[Qemu-devel] [PATCH 03/11] pseries: Clean up hash page table allocation error handling

[David Gibson <david@gibson.dropbear.id.au>]

The spapr_alloc_htab() and spapr_reset_htab() functions currently handle
all errors with error_setg(&error_abort, ...).  That's correct for
spapr_reset_htab() - if anything goes wrong there, there's really nothing
we can do about it.  For spapr_alloc_htab() &error_fatal would make more
sense, since it occurs during initialization.

But in any case the callers are really better placed to decide on the error
handling.  So, instead make the functions use the error propagation
infrastructure.

While we're at it improve the messages themselves a bit, and clean up the
indentation a little.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 hw/ppc/spapr.c | 26 ++++++++++++++++++--------
 1 file changed, 18 insertions(+), 8 deletions(-)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 91396cc..85474ee 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -1015,7 +1015,7 @@ static void emulate_spapr_hypercall(PowerPCCPU *cpu)
 #define CLEAN_HPTE(_hpte)  ((*(uint64_t *)(_hpte)) &= tswap64(~HPTE64_V_HPTE_DIRTY))
 #define DIRTY_HPTE(_hpte)  ((*(uint64_t *)(_hpte)) |= tswap64(HPTE64_V_HPTE_DIRTY))
 
-static void spapr_alloc_htab(sPAPRMachineState *spapr)
+static void spapr_alloc_htab(sPAPRMachineState *spapr, Error **errp)
 {
     long shift;
     int index;
@@ -1030,7 +1030,9 @@ static void spapr_alloc_htab(sPAPRMachineState *spapr)
          * For HV KVM, host kernel will return -ENOMEM when requested
          * HTAB size can't be allocated.
          */
-        error_setg(&error_abort, "Failed to allocate HTAB of requested size, try with smaller maxmem");
+        error_setg(errp,
+            "Error allocating KVM hash page table, try smaller maxmem: %s",
+            strerror(-shift));
     } else if (shift > 0) {
         /*
          * Kernel handles htab, we don't need to allocate one
@@ -1039,7 +1041,10 @@ static void spapr_alloc_htab(sPAPRMachineState *spapr)
          * but we don't allow booting of such guests.
          */
         if (shift != spapr->htab_shift) {
-            error_setg(&error_abort, "Failed to allocate HTAB of requested size, try with smaller maxmem");
+            error_setg(errp,
+                "Small allocation for KVM hash page table (%ld < %"
+                PRIu32 "), try smaller maxmem",
+                shift, spapr->htab_shift);
         }
 
         spapr->htab_shift = shift;
@@ -1063,17 +1068,22 @@ static void spapr_alloc_htab(sPAPRMachineState *spapr)
  * If host kernel has allocated HTAB, KVM_PPC_ALLOCATE_HTAB ioctl is
  * used to clear HTAB. Otherwise QEMU-allocated HTAB is cleared manually.
  */
-static void spapr_reset_htab(sPAPRMachineState *spapr)
+static void spapr_reset_htab(sPAPRMachineState *spapr, Error **errp)
 {
     long shift;
     int index;
 
     shift = kvmppc_reset_htab(spapr->htab_shift);
     if (shift < 0) {
-        error_setg(&error_abort, "Failed to reset HTAB");
+        error_setg(errp,
+            "Error resetting KVM hash page table, try smaller maxmem: %s",
+            strerror(-shift));
     } else if (shift > 0) {
         if (shift != spapr->htab_shift) {
-            error_setg(&error_abort, "Requested HTAB allocation failed during reset");
+            error_setg(errp,
+                "Reduced size on reset of KVM hash page table (%ld < %"
+                PRIu32 "), try smaller maxmem",
+                shift, spapr->htab_shift);
         }
 
         /* Tell readers to update their file descriptor */
@@ -1144,7 +1154,7 @@ static void ppc_spapr_reset(void)
     foreach_dynamic_sysbus_device(find_unknown_sysbus_device, NULL);
 
     /* Reset the hash table & recalc the RMA */
-    spapr_reset_htab(spapr);
+    spapr_reset_htab(spapr, &error_abort);
 
     qemu_devices_reset();
 
@@ -1784,7 +1794,7 @@ static void ppc_spapr_init(MachineState *machine)
         }
         spapr->htab_shift++;
     }
-    spapr_alloc_htab(spapr);
+    spapr_alloc_htab(spapr, &error_fatal);
 
     /* Set up Interrupt Controller before we create the VCPUs */
     spapr->icp = xics_system_init(machine,
-- 
2.5.0