Re: [PATCH v7 01/30] LoongArch: KVM: Add kvm related header files

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在 2023年04月19日 17:28, WANG Xuerui 写道:
On 2023/4/17 17:46, Tianrui Zhao 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.

Signed-off-by: Tianrui Zhao <zhaotianrui@xxxxxxxxxxx>
---
  arch/loongarch/include/asm/cpu-features.h |  22 ++
  arch/loongarch/include/asm/kvm_host.h     | 268 ++++++++++++++++++++++
  arch/loongarch/include/asm/kvm_types.h    |  11 +
  arch/loongarch/include/uapi/asm/kvm.h     | 107 +++++++++
  include/uapi/linux/kvm.h                  |   9 +
  5 files changed, 417 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/cpu-features.h b/arch/loongarch/include/asm/cpu-features.h
index b07974218393..345b7674a15f 100644
--- a/arch/loongarch/include/asm/cpu-features.h
+++ b/arch/loongarch/include/asm/cpu-features.h
@@ -64,5 +64,27 @@
  #define cpu_has_guestid        cpu_opt(LOONGARCH_CPU_GUESTID)
  #define cpu_has_hypervisor cpu_opt(LOONGARCH_CPU_HYPERVISOR)
  +#define cpu_has_matc_guest    (cpu_data[0].guest_cfg & BIT(0))
+#define cpu_has_matc_root    (cpu_data[0].guest_cfg & BIT(1))
+#define cpu_has_matc_nest    (cpu_data[0].guest_cfg & BIT(2))
+#define cpu_has_sitp        (cpu_data[0].guest_cfg & BIT(6))
+#define cpu_has_titp        (cpu_data[0].guest_cfg & BIT(8))
+#define cpu_has_toep        (cpu_data[0].guest_cfg & BIT(10))
+#define cpu_has_topp        (cpu_data[0].guest_cfg & BIT(12))
+#define cpu_has_torup        (cpu_data[0].guest_cfg & BIT(14))
+#define cpu_has_gcip_all    (cpu_data[0].guest_cfg & BIT(16))
+#define cpu_has_gcip_hit    (cpu_data[0].guest_cfg & BIT(17))
+#define cpu_has_gcip_secure    (cpu_data[0].guest_cfg & BIT(18))

We don't have guest_cfg yet in the cpu_data structure. You may have to re-organize a little bit to avoid referencing things from future commits.
Thanks, I will re-organize the order of commits to make the cpu_data structure suitable.

Thanks
Tianrui Zhao

Also you may want to make more use of the definitions already in <asm/loongarch.h>, e.g. the BIT(6) here is just CSR_GCFG_SITP, and it seems the matc_{guest,root,nest} definitions here conflict with the definitions in <asm/loongarch.h> which implies the MATC is a plain value instead of a bunch of bit flags.
Thanks, the MATC is really a plain value instead of bit flags, and I will re-consider this.

Thanks
Tianrui Zhao

+
+/*
+ * Guest capabilities
+ */
+#define cpu_guest_has_conf1    (cpu_data[0].guest.conf & BIT(1))
+#define cpu_guest_has_conf2    (cpu_data[0].guest.conf & BIT(2))
+#define cpu_guest_has_conf3    (cpu_data[0].guest.conf & BIT(3))
+#define cpu_guest_has_fpu (cpu_data[0].guest.options & LOONGARCH_CPU_FPU) +#define cpu_guest_has_perf (cpu_data[0].guest.options & LOONGARCH_CPU_PMP) +#define cpu_guest_has_watch (cpu_data[0].guest.options & LOONGARCH_CPU_WATCH) +#define cpu_guest_has_lsx (cpu_data[0].guest.ases & LOONGARCH_ASE_LSX)

There is no LOONGARCH_ASE_LSX either.

