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From: "Cédric Le Goater" <clg@kaod.org>
To: Nicholas Piggin <npiggin@gmail.com>, <qemu-ppc@nongnu.org>
Cc: qemu-devel@nongnu.org
Subject: Re: [RFC PATCH 3/3] spapr: implement nested-hv support for the TCG virtual hypervisor
Date: Mon, 14 Feb 2022 19:31:44 +0100	[thread overview]
Message-ID: <aaaf8ca4-9685-f600-9082-bc3a80eb59c9@kaod.org> (raw)
In-Reply-To: <20220210065340.1276367-4-npiggin@gmail.com>

On 2/10/22 07:53, Nicholas Piggin wrote:
> This implements the nested-hv hcall API for spapr under TCG.
> It's still a bit rough around the edges, concept seems to work.
> 
> Some HV exceptions can be raised now in the TCG spapr machine when
> running a nested guest. The main ones are the lev==1 syscall, the
> hdecr, hdsi and hisi, and h_virt external interrupts. These are
> dealt with in the interrupt delivery code by noticing MSR[HV] raised
> and instead of switching the machine to HV mode, it exits the
> H_ENTER_NESTED hcall with the interrupt vector as return value as
> required by the hcall API.
> 
> Address translation is provided by the 2-level page table walker
> that is implemented for the pnv machine. The partition scope page
> table is pointed to the L1's partition scope, and a few tests have
> to take into account that nested-hv translations are 2-level. This
> could perhaps be tidied up a bit e.g., with a 'bool two_level = ...'
> but it's surprisingly little code.
> 
> There is no TLB tagging between L1 and L2 translations at the moment
> so the TLB is flushed on any L1<->L2 transition (hcall entry and exit).
> 
> XXX: stop doing atomic RC on page table walks (not for nested but in general)
> 
> not-yet-Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
>   hw/ppc/ppc.c               |  20 +++
>   hw/ppc/spapr.c             |  16 ++
>   hw/ppc/spapr_caps.c        |   5 +-
>   hw/ppc/spapr_hcall.c       | 316 +++++++++++++++++++++++++++++++++++++
>   include/hw/ppc/ppc.h       |   3 +
>   include/hw/ppc/spapr.h     |  75 ++++++++-
>   target/ppc/cpu.h           |   6 +
>   target/ppc/excp_helper.c   |  60 ++++---
>   target/ppc/helper_regs.c   |   1 +
>   target/ppc/mmu-book3s-v3.c |  20 ++-
>   target/ppc/mmu-radix64.c   |  15 +-
>   11 files changed, 499 insertions(+), 38 deletions(-)
> 
> diff --git a/hw/ppc/ppc.c b/hw/ppc/ppc.c
> index a7c262db93..135900a6f4 100644
> --- a/hw/ppc/ppc.c
> +++ b/hw/ppc/ppc.c
> @@ -1083,6 +1083,26 @@ clk_setup_cb cpu_ppc_tb_init (CPUPPCState *env, uint32_t freq)
>       return &cpu_ppc_set_tb_clk;
>   }
>   
> +void cpu_ppc_hdecr_init (CPUPPCState *env)
> +{
> +    PowerPCCPU *cpu = env_archcpu(env);
> +
> +    assert(env->tb_env->hdecr_timer == NULL);
> +
> +    env->tb_env->hdecr_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, &cpu_ppc_hdecr_cb,
> +                                                 cpu);
> +}
> +
> +void cpu_ppc_hdecr_exit (CPUPPCState *env)
> +{
> +    PowerPCCPU *cpu = env_archcpu(env);
> +
> +    timer_free(env->tb_env->hdecr_timer);
> +    env->tb_env->hdecr_timer = NULL;
> +
> +    cpu_ppc_hdecr_lower(cpu);
> +}


So these are called every time a L2 enters or exits ?

>   /* Specific helpers for POWER & PowerPC 601 RTC */
>   void cpu_ppc601_store_rtcu (CPUPPCState *env, uint32_t value)
>   {
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 3d6ec309dd..f0c3f726f2 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -1273,6 +1273,8 @@ static void emulate_spapr_hypercall(PPCVirtualHypervisor *vhyp,
>       if (msr_pr) {
>           hcall_dprintf("Hypercall made with MSR[PR]=1\n");
>           env->gpr[3] = H_PRIVILEGE;
> +    } else if (env->gpr[3] == KVMPPC_H_ENTER_NESTED) {
> +        spapr_enter_nested(cpu);

Can not this be in the hcall table ?

>       } else {
>           env->gpr[3] = spapr_hypercall(cpu, env->gpr[3], &env->gpr[4]);
>       }
> @@ -4465,6 +4467,17 @@ PowerPCCPU *spapr_find_cpu(int vcpu_id)
>       return NULL;
>   }
>   
> +static bool spapr_cpu_in_nested(PowerPCCPU *cpu)
> +{
> +    return cpu->in_spapr_nested;
> +}

This handler is not very much used.

