Date:   Mon, 18 Sep 2023 09:36:21 +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 01/29] LoongArch: KVM: Add kvm related header files

Hi, Tianrui,

On Mon, Sep 18, 2023 at 9:32 AM zhaotianrui <zhaotianrui@...ngson.cn> wrote:
>
>
> 在 2023/9/16 下午4:48, Huacai Chen 写道:
> > Hi, Tianrui,
> >
> > On Fri, Sep 15, 2023 at 9:50 AM Tianrui Zhao <zhaotianrui@...ngson.cn> wrote:
> >> Add LoongArch KVM related header files, including kvm.h,
> >> kvm_host.h, kvm_types.h. All of those are about LoongArch
> >> virtualization features and kvm interfaces.
> >>
> >> Reviewed-by: Bibo Mao <maobibo@...ngson.cn>
> >> Signed-off-by: Tianrui Zhao <zhaotianrui@...ngson.cn>
> >> ---
> >>   arch/loongarch/include/asm/kvm_host.h  | 245 +++++++++++++++++++++++++
> >>   arch/loongarch/include/asm/kvm_types.h |  11 ++
> >>   arch/loongarch/include/uapi/asm/kvm.h  | 108 +++++++++++
> >>   include/uapi/linux/kvm.h               |   9 +
> >>   4 files changed, 373 insertions(+)
> >>   create mode 100644 arch/loongarch/include/asm/kvm_host.h
> >>   create mode 100644 arch/loongarch/include/asm/kvm_types.h
> >>   create mode 100644 arch/loongarch/include/uapi/asm/kvm.h
> >>
> >> diff --git a/arch/loongarch/include/asm/kvm_host.h b/arch/loongarch/include/asm/kvm_host.h
> >> new file mode 100644
> >> index 0000000000..00e0c1876b
> >> --- /dev/null
> >> +++ b/arch/loongarch/include/asm/kvm_host.h
> >> @@ -0,0 +1,245 @@
> >> +/* SPDX-License-Identifier: GPL-2.0 */
> >> +/*
> >> + * Copyright (C) 2020-2023 Loongson Technology Corporation Limited
> >> + */
> >> +
> >> +#ifndef __ASM_LOONGARCH_KVM_HOST_H__
> >> +#define __ASM_LOONGARCH_KVM_HOST_H__
> >> +
> >> +#include <linux/cpumask.h>
> >> +#include <linux/mutex.h>
> >> +#include <linux/hrtimer.h>
> >> +#include <linux/interrupt.h>
> >> +#include <linux/types.h>
> >> +#include <linux/kvm.h>
> >> +#include <linux/kvm_types.h>
> >> +#include <linux/threads.h>
> >> +#include <linux/spinlock.h>
> >> +
> >> +#include <asm/inst.h>
> >> +#include <asm/kvm_mmu.h>
> >> +#include <asm/loongarch.h>
> >> +
> >> +/* Loongarch KVM register ids */
> >> +#define KVM_GET_IOC_CSRIDX(id)         ((id & KVM_CSR_IDX_MASK) >> LOONGARCH_REG_SHIFT)
> >> +#define KVM_GET_IOC_CPUCFG_IDX(id)     ((id & KVM_CPUCFG_IDX_MASK) >> LOONGARCH_REG_SHIFT)
> >> +
> >> +#define KVM_MAX_VCPUS                  256
> >> +#define KVM_MAX_CPUCFG_REGS            21
> >> +/* memory slots that does not exposed to userspace */
> >> +#define KVM_PRIVATE_MEM_SLOTS          0
> >> +
> >> +#define KVM_HALT_POLL_NS_DEFAULT       500000
> >> +
> >> +struct kvm_vm_stat {
> >> +       struct kvm_vm_stat_generic generic;
> >> +       u64 pages;
> >> +       u64 hugepages;
> >> +};
> >> +
> >> +struct kvm_vcpu_stat {
> >> +       struct kvm_vcpu_stat_generic generic;
> >> +       u64 idle_exits;
> >> +       u64 signal_exits;
> >> +       u64 int_exits;
> >> +       u64 cpucfg_exits;
> >> +};
> >> +
> >> +struct kvm_arch_memory_slot {
> >> +};
> >> +
> >> +struct kvm_context {
> >> +       unsigned long vpid_cache;
> >> +       struct kvm_vcpu *last_vcpu;
> >> +};
> >> +
> >> +struct kvm_world_switch {
> >> +       int (*guest_eentry)(void);
> >> +       int (*enter_guest)(struct kvm_run *run, struct kvm_vcpu *vcpu);
> >> +       unsigned long page_order;
> >> +};
> >> +
> >> +#define MAX_PGTABLE_LEVELS     4
> >> +struct kvm_arch {
