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In-Reply-To: <7f16cac7-c712-40d4-a3f4-cc761e0dea93@loongson.cn>
From: Huacai Chen <chenhuacai@kernel.org>
Date: Wed, 8 May 2024 13:00:37 +0800
Message-ID: <CAAhV-H7ZwhrBma0mwFnuWBHXqH5gsJSz2hPL3jxHqfQVakh+SQ@mail.gmail.com>
Subject: Re: [PATCH v8 4/6] LoongArch: KVM: Add vcpu search support from
 physical cpuid
To: maobibo <maobibo@loongson.cn>
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
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

On Tue, May 7, 2024 at 11:06=E2=80=AFAM maobibo <maobibo@loongson.cn> wrote=
:
>
>
>
> On 2024/5/7 =E4=B8=8A=E5=8D=8810:05, Huacai Chen wrote:
> > On Tue, May 7, 2024 at 9:40=E2=80=AFAM maobibo <maobibo@loongson.cn> wr=
ote:
> >>
> >>
> >>
> >> On 2024/5/6 =E4=B8=8B=E5=8D=8810:17, Huacai Chen wrote:
> >>> On Mon, May 6, 2024 at 6:05=E2=80=AFPM maobibo <maobibo@loongson.cn> =
wrote:
> >>>>
> >>>>
> >>>>
> >>>> On 2024/5/6 =E4=B8=8B=E5=8D=885:40, Huacai Chen wrote:
> >>>>> On Mon, May 6, 2024 at 5:35=E2=80=AFPM maobibo <maobibo@loongson.cn=
> wrote:
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>> On 2024/5/6 =E4=B8=8B=E5=8D=884:59, Huacai Chen wrote:
> >>>>>>> On Mon, May 6, 2024 at 4:18=E2=80=AFPM maobibo <maobibo@loongson.=
cn> wrote:
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>
> >>>>>>>> On 2024/5/6 =E4=B8=8B=E5=8D=883:06, Huacai Chen wrote:
> >>>>>>>>> Hi, Bibo,
> >>>>>>>>>
> >>>>>>>>> On Mon, May 6, 2024 at 2:36=E2=80=AFPM maobibo <maobibo@loongso=
n.cn> wrote:
> >>>>>>>>>>
> >>>>>>>>>>
> >>>>>>>>>>
> >>>>>>>>>> On 2024/5/6 =E4=B8=8A=E5=8D=889:49, Huacai Chen wrote:
> >>>>>>>>>>> Hi, Bibo,
> >>>>>>>>>>>
> >>>>>>>>>>> On Sun, Apr 28, 2024 at 6:05=E2=80=AFPM Bibo Mao <maobibo@loo=
ngson.cn> wrote:
> >>>>>>>>>>>>
> >>>>>>>>>>>> Physical cpuid is used for interrupt routing for irqchips su=
ch as
> >>>>>>>>>>>> ipi/msi/extioi interrupt controller. And physical cpuid is s=
tored
> >>>>>>>>>>>> at CSR register LOONGARCH_CSR_CPUID, it can not be changed o=
nce vcpu
> >>>>>>>>>>>> is created and physical cpuid of two vcpus cannot be the sam=
e.
> >>>>>>>>>>>>
> >>>>>>>>>>>> Different irqchips have different size declaration about phy=
sical 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, a=
nd 65536
> >>>>>>>>>>>> for MSI irqchip.
> >>>>>>>>>>>>
> >>>>>>>>>>>> The smallest value from all interrupt controllers is selecte=
d 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/lo=
ongarch/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 mo=
st. 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/lo=
ongarch/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, s=
truct 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 =3D vcpu->arch.csr;
> >>>>>>>>>>>> +       struct kvm_phyid_map  *map;
> >>>>>>>>>>>> +
> >>>>>>>>>>>> +       if (val >=3D KVM_MAX_PHYID)
> >>>>>>>>>>>> +               return -EINVAL;
> >>>>>>>>>>>> +
> >>>>>>>>>>>> +       cpuid =3D kvm_read_sw_gcsr(csr, LOONGARCH_CSR_ESTAT)=
;
> >>>>>>>>>>>> +       map =3D 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 runtim=
e
> >>>>>>>>>>>> +                */
> >>>>>>>>>>>> +               if (cpuid !=3D 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_m=
ap_lock);
> >>>>>>>>>>>> +                       return 0;
> >>>>>>>>>>>> +               }
> >>>>>>>>>>>> +       }
> >>>>>>>>>>> I have changed the logic and comments when I apply, you can d=
ouble
> >>>>>>>>>>> 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 =3D=3D 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 ot=
hers
> >>>>>>>>> while map->phys_map[cpuid].enabled is 1.
> >>>>>>>> It is necessary since the default sw cpuid is zero :-( And we ca=
n
> >>>>>>>> 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=3D0,=
 then
> >>>>>>> map->phys_map[cpuid].enabled should be 0, then code won't come he=
re.
> >>>>>>> And if a vcpu with a real physid=3D0, then map->phys_map[cpuid].e=
nabled
> >>>>>>> is 1, but we shouldn't allow it to change physid in this case.
> >>>>>> yes, that is actually a problem.
> >>>>>>
> >>>>>> vcpu0 firstly set physid=3D0, and vcpu0 set physid=3D1 again is no=
t allowed.
> >>>>>> vcpu0 firstly set physid=3D0, and vcpu1 set physid=3D1 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 =3D=3D 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=3D0, and vcpu1 set physid=3D1 is allow=
ed 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 =3D kvm_read_sw_gcsr(csr, LOONGARCH_CSR_CPUID);
> >>>>
> >>>>            spin_lock(&vcpu->kvm->arch.phyid_map_lock);
> >>>> -       if (map->phys_map[cpuid].enabled) {
> >>>> +       if ((cpuid !=3D KVM_MAX_PHYID) && map->phys_map[cpuid].enabl=
ed) {
> >>>>                    /* Discard duplicated CPUID set operation */
> >>>>                    if (cpuid =3D=3D val) {
> >>>>                            spin_unlock(&vcpu->kvm->arch.phyid_map_lo=
ck);
> >>>> @@ -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 all=
ow
> >>>> -                * 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] =3D 0;
> >>> Very nice, but I think kvm_drop_cpuid() should also set to KVM_MAX_PH=
YID.
> >>> 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=3Dloongarch64
>   TARGET_BASE_ARCH=3Dloongarch
>   TARGET_SUPPORTS_MTTCG=3Dy
> +TARGET_KVM_HAVE_GUEST_DEBUG=3Dy
>   TARGET_XML_FILES=3D gdb-xml/loongarch-base32.xml
> gdb-xml/loongarch-base64.xml gdb-xml/loongarch-fpu.xml
>   TARGET_NEED_FDT=3Dy
Not enough, we need kvm_arch_update_guest_debug() and some other functions.

