According to section "Checks on Guest Control Registers, Debug Registers, and
and MSRs" in Intel SDM vol 3C, the following checks are performed on vmentry
of nested guests:
If the "load debug controls" VM-entry control is 1, bits 63:32 in the DR7
field must be 0.
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@xxxxxxxxxx>
Reviewed-by: Karl Heubaum <karl.heubaum@xxxxxxxxxx>
---
arch/x86/kvm/vmx/nested.c | 6 ++++++
arch/x86/kvm/x86.c | 2 +-
arch/x86/kvm/x86.h | 6 ++++++
3 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 4aea7d304beb..acde8a2f13e2 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -2899,6 +2899,12 @@ static int nested_vmx_check_guest_state(struct kvm_vcpu *vcpu,
CC(!nested_guest_cr4_valid(vcpu, vmcs12->guest_cr4)))
return -EINVAL;
+#ifdef CONFIG_X86_64
+ if ((vmcs12->vm_entry_controls & VM_ENTRY_LOAD_DEBUG_CONTROLS) &&
+ !kvm_dr7_valid(vmcs12->guest_dr7))
+ return -EINVAL;
+#endif
+
if ((vmcs12->vm_entry_controls & VM_ENTRY_LOAD_IA32_PAT) &&
CC(!kvm_pat_valid(vmcs12->guest_ia32_pat)))
return -EINVAL;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index cf917139de6b..220f20a2f9c3 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1064,7 +1064,7 @@ static int __kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val)
case 5:
/* fall through */
default: /* 7 */
- if (val & 0xffffffff00000000ULL)
+ if (!kvm_dr7_valid(val))
return -1; /* #GP */
vcpu->arch.dr7 = (val & DR7_VOLATILE) | DR7_FIXED_1;
kvm_update_dr7(vcpu);
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index 29391af8871d..76cd389ecf60 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -369,6 +369,12 @@ static inline bool kvm_pat_valid(u64 data)
return (data | ((data & 0x0202020202020202ull) << 1)) == data;
}
+static inline bool kvm_dr7_valid(u64 data)
+{
+ /* Bits [63:32] are reserved */
+ return ((data & 0xFFFFFFFF00000000ull) ? false : true);
+}
+
void kvm_load_guest_xsave_state(struct kvm_vcpu *vcpu);
void kvm_load_host_xsave_state(struct kvm_vcpu *vcpu);
--
2.20.1
