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KVM fixes for 6.7-rcN:

Browse source 
- When checking if a _running_ vCPU is "in-kernel", i.e. running at CPL0,
    get the CPL directly instead of relying on preempted_in_kernel, which
    is valid if and only if the vCPU was preempted, i.e. NOT running.
 
  - Set .owner for various KVM file_operations so that files refcount the
    KVM module until KVM is done executing _all_ code, including the last
    few instructions of kvm_put_kvm().  And then revert the misguided
    attempt to rely on "struct kvm" refcounts to pin KVM-the-module.
 
  - Fix a benign "return void" that was recently introduced.
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Merge tag 'kvm-x86-fixes-6.7-rcN' of https://github.com/kvm-x86/linux into kvm-master

KVM fixes for 6.7-rcN:

 - When checking if a _running_ vCPU is "in-kernel", i.e. running at CPL0,
   get the CPL directly instead of relying on preempted_in_kernel, which
   is valid if and only if the vCPU was preempted, i.e. NOT running.

 - Set .owner for various KVM file_operations so that files refcount the
   KVM module until KVM is done executing _all_ code, including the last
   few instructions of kvm_put_kvm().  And then revert the misguided
   attempt to rely on "struct kvm" refcounts to pin KVM-the-module.

 - Fix a benign "return void" that was recently introduced.
This commit is contained in:
Paolo Bonzini 2023-12-08 13:13:45 -05:00
parent aa0ae3df80 ef8d89033c
commit 6254eebad4
3 changed files with 15 additions and 13 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

1
arch/x86/kvm/debugfs.c
View file

@ -182,6 +182,7 @@ static int kvm_mmu_rmaps_stat_release(struct inode *inode, struct file *file)
}
static const struct file_operations mmu_rmaps_stat_fops = {
.owner = THIS_MODULE,
.open = kvm_mmu_rmaps_stat_open,
.read = seq_read,
.llseek = seq_lseek,

9
arch/x86/kvm/x86.c
View file

@ -5518,8 +5518,8 @@ static void kvm_vcpu_ioctl_x86_get_xsave2(struct kvm_vcpu *vcpu,
static void kvm_vcpu_ioctl_x86_get_xsave(struct kvm_vcpu *vcpu,
struct kvm_xsave *guest_xsave)
{
return kvm_vcpu_ioctl_x86_get_xsave2(vcpu, (void *)guest_xsave->region,
sizeof(guest_xsave->region));
kvm_vcpu_ioctl_x86_get_xsave2(vcpu, (void *)guest_xsave->region,
sizeof(guest_xsave->region));
}
static int kvm_vcpu_ioctl_x86_set_xsave(struct kvm_vcpu *vcpu,
@ -13031,7 +13031,10 @@ bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu)
if (vcpu->arch.guest_state_protected)
return true;
return vcpu->arch.preempted_in_kernel;
if (vcpu != kvm_get_running_vcpu())
return vcpu->arch.preempted_in_kernel;
return static_call(kvm_x86_get_cpl)(vcpu) == 0;
}
unsigned long kvm_arch_vcpu_get_ip(struct kvm_vcpu *vcpu)

18
virt/kvm/kvm_main.c
View file

@ -115,8 +115,6 @@ EXPORT_SYMBOL_GPL(kvm_debugfs_dir);
static const struct file_operations stat_fops_per_vm;
static struct file_operations kvm_chardev_ops;
static long kvm_vcpu_ioctl(struct file *file, unsigned int ioctl,
unsigned long arg);
#ifdef CONFIG_KVM_COMPAT
@ -1157,9 +1155,6 @@ static struct kvm *kvm_create_vm(unsigned long type, const char *fdname)
if (!kvm)
return ERR_PTR(-ENOMEM);
/* KVM is pinned via open("/dev/kvm"), the fd passed to this ioctl(). */
__module_get(kvm_chardev_ops.owner);
KVM_MMU_LOCK_INIT(kvm);
mmgrab(current->mm);
kvm->mm = current->mm;
@ -1279,7 +1274,6 @@ static struct kvm *kvm_create_vm(unsigned long type, const char *fdname)
out_err_no_srcu:
kvm_arch_free_vm(kvm);
mmdrop(current->mm);
module_put(kvm_chardev_ops.owner);
return ERR_PTR(r);
}
@ -1348,7 +1342,6 @@ static void kvm_destroy_vm(struct kvm *kvm)
preempt_notifier_dec();
hardware_disable_all();
mmdrop(mm);
module_put(kvm_chardev_ops.owner);
}
void kvm_get_kvm(struct kvm *kvm)
@ -3887,7 +3880,7 @@ static int kvm_vcpu_release(struct inode *inode, struct file *filp)
return 0;
}
static const struct file_operations kvm_vcpu_fops = {
static struct file_operations kvm_vcpu_fops = {
.release = kvm_vcpu_release,
.unlocked_ioctl = kvm_vcpu_ioctl,
.mmap = kvm_vcpu_mmap,
@ -4081,6 +4074,7 @@ static int kvm_vcpu_stats_release(struct inode *inode, struct file *file)
}
static const struct file_operations kvm_vcpu_stats_fops = {
.owner = THIS_MODULE,
.read = kvm_vcpu_stats_read,
.release = kvm_vcpu_stats_release,
.llseek = noop_llseek,
@ -4431,7 +4425,7 @@ static int kvm_device_release(struct inode *inode, struct file *filp)
return 0;
}
static const struct file_operations kvm_device_fops = {
static struct file_operations kvm_device_fops = {
.unlocked_ioctl = kvm_device_ioctl,
.release = kvm_device_release,
KVM_COMPAT(kvm_device_ioctl),
@ -4759,6 +4753,7 @@ static int kvm_vm_stats_release(struct inode *inode, struct file *file)
}
static const struct file_operations kvm_vm_stats_fops = {
.owner = THIS_MODULE,
.read = kvm_vm_stats_read,
.release = kvm_vm_stats_release,
.llseek = noop_llseek,
@ -5060,7 +5055,7 @@ static long kvm_vm_compat_ioctl(struct file *filp,
}
#endif
static const struct file_operations kvm_vm_fops = {
static struct file_operations kvm_vm_fops = {
.release = kvm_vm_release,
.unlocked_ioctl = kvm_vm_ioctl,
.llseek = noop_llseek,
@ -6095,6 +6090,9 @@ int kvm_init(unsigned vcpu_size, unsigned vcpu_align, struct module *module)
goto err_async_pf;
kvm_chardev_ops.owner = module;
kvm_vm_fops.owner = module;
kvm_vcpu_fops.owner = module;
kvm_device_fops.owner = module;
kvm_preempt_ops.sched_in = kvm_sched_in;
kvm_preempt_ops.sched_out = kvm_sched_out;