Re: [PATCH v3 6/9] pnv/xive2: Enable VST NVG and NVC index compression

[Cédric Le Goater]

On 7/16/24 21:56, Michael Kowal wrote:

From: Frederic Barrat <fbar...@linux.ibm.com>

Enable NVG and NVC VST tables for index compression which indicates the number
of bits the address is shifted to the right for the table accesses.
The compression values are defined as:
    0000 - No compression
    0001 - 1 bit shift
    0010 - 2 bit shift
    ....
    1000 - 8 bit shift
    1001-1111 - No compression

Signed-off-by: Frederic Barrat <fbar...@linux.ibm.com>
Signed-off-by: Michael Kowal <ko...@linux.vnet.ibm.com>

Reviewed-by: Cédric Le Goater <c...@redhat.com>

Thanks,

C.

---
  hw/intc/pnv_xive2_regs.h |  2 ++
  hw/intc/pnv_xive2.c      | 20 ++++++++++++++++++++
  2 files changed, 22 insertions(+)

diff --git a/hw/intc/pnv_xive2_regs.h b/hw/intc/pnv_xive2_regs.h
index ca05255d20..e8b87b3d2c 100644
--- a/hw/intc/pnv_xive2_regs.h
+++ b/hw/intc/pnv_xive2_regs.h
@@ -427,6 +427,8 @@
  #define X_PC_NXC_PROC_CONFIG                    0x28A
  #define PC_NXC_PROC_CONFIG                      0x450
  #define   PC_NXC_PROC_CONFIG_WATCH_ASSIGN       PPC_BITMASK(0, 3)
+#define   PC_NXC_PROC_CONFIG_NVG_TABLE_COMPRESS PPC_BITMASK(32, 35)
+#define   PC_NXC_PROC_CONFIG_NVC_TABLE_COMPRESS PPC_BITMASK(36, 39)

/* NxC Cache Watch 0 Specification */

  #define X_PC_NXC_WATCH0_SPEC                    0x2A0
diff --git a/hw/intc/pnv_xive2.c b/hw/intc/pnv_xive2.c
index d4ee104300..84ae10b710 100644
--- a/hw/intc/pnv_xive2.c
+++ b/hw/intc/pnv_xive2.c
@@ -217,6 +217,20 @@ static uint64_t pnv_xive2_vst_addr_indirect(PnvXive2 
*xive, uint32_t type,
      return pnv_xive2_vst_addr_direct(xive, type, vsd, (idx % vst_per_page));
  }

+static uint8_t pnv_xive2_nvc_table_compress_shift(PnvXive2 *xive)

+{
+    uint8_t shift =  GETFIELD(PC_NXC_PROC_CONFIG_NVC_TABLE_COMPRESS,
+                              xive->pc_regs[PC_NXC_PROC_CONFIG >> 3]);
+    return shift > 8 ? 0 : shift;
+}
+
+static uint8_t pnv_xive2_nvg_table_compress_shift(PnvXive2 *xive)
+{
+    uint8_t shift = GETFIELD(PC_NXC_PROC_CONFIG_NVG_TABLE_COMPRESS,
+                             xive->pc_regs[PC_NXC_PROC_CONFIG >> 3]);
+    return shift > 8 ? 0 : shift;
+}
+
  static uint64_t pnv_xive2_vst_addr(PnvXive2 *xive, uint32_t type, uint8_t blk,
                                     uint32_t idx)
  {
@@ -238,6 +252,12 @@ static uint64_t pnv_xive2_vst_addr(PnvXive2 *xive, 
uint32_t type, uint8_t blk,
          return xive ? pnv_xive2_vst_addr(xive, type, blk, idx) : 0;
      }

+ if (type == VST_NVG) {

+        idx >>= pnv_xive2_nvg_table_compress_shift(xive);
+    } else if (type == VST_NVC) {
+        idx >>= pnv_xive2_nvc_table_compress_shift(xive);
+    }
+
      if (VSD_INDIRECT & vsd) {
          return pnv_xive2_vst_addr_indirect(xive, type, vsd, idx);
      }