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Jaeyong Yoo

2013-Oct-08 06:30 UTC

Re: [PATCH v4 1/9] xen/arm: Implement hvm save and restore

>------- Original Message -------
>Sender : Julien Grall<julien.grall@linaro.org>
>Date : 2013-10-07 21:49 (GMT+09:00)
>Title : Re: [Xen-devel] [PATCH v4 1/9] xen/arm: Implement hvm save and
restore
>
>On 10/04/2013 05:43 AM, Jaeyong Yoo wrote:
>> Implement save/restore of hvm context hypercall. In hvm
>> context save/restore, we save gic, timer and vfp registers.
>> 
>> Signed-off-by: Jaeyong Yoo 
>> ---
>>  xen/arch/arm/Makefile                  |   1 +
>>  xen/arch/arm/domctl.c                  |  88 ++++++++++++-
>>  xen/arch/arm/hvm.c                     | 228
+++++++++++++++++++++++++++++++++
>>  xen/arch/arm/save.c                    |  66 ++++++++++
>>  xen/common/Makefile                    |   2 +
>>  xen/include/asm-arm/hvm/support.h      |  29 +++++
>>  xen/include/public/arch-arm/hvm/save.h |  66 ++++++++++
>>  7 files changed, 479 insertions(+), 1 deletion(-)
>>  create mode 100644 xen/arch/arm/save.c
>>  create mode 100644 xen/include/asm-arm/hvm/support.h
>> 
>> diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
>> index 003ac84..8910a6c 100644
>> --- a/xen/arch/arm/Makefile
>> +++ b/xen/arch/arm/Makefile
>> @@ -31,6 +31,7 @@ obj-y += vuart.o
>>  obj-y += hvm.o
>>  obj-y += device.o
>>  obj-y += decode.o
>> +obj-y += save.o
>>  
>>  #obj-bin-y += ....o
>>  
>> diff --git a/xen/arch/arm/domctl.c b/xen/arch/arm/domctl.c
>> index 851ee40..86c07de 100644
>> --- a/xen/arch/arm/domctl.c
>> +++ b/xen/arch/arm/domctl.c
>> @@ -9,12 +9,98 @@
>>  #include 
>>  #include 
>>  #include 
>> +#include 
>> +#include 
>>  #include 
>>  
>>  long arch_do_domctl(struct xen_domctl *domctl, struct domain *d,
>>                      XEN_GUEST_HANDLE_PARAM(xen_domctl_t) u_domctl)
>>  {
>> -    return -ENOSYS;
>> +    long ret = 0;
>> +    bool_t copyback = 0;
>> +
>> +    switch ( domctl->cmd )
>> +    {
>> +    case XEN_DOMCTL_sethvmcontext:
>> +    {
>> +        struct hvm_domain_context c = { .size =
domctl->u.hvmcontext.size };
>> +
>> +        ret = -ENOMEM;
>> +        if ( (c.data = xmalloc_bytes(c.size)) == NULL )
>> +            goto sethvmcontext_out;
>> +
>> +        ret = -EFAULT;
>> +        if ( copy_from_guest(c.data, domctl->u.hvmcontext.buffer,
c.size) != 0 )
>> +            goto sethvmcontext_out;
>> +
>> +        domain_pause(d);
>> +        ret = hvm_load(d, &c);
>> +        domain_unpause(d);
>> +
>> +    sethvmcontext_out:
>> +        if ( c.data != NULL )
>> +            xfree(c.data);
>> +    }
>> +    break;
>> +    case XEN_DOMCTL_gethvmcontext:
>> +    {
>> +        struct hvm_domain_context c = { 0 };
>> +
>> +        ret = -EINVAL;
>> +
>> +        c.size = hvm_save_size(d);
>> +
>> +        if ( guest_handle_is_null(domctl->u.hvmcontext.buffer) )
>> +        {
>> +            /* Client is querying for the correct buffer size */
