| Message ID | 1375292732-7627-5-git-send-email-stefano.stabellini@eu.citrix.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Stefano Stabellini <stefano.stabellini@eu.citrix.com> wrote: >Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> >--- >include/xen/interface/memory.h | 62 >++++++++++++++++++++++++++++++++++++++++ > 1 files changed, 62 insertions(+), 0 deletions(-) > >diff --git a/include/xen/interface/memory.h >b/include/xen/interface/memory.h >index 2ecfe4f..ffd7f4e 100644 >--- a/include/xen/interface/memory.h >+++ b/include/xen/interface/memory.h >@@ -263,4 +263,66 @@ struct xen_remove_from_physmap { > }; > DEFINE_GUEST_HANDLE_STRUCT(xen_remove_from_physmap); > >+#define XENMEM_get_dma_buf 26 >+/* >+ * This hypercall is similar to XENMEM_exchange: it exchanges the >pages Could you elaborate why the existing hyper call won't work? >+ * passed in with a new set of pages, contiguous and under 4G if so >+ * requested. The new pages are going to be "pinned": it's guaranteed >+ * that their p2m mapping won't be changed until explicitly >"unpinned". >+ * If return code is zero then @out.extent_list provides the MFNs of >the >+ * newly-allocated memory. Returns zero on complete success, >otherwise >+ * a negative error code. >+ * On complete success then always @nr_exchanged == @in.nr_extents. >On >+ * partial success @nr_exchanged indicates how much work was done. >+ */ >+struct xen_get_dma_buf { >+ /* >+ * [IN] Details of memory extents to be exchanged (GMFN bases). >+ * Note that @in.address_bits is ignored and unused. >+ */ >+ struct xen_memory_reservation in; >+ >+ /* >+ * [IN/OUT] Details of new memory extents. >+ * We require that: >+ * 1. @in.domid == @out.domid >+ * 2. @in.nr_extents << @in.extent_order == >+ * @out.nr_extents << @out.extent_order >+ * 3. @in.extent_start and @out.extent_start lists must not >overlap >+ * 4. @out.extent_start lists GPFN bases to be populated >+ * 5. @out.extent_start is overwritten with allocated GMFN bases >+ */ >+ struct xen_memory_reservation out; >+ >+ /* >+ * [OUT] Number of input extents that were successfully exchanged: >+ * 1. The first @nr_exchanged input extents were successfully >+ * deallocated. >+ * 2. The corresponding first entries in the output extent list >correctly >+ * indicate the GMFNs that were successfully exchanged. >+ * 3. All other input and output extents are untouched. >+ * 4. If not all input exents are exchanged then the return code >of this >+ * command will be non-zero. >+ * 5. THIS FIELD MUST BE INITIALISED TO ZERO BY THE CALLER! >+ */ >+ xen_ulong_t nr_exchanged; >+}; >+DEFINE_GUEST_HANDLE_STRUCT(xen_get_dma_buf); >+ >+#define XENMEM_put_dma_buf 27 >+/* >+ * XENMEM_put_dma_buf unpins a set of pages, previously pinned by >+ * XENMEM_get_dma_buf. After this call the p2m mapping of the pages >can >+ * be transparently changed by the hypervisor, as usual. The pages are >+ * still accessible from the guest. >+ */ >+struct xen_put_dma_buf { >+ /* >+ * [IN] Details of memory extents to be exchanged (GMFN bases). >+ * Note that @in.address_bits is ignored and unused. >+ */ >+ struct xen_memory_reservation in; >+}; >+DEFINE_GUEST_HANDLE_STRUCT(xen_put_dma_buf); >+ > #endif /* __XEN_PUBLIC_MEMORY_H__ */
On Wed, 31 Jul 2013, Konrad Rzeszutek Wilk wrote: > Stefano Stabellini <stefano.stabellini@eu.citrix.com> wrote: > >Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> > >--- > >include/xen/interface/memory.h | 62 > >++++++++++++++++++++++++++++++++++++++++ > > 1 files changed, 62 insertions(+), 0 deletions(-) > > > >diff --git a/include/xen/interface/memory.h > >b/include/xen/interface/memory.h > >index 2ecfe4f..ffd7f4e 100644 > >--- a/include/xen/interface/memory.h > >+++ b/include/xen/interface/memory.h > >@@ -263,4 +263,66 @@ struct xen_remove_from_physmap { > > }; > > DEFINE_GUEST_HANDLE_STRUCT(xen_remove_from_physmap); > > > >+#define XENMEM_get_dma_buf 26 > >+/* > >+ * This hypercall is similar to XENMEM_exchange: it exchanges the > >pages > > Could you elaborate why the existing hyper call won't work? Two reasons: - the existing XENMEM_exchange hypercall does not copy back the mfns into the out field for autotranslate guests; - the existing XENMEM_exchange hypercall does not guarantee that the hypervisor won't change the p2m mappings for the exchanged pages while the guest is using them. Keep in mind that Xen never promises to keep the p2m mapping stable for autotranslate guests in general. In practice it won't happen unless you use uncommon features like memory sharing or paging.
