Since 4.18, KVM/ARM exposes a KVM_MAX_VCPUS equal to 512. However it was
reported [1] that a VM with more than 256 vcpus cannot be launched. 5.4
is about to fix the situation with 2 patches:
- one upgrade of the KVM_IRQ_LINE API [2] supporting a vcpu id encoded
on 12 bits,
- the reduction of KVM IO devices consumed by each GICv3 redistributor [3]
This series uses the new KVM_IRQ_LINE API and also checks the associated
capability (KVM_CAP_ARM_IRQ_LINE_LAYOUT_2) in machvirt.
Without the series, as soon as the -smp arguments exceeds 256, QEMU exits
with "kvm_set_irq: Invalid argument".
Best Regards
Eric
References:
[1] Can we boot a 512U kvm guest?
https://patchwork.kernel.org/patch/11091501/
[2] [PATCH] KVM: arm/arm64: vgic: Allow more than 256 vcpus for KVM_IRQ_LINE
https://patchwork.kernel.org/patch/11099609/
[3] [PATCH] KVM: arm/arm64: vgic: Use a single IO device per redistributor
https://patchwork.kernel.org/patch/11112141/
This series can be found at:
https://github.com/eauger/qemu/tree/v4.1.0-256fix-rfc-v2
History:
v1 -> v2:
- New layout set for kvm_arm_gic_set_irq and
arm_cpu_kvm_set_irq through kvm_arm_set_irq
- Introduced kvm_arm_irq_line_layout_mismatch()
Eric Auger (3):
linux headers: update for KVM_CAP_ARM_IRQ_LINE_LAYOUT_2
intc/arm_gic: Support IRQ injection for more than 256 vpus
virt: Check KVM_CAP_ARM_IRQ_LINE_LAYOUT_2 for smp_cpus > 256
hw/arm/virt.c | 4 +++
hw/intc/arm_gic_kvm.c | 7 ++--
include/standard-headers/asm-x86/bootparam.h | 2 ++
include/standard-headers/asm-x86/kvm_para.h | 1 +
include/standard-headers/linux/ethtool.h | 2 ++
include/standard-headers/linux/pci_regs.h | 4 +++
include/standard-headers/linux/virtio_ids.h | 1 +
include/standard-headers/linux/virtio_pmem.h | 6 ++--
linux-headers/asm-arm/kvm.h | 16 ++++++++-
linux-headers/asm-arm/unistd-common.h | 2 ++
linux-headers/asm-arm64/kvm.h | 21 ++++++++++-
linux-headers/asm-generic/mman-common.h | 15 ++++----
linux-headers/asm-generic/mman.h | 10 +++---
linux-headers/asm-generic/unistd.h | 8 ++++-
linux-headers/asm-mips/unistd_n32.h | 1 +
linux-headers/asm-mips/unistd_n64.h | 1 +
linux-headers/asm-mips/unistd_o32.h | 1 +
linux-headers/asm-powerpc/mman.h | 6 +---
linux-headers/asm-powerpc/unistd_32.h | 2 ++
linux-headers/asm-powerpc/unistd_64.h | 2 ++
linux-headers/asm-s390/unistd_32.h | 2 ++
linux-headers/asm-s390/unistd_64.h | 2 ++
linux-headers/asm-x86/kvm.h | 28 +++++++++++----
linux-headers/asm-x86/unistd_32.h | 2 ++
linux-headers/asm-x86/unistd_64.h | 2 ++
linux-headers/asm-x86/unistd_x32.h | 2 ++
linux-headers/linux/kvm.h | 12 +++++--
linux-headers/linux/psp-sev.h | 5 +--
target/arm/cpu.c | 10 +++---
target/arm/kvm.c | 37 ++++++++++++++++++++
target/arm/kvm_arm.h | 16 +++++++++
31 files changed, 182 insertions(+), 48 deletions(-)
--
2.20.1