Huacai

>
> 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 dif=
ferent vcpus
> >>>>>>>>>>>> +                */
> >>>>>>>>>>>> +               if (map->phys_map[val].vcpu !=3D vcpu) {
> >>>>>>>>>>>> +                       spin_unlock(&vcpu->kvm->arch.phyid_m=
ap_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      =3D true;
> >>>>>>>>>>>> +       map->phys_map[val].vcpu         =3D vcpu;
> >>>>>>>>>>>> +       if (map->max_phyid < val)
> >>>>>>>>>>>> +               map->max_phyid =3D 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 >=3D KVM_MAX_PHYID)
> >>>>>>>>>>>> +               return NULL;
> >>>>>>>>>>>> +
> >>>>>>>>>>>> +       map =3D 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 =3D vcpu->arch.csr;
> >>>>>>>>>>>> +       struct kvm_phyid_map  *map;
> >>>>>>>>>>>> +
> >>>>>>>>>>>> +       map =3D vcpu->kvm->arch.phyid_map;
> >>>>>>>>>>>> +       cpuid =3D kvm_read_sw_gcsr(csr, LOONGARCH_CSR_ESTAT)=
;
> >>>>>>>>>>>> +       if (cpuid >=3D KVM_MAX_PHYID)
> >>>>>>>>>>>> +               return;
> >>>>>>>>>>>> +
> >>>>>>>>>>>> +       if (map->phys_map[cpuid].enabled) {
> >>>>>>>>>>>> +               map->phys_map[cpuid].vcpu =3D NULL;
> >>>>>>>>>>>> +               map->phys_map[cpuid].enabled =3D 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_c=
puid().
> >>>>>>>>>> And thinks for the efforts.
> >>>>>>>>>>
> >>>>>>>>>> Regards
> >>>>>>>>>> Bibo Mao
> >>>>>>>>>>>> +
> >>>>>>>>>>>>        static int _kvm_setcsr(struct kvm_vcpu *vcpu, unsigne=
d int id, u64 val)
> >>>>>>>>>>>>        {
> >>>>>>>>>>>>               int ret =3D 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_EST=
AT, gintc);
> >>>>>>>>>>>>
> >>>>>>>>>>>>                       return ret;
> >>>>>>>>>>>> -       }
> >>>>>>>>>>>> +       } else if (id =3D=3D 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_v=
cpu *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(), otherwi=
se 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, uns=
igned long type)
> >>>>>>>>>>>>               if (!kvm->arch.pgd)
> >>>>>>>>>>>>                       return -ENOMEM;
> >>>>>>>>>>>>
> >>>>>>>>>>>> +       kvm->arch.phyid_map =3D kvzalloc(sizeof(struct kvm_p=
hyid_map),
> >>>>>>>>>>>> +                               GFP_KERNEL_ACCOUNT);
> >>>>>>>>>>>> +       if (!kvm->arch.phyid_map) {
> >>>>>>>>>>>> +               free_page((unsigned long)kvm->arch.pgd);
> >>>>>>>>>>>> +               kvm->arch.pgd =3D NULL;
> >>>>>>>>>>>> +               return -ENOMEM;
> >>>>>>>>>>>> +       }
> >>>>>>>>>>>> +
> >>>>>>>>>>>>               kvm_init_vmcs(kvm);
> >>>>>>>>>>>>               kvm->arch.gpa_size =3D BIT(cpu_vabits - 1);
> >>>>>>>>>>>>               kvm->arch.root_level =3D CONFIG_PGTABLE_LEVELS=
 - 1;
> >>>>>>>>>>>> @@ -44,6 +52,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsi=
gned long type)
> >>>>>>>>>>>>               for (i =3D 0; i <=3D kvm->arch.root_level; i++=
)
> >>>>>>>>>>>>                       kvm->arch.pte_shifts[i] =3D 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 =3D NULL;
> >>>>>>>>>>>> +       kvm->arch.phyid_map =3D NULL;
> >>>>>>>>>>>>        }
> >>>>>>>>>>>>
> >>>>>>>>>>>>        int kvm_vm_ioctl_check_extension(struct kvm *kvm, lon=
g ext)
> >>>>>>>>>>>> --
> >>>>>>>>>>>> 2.39.3
> >>>>>>>>>>>>
> >>>>>>>>>>
> >>>>>>>>
> >>>>>>
> >>>>
> >>
> >>
>
>