On 25.08.14 15:45, 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 <aravi...@linux.vnet.ibm.com> > --- > 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 */ > + 0x6063f004, /* ori r3,r3,f004 */ > + /* Issue H_CALL */ > + 0x44000022, /* sc 1 */
So up to here we're saving r3 in SPRG2 (how do we know that we can clobber it?) and call our special hypercall. But what does all the cruft below here do? > + 0x7c9243a6, /* mtspr r4 sprg2 */ Apart from th fact that your order is wrong, this destroys the value of r3 that we saved above again. > + 0xe8830000, /* ld r4, 0(r3) */ > + 0x7c9a03a6, /* mtspr r4, srr0 */ > + 0xe8830008, /* ld r4, 8(r3) */ > + 0x7c9b03a6, /* mtspr r4, srr1 */ Can't we just set srr0 and srr1 directly? > + 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; > + } > + > + /* > + * Update the branch instruction in trampoline with the absolute > + * machine check address requested by OS > + */ > + branch_inst |= guest_machine_check_addr; Does this even work? You're creating a relative branch here. Alex > + 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); > +} > + > static struct rtas_call { > const char *name; > spapr_rtas_fn fn; > @@ -404,6 +489,12 @@ static void core_rtas_register_types(void) > spapr_rtas_register(RTAS_IBM_SET_SYSTEM_PARAMETER, > "ibm,set-system-parameter", > rtas_ibm_set_system_parameter); > + spapr_rtas_register(RTAS_IBM_NMI_REGISTER, > + "ibm,nmi-register", > + rtas_ibm_nmi_register); > + spapr_rtas_register(RTAS_IBM_NMI_INTERLOCK, > + "ibm,nmi-interlock", > + rtas_ibm_nmi_interlock); > } > > type_init(core_rtas_register_types) > diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h > index 57199f5..8c854ca 100644 > --- a/include/hw/ppc/spapr.h > +++ b/include/hw/ppc/spapr.h > @@ -386,8 +386,10 @@ int spapr_allocate_irq_block(int num, bool lsi, bool > msi); > #define RTAS_IBM_CONFIGURE_CONNECTOR (RTAS_TOKEN_BASE + 0x1E) > #define RTAS_IBM_OS_TERM (RTAS_TOKEN_BASE + 0x1F) > #define RTAS_IBM_EXTENDED_OS_TERM (RTAS_TOKEN_BASE + 0x20) > +#define RTAS_IBM_NMI_REGISTER (RTAS_TOKEN_BASE + 0x21) > +#define RTAS_IBM_NMI_INTERLOCK (RTAS_TOKEN_BASE + 0x22) > > -#define RTAS_TOKEN_MAX (RTAS_TOKEN_BASE + 0x21) > +#define RTAS_TOKEN_MAX (RTAS_TOKEN_BASE + 0x23) > > /* RTAS ibm,get-system-parameter token values */ > #define RTAS_SYSPARM_SPLPAR_CHARACTERISTICS 20 > @@ -485,4 +487,8 @@ int spapr_dma_dt(void *fdt, int node_off, const char > *propname, > int spapr_tcet_dma_dt(void *fdt, int node_off, const char *propname, > sPAPRTCETable *tcet); > > +/* Machine Check Interrupt related macros */ > +#define MC_INTERRUPT_VECTOR 0x200 > +#define MC_INTERRUPT_VECTOR_SIZE 0x100 > + > #endif /* !defined (__HW_SPAPR_H__) */ > >