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@xxxxxxxxxxxxx>
---
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
