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ppc/spapr: Add a nested state struct 
Rather than use a copy of CPUPPCState to store the host state while
the environment has been switched to the L2, use a new struct for
this purpose.

Have helper functions to save and load this host state.

Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
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@npiggin @legoater
npiggin authored and legoater committed Jun 25, 2023
1 parent cb2f6c3 commit c709e8e
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Showing 2 changed files with 115 additions and 40 deletions.
150 changes: 112 additions & 38 deletions hw/ppc/spapr_hcall.c
View file
Expand Up @@ -1546,6 +1546,112 @@ static target_ulong h_copy_tofrom_guest(PowerPCCPU *cpu,
return H_FUNCTION;
}

struct nested_ppc_state {
uint64_t gpr[32];
uint64_t lr;
uint64_t ctr;
uint64_t cfar;
uint64_t msr;
uint64_t nip;
uint32_t cr;

uint64_t xer;

uint64_t lpcr;
uint64_t lpidr;
uint64_t pidr;
uint64_t pcr;
uint64_t dpdes;
uint64_t hfscr;
uint64_t srr0;
uint64_t srr1;
uint64_t sprg0;
uint64_t sprg1;
uint64_t sprg2;
uint64_t sprg3;
uint64_t ppr;

int64_t tb_offset;
};

static void nested_save_state(struct nested_ppc_state *save, PowerPCCPU *cpu)
{
CPUPPCState *env = &cpu->env;

memcpy(save->gpr, env->gpr, sizeof(save->gpr));

save->lr = env->lr;
save->ctr = env->ctr;
save->cfar = env->cfar;
save->msr = env->msr;
save->nip = env->nip;

save->cr = ppc_get_cr(env);
save->xer = cpu_read_xer(env);

save->lpcr = env->spr[SPR_LPCR];
save->lpidr = env->spr[SPR_LPIDR];
save->pcr = env->spr[SPR_PCR];
save->dpdes = env->spr[SPR_DPDES];
save->hfscr = env->spr[SPR_HFSCR];
save->srr0 = env->spr[SPR_SRR0];
save->srr1 = env->spr[SPR_SRR1];
save->sprg0 = env->spr[SPR_SPRG0];
save->sprg1 = env->spr[SPR_SPRG1];
save->sprg2 = env->spr[SPR_SPRG2];
save->sprg3 = env->spr[SPR_SPRG3];
save->pidr = env->spr[SPR_BOOKS_PID];
save->ppr = env->spr[SPR_PPR];

save->tb_offset = env->tb_env->tb_offset;
}

static void nested_load_state(PowerPCCPU *cpu, struct nested_ppc_state *load)
{
CPUState *cs = CPU(cpu);
CPUPPCState *env = &cpu->env;

memcpy(env->gpr, load->gpr, sizeof(env->gpr));

env->lr = load->lr;
env->ctr = load->ctr;
env->cfar = load->cfar;
env->msr = load->msr;
env->nip = load->nip;

ppc_set_cr(env, load->cr);
cpu_write_xer(env, load->xer);

env->spr[SPR_LPCR] = load->lpcr;
env->spr[SPR_LPIDR] = load->lpidr;
env->spr[SPR_PCR] = load->pcr;
env->spr[SPR_DPDES] = load->dpdes;
env->spr[SPR_HFSCR] = load->hfscr;
env->spr[SPR_SRR0] = load->srr0;
env->spr[SPR_SRR1] = load->srr1;
env->spr[SPR_SPRG0] = load->sprg0;
env->spr[SPR_SPRG1] = load->sprg1;
env->spr[SPR_SPRG2] = load->sprg2;
env->spr[SPR_SPRG3] = load->sprg3;
env->spr[SPR_BOOKS_PID] = load->pidr;
env->spr[SPR_PPR] = load->ppr;

env->tb_env->tb_offset = load->tb_offset;

/*
* MSR updated, compute hflags and possible interrupts.
*/
hreg_compute_hflags(env);
ppc_maybe_interrupt(env);

/*
* Nested HV does not tag TLB entries between L1 and L2, so must
* flush on transition.
*/
tlb_flush(cs);
env->reserve_addr = -1; /* Reset the reservation */
}

/*
* When this handler returns, the environment is switched to the L2 guest
* and TCG begins running that. spapr_exit_nested() performs the switch from
Expand Down Expand Up @@ -1593,12 +1699,14 @@ static target_ulong h_enter_nested(PowerPCCPU *cpu,
return H_PARAMETER;
}

spapr_cpu->nested_host_state = g_try_new(CPUPPCState, 1);
spapr_cpu->nested_host_state = g_try_new(struct nested_ppc_state, 1);
if (!spapr_cpu->nested_host_state) {
return H_NO_MEM;
}

memcpy(spapr_cpu->nested_host_state, env, sizeof(CPUPPCState));
assert(env->spr[SPR_LPIDR] == 0);
assert(env->spr[SPR_DPDES] == 0);
nested_save_state(spapr_cpu->nested_host_state, cpu);