    #endif /* __ASM_CPU_FEATURES_H */
diff --git a/arch/loongarch/include/asm/kvm_host.h b/arch/loongarch/include/asm/kvm_host.h
new file mode 100644
index 000000000000..bd239079b36f
--- /dev/null
+++ b/arch/loongarch/include/asm/kvm_host.h
@@ -0,0 +1,268 @@
+/* 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/loongarch.h>
+
+/* Loongarch KVM register ids */
+#define LOONGARCH_CSR_32(_R, _S)    \
+    (KVM_REG_LOONGARCH_CSR | KVM_REG_SIZE_U32 | (8 * (_R) + (_S)))
+
+#define LOONGARCH_CSR_64(_R, _S)    \
+    (KVM_REG_LOONGARCH_CSR | KVM_REG_SIZE_U64 | (8 * (_R) + (_S)))
+
+#define KVM_IOC_CSRID(id)        LOONGARCH_CSR_64(id, 0)
+#define KVM_GET_IOC_CSRIDX(id)        ((id & KVM_CSR_IDX_MASK) >> 3)
+
+#define KVM_MAX_VCPUS            256
+/* 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;
+};
+
+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;
+};
+
+struct kvm_arch {
+    /* Guest physical mm */
+    struct mm_struct gpa_mm;
+    /* Mask of CPUs needing GPA ASID flush */
+    cpumask_t asid_flush_mask;
+
+    unsigned char online_vcpus;
+    unsigned char is_migrate;
+    s64 time_offset;
+    struct kvm_context __percpu *vmcs;
+    unsigned long gpa_size;
+};
+
+
+#define LOONGARCH_CSRS        0x100
+#define CSR_UCWIN_BASE        0x100
+#define CSR_UCWIN_SIZE        0x10
+#define CSR_DMWIN_BASE        0x180
+#define CSR_DMWIN_SIZE        0x4 > +#define CSR_PERF_BASE        0x200
+#define CSR_PERF_SIZE        0x8
+#define CSR_DEBUG_BASE        0x500
+#define CSR_DEBUG_SIZE        0x3
+#define CSR_ALL_SIZE        0x800

Is the "SIZE"'s actually "numbers"? 16-byte or even 3-byte CSRs make absolutely no sense in LoongArch. However e.g. there are indeed 4 DMWINs in total, so I think you may want to say "number of xxx" instead (in which case you should probably name them "CSR_XXX_NUM").

Also there are duplications here too. CSR_UCWIN_BASE is just LOONGARCH_CSR_UCAWIN, CSR_DMWIN_BASE is LOONGARCH_CSR_DMWIN0, CSR_PERF_BASE is LOONGARCH_CSR_PERFCTRL0, and CSR_DEBUG_BASE is LOONGARCH_CSR_DEBUG. You should at least avoid repeating the magic numbers.

+
+struct loongarch_csrs {
+    unsigned long csrs[CSR_ALL_SIZE];
+};
+
+/* Resume Flags */
+#define RESUME_GUEST        1
+#define RESUME_HOST        0
+
+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_WAIT,        /* WAIT instruction */
+    EMULATE_EXCEPT,        /* A guest exception has been generated */
+    EMULATE_DO_IOCSR,    /* handle IOCSR request */
+};
+
+#define KVM_NR_MEM_OBJS        4
+#define KVM_LARCH_FPU        (0x1 << 0)
+#define KVM_LARCH_CSR        (0x1 << 1)
+
+struct kvm_vcpu_arch {
+    /*
+     * Switch pointer-to-function type to unsigned long
+     * for loading the value into register directly.
+     */
+    unsigned long guest_eentry;
+    unsigned long host_eentry;
+
+    /* Pointers stored here for easy access from assembly code. */

nit: remove trailing period

+    int (*handle_exit)(struct kvm_run *run, struct kvm_vcpu *vcpu);
+
+    /* Host registers preserved across guest mode execution */
+    unsigned long host_stack;
+    unsigned long host_gp;
+    unsigned long host_pgd;
+    unsigned long host_pgdhi;
+    unsigned long host_entryhi;
+
+    /* Host CSR registers used when handling exits from guest */

nit: "Host CSRs"

