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-rw-r--r--arch/x86/include/asm/kvm_host.h11
-rw-r--r--arch/x86/kvm/vmx/tdx.c1
-rw-r--r--arch/x86/kvm/x86.c4
3 files changed, 13 insertions, 3 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 0c8453fa9f9e..3a6373fc58a1 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -606,8 +606,15 @@ struct kvm_pmu {
struct kvm_pmu_ops;
enum {
- KVM_DEBUGREG_BP_ENABLED = 1,
- KVM_DEBUGREG_WONT_EXIT = 2,
+ KVM_DEBUGREG_BP_ENABLED = BIT(0),
+ KVM_DEBUGREG_WONT_EXIT = BIT(1),
+ /*
+ * Guest debug registers (DR0-3, DR6 and DR7) are saved/restored by
+ * hardware on exit from or enter to guest. KVM needn't switch them.
+ * DR0-3, DR6 and DR7 are set to their architectural INIT value on VM
+ * exit, host values need to be restored.
+ */
+ KVM_DEBUGREG_AUTO_SWITCH = BIT(2),
};
struct kvm_mtrr {
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 7ad680b5f771..a6388eb95988 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -630,6 +630,7 @@ int tdx_vcpu_create(struct kvm_vcpu *vcpu)
vcpu->arch.efer = EFER_SCE | EFER_LME | EFER_LMA | EFER_NX;
+ vcpu->arch.switch_db_regs = KVM_DEBUGREG_AUTO_SWITCH;
vcpu->arch.cr0_guest_owned_bits = -1ul;
vcpu->arch.cr4_guest_owned_bits = -1ul;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 1133bec79a82..1ef83f24449d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10985,7 +10985,8 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
if (vcpu->arch.guest_fpu.xfd_err)
wrmsrl(MSR_IA32_XFD_ERR, vcpu->arch.guest_fpu.xfd_err);
- if (unlikely(vcpu->arch.switch_db_regs)) {
+ if (unlikely(vcpu->arch.switch_db_regs &&
+ !(vcpu->arch.switch_db_regs & KVM_DEBUGREG_AUTO_SWITCH))) {
set_debugreg(0, 7);
set_debugreg(vcpu->arch.eff_db[0], 0);
set_debugreg(vcpu->arch.eff_db[1], 1);
@@ -11037,6 +11038,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
*/
if (unlikely(vcpu->arch.switch_db_regs & KVM_DEBUGREG_WONT_EXIT)) {
WARN_ON(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP);
+ WARN_ON(vcpu->arch.switch_db_regs & KVM_DEBUGREG_AUTO_SWITCH);
kvm_x86_call(sync_dirty_debug_regs)(vcpu);
kvm_update_dr0123(vcpu);
kvm_update_dr7(vcpu);