KVM: VMX: Truncate GPR value for DR and CR reads in !64-bit mode

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@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210422022128.3464144-5-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index edc23c7..64354b0 100644 (file)
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -5121,12 +5121,12 @@ static int handle_cr(struct kvm_vcpu *vcpu)
                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);
                }
@@ -5199,7 +5199,7 @@ static int handle_dr(struct kvm_vcpu *vcpu)
                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));