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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH V2] Add a GNTTABOP to swap the content of two grant references under lock provided that they are not currently active.
On 25/01/2012 15:52, "Wei Liu" <wei.liu2@xxxxxxxxxx> wrote:
> Keir, ping?
It is already checked in.
-- Keir
> And got a SOB from Paul:
>
> Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
>
> On Mon, 2012-01-23 at 13:56 +0000, Wei Liu (Intern) wrote:
>> Fix issues commented by Jan - coding style, stubs and variable types.
>>
>> Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
>> ---
>> xen/arch/x86/hvm/hvm.c | 1 +
>> xen/common/compat/grant_table.c | 8 +++
>> xen/common/grant_table.c | 89
>> ++++++++++++++++++++++++++++++++++++++
>> xen/include/public/grant_table.h | 18 +++++++-
>> xen/include/xlat.lst | 1 +
>> 5 files changed, 115 insertions(+), 2 deletions(-)
>>
>> diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
>> index b3d9ac0..c46bd3e 100644
>> --- a/xen/arch/x86/hvm/hvm.c
>> +++ b/xen/arch/x86/hvm/hvm.c
>> @@ -2857,6 +2857,7 @@ static int grant_table_op_is_allowed(unsigned int cmd)
>> case GNTTABOP_copy:
>> case GNTTABOP_map_grant_ref:
>> case GNTTABOP_unmap_grant_ref:
>> + case GNTTABOP_swap_grant_ref:
>> return 1;
>> default:
>> /* all other commands need auditing */
>> diff --git a/xen/common/compat/grant_table.c
>> b/xen/common/compat/grant_table.c
>> index ca60395..edd20c6 100644
>> --- a/xen/common/compat/grant_table.c
>> +++ b/xen/common/compat/grant_table.c
>> @@ -47,6 +47,10 @@
>> DEFINE_XEN_GUEST_HANDLE(gnttab_get_status_frames_compat_t);
>> CHECK_gnttab_get_version;
>> #undef xen_gnttab_get_version
>>
>> +#define xen_gnttab_swap_grant_ref gnttab_swap_grant_ref
>> +CHECK_gnttab_swap_grant_ref;
>> +#undef xen_gnttab_swap_grant_ref
>> +
>> int compat_grant_table_op(unsigned int cmd,
>> XEN_GUEST_HANDLE(void) cmp_uop,
>> unsigned int count)
>> @@ -98,6 +102,10 @@ int compat_grant_table_op(unsigned int cmd,
>> CASE(get_status_frames);
>> #endif
>>
>> +#ifndef CHECK_gnttab_swap_grant_ref
>> + CASE(swap_grant_ref);
>> +#endif
>> +
>> #undef CASE
>> default:
>> return do_grant_table_op(cmd, cmp_uop, count);
>> diff --git a/xen/common/grant_table.c b/xen/common/grant_table.c
>> index 34a49db..2683324 100644
>> --- a/xen/common/grant_table.c
>> +++ b/xen/common/grant_table.c
>> @@ -2282,6 +2282,81 @@
>> gnttab_get_version(XEN_GUEST_HANDLE(gnttab_get_version_t uop))
>> return 0;
>> }
>>
>> +static s16
>> +__gnttab_swap_grant_ref(grant_ref_t ref_a, grant_ref_t ref_b)
>> +{
>> + struct domain *d;
>> + struct active_grant_entry *act;
>> + s16 rc = GNTST_okay;
>> +
>> + d = rcu_lock_current_domain();
>> +
>> + spin_lock(&d->grant_table->lock);
>> +
>> + act = &active_entry(d->grant_table, ref_a);
>> + if ( act->pin )
>> + PIN_FAIL(out, GNTST_eagain, "ref a %ld busy\n", (long)ref_a);
>> +
>> + act = &active_entry(d->grant_table, ref_b);
>> + if ( act->pin )
>> + PIN_FAIL(out, GNTST_eagain, "ref b %ld busy\n", (long)ref_b);
>> +
>> + if ( d->grant_table->gt_version == 1 )
>> + {
>> + grant_entry_v1_t shared;
>> +
>> + shared = shared_entry_v1(d->grant_table, ref_a);
>> +
>> + shared_entry_v1(d->grant_table, ref_a) =
>> + shared_entry_v1(d->grant_table, ref_b);
>> +
>> + shared_entry_v1(d->grant_table, ref_b) = shared;
>> + }
>> + else
>> + {
>> + grant_entry_v2_t shared;
>> + grant_status_t status;
>> +
>> + shared = shared_entry_v2(d->grant_table, ref_a);
>> + status = status_entry(d->grant_table, ref_a);
>> +
>> + shared_entry_v2(d->grant_table, ref_a) =
>> + shared_entry_v2(d->grant_table, ref_b);
