[Qemu-devel] [PATCH 05/10] ppc: Fix generation if ISI/DSI vs. HV mode

["Cédric Le Goater" <clg@kaod.org>]

From: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Under some circumstances, we need to direct ISI and DSI interrupts
at the hypervisor, turning them into HISI/HDSI, and using different
SPRs (HDSISR and HDAR) depending on the combination of MSR_DR and
the corresponding VPM bits in LPCR.

This moves part of the code into helpers that are fixed to select
the right exception type and registers. On pre-P7 processors, LPCR
is 0 which provides the old behaviour of directing the interrupts
at the supervisor.

Thanks to Andrei Warkentin for finding a bug when HV=1

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
---
 target-ppc/mmu-hash64.c | 69 +++++++++++++++++++++++++++++++++++--------------
 1 file changed, 50 insertions(+), 19 deletions(-)

diff --git a/target-ppc/mmu-hash64.c b/target-ppc/mmu-hash64.c
index 668da5e22653..072a952c8bd5 100644
--- a/target-ppc/mmu-hash64.c
+++ b/target-ppc/mmu-hash64.c
@@ -613,6 +613,47 @@ unsigned ppc_hash64_hpte_page_shift_noslb(PowerPCCPU *cpu,
     return 0;
 }
 
+static void ppc_hash64_set_isi(CPUState *cs, CPUPPCState *env,
+                               uint64_t error_code)
+{
+    bool vpm;
+
+    if (msr_ir) {
+        vpm = !!(env->spr[SPR_LPCR] & LPCR_VPM1);
+    } else {
+        vpm = !!(env->spr[SPR_LPCR] & LPCR_VPM0);
+    }
+    if (vpm && !msr_hv) {
+        cs->exception_index = POWERPC_EXCP_HISI;
+    } else {
+        cs->exception_index = POWERPC_EXCP_ISI;
+    }
+    env->error_code = error_code;
+}
+
+static void ppc_hash64_set_dsi(CPUState *cs, CPUPPCState *env, uint64_t dar,
+                               uint64_t dsisr)
+{
+    bool vpm;
+
+    if (msr_dr) {
+        vpm = !!(env->spr[SPR_LPCR] & LPCR_VPM1);
+    } else {
+        vpm = !!(env->spr[SPR_LPCR] & LPCR_VPM0);
+    }
+    if (vpm && msr_hv) {
+        cs->exception_index = POWERPC_EXCP_HDSI;
+        env->spr[SPR_HDAR] = dar;
+        env->spr[SPR_HDSISR] = dsisr;
+    } else {
+        cs->exception_index = POWERPC_EXCP_DSI;
+        env->spr[SPR_DAR] = dar;
+        env->spr[SPR_DSISR] = dsisr;
+   }
+    env->error_code = 0;
+}
+
+
 int ppc_hash64_handle_mmu_fault(PowerPCCPU *cpu, vaddr eaddr,
                                 int rwx, int mmu_idx)
 {
@@ -623,7 +664,7 @@ int ppc_hash64_handle_mmu_fault(PowerPCCPU *cpu, vaddr eaddr,
     hwaddr pte_offset;
     ppc_hash_pte64_t pte;
     int pp_prot, amr_prot, prot;
-    uint64_t new_pte1;
+    uint64_t new_pte1, dsisr;
     const int need_prot[] = {PAGE_READ, PAGE_WRITE, PAGE_EXEC};
     hwaddr raddr;
 
@@ -657,26 +698,21 @@ int ppc_hash64_handle_mmu_fault(PowerPCCPU *cpu, vaddr eaddr,
 
     /* 3. Check for segment level no-execute violation */
     if ((rwx == 2) && (slb->vsid & SLB_VSID_N)) {
-        cs->exception_index = POWERPC_EXCP_ISI;
-        env->error_code = 0x10000000;
+        ppc_hash64_set_isi(cs, env, 0x10000000);
         return 1;
     }
 
     /* 4. Locate the PTE in the hash table */
     pte_offset = ppc_hash64_htab_lookup(cpu, slb, eaddr, &pte);
     if (pte_offset == -1) {
+        dsisr = 0x40000000;
         if (rwx == 2) {
-            cs->exception_index = POWERPC_EXCP_ISI;
-            env->error_code = 0x40000000;
+            ppc_hash64_set_isi(cs, env, dsisr);
         } else {
-            cs->exception_index = POWERPC_EXCP_DSI;
-            env->error_code = 0;
-            env->spr[SPR_DAR] = eaddr;
             if (rwx == 1) {
-                env->spr[SPR_DSISR] = 0x42000000;
-            } else {
-                env->spr[SPR_DSISR] = 0x40000000;
+                dsisr |= 0x02000000;
             }
+            ppc_hash64_set_dsi(cs, env, eaddr, dsisr);
         }
         return 1;
     }
@@ -705,14 +741,9 @@ int ppc_hash64_handle_mmu_fault(PowerPCCPU *cpu, vaddr eaddr,
         /* Access right violation */
         qemu_log_mask(CPU_LOG_MMU, "PTE access rejected\n");
         if (rwx == 2) {
-            cs->exception_index = POWERPC_EXCP_ISI;
-            env->error_code = 0x08000000;
+            ppc_hash64_set_isi(cs, env, 0x08000000);
         } else {
-            target_ulong dsisr = 0;
-
-            cs->exception_index = POWERPC_EXCP_DSI;
-            env->error_code = 0;
-            env->spr[SPR_DAR] = eaddr;
+            dsisr = 0;
             if (need_prot[rwx] & ~pp_prot) {
                 dsisr |= 0x08000000;
             }
@@ -722,7 +753,7 @@ int ppc_hash64_handle_mmu_fault(PowerPCCPU *cpu, vaddr eaddr,
             if (need_prot[rwx] & ~amr_prot) {
                 dsisr |= 0x00200000;
             }
-            env->spr[SPR_DSISR] = dsisr;
+            ppc_hash64_set_dsi(cs, env, eaddr, dsisr);
         }
         return 1;
     }
-- 
2.1.4