> +static target_ulong spapr_get_nested_ptcr(PowerPCCPU *cpu, target_ulong lpid)
> +{
> +        SpaprMachineState *spapr = SPAPR_MACHINE(qdev_get_machine());
> +        return spapr->nested_ptcr;
> +}
> +
>   static void spapr_cpu_exec_enter(PPCVirtualHypervisor *vhyp, PowerPCCPU *cpu)
>   {
>       SpaprCpuState *spapr_cpu = spapr_cpu_state(cpu);
> @@ -4573,6 +4586,9 @@ static void spapr_machine_class_init(ObjectClass *oc, void *data)
>       fwc->get_dev_path = spapr_get_fw_dev_path;
>       nc->nmi_monitor_handler = spapr_nmi;
>       smc->phb_placement = spapr_phb_placement;
> +    vhc->cpu_in_nested = spapr_cpu_in_nested;
> +    vhc->get_nested_ptcr = spapr_get_nested_ptcr;
> +    vhc->exit_nested = spapr_exit_nested;
>       vhc->hypercall = emulate_spapr_hypercall;
>       vhc->hpt_mask = spapr_hpt_mask;
>       vhc->map_hptes = spapr_map_hptes;
> diff --git a/hw/ppc/spapr_caps.c b/hw/ppc/spapr_caps.c
> index ed7c077a0d..a665245f6f 100644
> --- a/hw/ppc/spapr_caps.c
> +++ b/hw/ppc/spapr_caps.c
> @@ -450,10 +450,7 @@ static void cap_nested_kvm_hv_apply(SpaprMachineState *spapr,
>           return;
>       }
>   
> -    if (tcg_enabled()) {
> -        error_setg(errp, "No Nested KVM-HV support in TCG");
> -        error_append_hint(errp, "Try appending -machine cap-nested-hv=off\n");
> -    } else if (kvm_enabled()) {
> +    if (!tcg_enabled()) {
>           if (!ppc_check_compat(cpu, CPU_POWERPC_LOGICAL_3_00, 0,
>                                 spapr->max_compat_pvr)) {
>               error_setg(errp, "Nested KVM-HV only supported on POWER9");
> diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
> index 222c1b6bbd..8ffb13ada0 100644
> --- a/hw/ppc/spapr_hcall.c
> +++ b/hw/ppc/spapr_hcall.c
> @@ -9,6 +9,7 @@
>   #include "qemu/error-report.h"
>   #include "exec/exec-all.h"
>   #include "helper_regs.h"
> +#include "hw/ppc/ppc.h"
>   #include "hw/ppc/spapr.h"
>   #include "hw/ppc/spapr_cpu_core.h"
>   #include "mmu-hash64.h"
> @@ -1497,6 +1498,317 @@ static void hypercall_register_softmmu(void)
>   }
>   #endif
>   
> +/* TCG only */
> +#define PRTS_MASK      0x1f
> +
> +static target_ulong h_set_ptbl(PowerPCCPU *cpu,
> +                               SpaprMachineState *spapr,
> +                               target_ulong opcode,
> +                               target_ulong *args)
> +{
> +    target_ulong ptcr = args[0];
> +
> +    if (!spapr_get_cap(spapr, SPAPR_CAP_NESTED_KVM_HV)) {
> +        return H_FUNCTION;
> +    }
> +
> +    if ((ptcr & PRTS_MASK) + 12 - 4 > 12) {
> +        return H_PARAMETER;
> +    }
> +
> +    spapr->nested_ptcr = ptcr; /* Save new partition table */
> +
> +    return H_SUCCESS;
> +}
> +
> +static target_ulong h_tlb_invalidate(PowerPCCPU *cpu,
> +                               SpaprMachineState *spapr,
> +                               target_ulong opcode,
> +                               target_ulong *args)
> +{
> +    CPUState *cs = CPU(cpu);
> +
> +    /*
> +     * The spapr virtual hypervisor nested HV implementation retains no
> +     * translation state except for TLB. This might be optimised to
> +     * invalidate fewer entries, but at the moment it's not important
> +     * because L1<->L2 transitions always flush the entire TLB for now.
> +     */
> +    tlb_flush(cs);
> +
> +    return H_SUCCESS;
> +}
> +
> +static target_ulong h_copy_tofrom_guest(PowerPCCPU *cpu,
> +                               SpaprMachineState *spapr,
> +                               target_ulong opcode,
> +                               target_ulong *args)
> +{
> +    /*
> +     * This HCALL is not required, L1 KVM will take a slow path and walk the
> +     * page tables manually to do the data copy.
> +     */
> +    return H_FUNCTION;
> +}
> +
> +void spapr_enter_nested(PowerPCCPU *cpu)
> +{
> +    SpaprMachineState *spapr = SPAPR_MACHINE(qdev_get_machine());
> +    PowerPCCPUClass *pcc = POWERPC_CPU_GET_CLASS(cpu);
> +    CPUState *cs = CPU(cpu);
> +    CPUPPCState *env = &cpu->env;
> +    target_ulong hv_ptr = env->gpr[4];
> +    target_ulong regs_ptr = env->gpr[5];
> +    target_ulong hdec, now = cpu_ppc_load_tbl(env);
> +    struct kvmppc_hv_guest_state *hvstate;
> +    struct kvmppc_hv_guest_state hv_state;
> +    struct kvmppc_pt_regs *regs;
> +    hwaddr len;
> +    uint32_t cr;
> +    int i;
> +
> +    if (cpu->in_spapr_nested) {
> +        env->gpr[3] = H_FUNCTION;
> +        return;
> +    }
> +    if (spapr->nested_ptcr == 0) {
> +        env->gpr[3] = H_NOT_AVAILABLE;
> +        return;
> +    }
> +
> +    len = sizeof(*hvstate);
> +    hvstate = cpu_physical_memory_map(hv_ptr, &len, 

Are you writing to the state ? address_space_map() is a better pratice.