>> +            domctl->u.hvmcontext.size = c.size;
>> +            ret = 0;
>> +            goto gethvmcontext_out;
>> +        }
>> +        /* Check that the client has a big enough buffer */
>> +        ret = -ENOSPC;
>> +        if ( domctl->u.hvmcontext.size < c.size )
>> +        {
>> +            printk("(gethvmcontext) size error: %d and
%d\n",
>> +                   domctl->u.hvmcontext.size, c.size );
>> +            goto gethvmcontext_out;
>> +        }
>> +
>> +        /* Allocate our own marshalling buffer */
>> +        ret = -ENOMEM;
>> +        if ( (c.data = xmalloc_bytes(c.size)) == NULL )
>> +        {
>> +            printk("(gethvmcontext) xmalloc_bytes failed:
%d\n", c.size );
>> +            goto gethvmcontext_out;
>> +        }
>> +
>> +        domain_pause(d);
>> +        ret = hvm_save(d, &c);
>> +        domain_unpause(d);
>> +
>> +        domctl->u.hvmcontext.size = c.cur;
>> +        if ( copy_to_guest(domctl->u.hvmcontext.buffer, c.data,
c.size) != 0 )
>> +        {
>> +            printk("(gethvmcontext) copy to guest
failed\n");
>> +            ret = -EFAULT;
>> +        }
>> +
>> +    gethvmcontext_out:
>> +        copyback = 1;
>> +
>> +        if ( c.data != NULL )
>> +            xfree(c.data);
>> +    }
>> +    break;
>> +
>> +    default:
>> +        return -EINVAL;
>> +    }
>> +
>> +    if ( copyback && __copy_to_guest(u_domctl, domctl, 1) )
>> +        ret = -EFAULT;
>> +
>> +    return ret;
>>  }
>>  
>>  void arch_get_info_guest(struct vcpu *v, vcpu_guest_context_u c)
>> diff --git a/xen/arch/arm/hvm.c b/xen/arch/arm/hvm.c
>> index 471c4cd..befd75d 100644
>> --- a/xen/arch/arm/hvm.c
>> +++ b/xen/arch/arm/hvm.c
>> @@ -7,11 +7,13 @@
>>  
>>  #include 
>>  
>> +#include 
>>  #include 
>>  #include 
>>  #include 
>>  
>>  #include 
>> +#include 
>>  
>>  long do_hvm_op(unsigned long op, XEN_GUEST_HANDLE_PARAM(void) arg)
>>  
>> @@ -65,3 +67,229 @@ long do_hvm_op(unsigned long op,
XEN_GUEST_HANDLE_PARAM(void) arg)
>>  
>>      return rc;
>>  }
>> +
>> +static void vgic_irq_rank_save(struct vgic_rank *ext,
>> +                               struct vgic_irq_rank *rank)
>> +{
>> +    spin_lock(&rank->lock);
>> +    /* Some of VGIC registers are not used yet, it is for a future
usage */
>> +    /* IENABLE, IACTIVE, IPEND,  PENDSGI registers */
>> +    ext->ienable = rank->ienable;
>> +    ext->iactive = rank->iactive;
>> +    ext->ipend = rank->ipend;
>> +    ext->pendsgi = rank->pendsgi;
>> +    /* ICFG */
>> +    ext->icfg[0] = rank->icfg[0];
>> +    ext->icfg[1] = rank->icfg[1];
>Can you use memcpy?
OK.
>
>> +    /* IPRIORITY */
>> +    memcpy(ext->ipriority, rank->ipriority,
sizeof(rank->ipriority));
>> +    /* ITARGETS */
>> +    memcpy(ext->itargets, rank->itargets,
sizeof(rank->itargets));
>> +    spin_unlock(&rank->lock);
>> +}
>> +
>> +static void vgic_irq_rank_restore(struct vgic_irq_rank *rank,
>> +                                  struct vgic_rank *ext)
>> +{
>> +    spin_lock(&rank->lock);
