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

commit 0884335a2e653b8a045083aa1d57ce74269ac81d upstream.

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>
[sudip: manual backport to old file]
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index cfd6e58e824b3c578482780185835817ef97e1f2..3571253b86907115719681e7cdff7db7dda4ddc0 100644 (file)
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -3532,7 +3532,7 @@ static int cr_interception(struct vcpu_svm *svm)
        err = 0;
        if (cr >= 16) { /* mov to cr */
                cr -= 16;
-               val = kvm_register_read(&svm->vcpu, reg);
+               val = kvm_register_readl(&svm->vcpu, reg);
                switch (cr) {
                case 0:
                        if (!check_selective_cr0_intercepted(svm, val))
@@ -3577,7 +3577,7 @@ static int cr_interception(struct vcpu_svm *svm)
                        kvm_queue_exception(&svm->vcpu, UD_VECTOR);
                        return 1;
                }
-               kvm_register_write(&svm->vcpu, reg, val);
+               kvm_register_writel(&svm->vcpu, reg, val);
        }
        return kvm_complete_insn_gp(&svm->vcpu, err);
 }
@@ -3607,13 +3607,13 @@ static int dr_interception(struct vcpu_svm *svm)
        if (dr >= 16) { /* mov to DRn */
                if (!kvm_require_dr(&svm->vcpu, dr - 16))
                        return 1;
-               val = kvm_register_read(&svm->vcpu, reg);
+               val = kvm_register_readl(&svm->vcpu, reg);
                kvm_set_dr(&svm->vcpu, dr - 16, val);
        } else {
                if (!kvm_require_dr(&svm->vcpu, dr))
                        return 1;
                kvm_get_dr(&svm->vcpu, dr, &val);
-               kvm_register_write(&svm->vcpu, reg, val);
+               kvm_register_writel(&svm->vcpu, reg, val);
        }
 
        return kvm_skip_emulated_instruction(&svm->vcpu);