| Message ID | 20210219114428.1936109-1-philmd@redhat.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | hw/kvm: Exit gracefully when KVM is not supported | expand |
On Fri, 19 Feb 2021 at 11:44, Philippe Mathieu-Daudé <philmd@redhat.com> wrote: > This series aims to improve user experience by providing > a better error message when the user tries to enable KVM > on machines not supporting it. Thanks for having a look at this; fixing the ugly assertion failure if you try to enable KVM for the raspi boards has been vaguely on my todo list but never made it up to the top... > Philippe Mathieu-Daudé (7): > accel/kvm: Check MachineClass kvm_type() return value > hw/boards: Introduce 'kvm_supported' field to MachineClass > hw/arm: Set kvm_supported for KVM-compatible machines > hw/mips: Set kvm_supported for KVM-compatible machines > hw/ppc: Set kvm_supported for KVM-compatible machines > hw/s390x: Set kvm_supported to s390-ccw-virtio machines > accel/kvm: Exit gracefully when KVM is not supported Don't we also need to set kvm_supported for the relevant machine types in hw/i386 ? thanks -- PMM
On Fri, Feb 19, 2021 at 12:44:21PM +0100, Philippe Mathieu-Daudé wrote: > Hi, > > This series aims to improve user experience by providing > a better error message when the user tries to enable KVM > on machines not supporting it. Improved error message is good, but it is better if the mgmt apps knows not to try this in the first place. IOW, I think we want "query-machines" to filter out machines which are not available with the currently configured accelerator. libvirt will probe separately with both TCG and KVM enabled, so if query-machines can give the right answer in these cases, libvirt will probably "just work" and not offer to even start such a VM. Regards, Daniel
On 2/19/21 12:55 PM, Peter Maydell wrote: > On Fri, 19 Feb 2021 at 11:44, Philippe Mathieu-Daudé <philmd@redhat.com> wrote: >> This series aims to improve user experience by providing >> a better error message when the user tries to enable KVM >> on machines not supporting it. > > Thanks for having a look at this; fixing the ugly assertion > failure if you try to enable KVM for the raspi boards has > been vaguely on my todo list but never made it up to the top... The other one annoying was the xlnx-zcu102 when creating the Cortex-R cores. >> Philippe Mathieu-Daudé (7): >> accel/kvm: Check MachineClass kvm_type() return value >> hw/boards: Introduce 'kvm_supported' field to MachineClass >> hw/arm: Set kvm_supported for KVM-compatible machines >> hw/mips: Set kvm_supported for KVM-compatible machines >> hw/ppc: Set kvm_supported for KVM-compatible machines >> hw/s390x: Set kvm_supported to s390-ccw-virtio machines >> accel/kvm: Exit gracefully when KVM is not supported > > Don't we also need to set kvm_supported for the relevant > machine types in hw/i386 ? Lol, clearly a parapraxis =) I'll send it as 8/7 until I get more review comments for a v2 (in particular on the PPC patch): -- >8 -- diff --git a/hw/i386/x86.c b/hw/i386/x86.c index 6329f90ef90..da895aa051d 100644 --- a/hw/i386/x86.c +++ b/hw/i386/x86.c @@ -1218,6 +1218,7 @@ static void x86_machine_class_init(ObjectClass *oc, void *data) mc->cpu_index_to_instance_props = x86_cpu_index_to_props; mc->get_default_cpu_node_id = x86_get_default_cpu_node_id; mc->possible_cpu_arch_ids = x86_possible_cpu_arch_ids; + mc->kvm_supported = true; x86mc->compat_apic_id_mode = false; x86mc->save_tsc_khz = true; nc->nmi_monitor_handler = x86_nmi; --- Regards, Phil.
On 2/19/21 1:00 PM, Daniel P. Berrangé wrote: > On Fri, Feb 19, 2021 at 12:44:21PM +0100, Philippe Mathieu-Daudé wrote: >> Hi, >> >> This series aims to improve user experience by providing >> a better error message when the user tries to enable KVM >> on machines not supporting it. > > Improved error message is good, but it is better if the mgmt apps knows > not to try this in the first place. I am not sure this is the same problem. This series addresses users from the command line (without mgmt app). > IOW, I think we want "query-machines" to filter out machines > which are not available with the currently configured accelerator. > > libvirt will probe separately with both TCG and KVM enabled, so if > query-machines can give the right answer in these cases, libvirt > will probably "just work" and not offer to even start such a VM. Yes, agreed. There are other discussions about 'query-machines' and an eventual 'query-accels'. This series doesn't aim to fix the mgmt app problems.