>> +    /* IENABLE, IACTIVE, IPEND,  PENDSGI registers */
>> +    rank->ienable = ext->ienable;
>> +    rank->iactive = ext->iactive;
>> +    rank->ipend = ext->ipend;
>> +    rank->pendsgi = ext->pendsgi;
>> +    /* ICFG */
>> +    rank->icfg[0] = ext->icfg[0];
>> +    rank->icfg[1] = ext->icfg[1];
>
>Same here.
OK.
>
>> +    /* IPRIORITY */
>> +    memcpy(rank->ipriority, ext->ipriority,
sizeof(rank->ipriority));
>> +    /* ITARGETS */
>> +    memcpy(rank->itargets, ext->itargets,
sizeof(rank->itargets));
>> +    spin_unlock(&rank->lock);
>> +}
>> +
>> +
>> +static int gic_save(struct domain *d, hvm_domain_context_t *h)
>> +{
>> +    struct hvm_hw_gic ctxt;
>> +    struct vcpu *v;
>> +
>> +    /* Save the state of GICs */
>> +    for_each_vcpu( d, v )
>> +    {
>> +        ctxt.gic_hcr = v->arch.gic_hcr;
>> +        ctxt.gic_vmcr = v->arch.gic_vmcr;
>> +        ctxt.gic_apr = v->arch.gic_apr;
>> +
>> +        /* Save list registers and masks */
>> +        /* (it is not necessary to save/restore them, but LR state can
have
>> +         * influence on downtime after Live Migration (to be tested)
>> +         */
>> +        memcpy(ctxt.gic_lr, v->arch.gic_lr, sizeof(ctxt.gic_lr));
>> +        ctxt.lr_mask = v->arch.lr_mask;
>> +        ctxt.event_mask = v->arch.event_mask;
>> +
>> +        /* Save PPI states (per-CPU) */
>> +        /* It is necessary if SMP enabled */
>> +        vgic_irq_rank_save(&ctxt.ppi_state, 
&v->arch.vgic.private_irqs);
>> +
>> +        if ( hvm_save_entry(GIC, v->vcpu_id, h, &ctxt) != 0 )
>> +            return 1;
>> +    }
>> +    return 0;
>> +}
>> +
>> +static int gic_load(struct domain *d, hvm_domain_context_t *h)
>> +{
>> +    int vcpuid;
>> +    struct hvm_hw_gic ctxt;
>> +    struct vcpu *v;
>> +
>> +    /* Which vcpu is this? */
>> +    vcpuid = hvm_load_instance(h);
>> +    if ( vcpuid >= d->max_vcpus || (v = d->vcpu[vcpuid]) ==
NULL )
>> +    {
>> +        dprintk(XENLOG_G_ERR, "HVM restore: dom%u has no
vcpu%u\n",
>> +                d->domain_id, vcpuid);
>> +        return -EINVAL;
>> +    }
>> +
>> +    if ( hvm_load_entry(GIC, h, &ctxt) != 0 )
>> +        return -EINVAL;
>> +
>> +    v->arch.gic_hcr = ctxt.gic_hcr;
>> +    v->arch.gic_vmcr = ctxt.gic_vmcr;
>> +    v->arch.gic_apr = ctxt.gic_apr;
>> +
>> +    /* Restore list registers and masks */
>> +    memcpy(v->arch.gic_lr, ctxt.gic_lr, sizeof(ctxt.gic_lr));
>> +    v->arch.lr_mask = ctxt.lr_mask;
>> +    v->arch.event_mask = ctxt.event_mask;
>> +
>> +    /* Restore PPI states */
>> +    vgic_irq_rank_restore(&v->arch.vgic.private_irqs,
&ctxt.ppi_state);
>> +
>> +    return 0;
>> +}
>> +
>> +HVM_REGISTER_SAVE_RESTORE(GIC, gic_save, gic_load, 1, HVMSR_PER_VCPU);
>> +
>> +static int timer_save(struct domain *d, hvm_domain_context_t *h)
>> +{
>> +    struct hvm_hw_timer ctxt;
>> +    struct vcpu *v;
>> +    struct vtimer *t;
>> +    int i;
>> +
>> +    /* Save the state of vtimer and ptimer */
>> +    for_each_vcpu( d, v )
