On 09/09/2017 09:39 AM, Benjamin Herrenschmidt wrote:
> On Wed, 2017-07-05 at 19:13 +0200, Cédric Le Goater wrote:
>> Signed-off-by: Cédric Le Goater <c...@kaod.org>
>> ---
>> hw/intc/xive.c | 21 +++++++++++++++++++++
>> 1 file changed, 21 insertions(+)
>>
>> diff --git a/hw/intc/xive.c b/hw/intc/xive.c
>> index c3c1e9c9db2d..cda1fa18e44d 100644
>> --- a/hw/intc/xive.c
>> +++ b/hw/intc/xive.c
>> @@ -53,6 +53,21 @@ static uint64_t xive_icp_accept(XiveICPState *xicp)
>> return (nsr << 8) | xicp->tima_os[TM_CPPR];
>> }
>>
>> +static uint8_t ipb_to_pipr(uint8_t ibp)
>> +{
>> + return ibp ? clz32((uint32_t)ibp << 24) : 0xff;
>> +}
>
> The PIPR needs to be updated also on accept etc... anything that change
> IPBs or CPPR really.
I did forget the update in accept ... thanks.
> Also I just learned something from the designers: The IPIR is clamped
> to CPPR.
>
> So basically the value in the PIPR is:
>
> v = leftmost_bit_of(ipb) (or 0xff);
> pipr = v < cppr ? v : cppr;
>
> which means it's never actually 0xff ... surprise !
ah. that is not what the specs say but it shouldn't be a problem.
I will change the code to reflect that.
C.
> That also means I need to fix my implementation of H_IPOLL in KVM.
>
>> +static void xive_icp_notify(XiveICPState *xicp)
>> +{
>> + xicp->tima_os[TM_PIPR] = ipb_to_pipr(xicp->tima_os[TM_IPB]);
>> +
>> + if (xicp->tima_os[TM_PIPR] < xicp->tima_os[TM_CPPR]) {
>> + xicp->tima_os[TM_NSR] |= TM_QW1_NSR_EO;
>> + qemu_irq_raise(ICP(xicp)->output);
>> + }
>> +}
>> +
>> static void xive_icp_set_cppr(XiveICPState *xicp, uint8_t cppr)
>> {
>> if (cppr > XIVE_PRIORITY_MAX) {
>> @@ -60,6 +75,10 @@ static void xive_icp_set_cppr(XiveICPState *xicp, uint8_t
>> cppr)
>> }
>>
>> xicp->tima_os[TM_CPPR] = cppr;
>> +
>> + /* CPPR has changed, inform the ICP which might raise an
>> + * exception */
>> + xive_icp_notify(xicp);
>> }
>>
>> /*
>> @@ -339,6 +358,8 @@ static void xive_icp_irq(XiveICSState *xs, int lisn)
>> } else {
>> qemu_log_mask(LOG_UNIMP, "XIVE: w7 format1 not implemented\n");
>> }
>> +
>> + xive_icp_notify(xicp);
>> }
>>
>> /*
