| Message ID | 20240412084703.1407412-1-wjduan@linx-info.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: loongarch: Add vcpu id check before create vcpu | expand |
On 2024/4/12 下午4:47, Wujie Duan wrote: > Add a pre-allocation arch condition to checks that vcpu id should > smaller than max_vcpus > > Signed-off-by: Wujie Duan <wjduan@linx-info.com> > --- > arch/loongarch/kvm/vcpu.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c > index 3a8779065f73..d41cacf39583 100644 > --- a/arch/loongarch/kvm/vcpu.c > +++ b/arch/loongarch/kvm/vcpu.c > @@ -884,6 +884,9 @@ long kvm_arch_vcpu_async_ioctl(struct file *filp, > > int kvm_arch_vcpu_precreate(struct kvm *kvm, unsigned int id) > { > + if (id >= kvm->max_vcpus) > + return -EINVAL; > + > return 0; > } > > Good catch, and thanks for your contribution. Reviewed-by: bibo mao <maobibo@loongson.cn>
On Fri, Apr 12, 2024, Wujie Duan wrote: > Add a pre-allocation arch condition to checks that vcpu id should > smaller than max_vcpus > > Signed-off-by: Wujie Duan <wjduan@linx-info.com> > --- > arch/loongarch/kvm/vcpu.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c > index 3a8779065f73..d41cacf39583 100644 > --- a/arch/loongarch/kvm/vcpu.c > +++ b/arch/loongarch/kvm/vcpu.c > @@ -884,6 +884,9 @@ long kvm_arch_vcpu_async_ioctl(struct file *filp, > > int kvm_arch_vcpu_precreate(struct kvm *kvm, unsigned int id) > { > + if (id >= kvm->max_vcpus) > + return -EINVAL; Do you have a testcase for this? If I'm following the LoongArch code correctly, I don't think this is actually necessary. In arch/loongarch/include/asm/kvm_host.h: #define KVM_MAX_VCPUS 256 without a #define KVM_MAX_VCPU_IDS in loongarch/, AFAICT. And so the common code in include/linux/kvm_host.h will do: #ifndef KVM_MAX_VCPU_IDS #define KVM_MAX_VCPU_IDS KVM_MAX_VCPUS #endif LoongArch's kvm_vm_ioctl_check_extension() reports that to userspace: case KVM_CAP_MAX_VCPU_ID: r = KVM_MAX_VCPU_IDS; and the common kvm_vm_ioctl_create_vcpu() does: if (id >= KVM_MAX_VCPU_IDS) return -EINVAL; and the common kvm_create_vm() does: kvm->max_vcpus = KVM_MAX_VCPUS; with again no override of max_vcpus in LoongArch or common KVM. So unless I'm missing something, manually checking max_vcpus in LoongArch's kvm_arch_vcpu_precreate() is unnecessary.
On 2024/4/13 上午2:41, Sean Christopherson wrote: > On Fri, Apr 12, 2024, Wujie Duan wrote: >> Add a pre-allocation arch condition to checks that vcpu id should >> smaller than max_vcpus >> >> Signed-off-by: Wujie Duan <wjduan@linx-info.com> >> --- >> arch/loongarch/kvm/vcpu.c | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c >> index 3a8779065f73..d41cacf39583 100644 >> --- a/arch/loongarch/kvm/vcpu.c >> +++ b/arch/loongarch/kvm/vcpu.c >> @@ -884,6 +884,9 @@ long kvm_arch_vcpu_async_ioctl(struct file *filp, >> >> int kvm_arch_vcpu_precreate(struct kvm *kvm, unsigned int id) >> { >> + if (id >= kvm->max_vcpus) >> + return -EINVAL; > > Do you have a testcase for this? If I'm following the LoongArch code correctly, > I don't think this is actually necessary. > > In arch/loongarch/include/asm/kvm_host.h: > > #define KVM_MAX_VCPUS 256 > > without a #define KVM_MAX_VCPU_IDS in loongarch/, AFAICT. And so the common > code in include/linux/kvm_host.h will do: > > #ifndef KVM_MAX_VCPU_IDS > #define KVM_MAX_VCPU_IDS KVM_MAX_VCPUS > #endif > > LoongArch's kvm_vm_ioctl_check_extension() reports that to userspace: > > case KVM_CAP_MAX_VCPU_ID: > r = KVM_MAX_VCPU_IDS; > > and the common kvm_vm_ioctl_create_vcpu() does: > > if (id >= KVM_MAX_VCPU_IDS) > return -EINVAL; > > and the common kvm_create_vm() does: > > kvm->max_vcpus = KVM_MAX_VCPUS; > > with again no override of max_vcpus in LoongArch or common KVM. So unless I'm > missing something, manually checking max_vcpus in LoongArch's kvm_arch_vcpu_precreate() > is unnecessary. > yes, you are right. There is already such checking in function kvm_vm_ioctl_create_vcpu(), and it is unnecessary to add the same checking in function kvm_arch_vcpu_precreate(). And thanks for pointing it out. Regards Bibo Mao
diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c index 3a8779065f73..d41cacf39583 100644 --- a/arch/loongarch/kvm/vcpu.c +++ b/arch/loongarch/kvm/vcpu.c @@ -884,6 +884,9 @@ long kvm_arch_vcpu_async_ioctl(struct file *filp, int kvm_arch_vcpu_precreate(struct kvm *kvm, unsigned int id) { + if (id >= kvm->max_vcpus) + return -EINVAL; + return 0; }
Add a pre-allocation arch condition to checks that vcpu id should smaller than max_vcpus Signed-off-by: Wujie Duan <wjduan@linx-info.com> --- arch/loongarch/kvm/vcpu.c | 3 +++ 1 file changed, 3 insertions(+)