[PATCH 5.12 119/677] KVM: VMX: Truncate GPR value for DR and CR reads in !64-bit mode

[Greg Kroah-Hartman]

From: Sean Christopherson <seanjc@xxxxxxxxxx>

commit d8971344f5739a9cc53f91f1f593ddd82265b93b upstream.

Drop bits 63:32 when storing a DR/CR to a GPR when the vCPU is not in
64-bit mode.  Per the SDM:

  The operand size for these instructions is always 32 bits in non-64-bit
  modes, regardless of the operand-size attribute.

CR8 technically isn't affected as CR8 isn't accessible outside of 64-bit
mode, but fix it up for consistency and to allow for future cleanup.

Fixes: 6aa8b732ca01 ("[PATCH] kvm: userspace interface")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Message-Id: <20210422022128.3464144-5-seanjc@xxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 arch/x86/kvm/vmx/vmx.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -5062,12 +5062,12 @@ static int handle_cr(struct kvm_vcpu *vc
 		case 3:
 			WARN_ON_ONCE(enable_unrestricted_guest);
 			val = kvm_read_cr3(vcpu);
-			kvm_register_write(vcpu, reg, val);
+			kvm_register_writel(vcpu, reg, val);
 			trace_kvm_cr_read(cr, val);
 			return kvm_skip_emulated_instruction(vcpu);
 		case 8:
 			val = kvm_get_cr8(vcpu);
-			kvm_register_write(vcpu, reg, val);
+			kvm_register_writel(vcpu, reg, val);
 			trace_kvm_cr_read(cr, val);
 			return kvm_skip_emulated_instruction(vcpu);
 		}
@@ -5140,7 +5140,7 @@ static int handle_dr(struct kvm_vcpu *vc
 		unsigned long val;
 
 		kvm_get_dr(vcpu, dr, &val);
-		kvm_register_write(vcpu, reg, val);
+		kvm_register_writel(vcpu, reg, val);
 		err = 0;
 	} else {
 		err = kvm_set_dr(vcpu, dr, kvm_register_readl(vcpu, reg));