KVM: SVM: Truncate GPR value for DR and CR accesses in !64-bit mode

Drop bits 63:32 on loads/stores to/from DRs and CRs when the vCPU is not
in 64-bit mode.  The APM states bits 63:32 are dropped for both DRs and
CRs:

  In 64-bit mode, the operand size is fixed at 64 bits without the need
  for a REX prefix. In non-64-bit mode, the operand size is fixed at 32
  bits and the upper 32 bits of the destination are forced to 0.

Fixes: 7ff76d58a9dc ("KVM: SVM: enhance MOV CR intercept handler")
Fixes: cae3797a4639 ("KVM: SVM: enhance mov DR intercept handler")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210422022128.3464144-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 301792542937d49718ead7a964832c423d76d3aa..857bcf3a4cda5d0d4da09c94bc37d28afb4053d6 100644 (file)
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2451,7 +2451,7 @@ static int cr_interception(struct kvm_vcpu *vcpu)
        err = 0;
        if (cr >= 16) { /* mov to cr */
                cr -= 16;
-               val = kvm_register_read(vcpu, reg);
+               val = kvm_register_readl(vcpu, reg);
                trace_kvm_cr_write(cr, val);
                switch (cr) {
                case 0:
@@ -2497,7 +2497,7 @@ static int cr_interception(struct kvm_vcpu *vcpu)
                        kvm_queue_exception(vcpu, UD_VECTOR);
                        return 1;
                }
-               kvm_register_write(vcpu, reg, val);
+               kvm_register_writel(vcpu, reg, val);
                trace_kvm_cr_read(cr, val);
        }
        return kvm_complete_insn_gp(vcpu, err);
@@ -2563,11 +2563,11 @@ static int dr_interception(struct kvm_vcpu *vcpu)
        dr = svm->vmcb->control.exit_code - SVM_EXIT_READ_DR0;
        if (dr >= 16) { /* mov to DRn  */
                dr -= 16;
-               val = kvm_register_read(vcpu, reg);
+               val = kvm_register_readl(vcpu, reg);
                err = kvm_set_dr(vcpu, dr, val);
        } else {
                kvm_get_dr(vcpu, dr, &val);
-               kvm_register_write(vcpu, reg, val);
+               kvm_register_writel(vcpu, reg, val);
        }
 
        return kvm_complete_insn_gp(vcpu, err);