return paddr >> HV_HYP_PAGE_SHIFT;
}
+/*
+ * hv_gpadl_size - Return the real size of a gpadl, the size that Hyper-V uses
+ *
+ * For BUFFER gpadl, Hyper-V uses the exact same size as the guest does.
+ *
+ * For RING gpadl, in each ring, the guest uses one PAGE_SIZE as the header
+ * (because of the alignment requirement), however, the hypervisor only
+ * uses the first HV_HYP_PAGE_SIZE as the header, therefore leaving a
+ * (PAGE_SIZE - HV_HYP_PAGE_SIZE) gap. And since there are two rings in a
+ * ringbuffer, the total size for a RING gpadl that Hyper-V uses is the
+ * total size that the guest uses minus twice of the gap size.
+ */
+static inline u32 hv_gpadl_size(enum hv_gpadl_type type, u32 size)
+{
+ switch (type) {
+ case HV_GPADL_BUFFER:
+ return size;
+ case HV_GPADL_RING:
+ /* The size of a ringbuffer must be page-aligned */
+ BUG_ON(size % PAGE_SIZE);
+ /*
+ * Two things to notice here:
+ * 1) We're processing two ring buffers as a unit
+ * 2) We're skipping any space larger than HV_HYP_PAGE_SIZE in
+ * the first guest-size page of each of the two ring buffers.
+ * So we effectively subtract out two guest-size pages, and add
+ * back two Hyper-V size pages.
+ */
+ return size - 2 * (PAGE_SIZE - HV_HYP_PAGE_SIZE);
+ }
+ BUG();
+ return 0;
+}
+
+/*
+ * hv_ring_gpadl_send_hvpgoffset - Calculate the send offset (in unit of
+ * HV_HYP_PAGE) in a ring gpadl based on the
+ * offset in the guest
+ *
+ * @offset: the offset (in bytes) where the send ringbuffer starts in the
+ * virtual address space of the guest
+ */
+static inline u32 hv_ring_gpadl_send_hvpgoffset(u32 offset)
+{
+
+ /*
+ * For RING gpadl, in each ring, the guest uses one PAGE_SIZE as the
+ * header (because of the alignment requirement), however, the
+ * hypervisor only uses the first HV_HYP_PAGE_SIZE as the header,
+ * therefore leaving a (PAGE_SIZE - HV_HYP_PAGE_SIZE) gap.
+ *
+ * And to calculate the effective send offset in gpadl, we need to
+ * substract this gap.
+ */
+ return (offset - (PAGE_SIZE - HV_HYP_PAGE_SIZE)) >> HV_HYP_PAGE_SHIFT;
+}
+
+/*
+ * hv_gpadl_hvpfn - Return the Hyper-V page PFN of the @i th Hyper-V page in
+ * the gpadl
+ *
+ * @type: the type of the gpadl
+ * @kbuffer: the pointer to the gpadl in the guest
+ * @size: the total size (in bytes) of the gpadl
+ * @send_offset: the offset (in bytes) where the send ringbuffer starts in the
+ * virtual address space of the guest
+ * @i: the index
+ */
+static inline u64 hv_gpadl_hvpfn(enum hv_gpadl_type type, void *kbuffer,
+ u32 size, u32 send_offset, int i)
+{
+ int send_idx = hv_ring_gpadl_send_hvpgoffset(send_offset);
+ unsigned long delta = 0UL;
+
+ switch (type) {
+ case HV_GPADL_BUFFER:
+ break;
+ case HV_GPADL_RING:
+ if (i == 0)
+ delta = 0;
+ else if (i <= send_idx)
+ delta = PAGE_SIZE - HV_HYP_PAGE_SIZE;
+ else
+ delta = 2 * (PAGE_SIZE - HV_HYP_PAGE_SIZE);
+ break;
+ default:
+ BUG();
+ break;
+ }
+
+ return virt_to_hvpfn(kbuffer + delta + (HV_HYP_PAGE_SIZE * i));
+}
+
/*
* vmbus_setevent- Trigger an event notification on the specified
* channel.