On Fri, Feb 19, 2021 at 01:15:25PM +0100, Philippe Mathieu-Daudé wrote: > On 2/19/21 1:00 PM, Daniel P. Berrangé wrote: > > On Fri, Feb 19, 2021 at 12:44:21PM +0100, Philippe Mathieu-Daudé wrote: > >> Hi, > >> > >> This series aims to improve user experience by providing > >> a better error message when the user tries to enable KVM > >> on machines not supporting it. > > > > Improved error message is good, but it is better if the mgmt apps knows > > not to try this in the first place. > > I am not sure this is the same problem. This series addresses > users from the command line (without mgmt app). Users of mgmt apps can launch the same problematic raspbi + KVM config as people who don't use a mgmt app. > > IOW, I think we want "query-machines" to filter out machines > > which are not available with the currently configured accelerator. > > > > libvirt will probe separately with both TCG and KVM enabled, so if > > query-machines can give the right answer in these cases, libvirt > > will probably "just work" and not offer to even start such a VM. > > Yes, agreed. There are other discussions about 'query-machines' > and an eventual 'query-accels'. This series doesn't aim to fix > the mgmt app problems. I think this should be fixing query-machines right now. It shouldn't be much harder than a single if (...) test in the code. Regards, Daniel
On 2/19/21 12:44 PM, Philippe Mathieu-Daudé wrote: > Hi, > > This series aims to improve user experience by providing > a better error message when the user tries to enable KVM > on machines not supporting it. > > Regards, > > Phil. Hi Philippe, not sure if it fits in this series, but also the experience of a user running on a machine with cortex-a72, choosing that very same cpu with -cpu and then getting: qemu-system-aarch64: kvm_init_vcpu: kvm_arch_init_vcpu failed (0): Invalid argument is not super-friendly. Maybe some suggestion to use -cpu host with KVM could be good? Thanks, Claudio > > Philippe Mathieu-Daudé (7): > accel/kvm: Check MachineClass kvm_type() return value > hw/boards: Introduce 'kvm_supported' field to MachineClass > hw/arm: Set kvm_supported for KVM-compatible machines > hw/mips: Set kvm_supported for KVM-compatible machines > hw/ppc: Set kvm_supported for KVM-compatible machines > hw/s390x: Set kvm_supported to s390-ccw-virtio machines > accel/kvm: Exit gracefully when KVM is not supported > > include/hw/boards.h | 6 +++++- > accel/kvm/kvm-all.c | 12 ++++++++++++ > hw/arm/sbsa-ref.c | 1 + > hw/arm/virt.c | 1 + > hw/arm/xlnx-versal-virt.c | 1 + > hw/mips/loongson3_virt.c | 1 + > hw/mips/malta.c | 1 + > hw/ppc/e500plat.c | 1 + > hw/ppc/mac_newworld.c | 1 + > hw/ppc/mac_oldworld.c | 1 + > hw/ppc/mpc8544ds.c | 1 + > hw/ppc/ppc440_bamboo.c | 1 + > hw/ppc/prep.c | 1 + > hw/ppc/sam460ex.c | 1 + > hw/ppc/spapr.c | 1 + > hw/s390x/s390-virtio-ccw.c | 1 + > 16 files changed, 31 insertions(+), 1 deletion(-) >
On 2/19/21 1:18 PM, Daniel P. Berrangé wrote: > On Fri, Feb 19, 2021 at 01:15:25PM +0100, Philippe Mathieu-Daudé wrote: >> On 2/19/21 1:00 PM, Daniel P. Berrangé wrote: >>> On Fri, Feb 19, 2021 at 12:44:21PM +0100, Philippe Mathieu-Daudé wrote: >>>> Hi, >>>> >>>> This series aims to improve user experience by providing >>>> a better error message when the user tries to enable KVM >>>> on machines not supporting it. >>> >>> Improved error message is good, but it is better if the mgmt apps knows >>> not to try this in the first place. >> >> I am not sure this is the same problem. This series addresses >> users from the command line (without mgmt app). > > Users of mgmt apps can launch the same problematic raspbi + KVM config > as people who don't use a mgmt app. > >>> IOW, I think we want "query-machines" to filter out machines >>> which are not available with the currently configured accelerator. >>> >>> libvirt will probe separately with both TCG and KVM enabled, so if >>> query-machines can give the right answer in these cases, libvirt >>> will probably "just work" and not offer to even start such a VM. >> >> Yes, agreed. There are other discussions about 'query-machines' >> and an eventual 'query-accels'. This series doesn't aim to fix >> the mgmt app problems. > > I think this should be fixing query-machines right now. It shouldn't > be much harder than a single if (...) test in the code. OK I misunderstood you at first, now I got it. Will include that in v2.
On 2/19/21 1:34 PM, Claudio Fontana wrote: > On 2/19/21 12:44 PM, Philippe Mathieu-Daudé wrote: >> Hi, >> >> This series aims to improve user experience by providing >> a better error message when the user tries to enable KVM >> on machines not supporting it. >> >> Regards, >> >> Phil. > > Hi Philippe, not sure if it fits in this series, > > but also the experience of a user running on a machine with cortex-a72, > choosing that very same cpu with -cpu and then getting: > > qemu-system-aarch64: kvm_init_vcpu: kvm_arch_init_vcpu failed (0): Invalid argument > > is not super-friendly. Maybe some suggestion to use -cpu host with KVM could be good? I agree this should be improved, but it is out of the scope of this series :)