On Tuesday 26 August 2014 11:32 AM, David Gibson wrote:
> On Mon, Aug 25, 2014 at 07:15:45PM +0530, Aravinda Prasad wrote:
>> This patch adds FWNMI support in qemu for powerKVM
>> guests by handling the ibm,nmi-register rtas call.
>> Whenever OS issues ibm,nmi-register RTAS call, the
>> machine check notification address is saved and the
>> machine check interrupt vector 0x200 is patched to
>> issue a private hcall.
>>
>> Signed-off-by: Aravinda Prasad <[email protected]>
>> ---
>> hw/ppc/spapr_rtas.c | 91
>> ++++++++++++++++++++++++++++++++++++++++++++++++
>> include/hw/ppc/spapr.h | 8 ++++
>> 2 files changed, 98 insertions(+), 1 deletion(-)
>>
>> diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
>> index 02ddbf9..1135d2b 100644
>> --- a/hw/ppc/spapr_rtas.c
>> +++ b/hw/ppc/spapr_rtas.c
>> @@ -277,6 +277,91 @@ static void rtas_ibm_set_system_parameter(PowerPCCPU
>> *cpu,
>> rtas_st(rets, 0, ret);
>> }
>>
>> +static void rtas_ibm_nmi_register(PowerPCCPU *cpu,
>> + sPAPREnvironment *spapr,
>> + uint32_t token, uint32_t nargs,
>> + target_ulong args,
>> + uint32_t nret, target_ulong rets)
>> +{
>> + int i;
>> + uint32_t branch_inst = 0x48000002;
>> + target_ulong guest_machine_check_addr;
>> + PowerPCCPUClass *pcc = POWERPC_CPU_GET_CLASS(cpu);
>> + /*
>> + * Trampoline saves r3 in sprg2 and issues private hcall
>> + * to request qemu to build error log. QEMU builds the
>> + * error log, copies to rtas-blob and returns the address.
>> + * The initial 16 bytes in rtas-blob consists of saved srr0
>> + * and srr1 which we restore and pass on the actual error
>> + * log address to OS handled mcachine check notification
>> + * routine
>> + */
>> + uint32_t trampoline[] = {
>> + 0x7c7243a6, /* mtspr SPRN_SPRG2,r3 */
>> + 0x38600000, /* li r3,0 */
>> + /* 0xf004 is the KVMPPC_H_REPORT_ERR private HCALL */
>
> You should construct the instruction from the KVMPPC_H_REPORT_ERR
> constant, otherwise it's an undocumented magic dependency between
> parts of the code.
hmm.. yes. will do
>
>> + 0x6063f004, /* ori r3,r3,f004 */
>> + /* Issue H_CALL */
>> + 0x44000022, /* sc 1 */
>> + 0x7c9243a6, /* mtspr r4 sprg2 */
>> + 0xe8830000, /* ld r4, 0(r3) */
>> + 0x7c9a03a6, /* mtspr r4, srr0 */
>> + 0xe8830008, /* ld r4, 8(r3) */
>> + 0x7c9b03a6, /* mtspr r4, srr1 */
>> + 0x38630010, /* addi r3,r3,16 */
>> + 0x7c9242a6, /* mfspr r4 sprg2 */
>> + 0x48000002, /* Branch to address registered
>> + * by OS. The branch address is
>> + * patched below */
>> + 0x48000000, /* b . */
>> + };
>> + int total_inst = sizeof(trampoline) / sizeof(uint32_t);
>> +
>> + /* Store the system reset and machine check address */
>> + guest_machine_check_addr = rtas_ld(args, 1);
>> +
>> + /* Safety Check */
>> + if (sizeof(trampoline) >= MC_INTERRUPT_VECTOR_SIZE) {
>> + fprintf(stderr, "Unable to register ibm,nmi_register: "
>> + "Trampoline size exceeded\n");
>> + rtas_st(rets, 0, RTAS_OUT_NOT_SUPPORTED);
>> + return;
>
> The guest has absolutely no influence over this, so this should be an
> assert() rather than returning an rtas error. Or better yet, detect
> the failure at compile time, since it doesn't depend on anything
> runtime either.
yes better to detect at compile time.
>
>> + }
>> +
>> + /*
>> + * Update the branch instruction in trampoline with the absolute
>> + * machine check address requested by OS
>> + */
>> + branch_inst |= guest_machine_check_addr;
>
> Surely there should be some sanity checking of the address here, or it
> can clobber any part of that branch instruction.
Will include a check to make sure instruction opcode is not clobbered.
>
>> + memcpy(&trampoline[11], &branch_inst, sizeof(branch_inst));
>> +
>> + /* Handle all Host/Guest LE/BE combinations */
>> + if ((*pcc->interrupts_big_endian)(cpu)) {
>> + for (i = 0; i < total_inst; i++) {
>> + trampoline[i] = cpu_to_be32(trampoline[i]);
>> + }
>> + } else {
>> + for (i = 0; i < total_inst; i++) {
>> + trampoline[i] = cpu_to_le32(trampoline[i]);
>> + }
>> + }
>> +
>> + /* Patch 0x200 NMI interrupt vector memory area of guest */
>> + cpu_physical_memory_write(MC_INTERRUPT_VECTOR, trampoline,
>> + sizeof(trampoline));
>> +
>> + rtas_st(rets, 0, RTAS_OUT_SUCCESS);
>> +}
>> +
>> +static void rtas_ibm_nmi_interlock(PowerPCCPU *cpu,
>> + sPAPREnvironment *spapr,
>> + uint32_t token, uint32_t nargs,
>> + target_ulong args,
>> + uint32_t nret, target_ulong rets)
>> +{
>> + rtas_st(rets, 0, RTAS_OUT_SUCCESS);
>> +}
>> +
>
> This nmi_interlock call isn't described in the commit message.
Yes. will include
Regards,
Aravinda
>
--
Regards,
Aravinda