> >> +       /* Guest physical mm */
> >> +       kvm_pte_t *pgd;
> >> +       unsigned long gpa_size;
> >> +       unsigned long invalid_ptes[MAX_PGTABLE_LEVELS];
> >> +       unsigned int  pte_shifts[MAX_PGTABLE_LEVELS];
> >> +       unsigned int  root_level;
> >> +
> >> +       s64 time_offset;
> >> +       struct kvm_context __percpu *vmcs;
> >> +};
> >> +
> >> +#define CSR_MAX_NUMS           0x800
> >> +
> >> +struct loongarch_csrs {
> >> +       unsigned long csrs[CSR_MAX_NUMS];
> >> +};
> >> +
> >> +/* Resume Flags */
> >> +#define RESUME_HOST            0
> >> +#define RESUME_GUEST           1
> >> +
> >> +enum emulation_result {
> >> +       EMULATE_DONE,           /* no further processing */
> >> +       EMULATE_DO_MMIO,        /* kvm_run filled with MMIO request */
> >> +       EMULATE_FAIL,           /* can't emulate this instruction */
> >> +       EMULATE_EXCEPT,         /* A guest exception has been generated */
> >> +       EMULATE_DO_IOCSR,       /* handle IOCSR request */
> >> +};
> >> +
> >> +#define KVM_LARCH_FPU          (0x1 << 0)
> >> +#define KVM_LARCH_CSR          (0x1 << 1)
> >> +#define KVM_LARCH_HWCSR_USABLE (0x1 << 2)
> >> +
> >> +struct kvm_vcpu_arch {
> >> +       /*
> >> +        * Switch pointer-to-function type to unsigned long
> >> +        * for loading the value into register directly.
> >> +        */
> >> +       unsigned long host_eentry;
> >> +       unsigned long guest_eentry;
> >> +
> >> +       /* Pointers stored here for easy accessing from assembly code */
> >> +       int (*handle_exit)(struct kvm_run *run, struct kvm_vcpu *vcpu);
> >> +
> >> +       /* Host registers preserved across guest mode execution */
> >> +       unsigned long host_sp;
> >> +       unsigned long host_tp;
> >> +       unsigned long host_pgd;
> >> +
> >> +       /* Host CSRs are used when handling exits from guest */
> >> +       unsigned long badi;
> >> +       unsigned long badv;
> >> +       unsigned long host_ecfg;
> >> +       unsigned long host_estat;
> >> +       unsigned long host_percpu;
> >> +
> >> +       /* GPRs */
> >> +       unsigned long gprs[32];
> >> +       unsigned long pc;
> >> +
> >> +       /* Which auxiliary state is loaded (KVM_LARCH_*) */
> >> +       unsigned int aux_inuse;
> >> +       /* FPU state */
> >> +       struct loongarch_fpu fpu FPU_ALIGN;
> >> +
> >> +       /* CSR state */
> >> +       struct loongarch_csrs *csr;
> >> +
> >> +       /* GPR used as IO source/target */
> >> +       u32 io_gpr;
> >> +
> >> +       struct hrtimer swtimer;
> >> +       /* KVM register to control count timer */
> >> +       u32 count_ctl;
> >> +
> >> +       /* Bitmask of intr that are pending */
> >> +       unsigned long irq_pending;
> >> +       /* Bitmask of pending intr to be cleared */
> >> +       unsigned long irq_clear;
> >> +
> >> +       /* Bitmask of exceptions that are pending */
> >> +       unsigned long exception_pending;
> >> +       unsigned int  subcode;
> >> +
> >> +       /* Cache for pages needed inside spinlock regions */
> >> +       struct kvm_mmu_memory_cache mmu_page_cache;
> >> +
> >> +       /* vcpu's vpid */
> >> +       u64 vpid;
> >> +
> >> +       /* Frequency of stable timer in Hz */
> >> +       u64 timer_mhz;
> >> +       ktime_t expire;
> >> +
> >> +       u64 core_ext_ioisr[4];
> >> +
> >> +       /* Last CPU the vCPU state was loaded on */
