This series adds initial KVM RISC-V support. Currently, we are able to boot RISC-V 64bit Linux Guests with multiple VCPUs.
Few key aspects of KVM RISC-V added by this series are: 1. Minimal possible KVM world-switch which touches only GPRs and few CSRs. 2. Full Guest/VM switch is done via vcpu_get/vcpu_put infrastructure. 3. KVM ONE_REG interface for VCPU register access from user-space. 4. PLIC emulation is done in user-space. 5. Timer and IPI emuation is done in-kernel. 6. MMU notifiers supported. 7. FP lazy save/restore supported. 8. SBI v0.1 emulation for KVM Guest available. 9. Forward unhandled SBI calls to KVM userspace. 10. Hugepage support for Guest/VM Here's a brief TODO list which we will work upon after this series: 1. SBI v0.2 emulation in-kernel 2. SBI v0.2 hart state management emulation in-kernel 3. In-kernel PLIC emulation 4. ..... and more ..... This series can be found in riscv_kvm_v13 branch at: https//github.com/avpatel/linux.git Our work-in-progress KVMTOOL RISC-V port can be found in riscv_v4 branch at: https//github.com/avpatel/kvmtool.git The QEMU RISC-V hypervisor emulation is done by Alistair and is available in mainline/anup/riscv-hyp-ext-v0.6.1 branch at: https://github.com/kvm-riscv/qemu.git To play around with KVM RISC-V, refer KVM RISC-V wiki at: https://github.com/kvm-riscv/howto/wiki https://github.com/kvm-riscv/howto/wiki/KVM-RISCV64-on-QEMU Changes since v12: - Rebased patches on Linux-5.8-rc4 - By default enable all counters in HCOUNTEREN - RISC-V H-Extension v0.6.1 spec support Changes since v11: - Rebased patches on Linux-5.7-rc3 - Fixed typo in typecast of stage2_map_size define - Introduced struct kvm_cpu_trap to represent trap details and use it as function parameter wherever applicable - Pass memslot to kvm_riscv_stage2_map() for supporing dirty page logging in future - RISC-V H-Extension v0.6 spec support - Send-out first three patches as separate series so that it can be taken by Palmer for Linux RISC-V Changes since v10: - Rebased patches on Linux-5.6-rc5 - Reduce RISCV_ISA_EXT_MAX from 256 to 64 - Separate PATCH for removing N-extension related defines - Added comments as requested by Palmer - Fixed HIDELEG CSR programming Changes since v9: - Rebased patches on Linux-5.5-rc3 - Squash PATCH19 and PATCH20 into PATCH5 - Squash PATCH18 into PATCH11 - Squash PATCH17 into PATCH16 - Added ONE_REG interface for VCPU timer in PATCH13 - Use HTIMEDELTA for VCPU timer in PATCH13 - Updated KVM RISC-V mailing list in MAINTAINERS entry - Update KVM kconfig option to depend on RISCV_SBI and MMU - Check for SBI v0.2 and SBI v0.2 RFENCE extension at boot-time - Use SBI v0.2 RFENCE extension in VMID implementation - Use SBI v0.2 RFENCE extension in Stage2 MMU implementation - Use SBI v0.2 RFENCE extension in SBI implementation - Moved to RISC-V Hypervisor v0.5 draft spec - Updated Documentation/virt/kvm/api.txt for timer ONE_REG interface Changes since v8: - Rebased series on Linux-5.4-rc3 and Atish's SBI v0.2 patches - Use HRTIMER_MODE_REL instead of HRTIMER_MODE_ABS in timer emulation - Fixed kvm_riscv_stage2_map() to handle hugepages - Added patch to forward unhandled SBI calls to user-space - Added patch for iterative/recursive stage2 page table programming - Added patch to remove per-CPU vsip_shadow variable - Added patch to fix race-condition in kvm_riscv_vcpu_sync_interrupts() Changes since v7: - Rebased series on Linux-5.4-rc1 and Atish's SBI v0.2 patches - Removed PATCH1, PATCH3, and PATCH20 because these already merged - Use kernel doc style comments for ISA bitmap functions - Don't parse X, Y, and Z extension in riscv_fill_hwcap() because it will be added in-future - Mark KVM RISC-V kconfig option as EXPERIMENTAL - Typo fix in commit description of PATCH6 of v7 series - Use separate structs for CORE and CSR registers of ONE_REG interface - Explicitly include asm/sbi.h in kvm/vcpu_sbi.c - Removed implicit switch-case fall-through in kvm_riscv_vcpu_exit() - No need to set VSSTATUS.MXR bit in kvm_riscv_vcpu_unpriv_read() - Removed register for instruction length in kvm_riscv_vcpu_unpriv_read() - Added defines for checking/decoding instruction length - Added separate patch to forward unhandled SBI calls to userspace tool Changes since v6: - Rebased patches on Linux-5.3-rc7 - Added "return_handled" in struct kvm_mmio_decode to ensure that kvm_riscv_vcpu_mmio_return() updates SEPC only once - Removed trap_stval parameter from kvm_riscv_vcpu_unpriv_read() - Updated git repo URL in MAINTAINERS entry Changes since v5: - Renamed KVM_REG_RISCV_CONFIG_TIMEBASE register to KVM_REG_RISCV_CONFIG_TBFREQ register in ONE_REG interface - Update SPEC in