[0/2] KVM: x86: never write to memory from kvm_vcpu_check_block

Message

Paolo Bonzini April 27, 2022, 5:37 p.m. UTC

Maxim reported the following backtrace:

[ 1355.807187]  kvm_vcpu_map+0x159/0x190 [kvm]
[ 1355.807628]  nested_svm_vmexit+0x4c/0x7f0 [kvm_amd]
[ 1355.808036]  ? kvm_vcpu_block+0x54/0xa0 [kvm]
[ 1355.808450]  svm_check_nested_events+0x97/0x390 [kvm_amd]
[ 1355.808920]  kvm_check_nested_events+0x1c/0x40 [kvm] 
[ 1355.809396]  kvm_arch_vcpu_runnable+0x4e/0x190 [kvm]
[ 1355.809892]  kvm_vcpu_check_block+0x4f/0x100 [kvm]
[ 1355.811259]  kvm_vcpu_block+0x6b/0xa0 [kvm] 

due to kmap being called in non-sleepable (!TASK_RUNNING) context.
Fix it by extending kvm_x86_ops->nested_ops.hv_timer_pending and
getting rid of one annoying instance of kvm_check_nested_events.

Paolo

Comments

Maxim Levitsky July 20, 2022, 9:31 a.m. UTC | #1

On Wed, 2022-04-27 at 13:37 -0400, Paolo Bonzini wrote:
> Maxim reported the following backtrace:
> 
> [ 1355.807187]  kvm_vcpu_map+0x159/0x190 [kvm]
> [ 1355.807628]  nested_svm_vmexit+0x4c/0x7f0 [kvm_amd]
> [ 1355.808036]  ? kvm_vcpu_block+0x54/0xa0 [kvm]
> [ 1355.808450]  svm_check_nested_events+0x97/0x390 [kvm_amd]
> [ 1355.808920]  kvm_check_nested_events+0x1c/0x40 [kvm] 
> [ 1355.809396]  kvm_arch_vcpu_runnable+0x4e/0x190 [kvm]
> [ 1355.809892]  kvm_vcpu_check_block+0x4f/0x100 [kvm]
> [ 1355.811259]  kvm_vcpu_block+0x6b/0xa0 [kvm] 
> 
> due to kmap being called in non-sleepable (!TASK_RUNNING) context.
> Fix it by extending kvm_x86_ops->nested_ops.hv_timer_pending and
> getting rid of one annoying instance of kvm_check_nested_events.
> 
> Paolo
> 

Any update on this patch series? Pinging so it is not forgotten.

Best regards,
	Maxim Levitsky