On Mon, May 6, 2024 at 4:18 PM maobibo <maobibo@xxxxxxxxxxx> wrote: > > > > On 2024/5/6 下午3:06, Huacai Chen wrote: > > Hi, Bibo, > > > > On Mon, May 6, 2024 at 2:36 PM maobibo <maobibo@xxxxxxxxxxx> wrote: > >> > >> > >> > >> On 2024/5/6 上午9:49, Huacai Chen wrote: > >>> Hi, Bibo, > >>> > >>> On Sun, Apr 28, 2024 at 6:05 PM Bibo Mao <maobibo@xxxxxxxxxxx> wrote: > >>>> > >>>> Physical cpuid is used for interrupt routing for irqchips such as > >>>> ipi/msi/extioi interrupt controller. And physical cpuid is stored > >>>> at CSR register LOONGARCH_CSR_CPUID, it can not be changed once vcpu > >>>> is created and physical cpuid of two vcpus cannot be the same. > >>>> > >>>> Different irqchips have different size declaration about physical cpuid, > >>>> max cpuid value for CSR LOONGARCH_CSR_CPUID on 3A5000 is 512, max cpuid > >>>> supported by IPI hardware is 1024, 256 for extioi irqchip, and 65536 > >>>> for MSI irqchip. > >>>> > >>>> The smallest value from all interrupt controllers is selected now, > >>>> and the max cpuid size is defines as 256 by KVM which comes from > >>>> extioi irqchip. > >>>> > >>>> Signed-off-by: Bibo Mao <maobibo@xxxxxxxxxxx> > >>>> --- > >>>> arch/loongarch/include/asm/kvm_host.h | 26 ++++++++ > >>>> arch/loongarch/include/asm/kvm_vcpu.h | 1 + > >>>> arch/loongarch/kvm/vcpu.c | 93 ++++++++++++++++++++++++++- > >>>> arch/loongarch/kvm/vm.c | 11 ++++ > >>>> 4 files changed, 130 insertions(+), 1 deletion(-) > >>>> > >>>> diff --git a/arch/loongarch/include/asm/kvm_host.h b/arch/loongarch/include/asm/kvm_host.h > >>>> index 2d62f7b0d377..3ba16ef1fe69 100644 > >>>> --- a/arch/loongarch/include/asm/kvm_host.h > >>>> +++ b/arch/loongarch/include/asm/kvm_host.h > >>>> @@ -64,6 +64,30 @@ struct kvm_world_switch { > >>>> > >>>> #define MAX_PGTABLE_LEVELS 4 > >>>> > >>>> +/* > >>>> + * Physical cpu id is used for interrupt routing, there are different > >>>> + * definitions about physical cpuid on different hardwares. > >>>> + * For LOONGARCH_CSR_CPUID register, max cpuid size if 512 > >>>> + * For IPI HW, max dest CPUID size 1024 > >>>> + * For extioi interrupt controller, max dest CPUID size is 256 > >>>> + * For MSI interrupt controller, max supported CPUID size is 65536 > >>>> + * > >>>> + * Currently max CPUID is defined as 256 for KVM hypervisor, in future > >>>> + * it will be expanded to 4096, including 16 packages at most. And every > >>>> + * package supports at most 256 vcpus > >>>> + */ > >>>> +#define KVM_MAX_PHYID 256 > >>>> + > >>>> +struct kvm_phyid_info { > >>>> + struct kvm_vcpu *vcpu; > >>>> + bool enabled; > >>>> +}; > >>>> + > >>>> +struct kvm_phyid_map { > >>>> + int max_phyid; > >>>> + struct kvm_phyid_info phys_map[KVM_MAX_PHYID]; > >>>> +}; > >>>> + > >>>> struct kvm_arch { > >>>> /* Guest physical mm */ > >>>> kvm_pte_t *pgd; > >>>> @@ -71,6 +95,8 @@ struct kvm_arch { > >>>> unsigned long invalid_ptes[MAX_PGTABLE_LEVELS]; > >>>> unsigned int pte_shifts[MAX_PGTABLE_LEVELS]; > >>>> unsigned int root_level; > >>>> + spinlock_t phyid_map_lock; > >>>> + struct kvm_phyid_map *phyid_map; > >>>> > >>>> s64 time_offset; > >>>> struct kvm_context __percpu *vmcs; > >>>> diff --git a/arch/loongarch/include/asm/kvm_vcpu.h b/arch/loongarch/include/asm/kvm_vcpu.h > >>>> index 0cb4fdb8a9b5..9f53950959da 100644 > >>>> --- a/arch/loongarch/include/asm/kvm_vcpu.h > >>>> +++ b/arch/loongarch/include/asm/kvm_vcpu.h > >>>> @@ -81,6 +81,7 @@ void kvm_save_timer(struct kvm_vcpu *vcpu); > >>>> void kvm_restore_timer(struct kvm_vcpu *vcpu); > >>>> > >>>> int kvm_vcpu_ioctl_interrupt(struct kvm_vcpu *vcpu, struct kvm_interrupt *irq); > >>>> +struct kvm_vcpu *kvm_get_vcpu_by_cpuid(struct kvm *kvm, int cpuid); > >>>> > >>>> /* > >>>> * Loongarch KVM guest interrupt handling > >>>> diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c > >>>> index 3a8779065f73..b633fd28b8db 100644 > >>>> --- a/arch/loongarch/kvm/vcpu.c > >>>> +++ b/arch/loongarch/kvm/vcpu.c > >>>> @@ -274,6 +274,95 @@ static int _kvm_getcsr(struct kvm_vcpu *vcpu, unsigned int id, u64 *val) > >>>> return 0; > >>>> } > >>>> > >>>> +static inline int kvm_set_cpuid(struct kvm_vcpu *vcpu, u64 val) > >>>> +{ > >>>> + int cpuid; > >>>> + struct loongarch_csrs *csr = vcpu->arch.csr; > >>>> + struct kvm_phyid_map *map; > >>>> + > >>>> + if (val >= KVM_MAX_PHYID) > >>>> + return -EINVAL; > >>>> + > >>>> + cpuid = kvm_read_sw_gcsr(csr, LOONGARCH_CSR_ESTAT); > >>>> + map = vcpu->kvm->arch.phyid_map; > >>>> + spin_lock(&vcpu->kvm->arch.phyid_map_lock); > >>>> + if (map->phys_map[cpuid].enabled) { > >>>> + /* > >>>> + * Cpuid is already set before > >>>> + * Forbid changing different cpuid at runtime > >>>> + */ > >>>> + if (cpuid != val) { > >>>> + /* > >>>> + * Cpuid 0 is initial value for vcpu, maybe invalid > >>>> + * unset value for vcpu > >>>> + */ > >>>> + if (cpuid) { > >>>> + spin_unlock(&vcpu->kvm->arch.phyid_map_lock); > >>>> + return -EINVAL; > >>>> + } > >>>> + } else { > >>>> + /* Discard duplicated cpuid set */ > >>>> + spin_unlock(&vcpu->kvm->arch.phyid_map_lock); > >>>> + return 0; > >>>> + } > >>>> + } > >>> I have changed the logic and comments when I apply, you can double > >>> check whether it is correct. > >> I checkout the latest version, the modification in function > >> kvm_set_cpuid() is good for me. > > Now the modified version is like this: > > > > + if (map->phys_map[cpuid].enabled) { > > + /* Discard duplicated CPUID set operation */ > > + if (cpuid == val) { > > + spin_unlock(&vcpu->kvm->arch.phyid_map_lock); > > + return 0; > > + } > > + > > + /* > > + * CPUID is already set before > > + * Forbid changing different CPUID at runtime > > + * But CPUID 0 is the initial value for vcpu, so allow > > + * changing from 0 to others > > + */ > > + if (cpuid) { > > + spin_unlock(&vcpu->kvm->arch.phyid_map_lock); > > + return -EINVAL; > > + } > > + } > > But I still doubt whether we should allow changing from 0 to others > > while map->phys_map[cpuid].enabled is 1. > It is necessary since the default sw cpuid is zero :-( And we can > optimize it in later, such as set INVALID cpuid in function > kvm_arch_vcpu_create() and logic will be simple in function kvm_set_cpuid(). In my opinion, if a vcpu with a uninitialized default physid=0, then map->phys_map[cpuid].enabled should be 0, then code won't come here. And if a vcpu with a real physid=0, then map->phys_map[cpuid].enabled is 1, but we shouldn't allow it to change physid in this case. Huacai > > Regards > Bibo Mao > > > > > Huacai > > > >>> > >>>> + > >>>> + if (map->phys_map[val].enabled) { > >>>> + /* > >>>> + * New cpuid is already set with other vcpu > >>>> + * Forbid sharing the same cpuid between different vcpus > >>>> + */ > >>>> + if (map->phys_map[val].vcpu != vcpu) { > >>>> + spin_unlock(&vcpu->kvm->arch.phyid_map_lock); > >>>> + return -EINVAL; > >>>> + } > >>>> + > >>>> + /* Discard duplicated cpuid set operation*/ > >>>> + spin_unlock(&vcpu->kvm->arch.phyid_map_lock); > >>>> + return 0; > >>>> + } > >>>> + > >>>> + kvm_write_sw_gcsr(csr, LOONGARCH_CSR_CPUID, val); > >>>> + map->phys_map[val].enabled = true; > >>>> + map->phys_map[val].vcpu = vcpu; > >>>> + if (map->max_phyid < val) > >>>> + map->max_phyid = val; > >>>> + spin_unlock(&vcpu->kvm->arch.phyid_map_lock); > >>>> + return 0; > >>>> +} > >>>> + > >>>> +struct kvm_vcpu *kvm_get_vcpu_by_cpuid(struct kvm *kvm, int cpuid) > >>>> +{ > >>>> + struct kvm_phyid_map *map; > >>>> + > >>>> + if (cpuid >= KVM_MAX_PHYID) > >>>> + return NULL; > >>>> + > >>>> + map = kvm->arch.phyid_map; > >>>> + if (map->phys_map[cpuid].enabled) > >>>> + return map->phys_map[cpuid].vcpu; > >>>> + > >>>> + return NULL; > >>>> +} > >>>> + > >>>> +static inline void kvm_drop_cpuid(struct kvm_vcpu *vcpu) > >>>> +{ > >>>> + int cpuid; > >>>> + struct loongarch_csrs *csr = vcpu->arch.csr; > >>>> + struct kvm_phyid_map *map; > >>>> + > >>>> + map = vcpu->kvm->arch.phyid_map; > >>>> + cpuid = kvm_read_sw_gcsr(csr, LOONGARCH_CSR_ESTAT); > >>>> + if (cpuid >= KVM_MAX_PHYID) > >>>> + return; > >>>> + > >>>> + if (map->phys_map[cpuid].enabled) { > >>>> + map->phys_map[cpuid].vcpu = NULL; > >>>> + map->phys_map[cpuid].enabled = false; > >>>> + kvm_write_sw_gcsr(csr, LOONGARCH_CSR_CPUID, 0); > >>>> + } > >>>> +} > >>> While kvm_set_cpuid() is protected by a spinlock, do kvm_drop_cpuid() > >>> and kvm_get_vcpu_by_cpuid() also need it? > >>> > >> It is good to me that spinlock is added in function kvm_drop_cpuid(). > >> And thinks for the efforts. > >> > >> Regards > >> Bibo Mao > >>>> + > >>>> static int _kvm_setcsr(struct kvm_vcpu *vcpu, unsigned int id, u64 val) > >>>> { > >>>> int ret = 0, gintc; > >>>> @@ -291,7 +380,8 @@ static int _kvm_setcsr(struct kvm_vcpu *vcpu, unsigned int id, u64 val) > >>>> kvm_set_sw_gcsr(csr, LOONGARCH_CSR_ESTAT, gintc); > >>>> > >>>> return ret; > >>>> - } > >>>> + } else if (id == LOONGARCH_CSR_CPUID) > >>>> + return kvm_set_cpuid(vcpu, val); > >>>> > >>>> kvm_write_sw_gcsr(csr, id, val); > >>>> > >>>> @@ -943,6 +1033,7 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu) > >>>> hrtimer_cancel(&vcpu->arch.swtimer); > >>>> kvm_mmu_free_memory_cache(&vcpu->arch.mmu_page_cache); > >>>> kfree(vcpu->arch.csr); > >>>> + kvm_drop_cpuid(vcpu); > >>> I think this line should be before the above kfree(), otherwise you > >>> get a "use after free". > >>> > >>> Huacai > >>> > >>>> > >>>> /* > >>>> * If the vCPU is freed and reused as another vCPU, we don't want the > >>>> diff --git a/arch/loongarch/kvm/vm.c b/arch/loongarch/kvm/vm.c > >>>> index 0a37f6fa8f2d..6006a28653ad 100644 > >>>> --- a/arch/loongarch/kvm/vm.c > >>>> +++ b/arch/loongarch/kvm/vm.c > >>>> @@ -30,6 +30,14 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) > >>>> if (!kvm->arch.pgd) > >>>> return -ENOMEM; > >>>> > >>>> + kvm->arch.phyid_map = kvzalloc(sizeof(struct kvm_phyid_map), > >>>> + GFP_KERNEL_ACCOUNT); > >>>> + if (!kvm->arch.phyid_map) { > >>>> + free_page((unsigned long)kvm->arch.pgd); > >>>> + kvm->arch.pgd = NULL; > >>>> + return -ENOMEM; > >>>> + } > >>>> + > >>>> kvm_init_vmcs(kvm); > >>>> kvm->arch.gpa_size = BIT(cpu_vabits - 1); > >>>> kvm->arch.root_level = CONFIG_PGTABLE_LEVELS - 1; > >>>> @@ -44,6 +52,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) > >>>> for (i = 0; i <= kvm->arch.root_level; i++) > >>>> kvm->arch.pte_shifts[i] = PAGE_SHIFT + i * (PAGE_SHIFT - 3); > >>>> > >>>> + spin_lock_init(&kvm->arch.phyid_map_lock); > >>>> return 0; > >>>> } > >>>> > >>>> @@ -51,7 +60,9 @@ void kvm_arch_destroy_vm(struct kvm *kvm) > >>>> { > >>>> kvm_destroy_vcpus(kvm); > >>>> free_page((unsigned long)kvm->arch.pgd); > >>>> + kvfree(kvm->arch.phyid_map); > >>>> kvm->arch.pgd = NULL; > >>>> + kvm->arch.phyid_map = NULL; > >>>> } > >>>> > >>>> int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) > >>>> -- > >>>> 2.39.3 > >>>> > >> >