> +    if (!hvstate || len != sizeof(*hvstate)) {
> +        env->gpr[3] = H_PARAMETER;
> +        return;
> +    }
> +
> +    memcpy(&hv_state, hvstate, len);
> +
> +    cpu_physical_memory_unmap(hvstate, len, 0 /* read */, len /* access len */);
> +
> +    if (hv_state.version != HV_GUEST_STATE_VERSION) {
> +        env->gpr[3] = H_PARAMETER;
> +        return;
> +    }
> +
> +    cpu->nested_host_state = g_try_malloc(sizeof(CPUPPCState));
> +    if (!cpu->nested_host_state) {
> +        env->gpr[3] = H_NO_MEM;
> +        return;
> +    }
> +
> +    memcpy(cpu->nested_host_state, env, sizeof(CPUPPCState));
> +
> +    len = sizeof(*regs);
> +    regs = cpu_physical_memory_map(regs_ptr, &len, true);
> +    if (!regs || len != sizeof(*regs)) {
> +        g_free(cpu->nested_host_state);
> +        env->gpr[3] = H_P2;
> +        return;
> +    }
> +
> +    len = sizeof(env->gpr);
> +    assert(len == sizeof(regs->gpr));
> +    memcpy(env->gpr, regs->gpr, len);
> +
> +    env->lr = regs->link;
> +    env->ctr = regs->ctr;
> +    cpu_write_xer(env, regs->xer);
> +
> +    cr = regs->ccr;
> +    for (i = 7; i >= 0; i--) {
> +        env->crf[i] = cr & 15;
> +        cr >>= 4;
> +    }
> +
> +    env->msr = regs->msr;
> +    env->nip = regs->nip;
> +
> +    cpu_physical_memory_unmap(regs, len, 0 /* read */, len /* access len */);
> +
> +    env->cfar = hv_state.cfar;
> +
> +    assert(env->spr[SPR_LPIDR] == 0);
> +    env->spr[SPR_LPCR] = hv_state.lpcr & pcc->lpcr_mask; // XXX any other mask?
> +    env->spr[SPR_LPIDR] = hv_state.lpid;
> +    env->spr[SPR_PCR] = hv_state.pcr;
> +//    env->spr[SPR_AMOR] = hv_state.amor;
> +    env->spr[SPR_DPDES] = hv_state.dpdes;
> +    env->spr[SPR_HFSCR] = hv_state.hfscr;
> +    hdec = hv_state.hdec_expiry - now;
> +    env->tb_env->tb_offset += hv_state.tb_offset; // XXX how to deal?
> +    // dec already set
> +//  DAWRetc, CIABR, [S]PURR, IC
> +    env->spr[SPR_VTB] = hv_state.vtb;
> +//    env->spr[SPR_HEIR] = hv_state.heir;
> +    env->spr[SPR_SRR0] = hv_state.srr0;
> +    env->spr[SPR_SRR1] = hv_state.srr1;
> +    env->spr[SPR_SPRG0] = hv_state.sprg[0];
> +    env->spr[SPR_SPRG1] = hv_state.sprg[1];
> +    env->spr[SPR_SPRG2] = hv_state.sprg[2];
> +    env->spr[SPR_SPRG3] = hv_state.sprg[3];
> +    env->spr[SPR_BOOKS_PID] = hv_state.pidr;
> +    env->spr[SPR_PPR] = hv_state.ppr;
> +
> +    cpu_ppc_hdecr_init(env);
> +    cpu_ppc_store_hdecr(env, hdec);
> +
> +    /*
> +     * The hv_state.vcpu_token is not needed. It is used by the KVM
> +     * implementation to remember which L2 vCPU last ran on which physical
> +     * CPU so as to invalidate process scope translations if it is moved
> +     * between physical CPUs. For now TLBs are always flushed on L1<->L2
> +     * transitions so this is not a problem.
> +     *
> +     * Could validate that the same vcpu_token does not attempt to run on
> +     * different L1 vCPUs at the same time, but that would be a L1 KVM bug
> +     * and it's not obviously worth a new data structure to do it.
> +     */
> +
> +    cpu->in_spapr_nested = true;
> +
> +    hreg_compute_hflags(env);
> +    tlb_flush(cs);
> +}
> +
> +void spapr_exit_nested(PowerPCCPU *cpu, int excp)
> +{
> +    CPUState *cs = CPU(cpu);
> +    CPUPPCState *env = &cpu->env;
> +    target_ulong r3_return = env->excp_vectors[excp]; // hcall return value
> +    target_ulong hv_ptr = cpu->nested_host_state->gpr[4];
> +    target_ulong regs_ptr = cpu->nested_host_state->gpr[5];
> +    struct kvmppc_hv_guest_state *hvstate;
> +    struct kvmppc_pt_regs *regs;
> +    hwaddr len;
> +    int i;
> +
> +    assert(cpu->in_spapr_nested);
> +    cpu->in_spapr_nested = false;
> +
> +    cpu_ppc_hdecr_exit(env);
> +
> +    len = sizeof(*hvstate);
> +    hvstate = cpu_physical_memory_map(hv_ptr, &len, true);
> +    if (!hvstate || len != sizeof(*hvstate)) {
> +        r3_return = H_PARAMETER;
> +        goto out_restore_l1;
> +    }
> +
> +    //XXX check linux kvm nested CTRL reg bug?
> +    //
> +    env->tb_env->tb_offset -= hvstate->tb_offset;
> +
> +    hvstate->cfar = env->cfar;
> +    hvstate->lpcr = env->spr[SPR_LPCR];
> +    hvstate->pcr = env->spr[SPR_PCR];
> +//    hvstate->amor = env->spr[SPR_AMOR];