>> +    {
>> +        t = &v->arch.virt_timer;
>> +        for ( i = 0; i < 2; i++ )
>> +        {
>> +            ctxt.cval = t->cval;
>> +            ctxt.ctl = t->ctl;
>> +            ctxt.vtb_offset = i ? d->arch.phys_timer_base.offset :
>> +                d->arch.virt_timer_base.offset;
>> +            ctxt.type = i;
>> +            if ( hvm_save_entry(A15_TIMER, v->vcpu_id, h,
&ctxt) != 0 )
>> +                return 1;
>> +            t = &v->arch.phys_timer;
>> +        }
>> +    }
>> +
>> +    return 0;
>> +}
>> +
>> +static int timer_load(struct domain *d, hvm_domain_context_t *h)
>> +{
>> +    int vcpuid;
>> +    struct hvm_hw_timer ctxt;
>> +    struct vcpu *v;
>> +    struct vtimer *t = NULL;
>> +
>> +    /* Which vcpu is this? */
>> +    vcpuid = hvm_load_instance(h);
>> +
>> +    if ( vcpuid >= d->max_vcpus || (v = d->vcpu[vcpuid]) ==
NULL )
>> +    {
>> +        dprintk(XENLOG_G_ERR, "HVM restore: dom%u has no
vcpu%u\n",
>> +                d->domain_id, vcpuid);
>> +        return -EINVAL;
>> +    }
>> +
>> +    if ( hvm_load_entry(A15_TIMER, h, &ctxt) != 0 )
>> +        return -EINVAL;
>> +
>> +
>> +    if ( ctxt.type == TIMER_TYPE_VIRT )
>> +    {
>> +        t = &v->arch.virt_timer;
>> +        d->arch.virt_timer_base.offset = ctxt.vtb_offset;
>> +
>> +    }
>> +    else
>> +    {
>> +        t = &v->arch.phys_timer;
>> +        d->arch.phys_timer_base.offset = ctxt.vtb_offset;
>> +    }
>> +
>> +    t->cval = ctxt.cval;
>> +    t->ctl = ctxt.ctl;
>> +    t->v = v;
>> +
>> +    return 0;
>> +}
>> +
>> +HVM_REGISTER_SAVE_RESTORE(A15_TIMER, timer_save, timer_load, 2,
HVMSR_PER_VCPU);
>> +
>> +static int vfp_save(struct domain *d, hvm_domain_context_t *h)
>> +{
>> +    struct hvm_hw_vfp ctxt;
>> +    struct vcpu *v;
>> +
>> +    /* Save the state of VFP */
>> +    for_each_vcpu( d, v )
>> +    {
>> +        if ( sizeof(v->arch.vfp) != sizeof (ctxt) )
>> +        {
>> +            dprintk(XENLOG_G_ERR, "HVM: check VFP structure
match\n");
>> +            return -EINVAL;
>> +        }
>> +        memcpy(&ctxt, &v->arch.vfp, sizeof(ctxt));
>> +
>> +        if ( hvm_save_entry(VFP, v->vcpu_id, h, &ctxt) != 0 )
>> +            return 1;
>> +    }
>> +    return 0;
>> +}
>> +
>> +static int vfp_load(struct domain *d, hvm_domain_context_t *h)
>> +{
>> +    int vcpuid;
>> +    struct hvm_hw_vfp ctxt;
>> +    struct vcpu *v;
>> +
>> +    /* Which vcpu is this? */
>> +    vcpuid = hvm_load_instance(h);
>> +    if ( vcpuid >= d->max_vcpus || (v = d->vcpu[vcpuid]) ==
NULL )
>> +    {
>> +        dprintk(XENLOG_G_ERR, "HVM restore: dom%u has no
vcpu%u\n",
>> +                d->domain_id, vcpuid);
>> +        return -EINVAL;
>> +    }
>> +
>> +    if ( sizeof(v->arch.vfp) != sizeof (ctxt) )
>> +    {
>> +        dprintk(XENLOG_G_ERR, "HVM: check VFP structure
match\n");
>> +        return -EINVAL;
>> +    }
>> +
>> +    if ( hvm_load_entry(VFP, h, &ctxt) != 0 )
>> +        return -EINVAL;
>> +
