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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v2] x86: generic MSRs save/restore
Jan Beulich wrote:
>>>> On 16.12.13 at 09:39, "Liu, Jinsong" <jinsong.liu@xxxxxxxxx> wrote:
>> Jan Beulich wrote:
>>>>>> On 16.12.13 at 04:01, "Liu, Jinsong" <jinsong.liu@xxxxxxxxx>
>>>>>> wrote:
>>>> Jan Beulich wrote:
>>>>> This patch introduces a generic MSRs save/restore mechanism, so
>>>>> that in the future new MSRs save/restore could be added w/
>>>>> smaller change than the full blown addition of a new save/restore
>>>>> type.
>>>>>
>>>>> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
>>>>>
>>>>> --- a/xen/arch/x86/hvm/hvm.c
>>>>> +++ b/xen/arch/x86/hvm/hvm.c
>>>>> @@ -1127,10 +1127,117 @@ static int hvm_load_cpu_xsave_states(str
>>>>> return 0; }
>>>>>
>>>>> -/* We need variable length data chunk for xsave area, hence
>>>>> customized
>>>>> - * declaration other than HVM_REGISTER_SAVE_RESTORE.
>>>>> +#define HVM_CPU_MSR_SIZE(cnt) offsetof(struct hvm_msr, msr[cnt])
>>>>> +static unsigned int __read_mostly msr_count_max;
>>>>> +
>>>>> +static int hvm_save_cpu_msrs(struct domain *d,
>>>>> hvm_domain_context_t *h) +{ + struct vcpu *v;
>>>>> +
>>>>> + for_each_vcpu ( d, v )
>>>>> + {
>>>>> + struct hvm_msr *ctxt;
>>>>> + unsigned int i;
>>>>> +
>>>>> + if ( _hvm_init_entry(h, CPU_MSR_CODE, v->vcpu_id,
>>>>> + HVM_CPU_MSR_SIZE(msr_count_max)) ) +
>>>>> return 1; + ctxt = (struct hvm_msr *)&h->data[h->cur]; +
>>>>> ctxt->count = 0; + + if ( hvm_funcs.save_msr )
>>>>> + hvm_funcs.save_msr(v, ctxt);
>>>>> +
>>>>> + for ( i = 0; i < ctxt->count; ++i )
>>>>> + ctxt->msr[i]._rsvd = 0;
>>>>> +
>>>>> + if ( ctxt->count )
>>>>> + h->cur += HVM_CPU_MSR_SIZE(ctxt->count); +
>>>>> else + h->cur -= sizeof(struct hvm_save_descriptor); +
>>>>> } + + return 0;
>>>>> +}
>>>>> +
>>>>> +static int hvm_load_cpu_msrs(struct domain *d,
>>>>> hvm_domain_context_t *h) +{ + unsigned int i, vcpuid =
>>>>> hvm_load_instance(h); + struct vcpu *v; + const struct
>>>>> hvm_save_descriptor *desc; + struct hvm_msr *ctxt; + int
>>>>> err = 0; +
>>>>> + if ( vcpuid >= d->max_vcpus || (v = d->vcpu[vcpuid]) == NULL
>>>>> ) + { + dprintk(XENLOG_G_ERR, "HVM restore: dom%d has no
>>>>> vcpu%u\n", + d->domain_id, vcpuid);
>>>>> + return -EINVAL;
>>>>> + }
>>>>> +
>>>>> + /* Customized checking for entry since our entry is of
>>>>> variable length */ + desc = (struct hvm_save_descriptor
>>>>> *)&h->data[h->cur]; + if ( sizeof (*desc) > h->size - h->cur)
>>>>> + { + printk(XENLOG_G_WARNING
>>>>> + "HVM%d.%d restore: not enough data left to read
>>>>> MSR descriptor\n", + d->domain_id, vcpuid); +
>>>>> return -ENODATA; + }
>>>>> + if ( desc->length + sizeof (*desc) > h->size - h->cur) + {
>>>>> + printk(XENLOG_G_WARNING
>>>>> + "HVM%d.%d restore: not enough data left to read %u
>>>>> MSR bytes\n", + d->domain_id, vcpuid, desc->length);
>>>>> + return -ENODATA; + }
>>>>> + if ( desc->length < HVM_CPU_MSR_SIZE(1) )
>>>>> + {
>>>>> + printk(XENLOG_G_WARNING
>>>>> + "HVM%d.%d restore mismatch: MSR length %u <
>>>>> %zu\n", + d->domain_id, vcpuid, desc->length,
>>>>> HVM_CPU_MSR_SIZE(1)); + return -EINVAL;
>>>>> + }
>>>>> +
>>>>> + h->cur += sizeof(*desc);
>>>>> + ctxt = (struct hvm_msr *)&h->data[h->cur];
>>>>> + h->cur += desc->length;
>>>>> +
>>>>> + if ( desc->length != HVM_CPU_MSR_SIZE(ctxt->count) ) + {
>>>>> + printk(XENLOG_G_WARNING
>>>>> + "HVM%d.%d restore mismatch: MSR length %u !=
>>>>> %zu\n", + d->domain_id, vcpuid, desc->length,
>>>>> + HVM_CPU_MSR_SIZE(ctxt->count));
