Re: [PATCH 5.10 1/3] KVM: Add infrastructure and macro to mark VM as bugged

[Paolo Bonzini <pbonzini@xxxxxxxxxx>]

On 8/10/22 22:24, Stefan Ghinea wrote:
> From: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
>
> commit 0b8f11737cffc1a406d1134b58687abc29d76b52 upstream
>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
> Reviewed-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> Message-Id: <3a0998645c328bf0895f1290e61821b70f048549.1625186503.git.isaku.yamahata@xxxxxxxxx>
> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> [SG: Adjusted context for kernel version 5.10]
> Signed-off-by: Stefan Ghinea <stefan.ghinea@xxxxxxxxxxxxx>
> ---
>   include/linux/kvm_host.h | 28 +++++++++++++++++++++++++++-
>   virt/kvm/kvm_main.c      | 10 +++++-----
>   2 files changed, 32 insertions(+), 6 deletions(-)
>
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index 439fbe0ee0c7..94871f12e536 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) ({ \
> @@ -505,6 +506,7 @@ struct kvm {
>   	struct srcu_struct irq_srcu;
>   	pid_t userspace_pid;
>   	unsigned int max_halt_poll_ns;
> +	bool vm_bugged;
>   };
>   
>   #define kvm_err(fmt, ...) \
> @@ -533,6 +535,31 @@ struct kvm {
>   #define vcpu_err(vcpu, fmt, ...)					\
>   	kvm_err("vcpu%i " fmt, (vcpu)->vcpu_id, ## __VA_ARGS__)
>   
> +bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req);
> +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);
> @@ -850,7 +877,6 @@ void *kvm_mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc);
>   bool kvm_make_vcpus_request_mask(struct kvm *kvm, unsigned int req,
>   				 struct kvm_vcpu *except,
>   				 unsigned long *vcpu_bitmap, cpumask_var_t tmp);
> -bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req);
>   bool kvm_make_all_cpus_request_except(struct kvm *kvm, unsigned int req,
>   				      struct kvm_vcpu *except);
>   bool kvm_make_cpus_request_mask(struct kvm *kvm, unsigned int req,
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index c5dbac10c372..bb7adddd6a85 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -3252,7 +3252,7 @@ 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))
> @@ -3458,7 +3458,7 @@ 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) {
> @@ -3524,7 +3524,7 @@ 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) {
> @@ -3743,7 +3743,7 @@ 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:
> @@ -3948,7 +3948,7 @@ 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) {
>   #ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT

Acked-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>