>> + status_entry(d->grant_table, ref_a) =
>> + status_entry(d->grant_table, ref_b);
>> +
>> + shared_entry_v2(d->grant_table, ref_b) = shared;
>> + status_entry(d->grant_table, ref_b) = status;
>> + }
>> +
>> +out:
>> + spin_unlock(&d->grant_table->lock);
>> +
>> + rcu_unlock_domain(d);
>> +
>> + return rc;
>> +}
>> +
>> +static long
>> +gnttab_swap_grant_ref(XEN_GUEST_HANDLE(gnttab_swap_grant_ref_t uop),
>> + unsigned int count)
>> +{
>> + int i;
>> + gnttab_swap_grant_ref_t op;
>> +
>> + for ( i = 0; i < count; i++ )
>> + {
>> + if ( i && hypercall_preempt_check() )
>> + return i;
>> + if ( unlikely(__copy_from_guest_offset(&op, uop, i, 1)) )
>> + return -EFAULT;
>> + op.status = __gnttab_swap_grant_ref(op.ref_a, op.ref_b);
>> + if ( unlikely(__copy_to_guest_offset(uop, i, &op, 1)) )
>> + return -EFAULT;
>> + }
>> + return 0;
>> +}
>> +
>> long
>> do_grant_table_op(
>> unsigned int cmd, XEN_GUEST_HANDLE(void) uop, unsigned int count)
>> @@ -2400,6 +2475,20 @@ do_grant_table_op(
>> rc = gnttab_get_version(guest_handle_cast(uop,
>> gnttab_get_version_t));
>> break;
>> }
>> + case GNTTABOP_swap_grant_ref:
>> + {
>> + XEN_GUEST_HANDLE(gnttab_swap_grant_ref_t) swap =
>> + guest_handle_cast(uop, gnttab_swap_grant_ref_t);
>> + if ( unlikely(!guest_handle_okay(swap, count)) )
>> + goto out;
>> + rc = gnttab_swap_grant_ref(swap, count);
>> + if ( rc > 0 )
>> + {
>> + guest_handle_add_offset(swap, rc);
>> + uop = guest_handle_cast(swap, void);
>> + }
>> + break;
>> + }
>> default:
>> rc = -ENOSYS;
>> break;
>> diff --git a/xen/include/public/grant_table.h
>> b/xen/include/public/grant_table.h
>> index 0bf20bc..54d9551 100644
>> --- a/xen/include/public/grant_table.h
>> +++ b/xen/include/public/grant_table.h
>> @@ -511,6 +511,20 @@ struct gnttab_get_version {
>> typedef struct gnttab_get_version gnttab_get_version_t;
>> DEFINE_XEN_GUEST_HANDLE(gnttab_get_version_t);
>>
>> +/*
>> + * GNTTABOP_swap_grant_ref: Swap the contents of two grant entries.
>> + */
>> +#define GNTTABOP_swap_grant_ref 11
>> +struct gnttab_swap_grant_ref {
>> + /* IN parameters */
>> + grant_ref_t ref_a;
>> + grant_ref_t ref_b;
>> + /* OUT parameters */
>> + int16_t status; /* GNTST_* */
>> +};
>> +typedef struct gnttab_swap_grant_ref gnttab_swap_grant_ref_t;
>> +DEFINE_XEN_GUEST_HANDLE(gnttab_swap_grant_ref_t);
>> +
>> #endif /* __XEN_INTERFACE_VERSION__ */
>>
>> /*
>> @@ -566,7 +580,7 @@ DEFINE_XEN_GUEST_HANDLE(gnttab_get_version_t);
>> #define GNTST_bad_page (-9) /* Specified page was invalid for op.
>> */
>> #define GNTST_bad_copy_arg (-10) /* copy arguments cross page boundary.
>> */
>> #define GNTST_address_too_big (-11) /* transfer page address too large.
>> */
>> -#define GNTST_eagain (-12) /* Could not map at the moment. Retry.
>> */
>> +#define GNTST_eagain (-12) /* Operation not done; try again.
>> */
>>
>> #define GNTTABOP_error_msgs { \
>> "okay", \
>> @@ -581,7 +595,7 @@ DEFINE_XEN_GUEST_HANDLE(gnttab_get_version_t);
>> "bad page", \
>> "copy arguments cross page boundary", \
>> "page address size too large", \
>> - "could not map at the moment, retry" \
>> + "operation not done; try again" \
>> }
>>
>> #endif /* __XEN_PUBLIC_GRANT_TABLE_H__ */
>> diff --git a/xen/include/xlat.lst b/xen/include/xlat.lst
>> index 3d92175..f602155 100644
>> --- a/xen/include/xlat.lst
>> +++ b/xen/include/xlat.lst
>> @@ -50,6 +50,7 @@
>> ? grant_entry_v1 grant_table.h
>> ? grant_entry_header grant_table.h
>> ? grant_entry_v2 grant_table.h
>> +? gnttab_swap_grant_ref grant_table.h
>> ? kexec_exec kexec.h
>> ! kexec_image kexec.h
>> ! kexec_range kexec.h
>
>
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