If we reset a vcpu on INIT, make sure to not touch dr7 as stored in the
VMCS/VMCB and also switch_db_regs if guest debugging is using hardware
breakpoints. Otherwise, the vcpu will not trigger hardware breakpoints
until userspace issues another KVM_SET_GUEST_DEBUG IOCTL for it.
Found while trying to stop on start_secondary.
Signed-off-by: Jan Kiszka <jan.kis...@siemens.com>
---
Nice to have for stable as well.
arch/x86/kvm/svm.c | 3 ++-
arch/x86/kvm/vmx.c | 3 ++-
arch/x86/kvm/x86.c | 3 ++-
3 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 611c728..4163ce2 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1146,7 +1146,8 @@ static void init_vmcb(struct vcpu_svm *svm)
svm_set_efer(&svm->vcpu, 0);
save->dr6 = 0xffff0ff0;
- save->dr7 = 0x400;
+ if (!(svm->vcpu.guest_debug & KVM_GUESTDBG_USE_HW_BP))
+ save->dr7 = 0x400;
kvm_set_rflags(&svm->vcpu, 2);
save->rip = 0x0000fff0;
svm->vcpu.arch.regs[VCPU_REGS_RIP] = save->rip;
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index d62b413..37f68f7 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3959,7 +3959,8 @@ static int vmx_vcpu_reset(struct kvm_vcpu *vcpu)
kvm_rip_write(vcpu, 0);
kvm_register_write(vcpu, VCPU_REGS_RSP, 0);
- vmcs_writel(GUEST_DR7, 0x400);
+ if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP))
+ vmcs_writel(GUEST_DR7, 0x400);
vmcs_writel(GUEST_GDTR_BASE, 0);
vmcs_write32(GUEST_GDTR_LIMIT, 0xffff);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c4d451e..7c8c2b8 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6043,7 +6043,8 @@ int kvm_arch_vcpu_reset(struct kvm_vcpu *vcpu)
vcpu->arch.nmi_pending = 0;
vcpu->arch.nmi_injected = false;
- vcpu->arch.switch_db_regs = 0;
+ if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP))
+ vcpu->arch.switch_db_regs = 0;
memset(vcpu->arch.db, 0, sizeof(vcpu->arch.db));
vcpu->arch.dr6 = DR6_FIXED_1;
vcpu->arch.dr7 = DR7_FIXED_1;
--
1.7.3.4
--
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