Deep dive into Kernel

KVM hugepage driver- PCI Memory Controller Device- Mapping PCI memory space in host hugepage- fast memory access with EPT hugepage Use case- Guest DPDK application with hugepage support

Overall Concept Memory Layout- qemu-system-x86_64 -device ivshmem,size=4,shm=abc system0000000000000000-ffffffffffffffff (prio 0, RW): system 0000000000000000-000000003fffffff (prio 0, RW): alias ram-below-4g @pc.ram 0000000000000000-000000003fffffff 0000000000000000-ffffffffffffffff (prio -1, RW): pci 00000000000a0000-00000000000bffff (prio 1, RW): cirrus-lowmem-container 00000000000a0000-00000..

•GVA -> GPA (guest page table)•GPA -> HVA (memslot)•HVA -> HPA (QEMU page table) •GPA -> HPA (nested page table)

root@cnode01-m:~/suprem/qemu/scripts/kvm# modprobe msrroot@cnode01-m:~/suprem/qemu/scripts/kvm# ./vmxcapBasic VMX Information Revision 16 VMCS size 1024 VMCS restricted to 32 bit addresses no Dual-monitor support yes VMCS memory type 6 INS/OUTS instruction information yes IA32_VMX_TRUE_*_CTLS support yespin-based controls External interrupt exiting yes NMI exiting yes Virtual NMIs yes Activate V..

IOMMU: Strategies for Mitigating the IOTLB Bottleneck - from Sixth Annual Workshop on the Interaction between Operating Systems and Computer Architecture- Nadav Ammit (@techion), Muli Ben-Yhhuda(@ibm), Ben-Ami Yassour(@ibm) The computational cost of the mapping and unmapping of memory regions in the DMAR units is therefore considered the main bottleneck. The IOMMU translates the virtual I/O addr..

QEMU initialization

sunshout2@choonho:~/opensource/qemu$ qemu-img create -f qcow2 a.img 1GFormatting 'a.img', fmt=qcow2 size=1073741824 encryption=off cluster_size=65536 lazy_refcounts=off sunshout2@choonho:~/opensource/qemu$ qemu-img info a.imgimage: a.imgfile format: qcow2virtual size: 1.0G (1073741824 bytes)disk size: 196Kcluster_size: 65536Format specific information: compat: 1.1 lazy refcounts: false 빈 qcow2 디..

MonitorCtrl-L (form feed) can be used to clear the screen in the monitor.More commands support command-line completion. Block devices in system emulationFilenames can be JSON objects preceded by "json:", for example json:{'driver':'raw','file.filename':'test.img'}. This new syntax can be used in the file property for -drive, but also in qemu-io, qemu-img or backing file names.The new "change-bac..

VM 생성시 PV-EOI를 enable 하기 위한 libvirt 설정 파일 sriov-vm 2097152 4 Sunshout KVM 2013.4 hvm qemu command 로 생성할 때는 -cpu +kvm_pv_eoi 를 추가 PV-EOI 를 off 하고 perf 를 통해서 분석한 결과. kvm:kvm_pv_eoi 의 결과가 없음을 확인 root@gaus01-m:/storage# perf stat --event "kvm:*" --all-cpus sleep 10 Performance counter stats for 'system wide': 1,512 kvm:kvm_entry [100.00%] 0 kvm:kvm_hypercall [100.00%] 0 kvm:kvm_hv_hypercall [100.00%..

MSI : Message Signaled Interrupt The bus driver is responsible for initializing the message address and message data of the device function's MSI/MSI-X capability structure during device initial configuration. An MSI capable device function indicates MSI support by implementing the MSI/MSI-X capability structure in its PCI capability list.The MSI capability structure contains Message Control reg..