From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jan Beulich" Subject: Re: [PATCH v2] x86: generic MSRs save/restore Date: Mon, 16 Dec 2013 08:52:08 +0000 Message-ID: <52AECD48020000780010D81B@nat28.tlf.novell.com> References: <529F47D2020000780010A0E4@nat28.tlf.novell.com> <52AB2165020000780010D068@nat28.tlf.novell.com> <52AEC238020000780010D789@nat28.tlf.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Disposition: inline List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Jinsong Liu Cc: Andrew Cooper , "xen-devel@lists.xen.org" , "keir@xen.org" , "Ian.Campbell@citrix.com" , "haoxudong.hao@gmail.com" List-Id: xen-devel@lists.xenproject.org >>> On 16.12.13 at 09:39, "Liu, Jinsong" wrote: > Jan Beulich wrote: >>>>> On 16.12.13 at 04:01, "Liu, Jinsong" 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 >>>> >>>> --- 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