KVM: vmx: handle_cr ignores 32/64-bit mode

On 32-bit mode only bits [31:0] of the CR should be used for setting the CR
value.  Otherwise, the host may incorrectly assume the value is invalid if bits
[63:32] are not zero.  Moreover, the CR is currently being read twice when CR8
is used.  Last, nested mov-cr exiting is modified to handle the CR value
correctly as well.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index b362a1a..45024bf 100644 (file)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -5058,7 +5058,7 @@ static int handle_cr(struct kvm_vcpu *vcpu)
        reg = (exit_qualification >> 8) & 15;
        switch ((exit_qualification >> 4) & 3) {
        case 0: /* mov to cr */
-               val = kvm_register_read(vcpu, reg);
+               val = kvm_register_readl(vcpu, reg);
                trace_kvm_cr_write(cr, val);
                switch (cr) {
                case 0:
@@ -5075,7 +5075,7 @@ static int handle_cr(struct kvm_vcpu *vcpu)
                        return 1;
                case 8: {
                                u8 cr8_prev = kvm_get_cr8(vcpu);
-                               u8 cr8 = kvm_register_read(vcpu, reg);
+                               u8 cr8 = (u8)val;
                                err = kvm_set_cr8(vcpu, cr8);
                                kvm_complete_insn_gp(vcpu, err);
                                if (irqchip_in_kernel(vcpu->kvm))
@@ -6770,7 +6770,7 @@ static bool nested_vmx_exit_handled_cr(struct kvm_vcpu *vcpu,
        unsigned long exit_qualification = vmcs_readl(EXIT_QUALIFICATION);
        int cr = exit_qualification & 15;
        int reg = (exit_qualification >> 8) & 15;
-       unsigned long val = kvm_register_read(vcpu, reg);
+       unsigned long val = kvm_register_readl(vcpu, reg);
 
        switch ((exit_qualification >> 4) & 3) {
        case 0: /* mov to cr */