Re: [Qemu-devel] [QEMU-PPC] [PATCH V2 3/3] ppc/spapr_caps: Add SPAPR_CAP_NESTED_KVM_HV

[David Gibson <david@gibson.dropbear.id.au>]

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On Mon, Oct 08, 2018 at 02:25:39PM +1100, Suraj Jitindar Singh wrote:
> Add the spapr cap SPAPR_CAP_NESTED_KVM_HV to be used to control the
> availability of nested kvm-hv to the level 1 (L1) guest.
> 
> Assuming a hypervisor with support enabled an L1 guest can be allowed to
> use the kvm-hv module (and thus run it's own kvm-hv guests) by setting:
> -machine pseries,cap-nested-hv=true
> or disabled with:
> -machine pseries,cap-nested-hv=false
> 
> Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

> ---
>  hw/ppc/spapr.c         |  2 ++
>  hw/ppc/spapr_caps.c    | 32 ++++++++++++++++++++++++++++++++
>  include/hw/ppc/spapr.h |  5 ++++-
>  target/ppc/kvm.c       | 12 ++++++++++++
>  target/ppc/kvm_ppc.h   | 12 ++++++++++++
>  5 files changed, 62 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 98868d893a..8ce97900e9 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -1915,6 +1915,7 @@ static const VMStateDescription vmstate_spapr = {
>          &vmstate_spapr_cap_sbbc,
>          &vmstate_spapr_cap_ibs,
>          &vmstate_spapr_irq_map,
> +        &vmstate_spapr_cap_nested_kvm_hv,
>          NULL
>      }
>  };
> @@ -3886,6 +3887,7 @@ static void spapr_machine_class_init(ObjectClass *oc, void *data)
>      smc->default_caps.caps[SPAPR_CAP_SBBC] = SPAPR_CAP_BROKEN;
>      smc->default_caps.caps[SPAPR_CAP_IBS] = SPAPR_CAP_BROKEN;
>      smc->default_caps.caps[SPAPR_CAP_HPT_MAXPAGESIZE] = 16; /* 64kiB */
> +    smc->default_caps.caps[SPAPR_CAP_NESTED_KVM_HV] = SPAPR_CAP_OFF;
>      spapr_caps_add_properties(smc, &error_abort);
>      smc->irq = &spapr_irq_xics;
>  }
> diff --git a/hw/ppc/spapr_caps.c b/hw/ppc/spapr_caps.c
> index aa605cea91..64f98ae68d 100644
> --- a/hw/ppc/spapr_caps.c
> +++ b/hw/ppc/spapr_caps.c
> @@ -368,6 +368,28 @@ static void cap_hpt_maxpagesize_cpu_apply(sPAPRMachineState *spapr,
>      ppc_hash64_filter_pagesizes(cpu, spapr_pagesize_cb, &maxshift);
>  }
>  
> +static void cap_nested_kvm_hv_apply(sPAPRMachineState *spapr,
> +                                    uint8_t val, Error **errp)
> +{
> +    if (!val) {
> +        /* capability disabled by default */
> +        return;
> +    }
> +
> +    if (tcg_enabled()) {
> +        error_setg(errp,
> +                   "No Nested KVM-HV support in tcg, try cap-nested-hv=off");
> +    } else if (kvm_enabled()) {
> +        if (!kvmppc_has_cap_nested_kvm_hv()) {
> +            error_setg(errp,
> +"KVM implementation does not support Nested KVM-HV, try cap-nested-hv=off");
> +        } else if (kvmppc_set_cap_nested_kvm_hv(val) < 0) {
> +                error_setg(errp,
> +"Error enabling cap-nested-hv with KVM, try cap-nested-hv=off");
> +        }
> +    }
> +}
> +
>  sPAPRCapabilityInfo capability_table[SPAPR_CAP_NUM] = {
>      [SPAPR_CAP_HTM] = {
>          .name = "htm",
> @@ -437,6 +459,15 @@ sPAPRCapabilityInfo capability_table[SPAPR_CAP_NUM] = {
>          .apply = cap_hpt_maxpagesize_apply,
>          .cpu_apply = cap_hpt_maxpagesize_cpu_apply,
>      },
> +    [SPAPR_CAP_NESTED_KVM_HV] = {
> +        .name = "nested-hv",
> +        .description = "Allow Nested KVM-HV",
> +        .index = SPAPR_CAP_NESTED_KVM_HV,
> +        .get = spapr_cap_get_bool,
> +        .set = spapr_cap_set_bool,
> +        .type = "bool",
> +        .apply = cap_nested_kvm_hv_apply,
> +    },
>  };
>  
>  static sPAPRCapabilities default_caps_with_cpu(sPAPRMachineState *spapr,
> @@ -564,6 +595,7 @@ SPAPR_CAP_MIG_STATE(dfp, SPAPR_CAP_DFP);
