizes >> right from the start: >> > > Huh, I always assumed that ram is handled in multiples of 1MB in QEMU. Me as well, I did not dig if that changed at some point ... or why such odd sizes would even be required :) Thanks! -- Cheers, David / dhildenb
On 11/09/2024 14.38, David Hildenbrand wrote: > On 11.09.24 13:28, Janosch Frank wrote: >> On 9/10/24 7:57 PM, David Hildenbrand wrote: >>> KVM is not happy when starting a VM with weird RAM sizes: >>> >>> # qemu-system-s390x --enable-kvm --nographic -m 1234K >>> qemu-system-s390x: kvm_set_user_memory_region: >>> KVM_SET_USER_MEMORY_REGION >>> failed, slot=0, start=0x0, size=0x244000: Invalid argument >>> kvm_set_phys_mem: error registering slot: Invalid argument >>> Aborted (core dumped) >>> >>> Let's handle that in a better way by rejecting such weird RAM sizes >>> right from the start: >>> >> >> Huh, I always assumed that ram is handled in multiples of 1MB in QEMU. > > Me as well, I did not dig if that changed at some point ... or why such odd > sizes would even be required :) I guess it's there for some old PC hardware ... Remember, 640K ought to be enough for anybody. Thomas
On 11.09.24 14:46, Thomas Huth wrote:
> On 11/09/2024 14.38, David Hildenbrand wrote:
>> On 11.09.24 13:28, Janosch Frank wrote:
>>> On 9/10/24 7:57 PM, David Hildenbrand wrote:
>>>> KVM is not happy when starting a VM with weird RAM sizes:
>>>>
>>>> # qemu-system-s390x --enable-kvm --nographic -m 1234K
>>>> qemu-system-s390x: kvm_set_user_memory_region:
>>>> KVM_SET_USER_MEMORY_REGION
>>>> failed, slot=0, start=0x0, size=0x244000: Invalid argument
>>>> kvm_set_phys_mem: error registering slot: Invalid argument
>>>> Aborted (core dumped)
>>>>
>>>> Let's handle that in a better way by rejecting such weird RAM sizes
>>>> right from the start:
>>>>
>>>
>>> Huh, I always assumed that ram is handled in multiples of 1MB in QEMU.
>>
>> Me as well, I did not dig if that changed at some point ... or why such odd
>> sizes would even be required :)
>
> I guess it's there for some old PC hardware ... Remember, 640K ought to be
> enough for anybody.
True, maybe the "default to MiB" made some of us believe that something
smaller is impossible :)
And in fact, I think suffix support was added in
commit 6e1d3c1c855818a6d1399698572afae0d11b872b
Author: Igor Mammedov <imammedo@redhat.com>
Date: Wed Nov 27 01:27:35 2013 +0100
vl: convert -m to QemuOpts
Adds option to -m
"size" - startup memory amount
For compatibility with legacy CLI if suffix-less number is passed,
it assumes amount in Mb.
Otherwise user is free to use suffixed number using suffixes b,k/K,M,G
--
Cheers,
David / dhildenb
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