> >> +       int last_sched_cpu;
> >> +       /* mp state */
> >> +       struct kvm_mp_state mp_state;
> >> +       /* cpucfg */
> >> +       u32 cpucfg[KVM_MAX_CPUCFG_REGS];
> >> +};
> >> +
> >> +static inline unsigned long readl_sw_gcsr(struct loongarch_csrs *csr, int reg)
> >> +{
> >> +       return csr->csrs[reg];
> >> +}
> >> +
> >> +static inline void writel_sw_gcsr(struct loongarch_csrs *csr, int reg, unsigned long val)
> >> +{
> >> +       csr->csrs[reg] = val;
> >> +}
> >> +
> >> +/* Helpers */
> >> +static inline bool kvm_guest_has_fpu(struct kvm_vcpu_arch *arch)
> >> +{
> >> +       return cpu_has_fpu;
> >> +}
> >> +
> >> +void kvm_init_fault(void);
> >> +
> >> +/* Debug: dump vcpu state */
> >> +int kvm_arch_vcpu_dump_regs(struct kvm_vcpu *vcpu);
> >> +
> >> +/* MMU handling */
> >> +int kvm_handle_mm_fault(struct kvm_vcpu *vcpu, unsigned long badv, bool write);
> >> +void kvm_flush_tlb_all(void);
> >> +
> >> +#define KVM_ARCH_WANT_MMU_NOTIFIER
> >> +int kvm_unmap_hva_range(struct kvm *kvm,
> >> +                       unsigned long start, unsigned long end, bool blockable);
> >> +void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte);
> >> +int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end);
> >> +int kvm_test_age_hva(struct kvm *kvm, unsigned long hva);
> >> +
> >> +static inline void update_pc(struct kvm_vcpu_arch *arch)
> >> +{
> >> +       arch->pc += 4;
> >> +}
> >> +
> >> +/**
> >> + * kvm_is_ifetch_fault() - Find whether a TLBL exception is due to ifetch fault.
> >> + * @vcpu:      Virtual CPU.
> >> + *
> >> + * Returns:    Whether the TLBL exception was likely due to an instruction
> >> + *             fetch fault rather than a data load fault.
> >> + */
> >> +static inline bool kvm_is_ifetch_fault(struct kvm_vcpu_arch *arch)
> >> +{
> >> +       return arch->pc == arch->badv;
> >> +}
> >> +
> >> +/* Misc */
> >> +static inline void kvm_arch_hardware_unsetup(void) {}
> >> +static inline void kvm_arch_sync_events(struct kvm *kvm) {}
> >> +static inline void kvm_arch_memslots_updated(struct kvm *kvm, u64 gen) {}
> >> +static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {}
> >> +static inline void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu) {}
> >> +static inline void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu) {}
> >> +static inline void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu) {}
> >> +static inline void kvm_arch_free_memslot(struct kvm *kvm,
> >> +                                  struct kvm_memory_slot *slot) {}
> >> +void kvm_check_vpid(struct kvm_vcpu *vcpu);
> >> +enum hrtimer_restart kvm_swtimer_wakeup(struct hrtimer *timer);
> >> +int kvm_flush_tlb_gpa(struct kvm_vcpu *vcpu, unsigned long gpa);
> >> +void kvm_arch_flush_remote_tlbs_memslot(struct kvm *kvm,
> >> +                                       const struct kvm_memory_slot *memslot);
> >> +void kvm_init_vmcs(struct kvm *kvm);
> >> +void kvm_vector_entry(void);
> >> +int  kvm_enter_guest(struct kvm_run *run, struct kvm_vcpu *vcpu);
> >> +extern const unsigned long kvm_vector_size;
> >> +extern const unsigned long kvm_enter_guest_size;
> >> +extern unsigned long vpid_mask;
> >> +extern struct kvm_world_switch *kvm_loongarch_ops;
> >> +
> >> +#define SW_GCSR                (1 << 0)
> >> +#define HW_GCSR                (1 << 1)
