Message-ID: <CAAhV-H5_KwmkEczws2diHpk5gDUZSAmy_7Zgi=CowhGZN9_d_A@mail.gmail.com>
Date:   Fri, 15 Sep 2023 15:10:43 +0800
From:   Huacai Chen <chenhuacai@...nel.org>
To:     zhaotianrui <zhaotianrui@...ngson.cn>
Cc:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        Paolo Bonzini <pbonzini@...hat.com>,
        WANG Xuerui <kernel@...0n.name>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        loongarch@...ts.linux.dev, Jens Axboe <axboe@...nel.dk>,
        Mark Brown <broonie@...nel.org>,
        Alex Deucher <alexander.deucher@....com>,
        Oliver Upton <oliver.upton@...ux.dev>, maobibo@...ngson.cn,
        Xi Ruoyao <xry111@...111.site>
Subject: Re: [PATCH v21 00/29] Add KVM LoongArch support

Hi, Tianrui,

On Fri, Sep 15, 2023 at 2:58 PM zhaotianrui <zhaotianrui@...ngson.cn> wrote:
>
>
> 在 2023/9/15 下午12:11, Huacai Chen 写道:
> > Hi, Tianrui,
> >
> > On Fri, Sep 15, 2023 at 9:50 AM Tianrui Zhao <zhaotianrui@...ngson.cn> wrote:
> >> This series adds KVM LoongArch support. Loongson 3A5000 supports hardware
> >> assisted virtualization. With cpu virtualization, there are separate
> >> hw-supported user mode and kernel mode in guest mode. With memory
> >> virtualization, there are two-level hw mmu table for guest mode and host
> >> mode. Also there is separate hw cpu timer with consant frequency in
> >> guest mode, so that vm can migrate between hosts with different freq.
> >> Currently, we are able to boot LoongArch Linux Guests.
> >>
> >> Few key aspects of KVM LoongArch added by this series are:
> >> 1. Enable kvm hardware function when kvm module is loaded.
> >> 2. Implement VM and vcpu related ioctl interface such as vcpu create,
> >>     vcpu run etc. GET_ONE_REG/SET_ONE_REG ioctl commands are use to
> >>     get general registers one by one.
> >> 3. Hardware access about MMU, timer and csr are emulated in kernel.
> >> 4. Hardwares such as mmio and iocsr device are emulated in user space
> >>     such as APIC, IPI, pci devices etc.
> >>
> >> The running environment of LoongArch virt machine:
> >> 1. Cross tools for building kernel and uefi:
> >>     https://github.com/loongson/build-tools
> >> 2. This series is based on the linux source code:
> >>     https://github.com/loongson/linux-loongarch-kvm
> >>     Build command:
> >>     git checkout kvm-loongarch
> >>     make ARCH=loongarch CROSS_COMPILE=loongarch64-unknown-linux-gnu- loongson3_defconfig
> >>     make ARCH=loongarch CROSS_COMPILE=loongarch64-unknown-linux-gnu-
> >> 3. QEMU hypervisor with LoongArch supported:
> >>     https://github.com/loongson/qemu
> >>     Build command:
> >>     git checkout kvm-loongarch
> >>     ./configure --target-list="loongarch64-softmmu"  --enable-kvm
> >>     make
> > When I build qemu, I get:
> > [3/964] Compiling C object
> > libqemu-loongarch64-softmmu.fa.p/target_loongarch_loongarch-qmp-cmds.c.o
> > FAILED: libqemu-loongarch64-softmmu.fa.p/target_loongarch_loongarch-qmp-cmds.c.o
> > cc -Ilibqemu-loongarch64-softmmu.fa.p -I. -I.. -Itarget/loongarch
> > -I../target/loongarch -Isubprojects/dtc/libfdt
> > -I../subprojects/dtc/libfdt -Iqapi -Itrace c
> > In file included from ../target/loongarch/loongarch-qmp-cmds.c:11:
> > ../target/loongarch/cpu.h:351:14: error: duplicate member 'CSR_CPUID'
> >    351 |     uint64_t CSR_CPUID;
> >        |              ^~~~~~~~~
> > ninja: build stopped: subcommand failed.
> > make[1]: *** [Makefile:162: run-ninja] Error 1
> > make[1]: Leaving directory '/root/qemu/build'
> > make: *** [GNUmakefile:11: all] Error 2
> >
> > Huacai
> Sorry, I have submitted patch to fix this error, you could git pull to
> update it.
