KVM: PPC: Fix emulation of H_SET_DABR/X on POWER8

[ Upstream commit 760a736 ]

In the old DABR register, the BT (Breakpoint Translation) bit
is bit number 61. In the new DAWRX register, the WT (Watchpoint
Translation) bit is bit number 59. So to move the DABR-BT bit
into the position of the DAWRX-WT bit, it has to be shifted by
two, not only by one. This fixes hardware watchpoints in gdb of
older guests that only use the H_SET_DABR/X interface instead
of the new H_SET_MODE interface.

Cc: [email protected] # v3.14+
Signed-off-by: Thomas Huth <[email protected]>
Reviewed-by: Laurent Vivier <[email protected]>
Reviewed-by: David Gibson <[email protected]>
Signed-off-by: Paul Mackerras <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>

Author: huth

arch/powerpc/kvm/book3s_hv_rmhandlers.S

@@ -2047,7 +2047,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
 
 	/* Emulate H_SET_DABR/X on P8 for the sake of compat mode guests */
 2:	rlwimi	r5, r4, 5, DAWRX_DR | DAWRX_DW
-	rlwimi	r5, r4, 1, DAWRX_WT
+	rlwimi	r5, r4, 2, DAWRX_WT
 	clrrdi	r4, r4, 3
 	std	r4, VCPU_DAWR(r3)
 	std	r5, VCPU_DAWRX(r3)