> >> +#define INVALID_GCSR   (1 << 2)
> >> +int get_gcsr_flag(int csr);
> >> +extern void set_hw_gcsr(int csr_id, unsigned long val);
> >> +#endif /* __ASM_LOONGARCH_KVM_HOST_H__ */
> >> diff --git a/arch/loongarch/include/asm/kvm_types.h b/arch/loongarch/include/asm/kvm_types.h
> >> new file mode 100644
> >> index 0000000000..2fe1d4bdff
> >> --- /dev/null
> >> +++ b/arch/loongarch/include/asm/kvm_types.h
> >> @@ -0,0 +1,11 @@
> >> +/* SPDX-License-Identifier: GPL-2.0 */
> >> +/*
> >> + * Copyright (C) 2020-2023 Loongson Technology Corporation Limited
> >> + */
> >> +
> >> +#ifndef _ASM_LOONGARCH_KVM_TYPES_H
> >> +#define _ASM_LOONGARCH_KVM_TYPES_H
> >> +
> >> +#define KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE      40
> >> +
> >> +#endif /* _ASM_LOONGARCH_KVM_TYPES_H */
> >> diff --git a/arch/loongarch/include/uapi/asm/kvm.h b/arch/loongarch/include/uapi/asm/kvm.h
> >> new file mode 100644
> >> index 0000000000..fafda487d6
> >> --- /dev/null
> >> +++ b/arch/loongarch/include/uapi/asm/kvm.h
> >> @@ -0,0 +1,108 @@
> >> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> >> +/*
> >> + * Copyright (C) 2020-2023 Loongson Technology Corporation Limited
> >> + */
> >> +
> >> +#ifndef __UAPI_ASM_LOONGARCH_KVM_H
> >> +#define __UAPI_ASM_LOONGARCH_KVM_H
> >> +
> >> +#include <linux/types.h>
> >> +
> >> +/*
> >> + * KVM Loongarch specific structures and definitions.
> >> + *
> >> + * Some parts derived from the x86 version of this file.
> >> + */
> >> +
> >> +#define __KVM_HAVE_READONLY_MEM
> >> +
> >> +#define KVM_COALESCED_MMIO_PAGE_OFFSET 1
> >> +#define KVM_DIRTY_LOG_PAGE_OFFSET      64
> >> +
> >> +/*
> >> + * for KVM_GET_REGS and KVM_SET_REGS
> >> + */
> >> +struct kvm_regs {
> >> +       /* out (KVM_GET_REGS) / in (KVM_SET_REGS) */
> >> +       __u64 gpr[32];
> >> +       __u64 pc;
> >> +};
> >> +
> >> +/*
> >> + * for KVM_GET_FPU and KVM_SET_FPU
> >> + */
> >> +struct kvm_fpu {
> >> +       __u32 fcsr;
> >> +       __u64 fcc;    /* 8x8 */
> >> +       struct kvm_fpureg {
> >> +               __u64 val64[4];
> >> +       } fpr[32];
> >> +};
> >> +
> >> +/*
> >> + * For LoongArch, we use KVM_SET_ONE_REG and KVM_GET_ONE_REG to access various
> >> + * registers.  The id field is broken down as follows:
> >> + *
> >> + *  bits[63..52] - As per linux/kvm.h
> >> + *  bits[51..32] - Must be zero.
> >> + *  bits[31..16] - Register set.
> >> + *
> >> + * Register set = 0: GP registers from kvm_regs (see definitions below).
> >> + *
> >> + * Register set = 1: CSR registers.
> >> + *
> >> + * Register set = 2: KVM specific registers (see definitions below).
> >> + *
> >> + * Register set = 3: FPU / SIMD registers (see definitions below).
> >> + *
> >> + * Other sets registers may be added in the future.  Each set would
> >> + * have its own identifier in bits[31..16].
> >> + */
> >> +
> >> +#define KVM_REG_LOONGARCH_GPR          (KVM_REG_LOONGARCH | 0x00000ULL)
> >> +#define KVM_REG_LOONGARCH_CSR          (KVM_REG_LOONGARCH | 0x10000ULL)
> >> +#define KVM_REG_LOONGARCH_KVM          (KVM_REG_LOONGARCH | 0x20000ULL)
> >> +#define KVM_REG_LOONGARCH_FPU          (KVM_REG_LOONGARCH | 0x30000ULL)
> > How about rename to KVM_REG_LOONGARCH_FPSIMD？
> >
> > Huacai
> It will broke uapi used by user space software, it may cause
> incompatible issue, so I think it is better to keep the original name.
