[PATCH 11/11] KVM-x86: Wire up host-managed debug registers

Jan Kiszka
2008-05-26T22:10:56Z

Add the remaining bits to make use of debug registers also for guest
debugging, thus enabling the use of hardware breakpoints and
watchpoints.

Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
---
arch/x86/kvm/svm.c | 5 +++++
arch/x86/kvm/vmx.c | 5 +++++
arch/x86/kvm/x86.c | 14 +++++++++++++-
3 files changed, 23 insertions(+), 1 deletion(-)

Index: b/arch/x86/kvm/svm.c
===================================================================
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -889,6 +889,11 @@ static int svm_guest_debug(struct kvm_vc
} else
vcpu->guest_debug = 0;

+ if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)
+ svm->vmcb->save.dr7 = dbg->arch.debugreg[7];
+ else
+ svm->vmcb->save.dr7 = vcpu->arch.dr7;
+
if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
svm->vmcb->save.rflags |= X86_EFLAGS_TF | X86_EFLAGS_RF;
else if (old_debug & KVM_GUESTDBG_SINGLESTEP)
Index: b/arch/x86/kvm/vmx.c
===================================================================
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -964,6 +964,11 @@ static int set_guest_debug(struct kvm_vc
if (!(vcpu->guest_debug & KVM_GUESTDBG_ENABLE))
vcpu->guest_debug = 0;

+ if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)
+ vmcs_writel(GUEST_DR7, dbg->arch.debugreg[7]);
+ else
+ vmcs_writel(GUEST_DR7, vcpu->arch.dr7);
+
flags = vmcs_readl(GUEST_RFLAGS);
if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
flags |= X86_EFLAGS_TF | X86_EFLAGS_RF;
Index: b/arch/x86/kvm/x86.c
===================================================================
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3612,10 +3612,22 @@ int kvm_arch_vcpu_ioctl_set_sregs(struct
int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
struct kvm_guest_debug *dbg)
{
- int r;
+ int i, r;

vcpu_load(vcpu);

+ if ((dbg->control & (KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_HW_BP)) ==
+ (KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_HW_BP)) {
+ for (i = 0; i < KVM_NR_DB_REGS; ++i)
+ vcpu->arch.eff_db[i] = dbg->arch.debugreg[i];
+ vcpu->arch.switch_db_regs =
+ (dbg->arch.debugreg[7] & DR7_BP_EN_MASK);
+ } else {
+ for (i = 0; i < KVM_NR_DB_REGS; i++)
+ vcpu->arch.eff_db[i] = vcpu->arch.db[i];
+ vcpu->arch.switch_db_regs = (vcpu->arch.dr7 & DR7_BP_EN_MASK);
+ }
+
r = kvm_x86_ops->set_guest_debug(vcpu, dbg);

if (dbg->control & KVM_GUESTDBG_INJECT_DB)