Introduce the concept of a "bugged VM", i.e. a VM that has encountered a KVM bug and/or a CPU bug and is, for all intents and purposes, dead in the water. Marking a VM as bugged is especially helpful to handle scenarios that can only be reach if there is a software/hardware bug, but can't easily return an error, e.g. x86's register caching callbacks.
Reject all ioctls() if a VM is bugged, and provide a new request so that arch specific code can kick running vCPUs out to userspace. Cc: Marc Zyngier <[email protected]> Cc: James Morse <[email protected]> Cc: Julien Thierry <[email protected]> Cc: Suzuki K Poulose <[email protected]> Cc: [email protected] Cc: Huacai Chen <[email protected]> Cc: Aleksandar Markovic <[email protected]> Cc: [email protected] Cc: Paul Mackerras <[email protected]> Cc: [email protected] Cc: Christian Borntraeger <[email protected]> Cc: Janosch Frank <[email protected]> Cc: David Hildenbrand <[email protected]> Cc: Cornelia Huck <[email protected]> Cc: Claudio Imbrenda <[email protected]> Cc: Vitaly Kuznetsov <[email protected]> Cc: Wanpeng Li <[email protected]> Cc: Jim Mattson <[email protected]> Cc: Joerg Roedel <[email protected]> Signed-off-by: Sean Christopherson <[email protected]> --- include/linux/kvm_host.h | 27 +++++++++++++++++++++++++++ virt/kvm/kvm_main.c | 10 +++++----- 2 files changed, 32 insertions(+), 5 deletions(-) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 1d70aeeb7ec3..cb527d55908d 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -146,6 +146,7 @@ static inline bool is_error_page(struct page *page) #define KVM_REQ_MMU_RELOAD (1 | KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP) #define KVM_REQ_PENDING_TIMER 2 #define KVM_REQ_UNHALT 3 +#define KVM_REQ_VM_BUGGED (4 | KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP) #define KVM_REQUEST_ARCH_BASE 8 #define KVM_ARCH_REQ_FLAGS(nr, flags) ({ \ @@ -513,6 +514,8 @@ struct kvm { struct srcu_struct irq_srcu; pid_t userspace_pid; unsigned int max_halt_poll_ns; + + bool vm_bugged; }; #define kvm_err(fmt, ...) \ @@ -541,6 +544,30 @@ struct kvm { #define vcpu_err(vcpu, fmt, ...) \ kvm_err("vcpu%i " fmt, (vcpu)->vcpu_id, ## __VA_ARGS__) +static inline void kvm_vm_bugged(struct kvm *kvm) +{ + kvm->vm_bugged = true; + kvm_make_all_cpus_request(kvm, KVM_REQ_VM_BUGGED); +} + +#define KVM_BUG(cond, kvm, fmt...) \ +({ \ + int __ret = (cond); \ + \ + if (WARN_ONCE(__ret && !(kvm)->vm_bugged, fmt)) \ + kvm_vm_bugged(kvm); \ + unlikely(__ret); \ +}) + +#define KVM_BUG_ON(cond, kvm) \ +({ \ + int __ret = (cond); \ + \ + if (WARN_ON_ONCE(__ret && !(kvm)->vm_bugged)) \ + kvm_vm_bugged(kvm); \ + unlikely(__ret); \ +}) + static inline bool kvm_dirty_log_manual_protect_and_init_set(struct kvm *kvm) { return !!(kvm->manual_dirty_log_protect & KVM_DIRTY_LOG_INITIALLY_SET); diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index bf3f333c7a19..e216ce9d1c39 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -3191,7 +3191,7 @@ static long kvm_vcpu_ioctl(struct file *filp, struct kvm_fpu *fpu = NULL; struct kvm_sregs *kvm_sregs = NULL; - if (vcpu->kvm->mm != current->mm) + if (vcpu->kvm->mm != current->mm || vcpu->kvm->vm_bugged) return -EIO; if (unlikely(_IOC_TYPE(ioctl) != KVMIO)) @@ -3397,7 +3397,7 @@ static long kvm_vcpu_compat_ioctl(struct file *filp, void __user *argp = compat_ptr(arg); int r; - if (vcpu->kvm->mm != current->mm) + if (vcpu->kvm->mm != current->mm || vcpu->kvm->vm_bugged) return -EIO; switch (ioctl) { @@ -3463,7 +3463,7 @@ static long kvm_device_ioctl(struct file *filp, unsigned int ioctl, { struct kvm_device *dev = filp->private_data; - if (dev->kvm->mm != current->mm) + if (dev->kvm->mm != current->mm || dev->kvm->vm_bugged) return -EIO; switch (ioctl) { @@ -3679,7 +3679,7 @@ static long kvm_vm_ioctl(struct file *filp, void __user *argp = (void __user *)arg; int r; - if (kvm->mm != current->mm) + if (kvm->mm != current->mm || kvm->vm_bugged) return -EIO; switch (ioctl) { case KVM_CREATE_VCPU: @@ -3874,7 +3874,7 @@ static long kvm_vm_compat_ioctl(struct file *filp, struct kvm *kvm = filp->private_data; int r; - if (kvm->mm != current->mm) + if (kvm->mm != current->mm || kvm->vm_bugged) return -EIO; switch (ioctl) { case KVM_GET_DIRTY_LOG: { -- 2.28.0
