[PATCH 5/7] KVM: nVMX: Allow nested guests to run with dirty debug registers

Paolo Bonzini
2014-03-07T11:42:49Z

When preparing the VMCS02, the CPU-based execution controls is computed
by vmx_exec_control. Turn off DR access exits there, too, if the
KVM_DEBUGREG_WONT_EXIT bit is set in switch_db_regs.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/vmx.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index e377522408b1..73ced6efc93e 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -4234,6 +4234,10 @@ static u32 vmx_pin_based_exec_ctrl(struct vcpu_vmx *vmx)
static u32 vmx_exec_control(struct vcpu_vmx *vmx)
{
u32 exec_control = vmcs_config.cpu_based_exec_ctrl;
+
+ if (vmx->vcpu.arch.switch_db_regs & KVM_DEBUGREG_WONT_EXIT)
+ exec_control &= ~CPU_BASED_MOV_DR_EXITING;
+
if (!vm_need_tpr_shadow(vmx->vcpu.kvm)) {
exec_control &= ~CPU_BASED_TPR_SHADOW;
#ifdef CONFIG_X86_64
--
1.8.3.1