> +    hvstate->dpdes = env->spr[SPR_DPDES];
> +    hvstate->hfscr = env->spr[SPR_HFSCR];
> +//    hvstate-> = // dec already set
> +//  DAWRetc, CIABR, [S]PURR, IC
> +    hvstate->vtb = env->spr[SPR_VTB];
> +
> +    if (excp == POWERPC_EXCP_HDSI) {
> +        hvstate->hdar = env->spr[SPR_HDAR];
> +        hvstate->hdsisr = env->spr[SPR_HDSISR];
> +        hvstate->asdr = env->spr[SPR_ASDR];
> +    } else if (excp == POWERPC_EXCP_HISI) {
> +        hvstate->asdr = env->spr[SPR_ASDR];
> +    }
> +
> +//    hvstate->heir = env->spr[SPR_HEIR]; XXX HEIR?
> +    hvstate->srr0 = env->spr[SPR_SRR0];
> +    hvstate->srr1 = env->spr[SPR_SRR1];
> +    hvstate->sprg[0] = env->spr[SPR_SPRG0];
> +    hvstate->sprg[1] = env->spr[SPR_SPRG1];
> +    hvstate->sprg[2] = env->spr[SPR_SPRG2];
> +    hvstate->sprg[3] = env->spr[SPR_SPRG3];
> +    hvstate->pidr = env->spr[SPR_BOOKS_PID];
> +    hvstate->ppr = env->spr[SPR_PPR];
> +
> +    cpu_physical_memory_unmap(hvstate, len, 0 /* read */, len /* access len */);
> +
> +    len = sizeof(*regs);
> +    regs = cpu_physical_memory_map(regs_ptr, &len, true);
> +    if (!regs || len != sizeof(*regs)) {
> +        r3_return = H_P2;
> +        goto out_restore_l1;
> +    }
> +
> +    len = sizeof(env->gpr);
> +    assert(len == sizeof(regs->gpr));
> +    memcpy(regs->gpr, env->gpr, len);
> +
> +    regs->link = env->lr;
> +    regs->ctr = env->ctr;
> +    regs->xer = cpu_read_xer(env);
> +
> +    regs->ccr = 0;
> +    for (i = 0; i < 8; i++) {
> +        regs->ccr |= (env->crf[i] & 15) << (4 * (7 - i));
> +    }
> +
> +    if (excp == POWERPC_EXCP_MCHECK ||
> +        excp == POWERPC_EXCP_RESET ||
> +        excp == POWERPC_EXCP_SYSCALL) {
> +        regs->nip = env->spr[SPR_SRR0];
> +        regs->msr = env->spr[SPR_SRR1];
> +    } else {
> +        regs->nip = env->spr[SPR_HSRR0];
> +        regs->msr = env->spr[SPR_HSRR1];
> +    }
> +    // XXX must msr be masked?
> +
> +    cpu_physical_memory_unmap(regs, len, 0 /* read */, len /* access len */);
> +
> +out_restore_l1:
> +    memcpy(env->gpr, cpu->nested_host_state->gpr, sizeof(env->gpr));
> +    env->lr = cpu->nested_host_state->lr;
> +    env->ctr = cpu->nested_host_state->ctr;
> +    memcpy(env->crf, cpu->nested_host_state->crf, sizeof(env->crf));
> +    env->cfar = cpu->nested_host_state->cfar;
> +    env->xer = cpu->nested_host_state->xer;
> +    env->so = cpu->nested_host_state->so;
> +    env->ov = cpu->nested_host_state->ov;
> +    env->ov32 = cpu->nested_host_state->ov32;
> +    env->ca32 = cpu->nested_host_state->ca32;
> +    env->msr = cpu->nested_host_state->msr;
> +    env->nip = cpu->nested_host_state->nip;
> +
> +    assert(env->spr[SPR_LPIDR] != 0);
> +    env->spr[SPR_LPCR] = cpu->nested_host_state->spr[SPR_LPCR];
> +    env->spr[SPR_LPIDR] = cpu->nested_host_state->spr[SPR_LPIDR];
> +    env->spr[SPR_PCR] = cpu->nested_host_state->spr[SPR_PCR];
> +//    env->spr[SPR_AMOR] = cpu->nested_host_state->spr[SPR_AMOR];
> +    env->spr[SPR_DPDES] = 0;
> +    env->spr[SPR_HFSCR] = cpu->nested_host_state->spr[SPR_HFSCR];
> +//  DAWRetc, CIABR, [S]PURR, IC
> +    env->spr[SPR_VTB] = cpu->nested_host_state->spr[SPR_VTB];
> +//    env->spr[SPR_HEIR] = hv_state.heir;
> +    env->spr[SPR_SRR0] = cpu->nested_host_state->spr[SPR_SRR0];
> +    env->spr[SPR_SRR1] = cpu->nested_host_state->spr[SPR_SRR1];
> +    env->spr[SPR_SPRG0] = cpu->nested_host_state->spr[SPR_SPRG0];
> +    env->spr[SPR_SPRG1] = cpu->nested_host_state->spr[SPR_SPRG1];
> +    env->spr[SPR_SPRG2] = cpu->nested_host_state->spr[SPR_SPRG2];
> +    env->spr[SPR_SPRG3] = cpu->nested_host_state->spr[SPR_SPRG3];
> +    env->spr[SPR_BOOKS_PID] = cpu->nested_host_state->spr[SPR_BOOKS_PID];
> +    env->spr[SPR_PPR] = cpu->nested_host_state->spr[SPR_PPR];
> +
> +    g_free(cpu->nested_host_state);
> +    cpu->nested_host_state = NULL;
> +
> +    /*
> +     * Return the interrupt vector address from H_ENTER_NESTED to the L1
> +     * (or error code).
> +     */
> +    env->gpr[3] = r3_return;
> +
> +    hreg_compute_hflags(env);
> +    tlb_flush(cs);
> +}
> +
>   static void hypercall_register_types(void)
>   {
>       hypercall_register_softmmu();