After git pull, I get a new error:
[70/912] Compiling C object
libqemu-loongarch64-softmmu.fa.p/accel_tcg_tcg-accel-ops-icount.c.o
[71/912] Compiling C object
libqemu-loongarch64-softmmu.fa.p/accel_tcg_tcg-accel-ops-rr.c.o
[72/912] Linking target qemu-system-loongarch64
FAILED: qemu-system-loongarch64
cc  -o qemu-system-loongarch64 libcommon.fa.p/hw_core_cpu-common.c.o
libcommon.fa.p/hw_core_machine-smp.c.o
libcommon.fa.p/gdbstub_syscalls.c.o libcommon.fap
/usr/bin/ld: libqemu-loongarch64-softmmu.fa.p/accel_kvm_kvm-all.c.o:
in function `kvm_init':
/root/qemu/build/../accel/kvm/kvm-all.c:2525:(.text+0x66f4): undefined
reference to `kvm_arch_get_default_type'
collect2: error: ld returned 1 exit status
ninja: build stopped: subcommand failed.
make[1]: *** [Makefile:162: run-ninja] Error 1
make[1]: Leaving directory '/root/qemu/build'
make: *** [GNUmakefile:11: all] Error 2

Huacai

>
> Thanks
> Tianrui Zhao
> >
> >> 4. Uefi bios of LoongArch virt machine:
> >>     Link: https://github.com/tianocore/edk2-platforms/tree/master/Platform/Loongson/LoongArchQemuPkg#readme
> >> 5. you can also access the binary files we have already build:
> >>     https://github.com/yangxiaojuan-loongson/qemu-binary
> >> The command to boot loongarch virt machine:
> >>     $ qemu-system-loongarch64 -machine virt -m 4G -cpu la464 \
> >>     -smp 1 -bios QEMU_EFI.fd -kernel vmlinuz.efi -initrd ramdisk \
> >>     -serial stdio   -monitor telnet:localhost:4495,server,nowait \
> >>     -append "root=/dev/ram rdinit=/sbin/init console=ttyS0,115200" \
> >>     --nographic
> >>
> >> Changes for v21:
> >> 1. Remove unnecessary prefix '_' in some kvm function names.
> >> 2. Replace check_vmid with check_vpid, and move the functions
> >> to main.c.
> >> 3. Re-order the file names and config names by alphabetical
> >> in KVM makefile and Kconfig.
> >> 4. Code clean up for KVM mmu and get,set gcsr and vcpu_arch
> >> ioctl functions.
> >>
> >> changes for v20:
> >> 1. Remove the binary code of virtualization instructions in
> >> insn_def.h and csr_ops.S and directly use the default csrrd,
> >> csrwr,csrxchg instructions. And let CONFIG_KVM depends on the
> >> AS_HAS_LVZ_EXTENSION, so we should use the binutils that have
> >> already supported them to compile the KVM. This can make our
> >> LoongArch KVM codes more maintainable and easier.
> >>
> >> changes for v19:
> >> 1. Use the common interface xfer_to_guest_mode_handle_work to
> >> Check conditions before entering the guest.
> >> 2. Add vcpu dirty ring support.
> >>
> >> changes for v18:
> >> 1. Code cleanup for vcpu timer: remove unnecessary timer_period_ns,
> >> timer_bias, timer_dyn_bias variables in kvm_vcpu_arch and rename
> >> the stable_ktime_saved variable to expire.
> >> 2. Change the value of KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE to 40.
> >>
> >> changes for v17:
> >> 1. Add CONFIG_AS_HAS_LVZ_EXTENSION config option which depends on
> >> binutils that support LVZ assemble instruction.
> >> 2. Change kvm mmu related functions, such as rename level2_ptw_pgd
> >> to kvm_ptw_pgd, replace kvm_flush_range with kvm_ptw_pgd pagewalk
> >> framework, replace kvm_arch.gpa_mm with kvm_arch.pgd, set
> >> mark_page_dirty/kvm_set_pfn_dirty out of mmu_lock in kvm page fault
> >> handling.
> >> 3. Replace kvm_loongarch_interrupt with standard kvm_interrupt
> >> when injecting IRQ.
> >> 4. Replace vcpu_arch.last_exec_cpu with existing vcpu.cpu, remove
> >> kvm_arch.online_vcpus and kvm_arch.is_migrating,
> >> 5. Remove EXCCODE_TLBNR and EXCCODE_TLBNX in kvm exception table,
> >> since NR/NX bit is not set in kvm page fault handling.