>> +    memcpy(&v->arch.vfp, &ctxt, sizeof(ctxt));
>> +
>> +    return 0;
>> +}
>> +
>> +HVM_REGISTER_SAVE_RESTORE(VFP, vfp_save, vfp_load, 1, HVMSR_PER_VCPU);
>> diff --git a/xen/arch/arm/save.c b/xen/arch/arm/save.c
>> new file mode 100644
>> index 0000000..c923910
>> --- /dev/null
>> +++ b/xen/arch/arm/save.c
>> @@ -0,0 +1,66 @@
>> +/*
>> + * hvm/save.c: Save and restore HVM guest''s emulated hardware
state for ARM.
>> + *
>> + * Copyright (c) 2013, Samsung Electronics.
>> + *
>> + * This program is free software; you can redistribute it and/or
modify it
>> + * under the terms and conditions of the GNU General Public License,
>> + * version 2, as published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope it will be useful, but
WITHOUT
>> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or
>> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
License for
>> + * more details.
>> + *
>> + * You should have received a copy of the GNU General Public License
along with
>> + * this program; if not, write to the Free Software Foundation, Inc.,
59 Temple
>> + * Place - Suite 330, Boston, MA 02111-1307 USA.
>> + */
>> +
>> +#include 
>> +#include 
>> +
>> +void arch_hvm_save(struct domain *d, struct hvm_save_header *hdr)
>> +{
>> +    hdr->cpuid = READ_SYSREG32(MIDR_EL1);
>> +}
>> +
>> +int arch_hvm_load(struct domain *d, struct hvm_save_header *hdr)
>> +{
>> +    uint32_t cpuid;
>> +
>> +    if ( hdr->magic != HVM_FILE_MAGIC )
>> +    {
>> +        printk(XENLOG_G_ERR "HVM%d restore: bad magic number
%#"PRIx32"\n",
>> +               d->domain_id, hdr->magic);
>> +        return -1;
>> +    }
>> +
>> +    if ( hdr->version != HVM_FILE_VERSION )
>> +    {
>> +        printk(XENLOG_G_ERR "HVM%d restore: unsupported version
%u\n",
>> +               d->domain_id, hdr->version);
>> +        return -1;
>> +    }
>> +
>> +    cpuid = READ_SYSREG32(MIDR_EL1);
>> +    if ( hdr->cpuid != cpuid )
>> +    {
>> +        printk(XENLOG_G_INFO "HVM%d restore: VM saved on one CPU
"
>> +               "(%#"PRIx32") and restored on another
(%#"PRIx32").\n",
>> +               d->domain_id, hdr->cpuid, cpuid);
>> +        return -1;
>> +    }
>> +
>> +    return 0;
>> +}
>> +
>> +/*
>> + * Local variables:
>> + * mode: C
>> + * c-file-style: "BSD"
>> + * c-basic-offset: 4
>> + * tab-width: 4
>> + * indent-tabs-mode: nil
>> + * End:
>> + */
>> diff --git a/xen/common/Makefile b/xen/common/Makefile
>> index 6da4651..733b19f 100644
>> --- a/xen/common/Makefile
>> +++ b/xen/common/Makefile
>> @@ -61,6 +61,8 @@ subdir-$(CONFIG_COMPAT) += compat
>>  
>>  subdir-$(x86_64) += hvm
>>  
>> +subdir-$(CONFIG_ARM) += hvm
>> +
>>  subdir-$(coverage) += gcov
>>  
>>  subdir-y += libelf
>> diff --git a/xen/include/asm-arm/hvm/support.h
b/xen/include/asm-arm/hvm/support.h
>> new file mode 100644
>> index 0000000..8311f2f
>> --- /dev/null
>> +++ b/xen/include/asm-arm/hvm/support.h
>> @@ -0,0 +1,29 @@
>> +/*
>> + * support.h: HVM support routines used by ARMv7 VE.
