Re: [Xen-devel] [PATCH V2 1/2] x86/altp2m: Add hypercall to set a range of sve bits

[Tamas K Lengyel <tamas@xxxxxxxxxxxxx>]

On Wed, Nov 6, 2019 at 11:46 PM Alexandru Stefan ISAILA
<aisaila@xxxxxxxxxxxxxxx> wrote:
>
>
>
> On 06.11.2019 23:06, Tamas K Lengyel wrote:
> > On Wed, Nov 6, 2019 at 7:35 AM Alexandru Stefan ISAILA
> > <aisaila@xxxxxxxxxxxxxxx> wrote:
> >>
> >> By default the sve bits are not set.
> >> This patch adds a new hypercall, xc_altp2m_set_supress_ve_multi(),
> >> to set a range of sve bits.
> >> The core function, p2m_set_suppress_ve_multi(), does not brake in case
> >> of a error and it is doing a best effort for setting the bits in the
> >> given range. A check for continuation is made in order to have
> >> preemption on big ranges.
> >>
> >> Signed-off-by: Alexandru Isaila <aisaila@xxxxxxxxxxxxxxx>
> >>
> >> ---
> >> Changes since V1:
> >>          - Remove "continue"
> >>          - Add a new field in xen_hvm_altp2m_suppress_ve to store the
> >> continuation value
> >>          - Have p2m_set_suppress_ve_multi() take
> >> xen_hvm_altp2m_suppress_ve as a param.
> >> ---
> >>   tools/libxc/include/xenctrl.h   |  3 ++
> >>   tools/libxc/xc_altp2m.c         | 25 ++++++++++++++
> >>   xen/arch/x86/hvm/hvm.c          | 20 ++++++++++--
> >>   xen/arch/x86/mm/p2m.c           | 58 +++++++++++++++++++++++++++++++++
> >>   xen/include/public/hvm/hvm_op.h |  5 ++-
> >>   xen/include/xen/mem_access.h    |  3 ++
> >>   6 files changed, 111 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h
> >> index f4431687b3..21b644f459 100644
> >> --- a/tools/libxc/include/xenctrl.h
> >> +++ b/tools/libxc/include/xenctrl.h
> >> @@ -1923,6 +1923,9 @@ int xc_altp2m_switch_to_view(xc_interface *handle, 
> >> uint32_t domid,
> >>                                uint16_t view_id);
> >>   int xc_altp2m_set_suppress_ve(xc_interface *handle, uint32_t domid,
> >>                                 uint16_t view_id, xen_pfn_t gfn, bool sve);
> >> +int xc_altp2m_set_supress_ve_multi(xc_interface *handle, uint32_t domid,
> >> +                                   uint16_t view_id, xen_pfn_t start_gfn,
> >> +                                   uint32_t nr, bool sve);
> >>   int xc_altp2m_get_suppress_ve(xc_interface *handle, uint32_t domid,
> >>                                 uint16_t view_id, xen_pfn_t gfn, bool 
> >> *sve);
> >>   int xc_altp2m_set_mem_access(xc_interface *handle, uint32_t domid,
> >> diff --git a/tools/libxc/xc_altp2m.c b/tools/libxc/xc_altp2m.c
> >> index 09dad0355e..6605d9abbe 100644
> >> --- a/tools/libxc/xc_altp2m.c
> >> +++ b/tools/libxc/xc_altp2m.c
> >> @@ -234,6 +234,31 @@ int xc_altp2m_set_suppress_ve(xc_interface *handle, 
> >> uint32_t domid,
> >>       return rc;
> >>   }
> >>
> >> +int xc_altp2m_set_supress_ve_multi(xc_interface *handle, uint32_t domid,
> >> +                                   uint16_t view_id, xen_pfn_t start_gfn,
> >> +                                   uint32_t nr, bool sve)
> >> +{
> >> +    int rc;
> >> +    DECLARE_HYPERCALL_BUFFER(xen_hvm_altp2m_op_t, arg);
> >> +
> >> +    arg = xc_hypercall_buffer_alloc(handle, arg, sizeof(*arg));
> >
> > Does xc_hypercall_buffer_alloc null-initialize the structure?
> >
>
> It calls xencall_alloc_buffer_pages() which calls memset(p, 0, nr_pages
> * PAGE_SIZE) before returning.

Thanks!

Reviewed-by: Tamas K Lengyel <tamas@xxxxxxxxxxxxx>

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