On Wed, Jun 12, 2019 at 02:51:04PM +0530, Aravinda Prasad wrote:
> Introduce 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.
>
> This patch also introduces fwnmi-mce capability to
> deal with the case when a guest with the
> KVM_CAP_PPC_FWNMI capability enabled is attempted
> to migrate to a host that does not support this
> capability.
>
> Signed-off-by: Aravinda Prasad <aravi...@linux.vnet.ibm.com>
> ---
> hw/ppc/spapr.c | 1 +
> hw/ppc/spapr_caps.c | 26 ++++++++++++++++++++++++++
> include/hw/ppc/spapr.h | 4 +++-
> target/ppc/kvm.c | 19 +++++++++++++++++++
> target/ppc/kvm_ppc.h | 12 ++++++++++++
> 5 files changed, 61 insertions(+), 1 deletion(-)
>
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 6dd8aaa..2ef86aa 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -4360,6 +4360,7 @@ static void spapr_machine_class_init(ObjectClass *oc,
> void *data)
> smc->default_caps.caps[SPAPR_CAP_NESTED_KVM_HV] = SPAPR_CAP_OFF;
> smc->default_caps.caps[SPAPR_CAP_LARGE_DECREMENTER] = SPAPR_CAP_ON;
> smc->default_caps.caps[SPAPR_CAP_CCF_ASSIST] = SPAPR_CAP_OFF;
> + smc->default_caps.caps[SPAPR_CAP_FWNMI_MCE] = SPAPR_CAP_OFF;
> spapr_caps_add_properties(smc, &error_abort);
> smc->irq = &spapr_irq_dual;
> smc->dr_phb_enabled = true;
> diff --git a/hw/ppc/spapr_caps.c b/hw/ppc/spapr_caps.c
> index 31b4661..2e92eb6 100644
> --- a/hw/ppc/spapr_caps.c
> +++ b/hw/ppc/spapr_caps.c
> @@ -479,6 +479,22 @@ static void cap_ccf_assist_apply(SpaprMachineState
> *spapr, uint8_t val,
> }
> }
>
> +static void cap_fwnmi_mce_apply(SpaprMachineState *spapr, uint8_t val,
> + Error **errp)
> +{
> + if (!val) {
> + return; /* Disabled by default */
> + }
> +
> + if (tcg_enabled()) {
> + error_setg(errp,
> +"No Firmware Assisted Non-Maskable Interrupts support in TCG, try
> cap-fwnmi-mce=off");
Not allowing this for TCG creates an awkward incompatibility between
KVM and TCG guests. I can't actually see any reason to ban it for TCG
- with the current code TCG won't ever generate NMIs, but I don't see
that anything will actually break.
In fact, we do have an nmi monitor command, currently wired to the
spapr_nmi() function which resets each cpu, but it probably makes
sense to wire it up to the fwnmi stuff when present.
> + } else if (kvm_enabled() && !kvmppc_has_cap_ppc_fwnmi()) {
> + error_setg(errp,
> +"Firmware Assisted Non-Maskable Interrupts not supported by KVM, try
> cap-fwnmi-mce=off");
> + }
> +}
> +
> SpaprCapabilityInfo capability_table[SPAPR_CAP_NUM] = {
> [SPAPR_CAP_HTM] = {
> .name = "htm",
> @@ -578,6 +594,15 @@ SpaprCapabilityInfo capability_table[SPAPR_CAP_NUM] = {
> .type = "bool",
> .apply = cap_ccf_assist_apply,
> },
> + [SPAPR_CAP_FWNMI_MCE] = {
> + .name = "fwnmi-mce",
> + .description = "Handle fwnmi machine check exceptions",
> + .index = SPAPR_CAP_FWNMI_MCE,
> + .get = spapr_cap_get_bool,
> + .set = spapr_cap_set_bool,
> + .type = "bool",
> + .apply = cap_fwnmi_mce_apply,
> + },
> };
>
> static SpaprCapabilities default_caps_with_cpu(SpaprMachineState *spapr,
> @@ -717,6 +742,7 @@ SPAPR_CAP_MIG_STATE(hpt_maxpagesize,
> SPAPR_CAP_HPT_MAXPAGESIZE);
> SPAPR_CAP_MIG_STATE(nested_kvm_hv, SPAPR_CAP_NESTED_KVM_HV);
> SPAPR_CAP_MIG_STATE(large_decr, SPAPR_CAP_LARGE_DECREMENTER);
> SPAPR_CAP_MIG_STATE(ccf_assist, SPAPR_CAP_CCF_ASSIST);
> +SPAPR_CAP_MIG_STATE(fwnmi, SPAPR_CAP_FWNMI_MCE);
>
> void spapr_caps_init(SpaprMachineState *spapr)
> {
> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> index 4f5becf..f891f8f 100644
> --- a/include/hw/ppc/spapr.h
> +++ b/include/hw/ppc/spapr.h
> @@ -78,8 +78,10 @@ typedef enum {
> #define SPAPR_CAP_LARGE_DECREMENTER 0x08
> /* Count Cache Flush Assist HW Instruction */
> #define SPAPR_CAP_CCF_ASSIST 0x09
> +/* FWNMI machine check handling */
> +#define SPAPR_CAP_FWNMI_MCE 0x0A
> /* Num Caps */
> -#define SPAPR_CAP_NUM (SPAPR_CAP_CCF_ASSIST + 1)
> +#define SPAPR_CAP_NUM (SPAPR_CAP_FWNMI_MCE + 1)
>
> /*
> * Capability Values
> diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c
> index 3bf0a46..afef4cd 100644
> --- a/target/ppc/kvm.c
> +++ b/target/ppc/kvm.c
> @@ -84,6 +84,7 @@ 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;
>
> @@ -152,6 +153,7 @@ 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.
> @@ -2114,6 +2116,18 @@ 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;
> @@ -2414,6 +2428,11 @@ bool kvmppc_has_cap_mmu_hash_v3(void)
> return cap_mmu_hash_v3;
> }
>
> +bool kvmppc_has_cap_ppc_fwnmi(void)
> +{
> + return cap_ppc_fwnmi;
> +}
> +
> static bool kvmppc_power8_host(void)
> {
> bool ret = false;
> diff --git a/target/ppc/kvm_ppc.h b/target/ppc/kvm_ppc.h
> index 45776ca..880cee9 100644
> --- a/target/ppc/kvm_ppc.h
> +++ b/target/ppc/kvm_ppc.h
> @@ -27,6 +27,8 @@ 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);
> +bool kvmppc_has_cap_ppc_fwnmi(void);
> int kvmppc_smt_threads(void);
> void kvmppc_hint_smt_possible(Error **errp);
> int kvmppc_set_smt_threads(int smt);
> @@ -158,6 +160,16 @@ static inline void kvmppc_set_mpic_proxy(PowerPCCPU
> *cpu, int mpic_proxy)
> {
> }
>
> +static inline int kvmppc_fwnmi_enable(PowerPCCPU *cpu)
> +{
> + return 1;
> +}
> +
> +static inline bool kvmppc_has_cap_ppc_fwnmi(void)
> +{
> + return false;
> +}
> +
> 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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