>>>>> + return -EOPNOTSUPP;
>>>>> + }
>>>>> +
>>>>> + for ( i = 0; i < ctxt->count; ++i )
>>>>> + if ( ctxt->msr[i]._rsvd )
>>>>> + return -EOPNOTSUPP;
>>>>> + /* Checking finished */
>>>>> +
>>>>> + if ( hvm_funcs.load_msr )
>>>>> + err = hvm_funcs.load_msr(v, ctxt);
>>>>> +
>>>>> + for ( i = 0; !err && i < ctxt->count; ++i )
>>>>> + {
>>>>> + switch ( ctxt->msr[i].index )
>>>>> + {
>>>>> + default:
>>>>> + if ( !ctxt->msr[i]._rsvd )
>>>>> + err = -ENXIO;
>>>>> + break;
>>>>> + }
>>>>> + }
>>>>> +
>>>>> + return err;
>>>>> +}
>>>>> +
>>>>> +/* We need variable length data chunks for XSAVE area and MSRs,
>>>>> hence + * a custom declaration rather than
>>>>> HVM_REGISTER_SAVE_RESTORE. */ -static int __init
>>>>> __hvm_register_CPU_XSAVE_save_and_restore(void) +static int __init
>>>>> hvm_register_CPU_save_and_restore(void) {
>>>>> hvm_register_savevm(CPU_XSAVE_CODE,
>>>>> "CPU_XSAVE", @@ -1139,9 +1246,22 @@ static int __init
>>>>> __hvm_register_CPU_XSA
>>>>> HVM_CPU_XSAVE_SIZE(xfeature_mask) +
>>>>> sizeof(struct hvm_save_descriptor),
>>>>> HVMSR_PER_VCPU); + + if ( hvm_funcs.init_msr )
>>>>> + msr_count_max += hvm_funcs.init_msr();
>>>>> +
>>>>> + if ( msr_count_max )
>>>>> + hvm_register_savevm(CPU_MSR_CODE,
>>>>> + "CPU_MSR",
>>>>> + hvm_save_cpu_msrs,
>>>>> + hvm_load_cpu_msrs,
>>>>> + HVM_CPU_MSR_SIZE(msr_count_max) +
>>>>> + sizeof(struct
>>>>> hvm_save_descriptor), +
>>>>> HVMSR_PER_VCPU); +
>>>>> return 0;
>>>>> }
>>>>> -__initcall(__hvm_register_CPU_XSAVE_save_and_restore);
>>>>> +__initcall(hvm_register_CPU_save_and_restore);
>>>>>
>>>>> int hvm_vcpu_initialise(struct vcpu *v)
>>>>> {
>>>>> --- a/xen/include/asm-x86/hvm/hvm.h
>>>>> +++ b/xen/include/asm-x86/hvm/hvm.h
>>>>> @@ -109,6 +109,10 @@ struct hvm_function_table {
>>>>> void (*save_cpu_ctxt)(struct vcpu *v, struct hvm_hw_cpu
>>>>> *ctxt); int (*load_cpu_ctxt)(struct vcpu *v, struct
>>>>> hvm_hw_cpu *ctxt);
>>>>>
>>>>> + unsigned int (*init_msr)(void);
>>>>> + void (*save_msr)(struct vcpu *, struct hvm_msr *);
>>>>> + int (*load_msr)(struct vcpu *, struct hvm_msr *); +
>>>>> /* Examine specifics of the guest state. */
>>>>> unsigned int (*get_interrupt_shadow)(struct vcpu *v);
>>>>> void (*set_interrupt_shadow)(struct vcpu *v, unsigned int
>>>>> intr_shadow); --- a/xen/include/public/arch-x86/hvm/save.h
>>>>> +++ b/xen/include/public/arch-x86/hvm/save.h
>>>>> @@ -592,9 +592,21 @@ struct hvm_tsc_adjust {
>>>>>
>>>>> DECLARE_HVM_SAVE_TYPE(TSC_ADJUST, 19, struct hvm_tsc_adjust);
>>>>>
>>>>> +
>>>>> +struct hvm_msr {
>>>>> + uint32_t count;
>>>>> + struct hvm_one_msr {
>>>>> + uint32_t index;
>>>>> + uint32_t _rsvd;
>>>>> + uint64_t val;
>>>>> + } msr[1 /* variable size */];
>>>>> +};
>>>>> +
>>>>> +#define CPU_MSR_CODE 20
>>>>> +
>>>>
>>>> +DECLARE_HVM_SAVE_TYPE(CPU_MSR, CPU_MSR_CODE, struct hvm_msr);
>>>> +msr dump patch at tools/misc/xen-hvmctx.c
>>>
>>> Sorry, I don't follow what this is to mean. If that other patch of
>>> yours needs adjustment, then this surely doesn't belong here.
>>>
>>
>> OK, I will adjust tools side msr dump patch.
>>
>> DECLARE_HVM_SAVE_TYPE(CPU_MSR, CPU_MSR_CODE, struct hvm_msr) is for
>> msr dump tools side patch, so if you don't add it here I can use a
>> distinct patch to add it.
>
> The main thing is - this does _not_ belong in the public header, just
> like the XSAVE one has no such declaration there.
>
> Jan
XSAVE didn't get dumped at xen-hvmctx.c, it just forget (?) to do so, hence it
didn't declare at Xen side.
Thanks,
Jinsong
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