Re: [PATCH v11 00/20] KVM RISC-V Support

From: Anup Patel
Date: Fri Apr 17 2020 - 08:45:48 EST


Hi Palmer,

On Fri, Mar 13, 2020 at 1:22 PM Anup Patel <anup.patel@xxxxxxx> wrote:
>
> 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_v11 branch at:
> https//github.com/avpatel/linux.git
>
> Our work-in-progress KVMTOOL RISC-V port can be found in riscv_v2 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-v0.5.3 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 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:
> - 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
> - Rebased patches on Linux-5.5-rc3
>
> 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 (16):
> RISC-V: Export riscv_cpuid_to_hartid_mask() API
> RISC-V: Add bitmap reprensenting ISA features common across CPUs
> RISC-V: Remove N-extension related defines
> 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 | 78 +-
> arch/riscv/include/asm/hwcap.h | 22 +
> arch/riscv/include/asm/kvm_host.h | 264 +++++++
> 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 | 148 ++++
> arch/riscv/kernel/cpufeature.c | 83 +-
> arch/riscv/kernel/smp.c | 2 +
> arch/riscv/kvm/Kconfig | 34 +
> arch/riscv/kvm/Makefile | 14 +
> arch/riscv/kvm/main.c | 97 +++
> arch/riscv/kvm/mmu.c | 762 ++++++++++++++++++
> arch/riscv/kvm/tlb.S | 43 +
> arch/riscv/kvm/vcpu.c | 997 ++++++++++++++++++++++++
> arch/riscv/kvm/vcpu_exit.c | 639 +++++++++++++++
> arch/riscv/kvm/vcpu_sbi.c | 171 ++++
> arch/riscv/kvm/vcpu_switch.S | 382 +++++++++
> 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 +
> 28 files changed, 4564 insertions(+), 15 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
>
> --
> 2.17.1
>

Can you please consider PATCH1, PATCH2, and PATCH3 of
this series for Linux-5.7-rcX ??

Regards,
Anup