[PATCH v2 4/6] KVM: x86: Use kvm_dr{6,7}_valid() to check DR{4,5,6,7} write values in emulator

[Sean Christopherson]

Use kvm_dr{6,7}_valid() to validate the incoming DR{4,5,6,7} value in the
emulator instead of open coding an equivalent check.  In the unlikely event
that the behavior of DR6/7 (and their aliases) changes in the future, using
common helpers will hopefully make it less likely the emulator logic will
be overlooked.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
 arch/x86/kvm/emulate.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index a1bccab0eefe..1df2dcfd8bef 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -3861,10 +3861,13 @@ static int check_dr_write(struct x86_emulate_ctxt *ctxt)
 
 	switch (ctxt->modrm_reg) {
 	case 4:
-	case 5:
 	case 6:
+		if (!kvm_dr6_valid(new_val))
+			return emulate_gp(ctxt, 0);
+		break;
+	case 5:
 	case 7:
-		if (new_val & 0xffffffff00000000ULL)
+		if (!kvm_dr7_valid(new_val))
 			return emulate_gp(ctxt, 0);
 		break;
 	default:
-- 
2.54.0.1032.g2f8565e1d1-goog