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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 2/18 V2]: PVH xen: add XENMEM_add_to_physmap_range
On Mon, Mar 18, 2013 at 11:38:35AM +0000, Jan Beulich wrote:
> >>> On 16.03.13 at 01:20, Mukesh Rathor <mukesh.rathor@xxxxxxxxxx> wrote:
> > In this patch we add a new function xenmem_add_to_physmap_range(), and
> > change xenmem_add_to_physmap_once parameters so it can be called from
> > xenmem_add_to_physmap_range. There is no PVH specific change here.
> >
> > Changes in V2:
> > - Do not break parameter so xenmem_add_to_physmap_once() but pass in
> > struct xen_add_to_physmap.
> >
> > Signed-off-by: Mukesh Rathor <mukesh.rathor@xxxxxxxxxx>
> > ---
> > xen/arch/x86/mm.c | 82
> > +++++++++++++++++++++++++++++++++++++++++++++++++++--
> > 1 files changed, 79 insertions(+), 3 deletions(-)
>
> This continued to lack compat mode support (i.e. modification to
> xen/arch/x86/x86_64/compat/mm.c:compat_arch_memory_op()).
Do we need it? Only 64-bit kernels can use PVH - and that was from the start the
idea.
>
> > --- a/xen/arch/x86/mm.c
> > +++ b/xen/arch/x86/mm.c
> > @@ -4268,7 +4268,8 @@ static int handle_iomem_range(unsigned long s,
> > unsigned long e, void *p)
> >
> > static int xenmem_add_to_physmap_once(
> > struct domain *d,
> > - const struct xen_add_to_physmap *xatp)
> > + const struct xen_add_to_physmap *xatp,
> > + domid_t foreign_domid)
>
> So you add this new parameter but don't use it?
>
> > {
> > struct page_info *page = NULL;
> > unsigned long gfn = 0; /* gcc ... */
> > @@ -4395,7 +4396,7 @@ static int xenmem_add_to_physmap(struct domain *d,
> > start_xatp = *xatp;
> > while ( xatp->size > 0 )
> > {
> > - rc = xenmem_add_to_physmap_once(d, xatp);
> > + rc = xenmem_add_to_physmap_once(d, xatp, -1);
>
> And if it indeed is being used, please use a proper DOMID_* value
> here.
>
> > if ( rc < 0 )
> > return rc;
> >
> > @@ -4421,7 +4422,52 @@ static int xenmem_add_to_physmap(struct domain *d,
> > return rc;
> > }
> >
> > - return xenmem_add_to_physmap_once(d, xatp);
> > + return xenmem_add_to_physmap_once(d, xatp, -1);
>
> And here.
>
> > +}
> > +
> > +static noinline int xenmem_add_to_physmap_range(struct domain *d,
> > + struct xen_add_to_physmap_range
> > *xatpr)
> > +{
> > + int rc;
> > +
> > + /* Process entries in reverse order to allow continuations */
> > + while ( xatpr->size > 0 )
> > + {
> > + xen_ulong_t idx;
> > + xen_pfn_t gpfn;
> > + struct xen_add_to_physmap xatp;
> > +
> > + rc = copy_from_guest_offset(&idx, xatpr->idxs, xatpr->size-1, 1);
> > + if ( rc < 0 )
> > + goto out;
> > +
> > + rc = copy_from_guest_offset(&gpfn, xatpr->gpfns, xatpr->size-1, 1);
> > + if ( rc < 0 )
> > + goto out;
> > +
> > + xatp.space = xatpr->space;
> > + xatp.idx = idx;
> > + xatp.gpfn = gpfn;
> > + rc = xenmem_add_to_physmap_once(d, &xatp, xatpr->foreign_domid);
> > +
> > + if (rc)
> > + goto out;
>
> That doesn't seem right, together with you apparently not using
> the "errs" array altogether.
>
> > +
> > + xatpr->size--;
> > +
> > + /* Check for continuation if it's not the last interation */
> > + if ( xatpr->size > 0 && hypercall_preempt_check() )
> > + {
> > + rc = -EAGAIN;
> > + goto out;
> > + }
> > + }
> > +
> > + rc = 0;
> > +
> > +out:
> > + return rc;
> > +
> > }
> >
> > long arch_memory_op(int op, XEN_GUEST_HANDLE_PARAM(void) arg)
> > @@ -4438,6 +4484,10 @@ long arch_memory_op(int op,
> > XEN_GUEST_HANDLE_PARAM(void) arg)
> > if ( copy_from_guest(&xatp, arg, 1) )
> > return -EFAULT;
> >
> > + /* This one is only supported for add_to_physmap_range */
> > + if ( xatp.space == XENMAPSPACE_gmfn_foreign )
> > + return -EINVAL;
> > +
> > d = rcu_lock_domain_by_any_id(xatp.domid);
> > if ( d == NULL )
> > return -ESRCH;
> > @@ -4465,6 +4515,32 @@ long arch_memory_op(int op,
> > XEN_GUEST_HANDLE_PARAM(void) arg)
> > return rc;
> > }
> >
> > + case XENMEM_add_to_physmap_range:
> > + {
> > + struct xen_add_to_physmap_range xatpr;
> > + struct domain *d;
> > +
> > + if ( copy_from_guest(&xatpr, arg, 1) )
> > + return -EFAULT;
> > +
> > + rc = rcu_lock_target_domain_by_id(xatpr.domid, &d);
> > + if ( rc != 0 )
> > + return rc;
> > +
> > + rc = xenmem_add_to_physmap_range(d, &xatpr);
> > +
> > + rcu_unlock_domain(d);
> > +
> > + if ( rc && copy_to_guest(arg, &xatpr, 1) )
>
> For one, shouldn't this be "!rc"?
>
> And then you update ->size, but that one is specified to be only
> and IN field. And considering that "errs" is the only OUT one, yet
> that isn't even formally correct (because the field itself is an IN,
> its what it points to where the output goes), I don't see why you
The 'err' is not formally correct? The memory.h says:
258 /* OUT */
259
260 /* Per index error code. */
261 XEN_GUEST_HANDLE(int) errs;
262 };
or are you referring to 'size' which I agree with - it is part of
'IN'.
> would need to copy back any part of the structure.
>
> Jan
>
> > + rc = -EFAULT;
> > +
> > + if ( rc == -EAGAIN )
> > + rc = hypercall_create_continuation(
> > + __HYPERVISOR_memory_op, "ih", op, arg);
> > +
> > + return rc;
> > + }
> > +
> > case XENMEM_set_memory_map:
> > {
> > struct xen_foreign_memory_map fmap;
> > --
> > 1.7.2.3
> >
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@xxxxxxxxxxxxx
> > http://lists.xen.org/xen-devel
>
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxx
> http://lists.xen.org/xen-devel
>
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