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Subject: Re: [RFC PATCH v2 17/69] KVM: Add infrastructure and macro to mark VM
 as bugged
To:     isaku.yamahata@intel.com, Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        "H . Peter Anvin" <hpa@zytor.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Joerg Roedel <joro@8bytes.org>, erdemaktas@google.com,
        Connor Kuehl <ckuehl@redhat.com>,
        Sean Christopherson <seanjc@google.com>, x86@kernel.org,
        linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc:     isaku.yamahata@gmail.com,
        Sean Christopherson <sean.j.christopherson@intel.com>
References: <cover.1625186503.git.isaku.yamahata@intel.com>
 <3a0998645c328bf0895f1290e61821b70f048549.1625186503.git.isaku.yamahata@intel.com>
From:   Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <1b69fd9b-fbe9-5fbc-83ed-4805e022e17d@redhat.com>
Date:   Tue, 6 Jul 2021 15:45:09 +0200
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On 03/07/21 00:04, isaku.yamahata@intel.com wrote:
> From: Sean Christopherson <sean.j.christopherson@intel.com>
> 
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
> ---
>   include/linux/kvm_host.h | 29 ++++++++++++++++++++++++++++-
>   virt/kvm/kvm_main.c      | 10 +++++-----
>   2 files changed, 33 insertions(+), 6 deletions(-)
> 
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index 8583ed3ff344..09618f8a1338 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -149,6 +149,7 @@ 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_UNBLOCK           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) ({ \
> @@ -585,6 +586,8 @@ struct kvm {
>   	pid_t userspace_pid;
>   	unsigned int max_halt_poll_ns;
>   	u32 dirty_ring_size;
> +
> +	bool vm_bugged;
>   };
>   
>   #define kvm_err(fmt, ...) \
> @@ -613,6 +616,31 @@ 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);
> @@ -930,7 +958,6 @@ 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 751d1f6890b0..dc752d0bd3ec 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -3435,7 +3435,7 @@ 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))
> @@ -3641,7 +3641,7 @@ 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) {
> @@ -3707,7 +3707,7 @@ 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) {
> @@ -3991,7 +3991,7 @@ 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:
> @@ -4189,7 +4189,7 @@ 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: {
> 

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>