> >>
> >> Changes for v16:
> >> 1. Free allocated memory of vmcs,kvm_loongarch_ops in kvm module init,
> >> exit to avoid memory leak problem.
> >> 2. Simplify some assemble codes in switch.S which are necessary to be
> >> replaced with pseudo-instructions. And any other instructions do not need
> >> to be replaced anymore.
> >> 3. Add kvm_{save,restore}_guest_gprs macros to replace these ld.d,st.d
> >> guest regs instructions when vcpu world switch.
> >> 4. It is more secure to disable irq when flush guest tlb by gpa, so replace
> >> preempt_disable with loacl_irq_save in kvm_flush_tlb_gpa.
> >>
> >> Changes for v15:
> >> 1. Re-order some macros and variables in LoongArch kvm headers, put them
> >> together which have the same meaning.
> >> 2. Make some function definitions in one line, as it is not needed to split
> >> them.
> >> 3. Re-name some macros such as KVM_REG_LOONGARCH_GPR.
> >>
> >> Changes for v14:
> >> 1. Remove the macro CONFIG_KVM_GENERIC_HARDWARE_ENABLING in
> >> loongarch/kvm/main.c, as it is not useful.
> >> 2. Add select KVM_GENERIC_HARDWARE_ENABLING in loongarch/kvm/Kconfig,
> >> as it is used by virt/kvm.
> >> 3. Fix the LoongArch KVM source link in MAINTAINERS.
> >> 4. Improve LoongArch KVM documentation, such as add comment for
> >> LoongArch kvm_regs.
> >>
> >> Changes for v13:
> >> 1. Remove patch-28 "Implement probe virtualization when cpu init", as the
> >> virtualization information about FPU,PMP,LSX in guest.options,options_dyn
> >> is not used and the gcfg reg value can be read in kvm_hardware_enable, so
> >> remove the previous cpu_probe_lvz function.
> >> 2. Fix vcpu_enable_cap interface, it should return -EINVAL directly, as
> >> FPU cap is enable by default, and do not support any other caps now.
> >> 3. Simplify the jirl instruction with jr when without return addr,
> >> simplify case HW0 ... HW7 statment in interrupt.c
> >> 4. Rename host_stack,host_gp in kvm_vcpu_arch to host_sp,host_tp.
> >> 5. Remove 'cpu' parameter in _kvm_check_requests, as 'cpu' is not used,
> >> and remove 'cpu' parameter in kvm_check_vmid function, as it can get
> >> cpu number by itself.
> >>
> >> Changes for v12:
> >> 1. Improve the gcsr write/read/xchg interface to avoid the previous
> >> instruction statment like parse_r and make the code easy understanding,
> >> they are implemented in asm/insn-def.h and the instructions consistent
> >> of "opcode" "rj" "rd" "simm14" arguments.
> >> 2. Fix the maintainers list of LoongArch KVM.
> >>
> >> Changes for v11:
> >> 1. Add maintainers for LoongArch KVM.
> >>
> >> Changes for v10:
> >> 1. Fix grammatical problems in LoongArch documentation.
> >> 2. It is not necessary to save or restore the LOONGARCH_CSR_PGD when
> >> vcpu put and vcpu load, so we remove it.
> >>
> >> Changes for v9:
> >> 1. Apply the new defined interrupt number macros in loongarch.h to kvm,
> >> such as INT_SWI0, INT_HWI0, INT_TI, INT_IPI, etc. And remove the
> >> previous unused macros.
> >> 2. Remove unused variables in kvm_vcpu_arch, and reorder the variables
> >> to make them more standard.
> >>
> >> Changes for v8:
> >> 1. Adjust the cpu_data.guest.options structure, add the ases flag into
> >> it, and remove the previous guest.ases. We do this to keep consistent
> >> with host cpu_data.options structure.
> >> 2. Remove the "#include <asm/kvm_host.h>" in some files which also
> >> include the "<linux/kvm_host.h>". As linux/kvm_host.h already include
> >> the asm/kvm_host.h.
> >> 3. Fix some unstandard spelling and grammar errors in comments, and
> >> improve a little code format to make it easier and standard.
> >>
> >> Changes for v7:
> >> 1. Fix the kvm_save/restore_hw_gcsr compiling warnings reported by
> >> kernel test robot. The report link is:
> >> https://lore.kernel.org/oe-kbuild-all/202304131526.iXfLaVZc-lkp@intel.com/
> >> 2. Fix loongarch kvm trace related compiling problems.