>> + *
>> + * Copyright (c) 2012, Citrix Systems
>> + *
>> + * This program is free software; you can redistribute it and/or
modify it
>> + * under the terms and conditions of the GNU General Public License,
>> + * version 2, as published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope it will be useful, but
WITHOUT
>> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or
>> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
License for
>> + * more details.
>> + *
>> + * You should have received a copy of the GNU General Public License
along with
>> + * this program; if not, write to the Free Software Foundation, Inc.,
59 Temple
>> + * Place - Suite 330, Boston, MA 02111-1307 USA.
>> + */
>> +
>> +#ifndef __ASM_ARM_HVM_SUPPORT_H__
>> +#define __ASM_ARM_HVM_SUPPORT_H__
>> +
>> +#include 
>> +#include 
>> +#include 
>> +#include 
>> +#include 
>> +
>> +#endif /* __ASM_ARM_HVM_SUPPORT_H__ */
>> diff --git a/xen/include/public/arch-arm/hvm/save.h
b/xen/include/public/arch-arm/hvm/save.h
>> index 75b8e65..7e55384 100644
>> --- a/xen/include/public/arch-arm/hvm/save.h
>> +++ b/xen/include/public/arch-arm/hvm/save.h
>> @@ -26,6 +26,72 @@
>>  #ifndef __XEN_PUBLIC_HVM_SAVE_ARM_H__
>>  #define __XEN_PUBLIC_HVM_SAVE_ARM_H__
>>  
>> +#define HVM_FILE_MAGIC   0x92385520
>> +#define HVM_FILE_VERSION 0x00000001
>> +
>> +
>> +struct hvm_save_header
>> +{
>> +    uint32_t magic;             /* Must be HVM_FILE_MAGIC */
>> +    uint32_t version;           /* File format version */
>> +    uint64_t changeset;         /* Version of Xen that saved this file
*/
>> +    uint32_t cpuid;             /* MIDR_EL1 on the saving machine */
>> +};
>> +
>> +DECLARE_HVM_SAVE_TYPE(HEADER, 1, struct hvm_save_header);
>> +
>> +struct vgic_rank
>> +{
>> +    uint32_t ienable, iactive, ipend, pendsgi;
>> +    uint32_t icfg[2];
>> +    uint32_t ipriority[8];
>> +    uint32_t itargets[8];
>> +};
>> +
>> +struct hvm_hw_gic
>> +{
>> +    uint32_t gic_hcr;
>> +    uint32_t gic_vmcr;
>> +    uint32_t gic_apr;
>> +    uint32_t gic_lr[64];
>> +    uint64_t event_mask;
>> +    uint64_t lr_mask;
>> +    struct vgic_rank ppi_state;
>> +};
>> +
>> +DECLARE_HVM_SAVE_TYPE(GIC, 2, struct hvm_hw_gic);
>> +
>> +#define TIMER_TYPE_VIRT 0
>> +#define TIMER_TYPE_PHYS 1
>> +
>> +struct hvm_hw_timer
>> +{
>> +    uint64_t vtb_offset;
>> +    uint32_t ctl;
>> +    uint64_t cval;
>> +    uint32_t type;
>> +};
>> +
>> +DECLARE_HVM_SAVE_TYPE(A15_TIMER, 3, struct hvm_hw_timer);
>> +
>> +struct hvm_hw_vfp
>> +{
>> +    uint64_t fpregs1[16]; /* {d0-d15} */
>> +    uint64_t fpregs2[16]; /* {d16-d31} */
>> +    uint32_t fpexc;
>> +    uint32_t fpscr;
>> +    /* VFP implementation specific state */
>> +    uint32_t fpinst;
>> +    uint32_t fpinst2;
>> +};
>> +
>> +DECLARE_HVM_SAVE_TYPE(VFP, 4, struct hvm_hw_vfp);
>> +
>> +/*
>> + * Largest type-code in use
>> + */
>> +#define HVM_SAVE_CODE_MAX 4
>> +
>>  #endif
>>  
>>  /*
>> 
>
>
>-- 
>Julien Grall

