From: Dongli Zhang Date: Fri, 5 Mar 2021 22:57:47 +0000 (-0800) Subject: KVM: x86: to track if L1 is running L2 VM X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=43c11d91fb1e4c41309db3d233ac1e048cdc8dd0;p=linux.git KVM: x86: to track if L1 is running L2 VM The new per-cpu stat 'nested_run' is introduced in order to track if L1 VM is running or used to run L2 VM. An example of the usage of 'nested_run' is to help the host administrator to easily track if any L1 VM is used to run L2 VM. Suppose there is issue that may happen with nested virtualization, the administrator will be able to easily narrow down and confirm if the issue is due to nested virtualization via 'nested_run'. For example, whether the fix like commit 88dddc11a8d6 ("KVM: nVMX: do not use dangling shadow VMCS after guest reset") is required. Cc: Joe Jin Signed-off-by: Dongli Zhang Message-Id: <20210305225747.7682-1-dongli.zhang@oracle.com> Signed-off-by: Paolo Bonzini --- diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 9bc091ecaaeb9..e198837305ff3 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1125,6 +1125,7 @@ struct kvm_vcpu_stat { u64 req_event; u64 halt_poll_success_ns; u64 halt_poll_fail_ns; + u64 nested_run; }; struct x86_instruction_info; diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 35891d9a1099b..18c02e958a09f 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -494,6 +494,8 @@ int nested_svm_vmrun(struct vcpu_svm *svm) struct kvm_host_map map; u64 vmcb12_gpa; + ++svm->vcpu.stat.nested_run; + if (is_smm(&svm->vcpu)) { kvm_queue_exception(&svm->vcpu, UD_VECTOR); return 1; diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index bcca0b80e0d04..bd1343a0896ec 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -3453,6 +3453,8 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch) u32 interrupt_shadow = vmx_get_interrupt_shadow(vcpu); enum nested_evmptrld_status evmptrld_status; + ++vcpu->stat.nested_run; + if (!nested_vmx_check_permission(vcpu)) return 1; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 47e021bdcc94a..3ef64959a443a 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -245,6 +245,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { VCPU_STAT("l1d_flush", l1d_flush), VCPU_STAT("halt_poll_success_ns", halt_poll_success_ns), VCPU_STAT("halt_poll_fail_ns", halt_poll_fail_ns), + VCPU_STAT("nested_run", nested_run), VM_STAT("mmu_shadow_zapped", mmu_shadow_zapped), VM_STAT("mmu_pte_write", mmu_pte_write), VM_STAT("mmu_pde_zapped", mmu_pde_zapped),