From 43c11d91fb1e4c41309db3d233ac1e048cdc8dd0 Mon Sep 17 00:00:00 2001 From: Dongli Zhang Date: Fri, 5 Mar 2021 14:57:47 -0800 Subject: [PATCH] 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 --- arch/x86/include/asm/kvm_host.h | 1 + arch/x86/kvm/svm/nested.c | 2 ++ arch/x86/kvm/vmx/nested.c | 2 ++ arch/x86/kvm/x86.c | 1 + 4 files changed, 6 insertions(+) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 9bc091ecaaeb..e198837305ff 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 35891d9a1099..18c02e958a09 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 bcca0b80e0d0..bd1343a0896e 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 47e021bdcc94..3ef64959a443 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), -- 2.11.0