Ian Campbell

2013-Oct-08 08:53 UTC

head link

Re: [PATCH v4 1/9] xen/arm: Implement hvm save and restore

On Tue, 2013-10-08 at 06:30 +0000, Jaeyong Yoo wrote:
> >> +static void vgic_irq_rank_save(struct vgic_rank *ext,
> >> +                               struct vgic_irq_rank *rank)
> >> +{
> >> +    spin_lock(&rank->lock);
> >> +    /* Some of VGIC registers are not used yet, it is for a
future usage */
> >> +    /* IENABLE, IACTIVE, IPEND,  PENDSGI registers */
> >> +    ext->ienable = rank->ienable;
> >> +    ext->iactive = rank->iactive;
> >> +    ext->ipend = rank->ipend;
> >> +    ext->pendsgi = rank->pendsgi;
> >> +    /* ICFG */
> >> +    ext->icfg[0] = rank->icfg[0];
> >> +    ext->icfg[1] = rank->icfg[1];
> >Can you use memcpy?
Why?
> OK.
If ext->icfg[0] rank->icfg[0] are the same type then I think using
assignment is better, since it is more type safe and it will effectively
get turned into a memcpy by the compiler anyway.

If they are different types then using memcpy just runs the risk that
one of them will silently change and break things.

With that in mind can these not be proper assignments too:
> >> +    /* IPRIORITY */
> >> +    memcpy(ext->ipriority, rank->ipriority,
sizeof(rank->ipriority));
> >> +    /* ITARGETS */
> >> +    memcpy(ext->itargets, rank->itargets,
sizeof(rank->itargets));
Or if not then copy field by field would actually be preferable IMHO. A
helper macro can make it a bit tidier sometimes:
        #define C(F) ext->#F = rank->#F

then
        C(itargets.foo);
        C(itergets.bar);
        #undef C
etc.

Ian.

Tim Deegan

2013-Oct-08 09:06 UTC

head link

Re: [PATCH v4 1/9] xen/arm: Implement hvm save and restore

At 09:53 +0100 on 08 Oct (1381226020), Ian Campbell
wrote:> On Tue, 2013-10-08 at 06:30 +0000, Jaeyong Yoo wrote:
> 
> > >> +static void vgic_irq_rank_save(struct vgic_rank *ext,
> > >> +                               struct vgic_irq_rank *rank)
> > >> +{
> > >> +    spin_lock(&rank->lock);
> > >> +    /* Some of VGIC registers are not used yet, it is for a
future usage */
> > >> +    /* IENABLE, IACTIVE, IPEND,  PENDSGI registers */
> > >> +    ext->ienable = rank->ienable;
> > >> +    ext->iactive = rank->iactive;
> > >> +    ext->ipend = rank->ipend;
> > >> +    ext->pendsgi = rank->pendsgi;
> > >> +    /* ICFG */
> > >> +    ext->icfg[0] = rank->icfg[0];
> > >> +    ext->icfg[1] = rank->icfg[1];
> > >Can you use memcpy?
> 
> Why?
> 
> > OK.
> 
> If ext->icfg[0] rank->icfg[0] are the same type then I think using
> assignment is better, since it is more type safe and it will effectively
> get turned into a memcpy by the compiler anyway.
+1. memcpy is dangerous here.

On x86 we avoided (much of) this kind of thing by just using the
API-defined structs directly in the internal ones.  Then there''s no
need
for any copying at all in this kind of function, just save the struct
out.

Of course, you have to be careful to separate architectural state (which
goes in the save record) from Xen implementation detail (which must not).

