On Fri, Mar 22, 2019 at 12:04:16PM +0530, Aravinda Prasad wrote:
> Enable the KVM capability KVM_CAP_PPC_FWNMI so that
> the KVM causes guest exit with NMI as exit reason
> when it encounters a machine check exception on the
> address belonging to a guest. Without this capability
> enabled, KVM redirects machine check exceptions to
> guest's 0x200 vector.
>
> Signed-off-by: Aravinda Prasad <aravi...@linux.vnet.ibm.com>
> ---
> hw/ppc/spapr_rtas.c | 15 +++++++++++++++
> target/ppc/kvm.c | 14 ++++++++++++++
> target/ppc/kvm_ppc.h | 6 ++++++
> 3 files changed, 35 insertions(+)
>
> diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
> index fb594a4..939f428 100644
> --- a/hw/ppc/spapr_rtas.c
> +++ b/hw/ppc/spapr_rtas.c
> @@ -49,6 +49,7 @@
> #include "hw/ppc/fdt.h"
> #include "target/ppc/mmu-hash64.h"
> #include "target/ppc/mmu-book3s-v3.h"
> +#include "kvm_ppc.h"
>
> static void rtas_display_character(PowerPCCPU *cpu, SpaprMachineState *spapr,
> uint32_t token, uint32_t nargs,
> @@ -354,6 +355,20 @@ static void rtas_ibm_nmi_register(PowerPCCPU *cpu,
> target_ulong args,
> uint32_t nret, target_ulong rets)
> {
> + int ret;
> +
> + ret = kvmppc_fwnmi_enable(cpu);
> +
> + if (ret == 1) {
> + rtas_st(rets, 0, RTAS_OUT_NOT_SUPPORTED);
Urgh, we're here making a guest visible different to the environment
depending on a host (KVM) capability. What happens if you start a
guest and it registers fwnmi support, then migrate it to a host that
lacks the necessary KVM support?
> + return;
> + }
> +
> + if (ret < 0) {
> + rtas_st(rets, 0, RTAS_OUT_HW_ERROR);
> + return;
> + }
> +
> spapr->mc_reset = 0;
> spapr->guest_machine_check_addr = rtas_ld(args, 1);
> rtas_st(rets, 0, RTAS_OUT_SUCCESS);
> diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c
> index a593448..161b45e 100644
> --- a/target/ppc/kvm.c
> +++ b/target/ppc/kvm.c
> @@ -93,6 +93,7 @@ static int cap_ppc_safe_indirect_branch;
> static int cap_ppc_count_cache_flush_assist;
> static int cap_ppc_nested_kvm_hv;
> static int cap_large_decr;
> +static int cap_ppc_fwnmi;
>
> static uint32_t debug_inst_opcode;
>
> @@ -155,6 +156,7 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
> kvmppc_get_cpu_characteristics(s);
> cap_ppc_nested_kvm_hv = kvm_vm_check_extension(s, KVM_CAP_PPC_NESTED_HV);
> cap_large_decr = kvmppc_get_dec_bits();
> + cap_ppc_fwnmi = kvm_check_extension(s, KVM_CAP_PPC_FWNMI);
> /*
> * Note: setting it to false because there is not such capability
> * in KVM at this moment.
> @@ -2091,6 +2093,18 @@ void kvmppc_set_mpic_proxy(PowerPCCPU *cpu, int
> mpic_proxy)
> }
> }
>
> +int kvmppc_fwnmi_enable(PowerPCCPU *cpu)
> +{
> + CPUState *cs = CPU(cpu);
> +
> + if (!cap_ppc_fwnmi) {
> + return 1;
> + }
> +
> + return kvm_vcpu_enable_cap(cs, KVM_CAP_PPC_FWNMI, 0);
> +}
> +
> +
> int kvmppc_smt_threads(void)
> {
> return cap_ppc_smt ? cap_ppc_smt : 1;
> diff --git a/target/ppc/kvm_ppc.h b/target/ppc/kvm_ppc.h
> index df5e85f..cf7b24f 100644
> --- a/target/ppc/kvm_ppc.h
> +++ b/target/ppc/kvm_ppc.h
> @@ -27,6 +27,7 @@ void kvmppc_enable_h_page_init(void);
> void kvmppc_set_papr(PowerPCCPU *cpu);
> int kvmppc_set_compat(PowerPCCPU *cpu, uint32_t compat_pvr);
> void kvmppc_set_mpic_proxy(PowerPCCPU *cpu, int mpic_proxy);
> +int kvmppc_fwnmi_enable(PowerPCCPU *cpu);
> int kvmppc_smt_threads(void);
> void kvmppc_hint_smt_possible(Error **errp);
> int kvmppc_set_smt_threads(int smt);
> @@ -158,6 +159,11 @@ static inline void kvmppc_set_mpic_proxy(PowerPCCPU
> *cpu, int mpic_proxy)
> {
> }
>
> +int kvmppc_fwnmi_enable(PowerPCCPU *cpu)
> +{
> + return 1;
> +}
> +
> static inline int kvmppc_smt_threads(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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