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

From: Anup Patel
Date: Fri Apr 24 2020 - 01:03:34 EST




> -----Original Message-----
> From: Palmer Dabbelt <palmerdabbelt@xxxxxxxxxx>
> Sent: 23 April 2020 21:13
> To: anup@xxxxxxxxxxxxxx
> Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx>; aou@xxxxxxxxxxxxxxxxx;
> pbonzini@xxxxxxxxxx; rkrcmar@xxxxxxxxxx; graf@xxxxxxxxxx; Atish Patra
> <Atish.Patra@xxxxxxx>; Alistair Francis <Alistair.Francis@xxxxxxx>;
> Damien Le Moal <Damien.LeMoal@xxxxxxx>; Christoph Hellwig
> <hch@xxxxxx>; kvm@xxxxxxxxxxxxxxx; kvm-riscv@xxxxxxxxxxxxxxxxxxx; linux-
> riscv@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Anup Patel
> <Anup.Patel@xxxxxxx>
> Subject: Re: [PATCH v11 00/20] KVM RISC-V Support
>
> On Fri, 17 Apr 2020 05:45:31 PDT (-0700), anup@xxxxxxxxxxxxxx wrote:
> > 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 ??
>
> Sure. Can you send them as their own patch set, based on a recent RC?

I have sent these three patches as separate patch set based on Linux-5.7-rc2.

Refer, https://patchwork.kernel.org/cover/11507095/

Regards,
Anup