Tim.
> If they are different types then using memcpy just runs the risk that
> one of them will silently change and break things.
> 
> With that in mind can these not be proper assignments too:
> 
> > >> +    /* IPRIORITY */
> > >> +    memcpy(ext->ipriority, rank->ipriority,
sizeof(rank->ipriority));
> > >> +    /* ITARGETS */
> > >> +    memcpy(ext->itargets, rank->itargets,
sizeof(rank->itargets));
> 
> Or if not then copy field by field would actually be preferable IMHO. A
> helper macro can make it a bit tidier sometimes:
>         #define C(F) ext->#F = rank->#F
> 
> then
>         C(itargets.foo);
>         C(itergets.bar);
>         #undef C
> etc.
> 
> Ian.
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel

Jaeyong Yoo

2013-Oct-09 12:34 UTC

head link

Re: [PATCH v4 1/9] xen/arm: Implement hvm save and restore

> -----Original Message-----
> From: Tim Deegan [mailto:tim@xen.org]
> Sent: Tuesday, October 08, 2013 6:06 PM
> To: Ian Campbell
> Cc: jaeyong.yoo@samsung.com; Julien Grall; xen-devel@lists.xen.org
> Subject: Re: [Xen-devel] [PATCH v4 1/9] xen/arm: Implement hvm save and
> restore
> 
> At 09:53 +0100 on 08 Oct (1381226020), Ian Campbell wrote:
> > On Tue, 2013-10-08 at 06:30 +0000, Jaeyong Yoo wrote:
> >
> > > >> +static void vgic_irq_rank_save(struct vgic_rank *ext,
> > > >> +                               struct vgic_irq_rank
*rank) {
> > > >> +    spin_lock(&rank->lock);
> > > >> +    /* Some of VGIC registers are not used yet, it is
for a future
> usage */
> > > >> +    /* IENABLE, IACTIVE, IPEND,  PENDSGI registers */
> > > >> +    ext->ienable = rank->ienable;
> > > >> +    ext->iactive = rank->iactive;
> > > >> +    ext->ipend = rank->ipend;
> > > >> +    ext->pendsgi = rank->pendsgi;
> > > >> +    /* ICFG */
> > > >> +    ext->icfg[0] = rank->icfg[0];
> > > >> +    ext->icfg[1] = rank->icfg[1];
> > > >Can you use memcpy?
> >
> > Why?
> >
> > > OK.
> >
> > If ext->icfg[0] rank->icfg[0] are the same type then I think
using
> > assignment is better, since it is more type safe and it will
> > effectively get turned into a memcpy by the compiler anyway.
> 
> +1. memcpy is dangerous here.
> 
> On x86 we avoided (much of) this kind of thing by just using the API-
> defined structs directly in the internal ones.  Then there''s no
need for
> any copying at all in this kind of function, just save the struct out.
> 
> Of course, you have to be careful to separate architectural state (which
> goes in the save record) from Xen implementation detail (which must not).
Sounds good to me. I will prepare next version with this idea.

Thanks,
Jaeyong
> 
> Tim.
> 
> > If they are different types then using memcpy just runs the risk that
> > one of them will silently change and break things.
> >
> > With that in mind can these not be proper assignments too:
> >
> > > >> +    /* IPRIORITY */
> > > >> +    memcpy(ext->ipriority, rank->ipriority,
sizeof(rank-
> >ipriority));
> > > >> +    /* ITARGETS */
> > > >> +    memcpy(ext->itargets, rank->itargets,
> > > >> + sizeof(rank->itargets));
> >
> > Or if not then copy field by field would actually be preferable IMHO.
> > A helper macro can make it a bit tidier sometimes:
> >         #define C(F) ext->#F = rank->#F
> >
> > then
> >         C(itargets.foo);
> >         C(itergets.bar);
> >         #undef C
> > etc.
> >
> > Ian.
> >
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@lists.xen.org
> > http://lists.xen.org/xen-devel

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