Re: [PATCH v2 01/29] LoongArch: KVM: Add kvm related header files

From: Tianrui Zhao
Date: Mon Feb 20 2023 - 21:57:21 EST




在 2023年02月21日 02:22, Paolo Bonzini 写道:
On 2/20/23 07:57, Tianrui Zhao wrote:
+
+/* Resume Flags */
+#define RESUME_FLAG_DR (1<<0) /* Reload guest nonvolatile state? */
+#define RESUME_FLAG_HOST (1<<1) /* Resume host? */
+
+#define RESUME_GUEST 0
+#define RESUME_GUEST_DR RESUME_FLAG_DR
+#define RESUME_HOST RESUME_FLAG_HOST
+

Most of this code is dead, I'll give more instructions in a reply to patch 8.

+ unsigned long guest_eentry;
+ unsigned long host_eentry;
+ int (*vcpu_run)(struct kvm_run *run, struct kvm_vcpu *vcpu);
+ 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 */
+ unsigned long badv;
+ unsigned long host_estat;
+ unsigned long badi;
+ unsigned long host_ecfg;
+ unsigned long host_percpu;
+
+ /* GPRS */
+ unsigned long gprs[32];
+ unsigned long pc;
+
+ /* FPU 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 */
+ 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 */
+ struct kvm_mmu_memory_cache mmu_page_cache;
+
+ /* vcpu's vpid is different on each host cpu in an smp system */
+ u64 vpid[NR_CPUS];

In _kvm_check_vmid(), you already have

+ if (migrated || (ver != old)) {
+ _kvm_update_vpid(vcpu, cpu);
+ trace_kvm_vpid_change(vcpu, vcpu->arch.vpid[cpu]);
+ }

so a vpid will never be recycled if a vCPU migrates from physical CPU A to B and back to A.

So please keep the current VPID in the per-cpu struct vmcs, and you can just copy it from there in _kvm_check_vmid().

Thanks, that is to say we should remove the vpid[NR_CPUS] array and it is enough to use only one vpid variable?

Thanks
Tianrui Zhao


+ /* Period of stable timer tick in ns */
+ u64 timer_period;
+ /* Frequency of stable timer in Hz */
+ u64 timer_mhz;
+ /* 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 */
+ ktime_t stable_ktime_saved;
+
+ u64 core_ext_ioisr[4];
+
+ /* Last CPU the VCPU state was loaded on */
+ int last_sched_cpu;
+ /* Last CPU the VCPU actually executed guest code on */
+ int last_exec_cpu;
+
+ u8 fpu_enabled;

This field is always true, please remove it.

Thanks, i will remove this variable.

Thanks
Tianrui Zhao


+ struct kvm_guest_debug_arch guest_debug;

This struct is empty, please remove it.

Ok, I will remove it.

Thanks
Tianrui Zhao


Paolo