kvm_riscv_vcpu_mmio_return() for MMIO exits - Use switch case instead of illegal instruction opcode table for simplicity - Improve comments in stage2_remote_tlb_flush() for a potential remote TLB flush optimization - Handle all unsupported SBI calls in default case of kvm_riscv_vcpu_sbi_ecall() function - Fixed kvm_riscv_vcpu_sync_interrupts() for software interrupts - Improved unprivilege reads to handle traps due to Guest stage1 page table - Added separate patch to document RISC-V specific things in Documentation/virt/kvm/api.txt Changes since v4: - Rebased patches on Linux-5.3-rc5 - Added Paolo's Acked-by and Reviewed-by - Updated mailing list in MAINTAINERS entry Changes since v3: - Moved patch for ISA bitmap from KVM prep series to this series - Make vsip_shadow as run-time percpu variable instead of compile-time - Flush Guest TLBs on all Host CPUs whenever we run-out of VMIDs Changes since v2: - Removed references of KVM_REQ_IRQ_PENDING from all patches - Use kvm->srcu within in-kernel KVM run loop - Added percpu vsip_shadow to track last value programmed in VSIP CSR - Added comments about irqs_pending and irqs_pending_mask - Used kvm_arch_vcpu_runnable() in-place-of kvm_riscv_vcpu_has_interrupt() in system_opcode_insn() - Removed unwanted smp_wmb() in kvm_riscv_stage2_vmid_update() - Use kvm_flush_remote_tlbs() in kvm_riscv_stage2_vmid_update() - Use READ_ONCE() in kvm_riscv_stage2_update_hgatp() for vmid Changes since v1: - Fixed compile errors in building KVM RISC-V as module - Removed unused kvm_riscv_halt_guest() and kvm_riscv_resume_guest() - Set KVM_CAP_SYNC_MMU capability only after MMU notifiers are implemented - Made vmid_version as unsigned long instead of atomic - Renamed KVM_REQ_UPDATE_PGTBL to KVM_REQ_UPDATE_HGATP - Renamed kvm_riscv_stage2_update_pgtbl() to kvm_riscv_stage2_update_hgatp() - Configure HIDELEG and HEDELEG in kvm_arch_hardware_enable() - Updated ONE_REG interface for CSR access to user-space - Removed irqs_pending_lock and use atomic bitops instead - Added separate patch for FP ONE_REG interface - Added separate patch for updating MAINTAINERS file Anup Patel (13): RISC-V: Add hypervisor extension related CSR defines RISC-V: Add initial skeletal KVM support RISC-V: KVM: Implement VCPU create, init and destroy functions RISC-V: KVM: Implement VCPU interrupts and requests handling RISC-V: KVM: Implement KVM_GET_ONE_REG/KVM_SET_ONE_REG ioctls RISC-V: KVM: Implement VCPU world-switch RISC-V: KVM: Handle MMIO exits for VCPU RISC-V: KVM: Handle WFI exits for VCPU RISC-V: KVM: Implement VMID allocator RISC-V: KVM: Implement stage2 page table programming RISC-V: KVM: Implement MMU notifiers RISC-V: KVM: Document RISC-V specific parts of KVM API RISC-V: KVM: Add MAINTAINERS entry Atish Patra (4): RISC-V: KVM: Add timer functionality RISC-V: KVM: FP lazy save/restore RISC-V: KVM: Implement ONE REG interface for FP registers RISC-V: KVM: Add SBI v0.1 support Documentation/virt/kvm/api.rst | 193 ++++- MAINTAINERS | 11 + arch/riscv/Kconfig | 2 + arch/riscv/Makefile | 2 + arch/riscv/include/asm/csr.h | 87 ++ arch/riscv/include/asm/kvm_host.h | 273 ++++++ arch/riscv/include/asm/kvm_vcpu_timer.h | 44 + arch/riscv/include/asm/pgtable-bits.h | 1 + arch/riscv/include/uapi/asm/kvm.h | 127 +++ arch/riscv/kernel/asm-offsets.c | 154 ++++ arch/riscv/kvm/Kconfig | 34 + arch/riscv/kvm/Makefile | 14 + arch/riscv/kvm/main.c | 99 +++ arch/riscv/kvm/mmu.c | 775 +++++++++++++++++ arch/riscv/kvm/tlb.S | 74 ++ arch/riscv/kvm/vcpu.c | 1012 +++++++++++++++++++++++ arch/riscv/kvm/vcpu_exit.c | 670 +++++++++++++++ arch/riscv/kvm/vcpu_sbi.c | 173 ++++ arch/riscv/kvm/vcpu_switch.S | 391 +++++++++ arch/riscv/kvm/vcpu_timer.c | 225 +++++ arch/riscv/kvm/vm.c | 86 ++ arch/riscv/kvm/vmid.c | 120 +++ drivers/clocksource/timer-riscv.c | 8 + include/clocksource/timer-riscv.h | 16 + include/uapi/linux/kvm.h | 8 + 25 files changed, 4590 insertions(+), 9 deletions(-) create mode 100644 arch/riscv/include/asm/kvm_host.h create mode 100644 arch/riscv/include/asm/kvm_vcpu_timer.h create mode 100644 arch/riscv/include/uapi/asm/kvm.h create mode 100644 arch/riscv/kvm/Kconfig create mode 100644 arch/riscv/kvm/Makefile create mode 100644 arch/riscv/kvm/main.c create mode 100644 arch/riscv/kvm/mmu.c create mode 100644 arch/riscv/kvm/tlb.S create mode 100644 arch/riscv/kvm/vcpu.c create mode 100644 arch/riscv/kvm/vcpu_exit.c create mode 100644 arch/riscv/kvm/vcpu_sbi.c create mode 100644 arch/riscv/kvm/vcpu_switch.S create mode 100644 arch/riscv/kvm/vcpu_timer.c create mode 100644 arch/riscv/kvm/vm.c create mode 100644 arch/riscv/kvm/vmid.c create mode 100644 include/clocksource/timer-riscv.h -- 2.25.1