target/arm: Implement DBGVCR32_EL2 system register

The DBGVCR_EL2 system register is needed to run a 32-bit
EL1 guest under a Linux EL2 64-bit hypervisor. Its only
purpose is to provide AArch64 with access to the state of
the DBGVCR AArch32 register. Since we only have a dummy
DBGVCR, implement a corresponding dummy DBGVCR32_EL2.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>

diff --git a/target/arm/helper.c b/target/arm/helper.c
index ba72ebb..7111c8c 100644 (file)
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -4066,6 +4066,13 @@ static const ARMCPRegInfo debug_cp_reginfo[] = {
       .cp = 14, .opc1 = 0, .crn = 0, .crm = 7, .opc2 = 0,
       .access = PL1_RW, .accessfn = access_tda,
       .type = ARM_CP_NOP },
+    /* Dummy DBGVCR32_EL2 (which is only for a 64-bit hypervisor
+     * to save and restore a 32-bit guest's DBGVCR)
+     */
+    { .name = "DBGVCR32_EL2", .state = ARM_CP_STATE_AA64,
+      .opc0 = 2, .opc1 = 4, .crn = 0, .crm = 7, .opc2 = 0,
+      .access = PL2_RW, .accessfn = access_tda,
+      .type = ARM_CP_NOP },
     /* Dummy MDCCINT_EL1, since we don't implement the Debug Communications
      * Channel but Linux may try to access this register. The 32-bit
      * alias is DBGDCCINT.