Thomas Huth <th...@redhat.com> writes:
> On 18.01.2016 05:24, David Gibson wrote:
>> The spapr_alloc_htab() and spapr_reset_htab() functions currently handle
>> all errors with error_setg(&error_abort, ...).
>>
>> But really, the callers are really better placed to decide on the error
>> handling. So, instead make the functions use the error propagation
>> infrastructure.
>>
>> In the callers we change to &error_fatal instead of &error_abort, since
>> this can be triggered by a bad configuration or kernel error rather than
>> indicating a programming error in qemu.
>>
>> While we're at it improve the messages themselves a bit, and clean up the
>> indentation a little.
>>
>> Signed-off-by: David Gibson <da...@gibson.dropbear.id.au>
>> ---
>> hw/ppc/spapr.c | 24 ++++++++++++++++--------
>> 1 file changed, 16 insertions(+), 8 deletions(-)
>>
>> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
>> index b7fd09a..d28e349 100644
>> --- a/hw/ppc/spapr.c
>> +++ b/hw/ppc/spapr.c
>> @@ -1016,7 +1016,7 @@ 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;
>> @@ -1031,7 +1031,8 @@ 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_errno(errp, -shift,
>> + "Error allocating KVM hash page table, try smaller
>> maxmem");
>> } else if (shift > 0) {
>> /*
>> * Kernel handles htab, we don't need to allocate one
>> @@ -1040,7 +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);
>
> Maybe you should add an "return" statement here - theoretically you do
> not want to continue with "kvmppc_kern_htab = true" in case of errors.
> (practically this does not happen because errp = error_fatal, but in
> case the caller gets changed, this might introduce subtle errors otherwise)
Good point.
With abort() / exit(), we don't have to worry about recovery. In
particular, we don't have to revert half-done changes.
Conversions away from abort() / exit() need to consider error recovery.
We have to make sure the function leaves things in a sane state on
error. This normally means taking an early return, and often means
reverting some state changes.
[...]
