Received-SPF: pass (google.com: domain of linux-kernel+bounces-170603-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45e3:2400::1 as permitted sender) client-ip=2604:1380:45e3:2400::1;
Subject: Re: [PATCH v8 4/6] LoongArch: KVM: Add vcpu search support from
 physical cpuid
To: Huacai Chen <chenhuacai@kernel.org>
Cc: Tianrui Zhao <zhaotianrui@loongson.cn>, Juergen Gross <jgross@suse.com>,
 Paolo Bonzini <pbonzini@redhat.com>, Jonathan Corbet <corbet@lwn.net>,
 loongarch@lists.linux.dev, linux-kernel@vger.kernel.org,
 virtualization@lists.linux.dev, kvm@vger.kernel.org
References: <20240428100518.1642324-1-maobibo@loongson.cn>
 <20240428100518.1642324-5-maobibo@loongson.cn>
 <CAAhV-H6kBO_RTTHoLfKdAtLO1Aqb0KmAJ6wn0wZrvbCkzMszDQ@mail.gmail.com>
 <7335dcde-1b3a-1260-ac62-d2d9fcbd6a78@loongson.cn>
 <CAAhV-H5WJ0o3bJZBq2zx7ejjFkFwYVTyVJEzJuAHEs+uMg-sxw@mail.gmail.com>
 <b10b46ce-8219-8863-470f-9bfa173b22b0@loongson.cn>
 <CAAhV-H7fbrOXTtSwBmR3kyTW7yhsifycjynky4HPrUJiS9s=cg@mail.gmail.com>
 <540aa8dd-eada-1f77-0a20-38196fb5472a@loongson.cn>
 <CAAhV-H7o3oG2KXc2Ou0aWXTLPSNiM3evSB5Z-5dH4bLRd_P_0Q@mail.gmail.com>
 <61670353-90c6-6d0c-4430-7655b5251e17@loongson.cn>
 <CAAhV-H5wNmgxGincGE7cJ8WvrpKFauAJvMHrPttW-LrKB4UeHg@mail.gmail.com>
 <a6d49710-1580-809d-5dcf-ea4207257ae7@loongson.cn>
 <CAAhV-H4ir++y+46-g43-9bLvY8cv79fB6bKbWgkhDzDV7QQg9g@mail.gmail.com>
From: maobibo <maobibo@loongson.cn>
Message-ID: <7f16cac7-c712-40d4-a3f4-cc761e0dea93@loongson.cn>
Date: Tue, 7 May 2024 11:06:02 +0800
User-Agent: Mozilla/5.0 (X11; Linux loongarch64; rv:68.0) Gecko/20100101
 Thunderbird/68.7.0
Precedence: bulk
MIME-Version: 1.0
In-Reply-To: <CAAhV-H4ir++y+46-g43-9bLvY8cv79fB6bKbWgkhDzDV7QQg9g@mail.gmail.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 8bit


On 2024/5/7 上午10:05, Huacai Chen wrote:
> On Tue, May 7, 2024 at 9:40 AM maobibo <maobibo@loongson.cn> wrote:
>>
>>
>>
>> On 2024/5/6 下午10:17, Huacai Chen wrote:
>>> On Mon, May 6, 2024 at 6:05 PM maobibo <maobibo@loongson.cn> wrote:
>>>>
>>>>
>>>>
>>>> On 2024/5/6 下午5:40, Huacai Chen wrote:
>>>>> On Mon, May 6, 2024 at 5:35 PM maobibo <maobibo@loongson.cn> wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>> On 2024/5/6 下午4:59, Huacai Chen wrote:
>>>>>>> On Mon, May 6, 2024 at 4:18 PM maobibo <maobibo@loongson.cn> 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@loongson.cn> 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@loongson.cn> 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@loongson.cn>
>>>>>>>>>>>> ---
>>>>>>>>>>>>        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.
yes, sw debug works well with patch from qemu. And I will refresh patch 
to qemu after it is merged.

https://lore.kernel.org/all/20240218070025.218680-1-maobibo@loongson.cn/

--- a/configs/targets/loongarch64-softmmu.mak
+++ b/configs/targets/loongarch64-softmmu.mak
@@ -1,5 +1,6 @@
  TARGET_ARCH=loongarch64
  TARGET_BASE_ARCH=loongarch
  TARGET_SUPPORTS_MTTCG=y
+TARGET_KVM_HAVE_GUEST_DEBUG=y
  TARGET_XML_FILES= gdb-xml/loongarch-base32.xml 
gdb-xml/loongarch-base64.xml gdb-xml/loongarch-fpu.xml
  TARGET_NEED_FDT=y

Regards
Bibo Mao
> 
> 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
>>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>
>>>>>>
>>>>
>>
>>