> @@ -1552,6 +1864,10 @@ static void hypercall_register_types(void)
>       spapr_register_hypercall(KVMPPC_H_CAS, h_client_architecture_support);
>   
>       spapr_register_hypercall(KVMPPC_H_UPDATE_DT, h_update_dt);
> +
> +    spapr_register_hypercall(KVMPPC_H_SET_PARTITION_TABLE, h_set_ptbl);
> +    spapr_register_hypercall(KVMPPC_H_TLB_INVALIDATE, h_tlb_invalidate);
> +    spapr_register_hypercall(KVMPPC_H_COPY_TOFROM_GUEST, h_copy_tofrom_guest);
>   }
>   
>   type_init(hypercall_register_types)
> diff --git a/include/hw/ppc/ppc.h b/include/hw/ppc/ppc.h
> index 93e614cffd..fcf9e495a0 100644
> --- a/include/hw/ppc/ppc.h
> +++ b/include/hw/ppc/ppc.h
> @@ -54,6 +54,9 @@ struct ppc_tb_t {
>   
>   uint64_t cpu_ppc_get_tb(ppc_tb_t *tb_env, uint64_t vmclk, int64_t tb_offset);
>   clk_setup_cb cpu_ppc_tb_init (CPUPPCState *env, uint32_t freq);
> +void cpu_ppc_hdecr_init (CPUPPCState *env);
> +void cpu_ppc_hdecr_exit (CPUPPCState *env);
> +
>   /* Embedded PowerPC DCR management */
>   typedef uint32_t (*dcr_read_cb)(void *opaque, int dcrn);
>   typedef void (*dcr_write_cb)(void *opaque, int dcrn, uint32_t val);
> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> index ee7504b976..3a9fa4c024 100644
> --- a/include/hw/ppc/spapr.h
> +++ b/include/hw/ppc/spapr.h
> @@ -197,6 +197,9 @@ struct SpaprMachineState {
>       bool has_graphics;
>       uint32_t vsmt;       /* Virtual SMT mode (KVM's "core stride") */
>   
> +    /* Nested HV support (TCG only) */
> +    uint64_t nested_ptcr;
> +
>       Notifier epow_notifier;
>       QTAILQ_HEAD(, SpaprEventLogEntry) pending_events;
>       bool use_hotplug_event_source;
> @@ -577,7 +580,14 @@ struct SpaprMachineState {
>   #define KVMPPC_H_UPDATE_DT      (KVMPPC_HCALL_BASE + 0x3)
>   /* 0x4 was used for KVMPPC_H_UPDATE_PHANDLE in SLOF */
>   #define KVMPPC_H_VOF_CLIENT     (KVMPPC_HCALL_BASE + 0x5)
> -#define KVMPPC_HCALL_MAX        KVMPPC_H_VOF_CLIENT
> +
> +/* Platform-specific hcalls used for nested HV KVM */
> +#define KVMPPC_H_SET_PARTITION_TABLE   (KVMPPC_HCALL_BASE + 0x800)
> +#define KVMPPC_H_ENTER_NESTED          (KVMPPC_HCALL_BASE + 0x804)
> +#define KVMPPC_H_TLB_INVALIDATE        (KVMPPC_HCALL_BASE + 0x808)
> +#define KVMPPC_H_COPY_TOFROM_GUEST     (KVMPPC_HCALL_BASE + 0x80C)
> +
> +#define KVMPPC_HCALL_MAX        KVMPPC_H_COPY_TOFROM_GUEST
>   
>   /*
>    * The hcall range 0xEF00 to 0xEF80 is reserved for use in facilitating
> @@ -587,6 +597,65 @@ struct SpaprMachineState {
>   #define SVM_H_TPM_COMM              0xEF10
>   #define SVM_HCALL_MAX               SVM_H_TPM_COMM
>   
> +/*
> + * Register state for entering a nested guest with H_ENTER_NESTED.
> + * New member must be added at the end.
> + */
> +struct kvmppc_hv_guest_state {
> +    uint64_t version;        /* version of this structure layout, must be first */
> +    uint32_t lpid;
> +    uint32_t vcpu_token;
> +    /* These registers are hypervisor privileged (at least for writing) */
> +    uint64_t lpcr;
> +    uint64_t pcr;
> +    uint64_t amor;
> +    uint64_t dpdes;
> +    uint64_t hfscr;
> +    int64_t tb_offset;
> +    uint64_t dawr0;
> +    uint64_t dawrx0;
> +    uint64_t ciabr;
> +    uint64_t hdec_expiry;
> +    uint64_t purr;
> +    uint64_t spurr;
> +    uint64_t ic;
> +    uint64_t vtb;
> +    uint64_t hdar;
> +    uint64_t hdsisr;
> +    uint64_t heir;
> +    uint64_t asdr;
> +    /* These are OS privileged but need to be set late in guest entry */
> +    uint64_t srr0;
> +    uint64_t srr1;
> +    uint64_t sprg[4];
> +    uint64_t pidr;
> +    uint64_t cfar;
> +    uint64_t ppr;
> +    /* Version 1 ends here */
> +    uint64_t dawr1;
> +    uint64_t dawrx1;
> +    /* Version 2 ends here */
> +};
> +
> +/* Latest version of hv_guest_state structure */
> +#define HV_GUEST_STATE_VERSION  2
> +
> +/* 64-bit powerpc pt_regs struct used by nested HV */
> +struct kvmppc_pt_regs {
> +    uint64_t gpr[32];
> +    uint64_t nip;
> +    uint64_t msr;
> +    uint64_t orig_gpr3;    /* Used for restarting system calls */
> +    uint64_t ctr;
> +    uint64_t link;
> +    uint64_t xer;
> +    uint64_t ccr;
> +    uint64_t softe;        /* Soft enabled/disabled */
> +    uint64_t trap;         /* Reason for being here */