len = sizeof(*regs);
regs = address_space_map(CPU(cpu)->as, regs_ptr, &len, false,
Expand Down Expand Up @@ -1639,7 +1747,6 @@ static target_ulong h_enter_nested(PowerPCCPU *cpu,
env->spr[SPR_DPDES] = hv_state.dpdes;
env->spr[SPR_HFSCR] = hv_state.hfscr;
hdec = hv_state.hdec_expiry - now;
spapr_cpu->nested_tb_offset = hv_state.tb_offset;
/* TCG does not implement DAWR*, CIABR, PURR, SPURR, IC, VTB, HEIR SPRs*/
env->spr[SPR_SRR0] = hv_state.srr0;
env->spr[SPR_SRR1] = hv_state.srr1;
Expand All @@ -1665,7 +1772,7 @@ static target_ulong h_enter_nested(PowerPCCPU *cpu,
* and it's not obviously worth a new data structure to do it.
*/

env->tb_env->tb_offset += spapr_cpu->nested_tb_offset;
env->tb_env->tb_offset += hv_state.tb_offset;
spapr_cpu->in_nested = true;

hreg_compute_hflags(env);
Expand All @@ -1684,7 +1791,6 @@ static target_ulong h_enter_nested(PowerPCCPU *cpu,

void spapr_exit_nested(PowerPCCPU *cpu, int excp)
{
CPUState *cs = CPU(cpu);
CPUPPCState *env = &cpu->env;
SpaprCpuState *spapr_cpu = spapr_cpu_state(cpu);
target_ulong r3_return = env->excp_vectors[excp]; /* hcall return value */
Expand Down Expand Up @@ -1766,49 +1872,17 @@ void spapr_exit_nested(PowerPCCPU *cpu, int excp)
address_space_unmap(CPU(cpu)->as, regs, len, len, true);

out_restore_l1:
memcpy(env->gpr, spapr_cpu->nested_host_state->gpr, sizeof(env->gpr));
env->lr = spapr_cpu->nested_host_state->lr;
env->ctr = spapr_cpu->nested_host_state->ctr;
memcpy(env->crf, spapr_cpu->nested_host_state->crf, sizeof(env->crf));
env->cfar = spapr_cpu->nested_host_state->cfar;
env->xer = spapr_cpu->nested_host_state->xer;
env->so = spapr_cpu->nested_host_state->so;
env->ca = spapr_cpu->nested_host_state->ca;
env->ov = spapr_cpu->nested_host_state->ov;
env->ov32 = spapr_cpu->nested_host_state->ov32;
env->ca32 = spapr_cpu->nested_host_state->ca32;
env->msr = spapr_cpu->nested_host_state->msr;
env->nip = spapr_cpu->nested_host_state->nip;

assert(env->spr[SPR_LPIDR] != 0);
env->spr[SPR_LPCR] = spapr_cpu->nested_host_state->spr[SPR_LPCR];
env->spr[SPR_LPIDR] = spapr_cpu->nested_host_state->spr[SPR_LPIDR];
env->spr[SPR_PCR] = spapr_cpu->nested_host_state->spr[SPR_PCR];
env->spr[SPR_DPDES] = 0;
env->spr[SPR_HFSCR] = spapr_cpu->nested_host_state->spr[SPR_HFSCR];
env->spr[SPR_SRR0] = spapr_cpu->nested_host_state->spr[SPR_SRR0];
env->spr[SPR_SRR1] = spapr_cpu->nested_host_state->spr[SPR_SRR1];
env->spr[SPR_SPRG0] = spapr_cpu->nested_host_state->spr[SPR_SPRG0];
env->spr[SPR_SPRG1] = spapr_cpu->nested_host_state->spr[SPR_SPRG1];
env->spr[SPR_SPRG2] = spapr_cpu->nested_host_state->spr[SPR_SPRG2];
env->spr[SPR_SPRG3] = spapr_cpu->nested_host_state->spr[SPR_SPRG3];
env->spr[SPR_BOOKS_PID] = spapr_cpu->nested_host_state->spr[SPR_BOOKS_PID];
env->spr[SPR_PPR] = spapr_cpu->nested_host_state->spr[SPR_PPR];
nested_load_state(cpu, spapr_cpu->nested_host_state);

/*
* Return the interrupt vector address from H_ENTER_NESTED to the L1
* (or error code).
*/
env->gpr[3] = r3_return;

env->tb_env->tb_offset -= spapr_cpu->nested_tb_offset;
spapr_cpu->in_nested = false;

hreg_compute_hflags(env);
ppc_maybe_interrupt(env);
tlb_flush(cs);
env->reserve_addr = -1; /* Reset the reservation */

g_free(spapr_cpu->nested_host_state);
spapr_cpu->nested_host_state = NULL;
}
Expand Down
5 changes: 3 additions & 2 deletions include/hw/ppc/spapr_cpu_core.h
View file
Expand Up @@ -41,6 +41,8 @@ void spapr_cpu_set_entry_state(PowerPCCPU *cpu, target_ulong nip,
target_ulong r1, target_ulong r3,
target_ulong r4);

struct nested_ppc_state;

typedef struct SpaprCpuState {
uint64_t vpa_addr;
uint64_t slb_shadow_addr, slb_shadow_size;
Expand All @@ -51,8 +53,7 @@ typedef struct SpaprCpuState {

/* Fields for nested-HV support */
bool in_nested; /* true while the L2 is executing */
CPUPPCState *nested_host_state; /* holds the L1 state while L2 executes */
int64_t nested_tb_offset; /* L1->L2 TB offset */
struct nested_ppc_state *nested_host_state; /* holds the L1 state while L2 executes */
} SpaprCpuState;

static inline SpaprCpuState *spapr_cpu_state(PowerPCCPU *cpu)
Expand Down

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