From a21a39c206f8a541ce9670666c0025d73383aa1a Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Fri, 28 Jun 2019 13:23:32 +0200 Subject: [PATCH] x86/KVM/nVMX: don't use clean fields data on enlightened VMLAUNCH Apparently, Windows doesn't maintain clean fields data after it does VMCLEAR for an enlightened VMCS so we can only use it on VMRESUME. The issue went unnoticed because currently we do nested_release_evmcs() in handle_vmclear() and the consecutive enlightened VMPTRLD invalidates clean fields when a new eVMCS is mapped but we're going to change the logic. Signed-off-by: Vitaly Kuznetsov Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx/nested.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 163d226..2d0fba6 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -1784,6 +1784,7 @@ static int nested_vmx_handle_enlightened_vmptrld(struct kvm_vcpu *vcpu, { struct vcpu_vmx *vmx = to_vmx(vcpu); struct hv_vp_assist_page assist_page; + bool evmcs_gpa_changed = false; if (likely(!vmx->nested.enlightened_vmcs_enabled)) return 1; @@ -1837,15 +1838,9 @@ static int nested_vmx_handle_enlightened_vmptrld(struct kvm_vcpu *vcpu, } vmx->nested.dirty_vmcs12 = true; - /* - * As we keep L2 state for one guest only 'hv_clean_fields' mask - * can't be used when we switch between them. Reset it here for - * simplicity. - */ - vmx->nested.hv_evmcs->hv_clean_fields &= - ~HV_VMX_ENLIGHTENED_CLEAN_FIELD_ALL; vmx->nested.hv_evmcs_vmptr = assist_page.current_nested_vmcs; + evmcs_gpa_changed = true; /* * Unlike normal vmcs12, enlightened vmcs12 is not fully * reloaded from guest's memory (read only fields, fields not @@ -1859,6 +1854,15 @@ static int nested_vmx_handle_enlightened_vmptrld(struct kvm_vcpu *vcpu, } } + + /* + * Clean fields data can't de used on VMLAUNCH and when we switch + * between different L2 guests as KVM keeps a single VMCS12 per L1. + */ + if (from_launch || evmcs_gpa_changed) + vmx->nested.hv_evmcs->hv_clean_fields &= + ~HV_VMX_ENLIGHTENED_CLEAN_FIELD_ALL; + return 1; } @@ -3092,7 +3096,7 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch) if (!nested_vmx_check_permission(vcpu)) return 1; - if (!nested_vmx_handle_enlightened_vmptrld(vcpu, true)) + if (!nested_vmx_handle_enlightened_vmptrld(vcpu, launch)) return 1; if (!vmx->nested.hv_evmcs && vmx->nested.current_vmptr == -1ull) -- 2.7.4