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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.
Keir, ping?
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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