In your comments above it is not only FPU but FPU&SIMD, and this code
hasn't been upstream yet, how to break UAPI?

Huacai

>
> Thanks
> Tianrui Zhao
> >
> >> +#define KVM_REG_LOONGARCH_CPUCFG       (KVM_REG_LOONGARCH | 0x40000ULL)
> >> +#define KVM_REG_LOONGARCH_MASK         (KVM_REG_LOONGARCH | 0x70000ULL)
> >> +#define KVM_CSR_IDX_MASK               0x7fff
> >> +#define KVM_CPUCFG_IDX_MASK            0x7fff
> >> +
> >> +/*
> >> + * KVM_REG_LOONGARCH_KVM - KVM specific control registers.
> >> + */
> >> +
> >> +#define KVM_REG_LOONGARCH_COUNTER      (KVM_REG_LOONGARCH_KVM | KVM_REG_SIZE_U64 | 3)
> >> +#define KVM_REG_LOONGARCH_VCPU_RESET   (KVM_REG_LOONGARCH_KVM | KVM_REG_SIZE_U64 | 4)
> >> +
> >> +#define LOONGARCH_REG_SHIFT            3
> >> +#define LOONGARCH_REG_64(TYPE, REG)    (TYPE | KVM_REG_SIZE_U64 | (REG << LOONGARCH_REG_SHIFT))
> >> +#define KVM_IOC_CSRID(REG)             LOONGARCH_REG_64(KVM_REG_LOONGARCH_CSR, REG)
> >> +#define KVM_IOC_CPUCFG(REG)            LOONGARCH_REG_64(KVM_REG_LOONGARCH_CPUCFG, REG)
> >> +
> >> +struct kvm_debug_exit_arch {
> >> +};
> >> +
> >> +/* for KVM_SET_GUEST_DEBUG */
> >> +struct kvm_guest_debug_arch {
> >> +};
> >> +
> >> +/* definition of registers in kvm_run */
> >> +struct kvm_sync_regs {
> >> +};
> >> +
> >> +/* dummy definition */
> >> +struct kvm_sregs {
> >> +};
> >> +
> >> +struct kvm_iocsr_entry {
> >> +       __u32 addr;
> >> +       __u32 pad;
> >> +       __u64 data;
> >> +};
> >> +
> >> +#define KVM_NR_IRQCHIPS                1
> >> +#define KVM_IRQCHIP_NUM_PINS   64
> >> +#define KVM_MAX_CORES          256
> >> +
> >> +#endif /* __UAPI_ASM_LOONGARCH_KVM_H */
> >> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> >> index 13065dd961..863f84619a 100644
> >> --- a/include/uapi/linux/kvm.h
> >> +++ b/include/uapi/linux/kvm.h
> >> @@ -264,6 +264,7 @@ struct kvm_xen_exit {
> >>   #define KVM_EXIT_RISCV_SBI        35
> >>   #define KVM_EXIT_RISCV_CSR        36
> >>   #define KVM_EXIT_NOTIFY           37
> >> +#define KVM_EXIT_LOONGARCH_IOCSR  38
> >>
> >>   /* For KVM_EXIT_INTERNAL_ERROR */
> >>   /* Emulate instruction failed. */
> >> @@ -336,6 +337,13 @@ struct kvm_run {
> >>                          __u32 len;
> >>                          __u8  is_write;
> >>                  } mmio;
> >> +               /* KVM_EXIT_LOONGARCH_IOCSR */
> >> +               struct {
> >> +                       __u64 phys_addr;
> >> +                       __u8  data[8];
> >> +                       __u32 len;
> >> +                       __u8  is_write;
> >> +               } iocsr_io;
> >>                  /* KVM_EXIT_HYPERCALL */
> >>                  struct {
> >>                          __u64 nr;
> >> @@ -1362,6 +1370,7 @@ struct kvm_dirty_tlb {
> >>   #define KVM_REG_ARM64          0x6000000000000000ULL
> >>   #define KVM_REG_MIPS           0x7000000000000000ULL
> >>   #define KVM_REG_RISCV          0x8000000000000000ULL
> >> +#define KVM_REG_LOONGARCH      0x9000000000000000ULL
> >>
> >>   #define KVM_REG_SIZE_SHIFT     52
> >>   #define KVM_REG_SIZE_MASK      0x00f0000000000000ULL
> >> --
> >> 2.39.1
> >>
>
>

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