| Message ID | 20190827160554.30995-4-eric.auger@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | KVM/ARM: Fix >256 vcpus | expand |
On 8/27/19 9:05 AM, Eric Auger wrote: > +++ b/target/arm/kvm_arm.h > @@ -233,6 +233,14 @@ bool kvm_arm_pmu_supported(CPUState *cs); > */ > int kvm_arm_get_max_vm_ipa_size(MachineState *ms); > > +/** > + * kvm_arm_irq_line_layout_2 - Returns whether more than 256 > + * vcpus are supported by KVM_IRQ_LINE > + * > + * @ms: Machine state handle > + */ > +bool kvm_arm_irq_line_layout_2(MachineState *ms); > + > /** > * kvm_arm_sync_mpstate_to_kvm > * @cpu: ARMCPU > @@ -280,6 +288,11 @@ static inline int kvm_arm_get_max_vm_ipa_size(MachineState *ms) > return -ENOENT; > } > > +static inline int kvm_arm_irq_line_layout_2(MachineState *ms) > +{ > + return -ENOENT; > +} > + These signatures don't match. r~
Hi Richard, On 8/28/19 5:28 AM, Richard Henderson wrote: > On 8/27/19 9:05 AM, Eric Auger wrote: >> +++ b/target/arm/kvm_arm.h >> @@ -233,6 +233,14 @@ bool kvm_arm_pmu_supported(CPUState *cs); >> */ >> int kvm_arm_get_max_vm_ipa_size(MachineState *ms); >> >> +/** >> + * kvm_arm_irq_line_layout_2 - Returns whether more than 256 >> + * vcpus are supported by KVM_IRQ_LINE >> + * >> + * @ms: Machine state handle >> + */ >> +bool kvm_arm_irq_line_layout_2(MachineState *ms); >> + >> /** >> * kvm_arm_sync_mpstate_to_kvm >> * @cpu: ARMCPU >> @@ -280,6 +288,11 @@ static inline int kvm_arm_get_max_vm_ipa_size(MachineState *ms) >> return -ENOENT; >> } >> >> +static inline int kvm_arm_irq_line_layout_2(MachineState *ms) >> +{ >> + return -ENOENT; >> +} >> + > > These signatures don't match. thanks for spotting this. I will fix it. Best Regards Eric > > > r~ >
On Tue, 27 Aug 2019 at 17:06, Eric Auger <eric.auger@redhat.com> wrote: > > Host kernel within [4.18, 5.3] report an erroneous KVM_MAX_VCPUS=512 > for ARM. The actual capability to instantiate more than 256 vcpus > was fixed in 5.4 with the upgrade of the KVM_IRQ_LINE ABI to support > vcpu id encoded on 12 bits instead of 8 and a redistributor consuming > a single KVM IO device instead of 2. > > So let's check this capability when attempting to use more than 256 > vcpus. > > Signed-off-by: Eric Auger <eric.auger@redhat.com> > --- > hw/arm/virt.c | 7 +++++++ > target/arm/kvm.c | 7 +++++++ > target/arm/kvm_arm.h | 13 +++++++++++++ > 3 files changed, 27 insertions(+) > > diff --git a/hw/arm/virt.c b/hw/arm/virt.c > index 0d1629ccb3..bcc8d64384 100644 > --- a/hw/arm/virt.c > +++ b/hw/arm/virt.c > @@ -1575,6 +1575,13 @@ static void machvirt_init(MachineState *machine) > virt_max_cpus = GIC_NCPU; > } > > + if (kvm_enabled() && max_cpus > 256 && > + !kvm_arm_irq_line_layout_2(MACHINE(vms))) { > + error_report("Using more than 256 vcpus require a host kernel " > + "with KVM_CAP_ARM_IRQ_LINE_LAYOUT_2"); > + exit(1); > + } Is there some place we could put this check that isn't specific to the virt board, so that we don't need to duplicate it in any other future KVM-supporting boards we add? thanks -- PMM
diff --git a/hw/arm/virt.c b/hw/arm/virt.c index 0d1629ccb3..bcc8d64384 100644 --- a/hw/arm/virt.c +++ b/hw/arm/virt.c @@ -1575,6 +1575,13 @@ static void machvirt_init(MachineState *machine) virt_max_cpus = GIC_NCPU; } + if (kvm_enabled() && max_cpus > 256 && + !kvm_arm_irq_line_layout_2(MACHINE(vms))) { + error_report("Using more than 256 vcpus require a host kernel " + "with KVM_CAP_ARM_IRQ_LINE_LAYOUT_2"); + exit(1); + } + if (max_cpus > virt_max_cpus) { error_report("Number of SMP CPUs requested (%d) exceeds max CPUs " "supported by machine 'mach-virt' (%d)", diff --git a/target/arm/kvm.c b/target/arm/kvm.c index b2eaa50b8d..db88fcc5bf 100644 --- a/target/arm/kvm.c +++ b/target/arm/kvm.c @@ -171,6 +171,13 @@ bool kvm_arm_pmu_supported(CPUState *cpu) return kvm_check_extension(s, KVM_CAP_ARM_PMU_V3); } +bool kvm_arm_irq_line_layout_2(MachineState *ms) +{ + KVMState *s = KVM_STATE(ms->accelerator); + + return kvm_check_extension(s, KVM_CAP_ARM_IRQ_LINE_LAYOUT_2); +} + int kvm_arm_get_max_vm_ipa_size(MachineState *ms) { KVMState *s = KVM_STATE(ms->accelerator); diff --git a/target/arm/kvm_arm.h b/target/arm/kvm_arm.h index b3106c8600..06b4db4513 100644 --- a/target/arm/kvm_arm.h +++ b/target/arm/kvm_arm.h @@ -233,6 +233,14 @@ bool kvm_arm_pmu_supported(CPUState *cs); */ int kvm_arm_get_max_vm_ipa_size(MachineState *ms); +/** + * kvm_arm_irq_line_layout_2 - Returns whether more than 256 + * vcpus are supported by KVM_IRQ_LINE + * + * @ms: Machine state handle + */ +bool kvm_arm_irq_line_layout_2(MachineState *ms); + /** * kvm_arm_sync_mpstate_to_kvm * @cpu: ARMCPU @@ -280,6 +288,11 @@ static inline int kvm_arm_get_max_vm_ipa_size(MachineState *ms) return -ENOENT; } +static inline int kvm_arm_irq_line_layout_2(MachineState *ms) +{ + return -ENOENT; +} + static inline int kvm_arm_vgic_probe(void) { return 0;
Host kernel within [4.18, 5.3] report an erroneous KVM_MAX_VCPUS=512 for ARM. The actual capability to instantiate more than 256 vcpus was fixed in 5.4 with the upgrade of the KVM_IRQ_LINE ABI to support vcpu id encoded on 12 bits instead of 8 and a redistributor consuming a single KVM IO device instead of 2. So let's check this capability when attempting to use more than 256 vcpus. Signed-off-by: Eric Auger <eric.auger@redhat.com> --- hw/arm/virt.c | 7 +++++++ target/arm/kvm.c | 7 +++++++ target/arm/kvm_arm.h | 13 +++++++++++++ 3 files changed, 27 insertions(+)