On Tue, May 7, 2024 at 9:40 AM maobibo <maobibo@xxxxxxxxxxx> wrote:
>
>
>
> On 2024/5/6 下午10:17, Huacai Chen wrote:
> > On Mon, May 6, 2024 at 6:05 PM maobibo <maobibo@xxxxxxxxxxx> wrote:
> >>
> >>
> >>
> >> On 2024/5/6 下午5:40, Huacai Chen wrote:
> >>> On Mon, May 6, 2024 at 5:35 PM maobibo <maobibo@xxxxxxxxxxx> wrote:
> >>>>
> >>>>
> >>>>
> >>>> On 2024/5/6 下午4:59, Huacai Chen wrote:
> >>>>> 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.
> >>>> yes, that is actually a problem.
> >>>>
> >>>> vcpu0 firstly set physid=0, and vcpu0 set physid=1 again is not allowed.
> >>>> vcpu0 firstly set physid=0, and vcpu1 set physid=1 is allowed.
> >>>
> >>> So can we simply drop the if (cpuid) checking? That means:
> >>> + if (map->phys_map[cpuid].enabled) {
> >>> + /* Discard duplicated CPUID set operation */
> >>> + if (cpuid == val) {
> >>> + spin_unlock(&vcpu->kvm->arch.phyid_map_lock);
> >>> + return 0;
> >>> + }
> >>> +
> >>> + spin_unlock(&vcpu->kvm->arch.phyid_map_lock);
> >>> + return -EINVAL;
> >>> + }
> >> yes, the similar modification such as following, since the secondary
> >> scenario should be allowed.
> >> "vcpu0 firstly set physid=0, and vcpu1 set physid=1 is allowed though
> >> default sw cpuid is zero"
> >>
> >> --- a/arch/loongarch/kvm/vcpu.c
> >> +++ b/arch/loongarch/kvm/vcpu.c
> >> @@ -272,7 +272,7 @@ static inline int kvm_set_cpuid(struct kvm_vcpu
> >> *vcpu, u64 val)
> >> cpuid = kvm_read_sw_gcsr(csr, LOONGARCH_CSR_CPUID);
> >>
> >> spin_lock(&vcpu->kvm->arch.phyid_map_lock);
> >> - if (map->phys_map[cpuid].enabled) {
> >> + if ((cpuid != KVM_MAX_PHYID) && map->phys_map[cpuid].enabled) {
> >> /* Discard duplicated CPUID set operation */
> >> if (cpuid == val) {
> >> spin_unlock(&vcpu->kvm->arch.phyid_map_lock);
> >> @@ -282,13 +282,9 @@ static inline int kvm_set_cpuid(struct kvm_vcpu
> >> *vcpu, u64 val)
> >> /*
> >> * 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;
> >> - }
> >> + spin_unlock(&vcpu->kvm->arch.phyid_map_lock);
> >> + return -EINVAL;
> >> }
> >>
> >> if (map->phys_map[val].enabled) {
> >> @@ -1029,6 +1025,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
> >>
> >> /* Set cpuid */
> >> kvm_write_sw_gcsr(csr, LOONGARCH_CSR_TMID, vcpu->vcpu_id);
> >> + kvm_write_sw_gcsr(csr, LOONGARCH_CSR_CPUID, KVM_MAX_PHYID);
> >>
> >> /* Start with no pending virtual guest interrupts */
> >> csr->csrs[LOONGARCH_CSR_GINTC] = 0;
> > Very nice, but I think kvm_drop_cpuid() should also set to KVM_MAX_PHYID.
> > Now I update my loongarch-kvm branch, you can test it again, and hope
> > it is in the perfect status.
> I sync and test the latest code from loongarch-kvm, pv ipi works well
> with 256 vcpus. And the code looks good to me, thanks for your review in
> short time.
OK, if SWDBG also works well, I will send PR to Paolo tomorrow.
Huacai
>
> Regards
> Bibo Mao
> >
> > Huacai
> >>
> >>
> >>>
> >>> Huacai
> >>>
> >>>>
> >>>>
> >>>>>
> >>>>> 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
> >>>>>>>>>>
> >>>>>>>>
> >>>>>>
> >>>>
> >>
>
>
