On Thu, Oct 10, 2019 at 12:29:45PM +0530, Ganesh Goudar wrote: > From: Aravinda Prasad <arawind...@gmail.com> > > 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.
I think the commit message needs some updating. This doesn't really
introduce the KVM cap. It introduces the spapr capability, and
validates it against the kernel's exising capability.
>
> [eliminate cap_ppc_fwnmi]
> Signed-off-by: Ganesh Goudar <ganes...@linux.ibm.com>
> Signed-off-by: Aravinda Prasad <arawind...@gmail.com>
> ---
> hw/ppc/spapr.c | 1 +
> hw/ppc/spapr_caps.c | 29 +++++++++++++++++++++++++++++
> include/hw/ppc/spapr.h | 4 +++-
> target/ppc/kvm.c | 8 ++++++++
> target/ppc/kvm_ppc.h | 6 ++++++
> 5 files changed, 47 insertions(+), 1 deletion(-)
>
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 514a17ae74..7e6a15c9b4 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -4441,6 +4441,7 @@ 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;
To have migration work correctly, you also need to add
&vmstate_spapr_cap_fwnmi_mce to the list in vmstate_spapr. (Yes,
that makes three places you have to put things to get migration
right, which is really easy to mess up - I've done it more than once
myself - unfortunately, I haven't come up with a better way yet).
> diff --git a/hw/ppc/spapr_caps.c b/hw/ppc/spapr_caps.c
> index 481dfd2a27..778bf32181 100644
> --- a/hw/ppc/spapr_caps.c
> +++ b/hw/ppc/spapr_caps.c
> @@ -496,6 +496,25 @@ 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()) {
> + /*
> + * TCG support may not be correct in some conditions (e.g., in case
> + * of software injected faults like duplicate SLBs).
> + */
> + warn_report("Firmware Assisted Non-Maskable Interrupts not supported
> in TCG");
> + } else if (kvm_enabled() && kvmppc_set_fwnmi()) {
When checking integer error code return values (like
kvmppc_set_fwnmi()) please include an explicit != 0, to make it
clearer that's what's happening, rather than a function returning a bool.
> + 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",
> @@ -595,6 +614,15 @@ 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,
> @@ -734,6 +762,7 @@ 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 cbd1a4c9f3..dcd2e7d0cc 100644
> --- a/include/hw/ppc/spapr.h
> +++ b/include/hw/ppc/spapr.h
> @@ -79,8 +79,10 @@ 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 820724cc7d..d56f11a883 100644
> --- a/target/ppc/kvm.c
> +++ b/target/ppc/kvm.c
> @@ -2060,6 +2060,14 @@ void kvmppc_set_mpic_proxy(PowerPCCPU *cpu, int
> mpic_proxy)
> }
> }
>
> +int kvmppc_set_fwnmi(void)
> +{
> + PowerPCCPU *cpu = POWERPC_CPU(first_cpu);
> + CPUState *cs = CPU(cpu);
> +
> + 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 98bd7d5da6..5727a5025f 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_set_fwnmi(void);
> int kvmppc_smt_threads(void);
> void kvmppc_hint_smt_possible(Error **errp);
> int kvmppc_set_smt_threads(int smt);
> @@ -159,6 +160,11 @@ static inline void kvmppc_set_mpic_proxy(PowerPCCPU
> *cpu, int mpic_proxy)
> {
> }
>
> +static inline int kvmppc_set_fwnmi(void)
> +{
> + 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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