KVM: s390: correct fprs on SIGP (STOP AND) STORE STATUS

commit 9522b37f5a8c7bfabe46eecadf2e130f1103f337 upstream.

With MACHINE_HAS_VX, we convert the floating point registers from the
vector registeres when storing the status. For other VCPUs, these are
stored to vcpu->run->s.regs.vrs, but we are using current->thread.fpu.vxrs,
which resolves to the currently loaded VCPU.

So kvm_s390_store_status_unloaded() currently writes the wrong floating
point registers (converted from the vector registers) when called from
another VCPU on a z13.

This is only the case for old user space not handling SIGP STORE STATUS and
SIGP STOP AND STORE STATUS, but relying on the kernel implementation. All
other calls come from the loaded VCPU via kvm_s390_store_status().

Fixes: 9abc2a08a7d6 (KVM: s390: fix memory overwrites when vx is disabled)
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index a08d0afd5ff6e8a99f888431c784a0f3b8d85123..575dc123bda20a060bba70cbc5e48aa0ce90288e 100644 (file)
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -2249,7 +2249,7 @@ int kvm_s390_store_status_unloaded(struct kvm_vcpu *vcpu, unsigned long gpa)
 
        /* manually convert vector registers if necessary */
        if (MACHINE_HAS_VX) {
-               convert_vx_to_fp(fprs, current->thread.fpu.vxrs);
+               convert_vx_to_fp(fprs, (__vector128 *) vcpu->run->s.regs.vrs);
                rc = write_guest_abs(vcpu, gpa + __LC_FPREGS_SAVE_AREA,
                                     fprs, 128);
        } else {