Re: [PATCH 2/6] target/ppc: Fix VRMA page size for ISA v3.0

[Cédric Le Goater]

On 7/26/23 20:22, Nicholas Piggin wrote:

Until v2.07s, the VRMA page size (L||LP) was encoded in LPCR[VRMASD].
In v3.0 that moved to the partition table PS field.

The powernv machine can now run KVM HPT guests on POWER9/10 CPUs with
this fix and the patch to add ASDR.

Fixes: 3367c62f522b ("target/ppc: Support for POWER9 native hash")
Signed-off-by: Nicholas Piggin <npig...@gmail.com>
---
  target/ppc/mmu-hash64.c | 41 +++++++++++++++++++++++++++++++++++------
  1 file changed, 35 insertions(+), 6 deletions(-)

diff --git a/target/ppc/mmu-hash64.c b/target/ppc/mmu-hash64.c
index a0c90df3ce..7f8bbbbdb0 100644
--- a/target/ppc/mmu-hash64.c
+++ b/target/ppc/mmu-hash64.c
@@ -874,12 +874,41 @@ static target_ulong rmls_limit(PowerPCCPU *cpu)
      return rma_sizes[rmls];
  }

-static int build_vrma_slbe(PowerPCCPU *cpu, ppc_slb_t *slb)

+/* Return the LLP in SLB_VSID format */
+static uint64_t get_vrma_llp(PowerPCCPU *cpu)
  {
      CPUPPCState *env = &cpu->env;
-    target_ulong lpcr = env->spr[SPR_LPCR];
-    uint32_t vrmasd = (lpcr & LPCR_VRMASD) >> LPCR_VRMASD_SHIFT;
-    target_ulong vsid = SLB_VSID_VRMA | ((vrmasd << 4) & SLB_VSID_LLP_MASK);
+    uint64_t llp;
+
+    if (env->mmu_model == POWERPC_MMU_3_00) {
+        ppc_v3_pate_t pate;
+        uint64_t ps;
+
+        /*
+         * ISA v3.0 removes the LPCR[VRMASD] field and puts the VRMA base
+         * page size (L||LP equivalent) in the PS field in the HPT partition
+         * table entry.
+         */
+        if (!ppc64_v3_get_pate(cpu, cpu->env.spr[SPR_LPIDR], &pate)) {
+            error_report("Bad VRMA with no partition table entry");
+            return 0;
+        }
+        ps = pate.dw0 >> (63 - 58);
+        llp = ((ps & 0x4) << (63 - 55 - 2)) | ((ps & 0x3) << (63 - 59));

Please add bitfield definitions for these numbers :)

+
+    } else {
+        uint64_t lpcr = env->spr[SPR_LPCR];
+        target_ulong vrmasd = (lpcr & LPCR_VRMASD) >> LPCR_VRMASD_SHIFT;
+
+        llp = (vrmasd << 4) & SLB_VSID_LLP_MASK;
+    }
+
+    return llp;
+}
+
+static int build_vrma_slbe(PowerPCCPU *cpu, ppc_slb_t *slb)
+{
+    target_ulong vsid = SLB_VSID_VRMA | get_vrma_llp(cpu);

May be you could introduce a 'uint64_t llp' variable instead and use it
directly in error_report and in the slb encoding test. This is minor.

Thanks,

C.

      int i;

for (i = 0; i < PPC_PAGE_SIZES_MAX_SZ; i++) {

@@ -897,8 +926,8 @@ static int build_vrma_slbe(PowerPCCPU *cpu, ppc_slb_t *slb)
          }
      }

- error_report("Bad page size encoding in LPCR[VRMASD]; LPCR=0x"

-                 TARGET_FMT_lx, lpcr);
+    error_report("Bad VRMA page size encoding 0x" TARGET_FMT_lx,
+                 get_vrma_llp(cpu));

return -1;

  }