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-v1 Eric Auger (3): linux headers: update for KVM_CAP_ARM_IRQ_LINE_LAYOUT_2 intc/arm_gic: Support PPI injection for more than 256 vpus virt: Check KVM_CAP_ARM_IRQ_LINE_LAYOUT_2 for smp_cpus > 256 hw/arm/virt.c | 7 +++++ hw/intc/arm_gic_kvm.c | 10 ++++--- 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/kvm.c | 7 +++++ target/arm/kvm_arm.h | 13 +++++++++ 30 files changed, 153 insertions(+), 40 deletions(-) -- 2.20.1