target-arm: Add raw_readfn and raw_writefn to ARMCPRegInfo

    
For reading and writing register values from the kernel for KVM,
we need to provide accessor functions which are guaranteed to succeed
and don't impose access checks, mask out unwritable bits, etc.
Define new fields raw_readfn and raw_writefn for this purpose;
these only need to be provided if there is a readfn or writefn
already and it is not suitable.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 13 insertions, 0 deletions

diff --git a/target-arm/helper.c b/target-arm/helper.c
index fd055e89f2..2585d59daf 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -1392,6 +1392,19 @@ void define_one_arm_cp_reg_with_opaque(ARMCPU *cpu,
                 r2->crm = crm;
                 r2->opc1 = opc1;
                 r2->opc2 = opc2;
+                /* By convention, for wildcarded registers only the first
+                 * entry is used for migration; the others are marked as
+                 * NO_MIGRATE so we don't try to transfer the register
+                 * multiple times. Special registers (ie NOP/WFI) are
+                 * never migratable.
+                 */
+                if ((r->type & ARM_CP_SPECIAL) ||
+                    ((r->crm == CP_ANY) && crm != 0) ||
+                    ((r->opc1 == CP_ANY) && opc1 != 0) ||
+                    ((r->opc2 == CP_ANY) && opc2 != 0)) {
+                    r2->type |= ARM_CP_NO_MIGRATE;
+                }
+
                 /* Overriding of an existing definition must be explicitly
                  * requested.
                  */