hw/intc/arm_gicv3: Remove incorrect usage of fieldoffset

In the ARMCPRegInfo definitions for the GICv3 CPU interface
registers, we were trying to use .fieldoffset to specify
the locations of data fields within the GICv3CPUState struct.
This is completely broken, because .fieldoffset is for offsets
into the CPUARMState struct. We didn't notice because we
were only using this for reads to BPR0, AP0R<n>, IGRPEN0
and CTLR_EL3, and Linux doesn't use these registers.

Replace the .fieldoffset uses with explicit read functions.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: NEdgar E. Iglesias <edgar.iglesias@xilinx.com>

hw/intc/arm_gicv3_cpuif.c

@@ -1118,35 +1118,35 @@ static const ARMCPRegInfo gicv3_cpuif_reginfo[] = {
       .opc0 = 3, .opc1 = 0, .crn = 12, .crm = 8, .opc2 = 3,
       .type = ARM_CP_IO | ARM_CP_NO_RAW,
       .access = PL1_RW, .accessfn = gicv3_fiq_access,
-      .fieldoffset = offsetof(GICv3CPUState, icc_bpr[GICV3_G0]),
+      .readfn = icc_bpr_read,
       .writefn = icc_bpr_write,
     },
     { .name = "ICC_AP0R0_EL1", .state = ARM_CP_STATE_BOTH,
       .opc0 = 3, .opc1 = 0, .crn = 12, .crm = 8, .opc2 = 4,
       .type = ARM_CP_IO | ARM_CP_NO_RAW,
       .access = PL1_RW, .accessfn = gicv3_fiq_access,
-      .fieldoffset = offsetof(GICv3CPUState, icc_apr[GICV3_G0][0]),
+      .readfn = icc_ap_read,
       .writefn = icc_ap_write,
     },
     { .name = "ICC_AP0R1_EL1", .state = ARM_CP_STATE_BOTH,
       .opc0 = 3, .opc1 = 0, .crn = 12, .crm = 8, .opc2 = 5,
       .type = ARM_CP_IO | ARM_CP_NO_RAW,
       .access = PL1_RW, .accessfn = gicv3_fiq_access,
-      .fieldoffset = offsetof(GICv3CPUState, icc_apr[GICV3_G0][1]),
+      .readfn = icc_ap_read,
       .writefn = icc_ap_write,
     },
     { .name = "ICC_AP0R2_EL1", .state = ARM_CP_STATE_BOTH,
       .opc0 = 3, .opc1 = 0, .crn = 12, .crm = 8, .opc2 = 6,
       .type = ARM_CP_IO | ARM_CP_NO_RAW,
       .access = PL1_RW, .accessfn = gicv3_fiq_access,
-      .fieldoffset = offsetof(GICv3CPUState, icc_apr[GICV3_G0][2]),
+      .readfn = icc_ap_read,
       .writefn = icc_ap_write,
     },
     { .name = "ICC_AP0R3_EL1", .state = ARM_CP_STATE_BOTH,
       .opc0 = 3, .opc1 = 0, .crn = 12, .crm = 8, .opc2 = 7,
       .type = ARM_CP_IO | ARM_CP_NO_RAW,
       .access = PL1_RW, .accessfn = gicv3_fiq_access,
-      .fieldoffset = offsetof(GICv3CPUState, icc_apr[GICV3_G0][3]),
+      .readfn = icc_ap_read,
       .writefn = icc_ap_write,
     },
     /* All the ICC_AP1R*_EL1 registers are banked */
@@ -1275,7 +1275,7 @@ static const ARMCPRegInfo gicv3_cpuif_reginfo[] = {
       .opc0 = 3, .opc1 = 0, .crn = 12, .crm = 12, .opc2 = 6,
       .type = ARM_CP_IO | ARM_CP_NO_RAW,
       .access = PL1_RW, .accessfn = gicv3_fiq_access,
-      .fieldoffset = offsetof(GICv3CPUState, icc_igrpen[GICV3_G0]),
+      .readfn = icc_igrpen_read,
       .writefn = icc_igrpen_write,
     },
     /* This register is banked */
@@ -1299,7 +1299,6 @@ static const ARMCPRegInfo gicv3_cpuif_reginfo[] = {
       .opc0 = 3, .opc1 = 6, .crn = 12, .crm = 12, .opc2 = 4,
       .type = ARM_CP_IO | ARM_CP_NO_RAW,
       .access = PL3_RW,
-      .fieldoffset = offsetof(GICv3CPUState, icc_ctlr_el3),
       .readfn = icc_ctlr_el3_read,
       .writefn = icc_ctlr_el3_write,
     },