powerpc: Fix definition of SIAR and SDAR registers
authorThomas Huth <thuth@redhat.com>
Thu, 12 May 2016 11:26:44 +0000 (13:26 +0200)
committerMichael Ellerman <mpe@ellerman.id.au>
Tue, 31 May 2016 10:07:56 +0000 (20:07 +1000)
commitd23fac2b27d94aeb7b65536a50d32bfdc21fe01e
tree9b60ba21b6bac88d3217a42fffbbb917be94ae9b
parentbd000b82e86503d5e8b9e6d40a3257bc9dddb96d
powerpc: Fix definition of SIAR and SDAR registers

The SIAR and SDAR registers are available twice, one time as SPRs
780 / 781 (unprivileged, but read-only), and one time as the SPRs
796 / 797 (privileged, but read and write). The Linux kernel code
currently uses the unprivileged  SPRs - while this is OK for reading,
writing to that register of course does not work.
Since the KVM code tries to write to this register, too (see the mtspr
in book3s_hv_rmhandlers.S), the contents of this register sometimes get
lost for the guests, e.g. during migration of a VM.
To fix this issue, simply switch to the privileged SPR numbers instead.

Cc: stable@vger.kernel.org
Signed-off-by: Thomas Huth <thuth@redhat.com>
Acked-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
arch/powerpc/include/asm/reg.h