diff --git a/include/xen/interface/memory.h b/include/xen/interface/memory.h index 2ecfe4f..ffd7f4e 100644 --- a/include/xen/interface/memory.h +++ b/include/xen/interface/memory.h @@ -263,4 +263,66 @@ struct xen_remove_from_physmap { }; DEFINE_GUEST_HANDLE_STRUCT(xen_remove_from_physmap); +#define XENMEM_get_dma_buf 26 +/* + * This hypercall is similar to XENMEM_exchange: it exchanges the pages + * passed in with a new set of pages, contiguous and under 4G if so + * requested. The new pages are going to be "pinned": it's guaranteed + * that their p2m mapping won't be changed until explicitly "unpinned". + * If return code is zero then @out.extent_list provides the MFNs of the + * newly-allocated memory. Returns zero on complete success, otherwise + * a negative error code. + * On complete success then always @nr_exchanged == @in.nr_extents. On + * partial success @nr_exchanged indicates how much work was done. + */ +struct xen_get_dma_buf { + /* + * [IN] Details of memory extents to be exchanged (GMFN bases). + * Note that @in.address_bits is ignored and unused. + */ + struct xen_memory_reservation in; + + /* + * [IN/OUT] Details of new memory extents. + * We require that: + * 1. @in.domid == @out.domid + * 2. @in.nr_extents << @in.extent_order == + * @out.nr_extents << @out.extent_order + * 3. @in.extent_start and @out.extent_start lists must not overlap + * 4. @out.extent_start lists GPFN bases to be populated + * 5. @out.extent_start is overwritten with allocated GMFN bases + */ + struct xen_memory_reservation out; + + /* + * [OUT] Number of input extents that were successfully exchanged: + * 1. The first @nr_exchanged input extents were successfully + * deallocated. + * 2. The corresponding first entries in the output extent list correctly + * indicate the GMFNs that were successfully exchanged. + * 3. All other input and output extents are untouched. + * 4. If not all input exents are exchanged then the return code of this + * command will be non-zero. + * 5. THIS FIELD MUST BE INITIALISED TO ZERO BY THE CALLER! + */ + xen_ulong_t nr_exchanged; +}; +DEFINE_GUEST_HANDLE_STRUCT(xen_get_dma_buf); + +#define XENMEM_put_dma_buf 27 +/* + * XENMEM_put_dma_buf unpins a set of pages, previously pinned by + * XENMEM_get_dma_buf. After this call the p2m mapping of the pages can + * be transparently changed by the hypervisor, as usual. The pages are + * still accessible from the guest. + */ +struct xen_put_dma_buf { + /* + * [IN] Details of memory extents to be exchanged (GMFN bases). + * Note that @in.address_bits is ignored and unused. + */ + struct xen_memory_reservation in; +}; +DEFINE_GUEST_HANDLE_STRUCT(xen_put_dma_buf); + #endif /* __XEN_PUBLIC_MEMORY_H__ */
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> --- include/xen/interface/memory.h | 62 ++++++++++++++++++++++++++++++++++++++++ 1 files changed, 62 insertions(+), 0 deletions(-)