> >>
> >> Changes for v6:
> >> 1. Fix the Documentation/virt/kvm/api.rst compile warning about
> >> loongarch parts.
> >>
> >> Changes for v5:
> >> 1. Implement get/set mp_state ioctl interface, and only the
> >> KVM_MP_STATE_RUNNABLE state is supported now, and other states
> >> will be completed in the future. The state is also used when vcpu
> >> run idle instruction, if vcpu state is changed to RUNNABLE, the
> >> vcpu will have the possibility to be woken up.
> >> 2. Supplement kvm document about loongarch-specific part, such as add
> >> api introduction for GET/SET_ONE_REG, GET/SET_FPU, GET/SET_MP_STATE,
> >> etc.
> >> 3. Improve the kvm_switch_to_guest function in switch.S, remove the
> >> previous tmp,tmp1 arguments and replace it with t0,t1 reg.
> >>
> >> Changes for v4:
> >> 1. Add a csr_need_update flag in _vcpu_put, as most csr registers keep
> >> unchanged during process context switch, so we need not to update it
> >> every time. We can do this only if the soft csr is different form hardware.
> >> That is to say all of csrs should update after vcpu enter guest, as for
> >> set_csr_ioctl, we have written soft csr to keep consistent with hardware.
> >> 2. Improve get/set_csr_ioctl interface, we set SW or HW or INVALID flag
> >> for all csrs according to it's features when kvm init. In get/set_csr_ioctl,
> >> if csr is HW, we use gcsrrd/ gcsrwr instruction to access it, else if csr is
> >> SW, we use software to emulate it, and others return false.
> >> 3. Add set_hw_gcsr function in csr_ops.S, and it is used in set_csr_ioctl.
> >> We have splited hw gcsr into three parts, so we can calculate the code offset
> >> by gcsrid and jump here to run the gcsrwr instruction. We use this function to
> >> make the code easier and avoid to use the previous SET_HW_GCSR(XXX) interface.
> >> 4. Improve kvm mmu functions, such as flush page table and make clean page table
> >> interface.
> >>
> >> Changes for v3:
> >> 1. Remove the vpid array list in kvm_vcpu_arch and use a vpid variable here,
> >> because a vpid will never be recycled if a vCPU migrates from physical CPU A
> >> to B and back to A.
> >> 2. Make some constant variables in kvm_context to global such as vpid_mask,
> >> guest_eentry, enter_guest, etc.
> >> 3. Add some new tracepoints, such as kvm_trace_idle, kvm_trace_cache,
> >> kvm_trace_gspr, etc.
> >> 4. There are some duplicate codes in kvm_handle_exit and kvm_vcpu_run,
> >> so we move it to a new function kvm_pre_enter_guest.
> >> 5. Change the RESUME_HOST, RESUME_GUEST value, return 1 for resume guest
> >> and "<= 0" for resume host.
> >> 6. Fcsr and fpu registers are saved/restored together.
> >>
> >> Changes for v2:
> >> 1. Seprate the original patch-01 and patch-03 into small patches, and the
> >> patches mainly contain kvm module init, module exit, vcpu create, vcpu run,
> >> etc.
> >> 2. Remove the original KVM_{GET,SET}_CSRS ioctl in the kvm uapi header,
> >> and we use the common KVM_{GET,SET}_ONE_REG to access register.
> >> 3. Use BIT(x) to replace the "1 << n_bits" statement.
