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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 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.
Thanks,
Jinsong
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