> +    uint64_t dar;          /* Fault registers */
> +    uint64_t dsisr;        /* on 4xx/Book-E used for ESR */
> +    uint64_t result;       /* Result of a system call */
> +};
>   
>   typedef struct SpaprDeviceTreeUpdateHeader {
>       uint32_t version_id;
> @@ -604,6 +673,10 @@ typedef target_ulong (*spapr_hcall_fn)(PowerPCCPU *cpu, SpaprMachineState *sm,
>   void spapr_register_hypercall(target_ulong opcode, spapr_hcall_fn fn);
>   target_ulong spapr_hypercall(PowerPCCPU *cpu, target_ulong opcode,
>                                target_ulong *args);
> +
> +void spapr_enter_nested(PowerPCCPU *cpu);
> +void spapr_exit_nested(PowerPCCPU *cpu, int excp);
> +
>   target_ulong softmmu_resize_hpt_prepare(PowerPCCPU *cpu, SpaprMachineState *spapr,
>                                            target_ulong shift);
>   target_ulong softmmu_resize_hpt_commit(PowerPCCPU *cpu, SpaprMachineState *spapr,
> diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h
> index dcd83b503c..1806a8e776 100644
> --- a/target/ppc/cpu.h
> +++ b/target/ppc/cpu.h
> @@ -1306,6 +1306,9 @@ struct PowerPCCPU {
>       bool pre_2_10_migration;
>       bool pre_3_0_migration;
>       int32_t mig_slb_nr;
> +
> +    bool in_spapr_nested;
> +    CPUPPCState *nested_host_state;
>   };
>   
>   
> @@ -1316,6 +1319,9 @@ PowerPCCPUClass *ppc_cpu_get_family_class(PowerPCCPUClass *pcc);
>   #ifndef CONFIG_USER_ONLY
>   struct PPCVirtualHypervisorClass {
>       InterfaceClass parent;
> +    bool (*cpu_in_nested)(PowerPCCPU *cpu);
> +    target_ulong (*get_nested_ptcr)(PowerPCCPU *cpu, target_ulong lpid);
> +    void (*exit_nested)(PowerPCCPU *cpu, int excp);
>       void (*hypercall)(PPCVirtualHypervisor *vhyp, PowerPCCPU *cpu);
>       hwaddr (*hpt_mask)(PPCVirtualHypervisor *vhyp);
>       const ppc_hash_pte64_t *(*map_hptes)(PPCVirtualHypervisor *vhyp,
> diff --git a/target/ppc/excp_helper.c b/target/ppc/excp_helper.c
> index c107953dec..239c253dbc 100644
> --- a/target/ppc/excp_helper.c
> +++ b/target/ppc/excp_helper.c
> @@ -361,8 +361,8 @@ static void ppc_excp_apply_ail(PowerPCCPU *cpu, int excp_model, int excp,
>   #endif
>   }
>   
> -static void powerpc_set_excp_state(PowerPCCPU *cpu,
> -                                          target_ulong vector, target_ulong msr)
> +static void powerpc_set_excp_state(PowerPCCPU *cpu, int excp,
> +                                   target_ulong vector, target_ulong msr)
>   {
>       CPUState *cs = CPU(cpu);
>       CPUPPCState *env = &cpu->env;
> @@ -375,9 +375,17 @@ static void powerpc_set_excp_state(PowerPCCPU *cpu,
>        * will prevent setting of the HV bit which some exceptions might need
>        * to do.
>        */
> -    env->msr = msr & env->msr_mask;
> -    hreg_compute_hflags(env);
> -    env->nip = vector;
> +    if (cpu->vhyp && cpu->in_spapr_nested && (msr & MSR_HVB)) {
> +        PPCVirtualHypervisorClass *vhc =
> +            PPC_VIRTUAL_HYPERVISOR_GET_CLASS(cpu->vhyp);
> +        // Deliver interrupt to L1 by returning from the H_ENTER_NESTED call
> +        vhc->exit_nested(cpu, excp);
> +    } else {
> +        env->nip = vector;
> +        env->msr = msr & env->msr_mask;
> +        hreg_compute_hflags(env);
> +    }
> +
>       /* Reset exception state */
>       cs->exception_index = POWERPC_EXCP_NONE;
>       env->error_code = 0;
> @@ -548,7 +556,7 @@ static void powerpc_excp_40x(PowerPCCPU *cpu, int excp)
>       /* Save MSR */
>       env->spr[srr1] = msr;
>   
> -    powerpc_set_excp_state(cpu, vector, new_msr);
> +    powerpc_set_excp_state(cpu, excp, vector, new_msr);
>   }
>   
>   static void powerpc_excp_74xx(PowerPCCPU *cpu, int excp)
> @@ -742,7 +750,7 @@ static void powerpc_excp_74xx(PowerPCCPU *cpu, int excp)
>       /* Save MSR */
>       env->spr[SPR_SRR1] = msr;
>   
> -    powerpc_set_excp_state(cpu, vector, new_msr);
> +    powerpc_set_excp_state(cpu, excp, vector, new_msr);
>   }
>   
>   #ifdef TARGET_PPC64
> @@ -916,7 +924,7 @@ static void powerpc_excp_books(PowerPCCPU *cpu, int excp)
>           env->nip += 4;
>   
>           /* "PAPR mode" built-in hypercall emulation */
> -        if ((lev == 1) && cpu->vhyp) {
> +        if ((lev == 1) && cpu->vhyp && !cpu->in_spapr_nested) {

