target/ppc: Don't check UPRT in radix mode when in HV real mode

It appears that during kexec, we run for a while in hypervisor
real mode with LPCR:HR set and LPCR:UPRT clear, which trips
the assertion in ppc_radix64_handle_mmu_fault().

First this shouldn't be an assertion, it's a guest error.

Then we shouldn't be checking these things in hypervisor real
mode (or in virtual hypervisor guest real mode which is similar)
as the real HW won't use those LPCR bits in those cases anyway,
so technically it's ok to have this discrepancy.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20190411080004.8690-2-clg@kaod.org>
[dwg: Fix for 32-bit builds]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

target/ppc/mmu-radix64.c

@@ -228,10 +228,10 @@ int ppc_radix64_handle_mmu_fault(PowerPCCPU *cpu, vaddr eaddr, int rwx,
     ppc_v3_pate_t pate;
 
     assert((rwx == 0) || (rwx == 1) || (rwx == 2));
-    assert(ppc64_use_proc_tbl(cpu));
 
-    /* Real Mode Access */
-    if (((rwx == 2) && (msr_ir == 0)) || ((rwx != 2) && (msr_dr == 0))) {
+    /* HV or virtual hypervisor Real Mode Access */
+    if ((msr_hv || cpu->vhyp) &&
+        (((rwx == 2) && (msr_ir == 0)) || ((rwx != 2) && (msr_dr == 0)))) {
         /* In real mode top 4 effective addr bits (mostly) ignored */
         raddr = eaddr & 0x0FFFFFFFFFFFFFFFULL;
 
@@ -241,6 +241,16 @@ int ppc_radix64_handle_mmu_fault(PowerPCCPU *cpu, vaddr eaddr, int rwx,
         return 0;
     }
 
+    /*
+     * Check UPRT (we avoid the check in real mode to deal with
+     * transitional states during kexec.
+     */
+    if (!ppc64_use_proc_tbl(cpu)) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "LPCR:UPRT not set in radix mode ! LPCR="
+                      TARGET_FMT_lx "\n", env->spr[SPR_LPCR]);
+    }
+
     /* Virtual Mode Access - get the fully qualified address */
     if (!ppc_radix64_get_fully_qualified_addr(env, eaddr, &lpid, &pid)) {
         ppc_radix64_raise_segi(cpu, rwx, eaddr);