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Re: [Qemu-devel] [Qemu-ppc] [PATCH v7 5/6] ppc: spapr: Enable FWNMI capa
From: |
Aravinda Prasad |
Subject: |
Re: [Qemu-devel] [Qemu-ppc] [PATCH v7 5/6] ppc: spapr: Enable FWNMI capability |
Date: |
Mon, 15 Apr 2019 15:42:46 +0530 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 |
On Tuesday 26 March 2019 05:03 AM, David Gibson wrote:
> On Mon, Mar 25, 2019 at 02:27:45PM +0530, Aravinda Prasad wrote:
>>
>>
>> On Monday 25 March 2019 12:02 PM, David Gibson wrote:
>>> 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 <address@hidden>
>>>> ---
>>>> 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?
>>
>> I just checked how such scenarios are handled for other KVM
>> capabilities. Should I need to add an Spapr cap for this?
>
> Yes, I think that's what we'll need to do.
I was looking into SPAPR Cap, and I am not sure that the following code
will help in handling the migration. I need some help here.
diff --git a/hw/ppc/spapr_caps.c b/hw/ppc/spapr_caps.c
index edc5ed0..ef96192 100644
--- a/hw/ppc/spapr_caps.c
+++ b/hw/ppc/spapr_caps.c
@@ -473,6 +473,15 @@ static void cap_ccf_assist_apply(SpaprMachineState
*spapr, uint8_t val,
}
}
+static void cap_machine_check_apply(SpaprMachineState *spapr, uint8_t val,
+ Error **errp)
+{
+ if (kvm_enabled()) {
+ if (kvmppc_fwnmi_enable(cpu)) {
+ error_setg(errp, "Unable to enable fwnmi capability");
+ }
+}
+
SpaprCapabilityInfo capability_table[SPAPR_CAP_NUM] = {
[SPAPR_CAP_HTM] = {
.name = "htm",
@@ -571,6 +580,15 @@ SpaprCapabilityInfo capability_table[SPAPR_CAP_NUM] = {
.type = "bool",
.apply = cap_ccf_assist_apply,
},
+ [SPAPR_CAP_MACHINE_CHECK] = {
+ .name = "machine-check",
+ .description = "Handle machine check exceptions",
+ .index = SPAPR_CAP_MACHINE_CHECK,
+ .get = spapr_cap_get_bool,
+ .set = spapr_cap_set_bool,
+ .type = "bool",
+ .apply = cap_machine_check_apply,
+ },
};
static SpaprCapabilities default_caps_with_cpu(SpaprMachineState *spapr,
@@ -706,6 +724,7 @@ SPAPR_CAP_MIG_STATE(ibs, SPAPR_CAP_IBS);
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(mce, SPAPR_CAP_MACHINE_CHECK);
void spapr_caps_init(SpaprMachineState *spapr)
{
Or is it that just adding SPAPR_CAP_MIG_STATE(mce,
SPAPR_CAP_MACHINE_CHECK); is enough as it is checking or cap values?
>
--
Regards,
Aravinda
- Re: [Qemu-devel] [Qemu-ppc] [PATCH v7 5/6] ppc: spapr: Enable FWNMI capability,
Aravinda Prasad <=