> >>
> >> Tianrui Zhao (29):
> >>    LoongArch: KVM: Add kvm related header files
> >>    LoongArch: KVM: Implement kvm module related interface
> >>    LoongArch: KVM: Implement kvm hardware enable, disable interface
> >>    LoongArch: KVM: Implement VM related functions
> >>    LoongArch: KVM: Add vcpu related header files
> >>    LoongArch: KVM: Implement vcpu create and destroy interface
> >>    LoongArch: KVM: Implement vcpu run interface
> >>    LoongArch: KVM: Implement vcpu handle exit interface
> >>    LoongArch: KVM: Implement vcpu get, vcpu set registers
> >>    LoongArch: KVM: Implement vcpu ENABLE_CAP ioctl interface
> >>    LoongArch: KVM: Implement fpu related operations for vcpu
> >>    LoongArch: KVM: Implement vcpu interrupt operations
> >>    LoongArch: KVM: Implement misc vcpu related interfaces
> >>    LoongArch: KVM: Implement vcpu load and vcpu put operations
> >>    LoongArch: KVM: Implement vcpu status description
> >>    LoongArch: KVM: Implement virtual machine tlb operations
> >>    LoongArch: KVM: Implement vcpu timer operations
> >>    LoongArch: KVM: Implement kvm mmu operations
> >>    LoongArch: KVM: Implement handle csr exception
> >>    LoongArch: KVM: Implement handle iocsr exception
> >>    LoongArch: KVM: Implement handle idle exception
> >>    LoongArch: KVM: Implement handle gspr exception
> >>    LoongArch: KVM: Implement handle mmio exception
> >>    LoongArch: KVM: Implement handle fpu exception
> >>    LoongArch: KVM: Implement kvm exception vector
> >>    LoongArch: KVM: Implement vcpu world switch
> >>    LoongArch: KVM: Enable kvm config and add the makefile
> >>    LoongArch: KVM: Supplement kvm document about LoongArch-specific part
> >>    LoongArch: KVM: Add maintainers for LoongArch KVM
> >>
> >>   Documentation/virt/kvm/api.rst             |  70 +-
> >>   MAINTAINERS                                |  12 +
> >>   arch/loongarch/Kbuild                      |   1 +
> >>   arch/loongarch/Kconfig                     |   3 +
> >>   arch/loongarch/configs/loongson3_defconfig |   2 +
> >>   arch/loongarch/include/asm/inst.h          |  16 +
> >>   arch/loongarch/include/asm/kvm_csr.h       | 221 +++++
> >>   arch/loongarch/include/asm/kvm_host.h      | 245 ++++++
> >>   arch/loongarch/include/asm/kvm_mmu.h       | 138 +++
> >>   arch/loongarch/include/asm/kvm_types.h     |  11 +
> >>   arch/loongarch/include/asm/kvm_vcpu.h      | 107 +++
> >>   arch/loongarch/include/asm/loongarch.h     |  19 +-
> >>   arch/loongarch/include/uapi/asm/kvm.h      | 108 +++
> >>   arch/loongarch/kernel/asm-offsets.c        |  32 +
> >>   arch/loongarch/kvm/Kconfig                 |  45 +
> >>   arch/loongarch/kvm/Makefile                |  20 +
> >>   arch/loongarch/kvm/exit.c                  | 711 ++++++++++++++++
> >>   arch/loongarch/kvm/interrupt.c             | 185 ++++
> >>   arch/loongarch/kvm/main.c                  | 429 ++++++++++
> >>   arch/loongarch/kvm/mmu.c                   | 922 ++++++++++++++++++++
> >>   arch/loongarch/kvm/switch.S                | 255 ++++++
> >>   arch/loongarch/kvm/timer.c                 | 200 +++++
> >>   arch/loongarch/kvm/tlb.c                   |  34 +
> >>   arch/loongarch/kvm/trace.h                 | 166 ++++
> >>   arch/loongarch/kvm/vcpu.c                  | 940 +++++++++++++++++++++
> >>   arch/loongarch/kvm/vm.c                    |  92 ++
> >>   include/uapi/linux/kvm.h                   |   9 +
> >>   27 files changed, 4979 insertions(+), 14 deletions(-)
> >>   create mode 100644 arch/loongarch/include/asm/kvm_csr.h
> >>   create mode 100644 arch/loongarch/include/asm/kvm_host.h
> >>   create mode 100644 arch/loongarch/include/asm/kvm_mmu.h
> >>   create mode 100644 arch/loongarch/include/asm/kvm_types.h
> >>   create mode 100644 arch/loongarch/include/asm/kvm_vcpu.h
> >>   create mode 100644 arch/loongarch/include/uapi/asm/kvm.h
> >>   create mode 100644 arch/loongarch/kvm/Kconfig
> >>   create mode 100644 arch/loongarch/kvm/Makefile
> >>   create mode 100644 arch/loongarch/kvm/exit.c
> >>   create mode 100644 arch/loongarch/kvm/interrupt.c
> >>   create mode 100644 arch/loongarch/kvm/main.c
> >>   create mode 100644 arch/loongarch/kvm/mmu.c
> >>   create mode 100644 arch/loongarch/kvm/switch.S
> >>   create mode 100644 arch/loongarch/kvm/timer.c
> >>   create mode 100644 arch/loongarch/kvm/tlb.c
> >>   create mode 100644 arch/loongarch/kvm/trace.h
> >>   create mode 100644 arch/loongarch/kvm/vcpu.c
> >>   create mode 100644 arch/loongarch/kvm/vm.c
> >>
> >> --
> >> 2.39.1
> >>
>

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