an helper for (cpu->vhyp && !cpu->in_spapr_nested) would help.

>               PPCVirtualHypervisorClass *vhc =
>                   PPC_VIRTUAL_HYPERVISOR_GET_CLASS(cpu->vhyp);
>               vhc->hypercall(cpu->vhyp, cpu);
> @@ -1004,18 +1012,6 @@ static void powerpc_excp_books(PowerPCCPU *cpu, int excp)
>           break;
>       }
>   
> -    /* Sanity check */
> -    if (!(env->msr_mask & MSR_HVB)) {
> -        if (new_msr & MSR_HVB) {
> -            cpu_abort(cs, "Trying to deliver HV exception (MSR) %d with "
> -                      "no HV support\n", excp);
> -        }
> -        if (srr0 == SPR_HSRR0) {
> -            cpu_abort(cs, "Trying to deliver HV exception (HSRR) %d with "
> -                      "no HV support\n", excp);
> -        }
> -    }
> -
>       /*
>        * Sort out endianness of interrupt, this differs depending on the
>        * CPU, the HV mode, etc...
> @@ -1037,7 +1033,19 @@ static void powerpc_excp_books(PowerPCCPU *cpu, int excp)
>       /* This can update new_msr and vector if AIL applies */
>       ppc_excp_apply_ail(cpu, excp_model, excp, msr, &new_msr, &vector);
>   
> -    powerpc_set_excp_state(cpu, vector, new_msr);
> +    powerpc_set_excp_state(cpu, excp, vector, new_msr);
> +
> +    /* Sanity check */
> +    if (!(env->msr_mask & MSR_HVB)) {
> +        if (env->msr & MSR_HVB) {
> +            cpu_abort(cs, "Trying to deliver HV exception (MSR) %d with "
> +                      "no HV support\n", excp);
> +        }
> +        if (0 && srr0 == SPR_HSRR0) {
> +            cpu_abort(cs, "Trying to deliver HV exception (HSRR) %d with "
> +                      "no HV support\n", excp);
> +        }
> +    }
>   }
>   #else
>   static inline void powerpc_excp_books(PowerPCCPU *cpu, int excp)
> @@ -1517,7 +1525,7 @@ static inline void powerpc_excp_legacy(PowerPCCPU *cpu, int excp)
>       /* This can update new_msr and vector if AIL applies */
>       ppc_excp_apply_ail(cpu, excp_model, excp, msr, &new_msr, &vector);
>   
> -    powerpc_set_excp_state(cpu, vector, new_msr);
> +    powerpc_set_excp_state(cpu, excp, vector, new_msr);
>   }
>   
>   static void powerpc_excp(PowerPCCPU *cpu, int excp)
> @@ -1613,7 +1621,11 @@ static void ppc_hw_interrupt(CPUPPCState *env)
>           /* HEIC blocks delivery to the hypervisor */
>           if ((async_deliver && !(heic && msr_hv && !msr_pr)) ||
>               (env->has_hv_mode && msr_hv == 0 && !lpes0)) {
> -            powerpc_excp(cpu, POWERPC_EXCP_EXTERNAL);
> +            if (cpu->in_spapr_nested) {
> +                powerpc_excp(cpu, POWERPC_EXCP_HVIRT);
> +            } else {
> +                powerpc_excp(cpu, POWERPC_EXCP_EXTERNAL);
> +            }
>               return;
>           }
>       }
> @@ -1723,7 +1735,7 @@ void ppc_cpu_do_fwnmi_machine_check(CPUState *cs, target_ulong vector)
>           msr |= (1ULL << MSR_LE);
>       }
>   
> -    powerpc_set_excp_state(cpu, vector, msr);
> +    powerpc_set_excp_state(cpu, POWERPC_EXCP_MCHECK, vector, msr);
>   }
>   
>   bool ppc_cpu_exec_interrupt(CPUState *cs, int interrupt_request)
> diff --git a/target/ppc/helper_regs.c b/target/ppc/helper_regs.c
> index 5b12cb03c9..7f92606522 100644
> --- a/target/ppc/helper_regs.c
> +++ b/target/ppc/helper_regs.c
> @@ -163,6 +163,7 @@ static uint32_t hreg_compute_hflags_value(CPUPPCState *env)
>           immu_idx |= msr & (1 << MSR_IS) ? 2 : 0;
>           dmmu_idx |= msr & (1 << MSR_DS) ? 2 : 0;
>       } else {
> +        /* Could have nested IDX instead of HV to avoid tlb flush on nested enter/exit? */

