MIPS: KVM: Don't hardcode restored HWREna

KVM modifies CP0_HWREna during guest execution so it can trap and
emulate RDHWR instructions, however it always restores the hardcoded
value 0x2000000F. This assumes the presence of the UserLocal register,
and the absence of any implementation dependent or future HW registers.

Fix by exporting the value that traps.c write into CP0_HWREna, and
loading from there instead of hard coding.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 7176a6057e26..6fb4704bd156 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -2064,10 +2064,13 @@ static void configure_status(void)
 			 status_set);
 }
 
+unsigned int hwrena;
+EXPORT_SYMBOL_GPL(hwrena);
+
 /* configure HWRENA register */
 static void configure_hwrena(void)
 {
-	unsigned int hwrena = cpu_hwrena_impl_bits;
+	hwrena = cpu_hwrena_impl_bits;
 
 	if (cpu_has_mips_r2_r6)
 		hwrena |= MIPS_HWRENA_CPUNUM |