+    unsigned long badv;
+    unsigned long host_estat;
+    unsigned long badi;
+    unsigned long host_ecfg;
+    unsigned long host_percpu;
+
+    /* GPRS */

nit: "GPRs"

+    unsigned long gprs[32];
+    unsigned long pc;
+
+    /* FPU State */

nit: "state"

+    struct loongarch_fpu fpu FPU_ALIGN;
+    /* Which auxiliary state is loaded (KVM_LOONGARCH_AUX_*) */
+    unsigned int aux_inuse;
+
+    /* CSR State */
+    struct loongarch_csrs *csr;
+
+    /* GPR used as IO source/target */
+    u32 io_gpr;
+
+    struct hrtimer swtimer;
+    /* Count timer control KVM register */

This doesn't make sense, how can the timer control KVM? Seems something like "KVM register to control count timer" but I'm not sure.

+    u32 count_ctl;
+
+    /* Bitmask of exceptions that are pending */
+    unsigned long irq_pending;
+    /* Bitmask of pending exceptions to be cleared */
+    unsigned long irq_clear;
+
+    /* Cache some mmu pages needed inside spinlock regions */

"Cache for pages needed inside ..."?

+    struct kvm_mmu_memory_cache mmu_page_cache;
+
+    /* vcpu's vpid */
+    u64 vpid;
+
+    /* Period of stable timer tick in ns */
+    u64 timer_period;

Can you make it "timer_period_ns" or are you following other arches' conventions?

+    /* Frequency of stable timer in Hz */
+    u64 timer_mhz;

Is it really MHz or Hz?

+    /* Stable bias from the raw time */
+    u64 timer_bias;
+ /* Dynamic nanosecond bias (multiple of timer_period) to avoid overflow */
+    s64 timer_dyn_bias;
+    /* Save ktime */

The comment seems redundant (code is too trivial so the comment doesn't add any information).

+    ktime_t stable_ktime_saved;
+
+    u64 core_ext_ioisr[4];
+
+    /* Last CPU the VCPU state was loaded on */

Use consistent spelling: "vCPU".

+    int last_sched_cpu;
+    /* Last CPU the VCPU actually executed guest code on */
+    int last_exec_cpu;
+    /* mp state */
+    struct kvm_mp_state mp_state;
+};
+
+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);
+void _kvm_destroy_mm(struct kvm *kvm);
+pgd_t *kvm_pgd_alloc(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)
+{
+    if (arch->pc == arch->badv)
+        return true;
+
+    return false;

return arch->pc == arch->badv;

All other such occurrences should preferably be simplified too.

+}
+
+/* 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_vmid(struct kvm_vcpu *vcpu, int cpu);
+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)
+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 000000000000..060647b5fe2e
--- /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    4

Is there any difference with KVM_NR_MEM_OBJS in <asm/kvm_host.h> in the same commit? If they are actually the same thing you should avoid duplicating the "4".

+
+#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 000000000000..074d86ba532c
--- /dev/null
+++ b/arch/loongarch/include/uapi/asm/kvm.h
@@ -0,0 +1,107 @@
+/* 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
+
+/*
+ * 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;
+    __u32 none;

Is this field an explicit padding? Probably it's better to use a more descriptive name like __pad0 if it's the case.

+    __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_GP        (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)
+#define KVM_REG_LOONGARCH_MASK        (KVM_REG_LOONGARCH | 0x30000ULL)
+#define KVM_CSR_IDX_MASK        (0x10000 - 1)
+
+/*
+ * 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)
+
+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;
+};
+
+struct kvm_loongarch_interrupt {
+    /* in */
+    __u32 cpu;
+    __u32 irq;
+};
+
+#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 d77aef872a0a..d14fde87ae35 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;
@@ -1354,6 +1362,7 @@ 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





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