>  SPAPR_CAP_MIG_STATE(cfpc, SPAPR_CAP_CFPC);
>  SPAPR_CAP_MIG_STATE(sbbc, SPAPR_CAP_SBBC);
>  SPAPR_CAP_MIG_STATE(ibs, SPAPR_CAP_IBS);
> +SPAPR_CAP_MIG_STATE(nested_kvm_hv, SPAPR_CAP_NESTED_KVM_HV);
>  
>  void spapr_caps_init(sPAPRMachineState *spapr)
>  {
> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> index ad4d7cfd97..bced85dd92 100644
> --- a/include/hw/ppc/spapr.h
> +++ b/include/hw/ppc/spapr.h
> @@ -70,8 +70,10 @@ typedef enum {
>  #define SPAPR_CAP_IBS                   0x05
>  /* HPT Maximum Page Size (encoded as a shift) */
>  #define SPAPR_CAP_HPT_MAXPAGESIZE       0x06
> +/* Nested KVM-HV */
> +#define SPAPR_CAP_NESTED_KVM_HV         0x07
>  /* Num Caps */
> -#define SPAPR_CAP_NUM                   (SPAPR_CAP_HPT_MAXPAGESIZE + 1)
> +#define SPAPR_CAP_NUM                   (SPAPR_CAP_NESTED_KVM_HV + 1)
>  
>  /*
>   * Capability Values
> @@ -793,6 +795,7 @@ extern const VMStateDescription vmstate_spapr_cap_dfp;
>  extern const VMStateDescription vmstate_spapr_cap_cfpc;
>  extern const VMStateDescription vmstate_spapr_cap_sbbc;
>  extern const VMStateDescription vmstate_spapr_cap_ibs;
> +extern const VMStateDescription vmstate_spapr_cap_nested_kvm_hv;
>  
>  static inline uint8_t spapr_get_cap(sPAPRMachineState *spapr, int cap)
>  {
> diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c
> index 30aeafa7de..f81327d6cd 100644
> --- a/target/ppc/kvm.c
> +++ b/target/ppc/kvm.c
> @@ -91,6 +91,7 @@ static int cap_ppc_pvr_compat;
>  static int cap_ppc_safe_cache;
>  static int cap_ppc_safe_bounds_check;
>  static int cap_ppc_safe_indirect_branch;
> +static int cap_ppc_nested_kvm_hv;
>  
>  static uint32_t debug_inst_opcode;
>  
> @@ -150,6 +151,7 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
>      cap_mmu_hash_v3 = kvm_vm_check_extension(s, KVM_CAP_PPC_MMU_HASH_V3);
>      cap_resize_hpt = kvm_vm_check_extension(s, KVM_CAP_SPAPR_RESIZE_HPT);
>      kvmppc_get_cpu_characteristics(s);
> +    cap_ppc_nested_kvm_hv = kvm_vm_check_extension(s, KVM_CAP_PPC_NESTED_HV);
>      /*
>       * Note: setting it to false because there is not such capability
>       * in KVM at this moment.
> @@ -2422,6 +2424,16 @@ int kvmppc_get_cap_safe_indirect_branch(void)
>      return cap_ppc_safe_indirect_branch;
>  }
>  
> +bool kvmppc_has_cap_nested_kvm_hv(void)
> +{
> +    return !!cap_ppc_nested_kvm_hv;
> +}
> +
> +int kvmppc_set_cap_nested_kvm_hv(int enable)
> +{
> +    return kvm_vm_enable_cap(kvm_state, KVM_CAP_PPC_NESTED_HV, 0, enable);
> +}
> +
>  bool kvmppc_has_cap_spapr_vfio(void)
>  {
>      return cap_spapr_vfio;
> diff --git a/target/ppc/kvm_ppc.h b/target/ppc/kvm_ppc.h
> index f696c6e498..bdfaa4e70a 100644
> --- a/target/ppc/kvm_ppc.h
> +++ b/target/ppc/kvm_ppc.h
> @@ -62,6 +62,8 @@ bool kvmppc_has_cap_mmu_hash_v3(void);
>  int kvmppc_get_cap_safe_cache(void);
>  int kvmppc_get_cap_safe_bounds_check(void);
>  int kvmppc_get_cap_safe_indirect_branch(void);
> +bool kvmppc_has_cap_nested_kvm_hv(void);
> +int kvmppc_set_cap_nested_kvm_hv(int enable);
>  int kvmppc_enable_hwrng(void);
>  int kvmppc_put_books_sregs(PowerPCCPU *cpu);
>  PowerPCCPUClass *kvm_ppc_get_host_cpu_class(void);
> @@ -320,6 +322,16 @@ static inline int kvmppc_get_cap_safe_indirect_branch(void)
>      return 0;
>  }
>  
> +static inline bool kvmppc_has_cap_nested_kvm_hv(void)
> +{
> +    return false;
> +}
> +
> +static inline int kvmppc_set_cap_nested_kvm_hv(int enable)
> +{
> +    return -1;
> +}
> +
>  static inline int kvmppc_enable_hwrng(void)
>  {
>      return -1;

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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