yes.

>           dmmu_idx |= msr & (1ull << MSR_HV) ? 4 : 0;
>           immu_idx = dmmu_idx;
>           immu_idx |= msr & (1 << MSR_IR) ? 0 : 2;
> diff --git a/target/ppc/mmu-book3s-v3.c b/target/ppc/mmu-book3s-v3.c
> index f4985bae78..0810be3668 100644
> --- a/target/ppc/mmu-book3s-v3.c
> +++ b/target/ppc/mmu-book3s-v3.c
> @@ -25,8 +25,23 @@
>   
>   bool ppc64_v3_get_pate(PowerPCCPU *cpu, target_ulong lpid, ppc_v3_pate_t *entry)
>   {
> -    uint64_t patb = cpu->env.spr[SPR_PTCR] & PTCR_PATB;
> -    uint64_t pats = cpu->env.spr[SPR_PTCR] & PTCR_PATS;
> +    uint64_t patb, pats;
> +
> +    if (cpu->vhyp) {
> +        PPCVirtualHypervisorClass *vhc =
> +            PPC_VIRTUAL_HYPERVISOR_GET_CLASS(cpu->vhyp);
> +        target_ulong nested_ptcr;
> +
> +        assert(cpu->in_spapr_nested);
> +
> +        nested_ptcr = vhc->get_nested_ptcr(cpu, lpid);
> +
> +        patb = nested_ptcr & PTCR_PATB;
> +        pats = nested_ptcr & PTCR_PATS;
> +    } else {
> +        patb = cpu->env.spr[SPR_PTCR] & PTCR_PATB;
> +        pats = cpu->env.spr[SPR_PTCR] & PTCR_PATS;
> +    }
>   
>       /* Calculate number of entries */
>       pats = 1ull << (pats + 12 - 4);
> @@ -38,5 +53,6 @@ bool ppc64_v3_get_pate(PowerPCCPU *cpu, target_ulong lpid, ppc_v3_pate_t *entry)
>       patb += 16 * lpid;
>       entry->dw0 = ldq_phys(CPU(cpu)->as, patb);
>       entry->dw1 = ldq_phys(CPU(cpu)->as, patb + 8);
> +
>       return true;
>   }
> diff --git a/target/ppc/mmu-radix64.c b/target/ppc/mmu-radix64.c
> index 54fb3ce98d..6304a23d05 100644
> --- a/target/ppc/mmu-radix64.c
> +++ b/target/ppc/mmu-radix64.c
> @@ -304,7 +304,7 @@ static bool validate_pate(PowerPCCPU *cpu, uint64_t lpid, ppc_v3_pate_t *pate)
>       if (!(pate->dw0 & PATE0_HR)) {
>           return false;
>       }
> -    if (lpid == 0 && !msr_hv) {
> +    if (lpid == 0 && (!msr_hv && !(cpu->vhyp && cpu->in_spapr_nested))) {
>           return false;
>       }
>       if ((pate->dw0 & PATE1_R_PRTS) < 5) {
> @@ -336,6 +336,7 @@ static int ppc_radix64_partition_scoped_xlate(PowerPCCPU *cpu,
>                     g_raddr);
>   
>       *h_page_size = PRTBE_R_GET_RTS(pate.dw0);
> +
>       /* No valid pte or access denied due to protection */
>       if (ppc_radix64_walk_tree(CPU(cpu)->as, g_raddr, pate.dw0 & PRTBE_R_RPDB,
>                                 pate.dw0 & PRTBE_R_RPDS, h_raddr, h_page_size,
> @@ -389,7 +390,7 @@ static int ppc_radix64_process_scoped_xlate(PowerPCCPU *cpu,
>       }
>       prtbe_addr = (pate.dw1 & PATE1_R_PRTB) + offset;
>   
> -    if (cpu->vhyp) {
> +    if (cpu->vhyp && !cpu->in_spapr_nested) {
>           prtbe0 = ldq_phys(cs->as, prtbe_addr);
>       } else {
>           /*
> @@ -415,7 +416,7 @@ static int ppc_radix64_process_scoped_xlate(PowerPCCPU *cpu,
>       *g_page_size = PRTBE_R_GET_RTS(prtbe0);
>       base_addr = prtbe0 & PRTBE_R_RPDB;
>       nls = prtbe0 & PRTBE_R_RPDS;
> -    if (msr_hv || cpu->vhyp) {
> +    if (msr_hv || (cpu->vhyp && !cpu->in_spapr_nested)) {
>           /*
>            * Can treat process table addresses as real addresses
>            */
> @@ -519,7 +520,7 @@ static bool ppc_radix64_xlate_impl(PowerPCCPU *cpu, vaddr eaddr,
>       relocation = !mmuidx_real(mmu_idx);
>   
>       /* HV or virtual hypervisor Real Mode Access */
> -    if (!relocation && (mmuidx_hv(mmu_idx) || cpu->vhyp)) {
> +    if (!relocation && (mmuidx_hv(mmu_idx) || (cpu->vhyp && !cpu->in_spapr_nested))) {
>           /* In real mode top 4 effective addr bits (mostly) ignored */
>           *raddr = eaddr & 0x0FFFFFFFFFFFFFFFULL;
>   
> @@ -553,7 +554,7 @@ static bool ppc_radix64_xlate_impl(PowerPCCPU *cpu, vaddr eaddr,
>       }
>   
>       /* Get Process Table */
> -    if (cpu->vhyp) {
> +    if (cpu->vhyp && !cpu->in_spapr_nested) {
>           PPCVirtualHypervisorClass *vhc;
>           vhc = PPC_VIRTUAL_HYPERVISOR_GET_CLASS(cpu->vhyp);
>           vhc->get_pate(cpu->vhyp, &pate);
> @@ -596,7 +597,7 @@ static bool ppc_radix64_xlate_impl(PowerPCCPU *cpu, vaddr eaddr,
>           g_raddr = eaddr & R_EADDR_MASK;
>       }
>   
> -    if (cpu->vhyp) {
> +    if (cpu->vhyp && !cpu->in_spapr_nested) {
>           *raddr = g_raddr;
>       } else {
>           /*
> @@ -604,7 +605,7 @@ static bool ppc_radix64_xlate_impl(PowerPCCPU *cpu, vaddr eaddr,
>            * quadrants 1 or 2. Translates a guest real address to a host
>            * real address.
>            */
> -        if (lpid || !mmuidx_hv(mmu_idx)) {
> +        if (lpid || !mmuidx_hv(mmu_idx) || cpu->in_spapr_nested) {
>               int ret;
>   
>               ret = ppc_radix64_partition_scoped_xlate(cpu, access_type, eaddr,
> 



  parent reply	other threads:[~2022-02-14 18:43 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-10  6:53 [RFC PATCH 0/3] spapr: nested-hv support for TCG Nicholas Piggin
2022-02-10  6:53 ` [RFC PATCH 1/3] target/ppc: raise HV interrupts for partition table entry problems Nicholas Piggin
2022-02-10  6:53 ` [RFC PATCH 2/3] spapr: prevent hdec timer being set up under virtual hypervisor Nicholas Piggin
2022-02-10  6:53 ` [RFC PATCH 3/3] spapr: implement nested-hv support for the TCG " Nicholas Piggin
2022-02-14 14:32   ` Fabiano Rosas
2022-02-14 23:24     ` Nicholas Piggin
2022-02-14 18:31   ` Cédric Le Goater [this message]
2022-02-14 23:28     ` Nicholas Piggin
2022-02-15  2:57       ` Nicholas Piggin

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