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* [PATCH] kvm: Fixes lack of KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 enabled check
@ 2021-01-12  9:29 Kunkun Jiang
  2021-01-12 10:20 ` Paolo Bonzini
  0 siblings, 1 reply; 2+ messages in thread
From: Kunkun Jiang @ 2021-01-12  9:29 UTC (permalink / raw)
  To: Paolo Bonzini, kvm, linux-kernel; +Cc: wanghaibin.wang, Keqian Zhu

The KVM_CLEAR_DIRTY_LOG ioctl lacks the check whether the capability
KVM_CAP_MANUAL_DIRTY_LOG_PROTECT is enabled or not. This may cause
some problems if userspace calls the KVM_CLEAR_DIRTY_LOG ioctl, but
dose't enable this capability. So we'd better to add it.

Fixes: 2a31b9db15353 ("kvm: introduce manual dirty log reprotect")
Signed-off-by: Kunkun Jiang <jiangkunkun@huawei.com>
---
 virt/kvm/kvm_main.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index fa9e3614d30e..8f5633d8a0e8 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1602,6 +1602,9 @@ static int kvm_clear_dirty_log_protect(struct kvm *kvm,
 	unsigned long *dirty_bitmap_buffer;
 	bool flush;
 
+	if (!kvm->manual_dirty_log_protect)
+		return -EPERM;
+
 	/* Dirty ring tracking is exclusive to dirty log tracking */
 	if (kvm->dirty_ring_size)
 		return -ENXIO;
-- 
2.19.1


^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [PATCH] kvm: Fixes lack of KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 enabled check
  2021-01-12  9:29 [PATCH] kvm: Fixes lack of KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 enabled check Kunkun Jiang
@ 2021-01-12 10:20 ` Paolo Bonzini
  0 siblings, 0 replies; 2+ messages in thread
From: Paolo Bonzini @ 2021-01-12 10:20 UTC (permalink / raw)
  To: Kunkun Jiang, kvm, linux-kernel; +Cc: wanghaibin.wang, Keqian Zhu

On 12/01/21 10:29, Kunkun Jiang wrote:
> The KVM_CLEAR_DIRTY_LOG ioctl lacks the check whether the capability
> KVM_CAP_MANUAL_DIRTY_LOG_PROTECT is enabled or not. This may cause
> some problems if userspace calls the KVM_CLEAR_DIRTY_LOG ioctl, but
> dose't enable this capability. So we'd better to add it.
> 
> Fixes: 2a31b9db15353 ("kvm: introduce manual dirty log reprotect")
> Signed-off-by: Kunkun Jiang <jiangkunkun@huawei.com>
> ---
>   virt/kvm/kvm_main.c | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index fa9e3614d30e..8f5633d8a0e8 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -1602,6 +1602,9 @@ static int kvm_clear_dirty_log_protect(struct kvm *kvm,
>   	unsigned long *dirty_bitmap_buffer;
>   	bool flush;
>   
> +	if (!kvm->manual_dirty_log_protect)
> +		return -EPERM;
> +
>   	/* Dirty ring tracking is exclusive to dirty log tracking */
>   	if (kvm->dirty_ring_size)
>   		return -ENXIO;

This is not a problem, KVM_CLEAR_DIRTY_LOG can always be used even if 
KVM_CAP_MANUAL_DIRTY_LOG_PROTECT was not enabled.  The meaning is the 
same: clear the bits without returning them.

Paolo


^ permalink raw reply	[flat|nested] 2+ messages in thread

end of thread, other threads:[~2021-01-12 10:22 UTC | newest]

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2021-01-12  9:29 [PATCH] kvm: Fixes lack of KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 enabled check Kunkun Jiang
2021-01-12 10:20 ` Paolo Bonzini

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