/*
* create_gpadl_header - Creates a gpadl for the specified buffer
*/
-static int create_gpadl_header(void *kbuffer, u32 size,
+static int create_gpadl_header(enum hv_gpadl_type type, void *kbuffer,
+ u32 size, u32 send_offset,
struct vmbus_channel_msginfo **msginfo)
{
int i;
int pfnsum, pfncount, pfnleft, pfncurr, pfnsize;
- pagecount = size >> HV_HYP_PAGE_SHIFT;
+ pagecount = hv_gpadl_size(type, size) >> HV_HYP_PAGE_SHIFT;
/* do we need a gpadl body msg */
pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
gpadl_header->range_buflen = sizeof(struct gpa_range) +
pagecount * sizeof(u64);
gpadl_header->range[0].byte_offset = 0;
- gpadl_header->range[0].byte_count = size;
+ gpadl_header->range[0].byte_count = hv_gpadl_size(type, size);
for (i = 0; i < pfncount; i++)
- gpadl_header->range[0].pfn_array[i] = virt_to_hvpfn(
- kbuffer + HV_HYP_PAGE_SIZE * i);
+ gpadl_header->range[0].pfn_array[i] = hv_gpadl_hvpfn(
+ type, kbuffer, size, send_offset, i);
*msginfo = msgheader;
pfnsum = pfncount;
* so the hypervisor guarantees that this is ok.
*/
for (i = 0; i < pfncurr; i++)
- gpadl_body->pfn[i] = virt_to_hvpfn(
- kbuffer + HV_HYP_PAGE_SIZE * (pfnsum + i));
+ gpadl_body->pfn[i] = hv_gpadl_hvpfn(type,
+ kbuffer, size, send_offset, pfnsum + i);
/* add to msg header */
list_add_tail(&msgbody->msglistentry,
gpadl_header->range_buflen = sizeof(struct gpa_range) +
pagecount * sizeof(u64);
gpadl_header->range[0].byte_offset = 0;
- gpadl_header->range[0].byte_count = size;
+ gpadl_header->range[0].byte_count = hv_gpadl_size(type, size);
for (i = 0; i < pagecount; i++)
- gpadl_header->range[0].pfn_array[i] = virt_to_hvpfn(
- kbuffer + HV_HYP_PAGE_SIZE * i);
+ gpadl_header->range[0].pfn_array[i] = hv_gpadl_hvpfn(
+ type, kbuffer, size, send_offset, i);
*msginfo = msgheader;
}
}
/*
- * vmbus_establish_gpadl - Establish a GPADL for the specified buffer
+ * __vmbus_establish_gpadl - Establish a GPADL for a buffer or ringbuffer
*
* @channel: a channel
+ * @type: the type of the corresponding GPADL, only meaningful for the guest.
* @kbuffer: from kmalloc or vmalloc
* @size: page-size multiple
+ * @send_offset: the offset (in bytes) where the send ring buffer starts,
+ * should be 0 for BUFFER type gpadl
* @gpadl_handle: some funky thing
*/
-int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer,
- u32 size, u32 *gpadl_handle)
+static int __vmbus_establish_gpadl(struct vmbus_channel *channel,
+ enum hv_gpadl_type type, void *kbuffer,
+ u32 size, u32 send_offset,
+ u32 *gpadl_handle)
{
struct vmbus_channel_gpadl_header *gpadlmsg;
struct vmbus_channel_gpadl_body *gpadl_body;
next_gpadl_handle =
(atomic_inc_return(&vmbus_connection.next_gpadl_handle) - 1);
- ret = create_gpadl_header(kbuffer, size, &msginfo);
+ ret = create_gpadl_header(type, kbuffer, size, send_offset, &msginfo);
if (ret)
return ret;
kfree(msginfo);
return ret;
}
+
+/*
+ * vmbus_establish_gpadl - Establish a GPADL for the specified buffer
+ *
+ * @channel: a channel
+ * @kbuffer: from kmalloc or vmalloc
+ * @size: page-size multiple
+ * @gpadl_handle: some funky thing
+ */
+int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer,
+ u32 size, u32 *gpadl_handle)
+{
+ return __vmbus_establish_gpadl(channel, HV_GPADL_BUFFER, kbuffer, size,
+ 0U, gpadl_handle);
+}
EXPORT_SYMBOL_GPL(vmbus_establish_gpadl);
static int __vmbus_open(struct vmbus_channel *newchannel,
/* Establish the gpadl for the ring buffer */
newchannel->ringbuffer_gpadlhandle = 0;
- err = vmbus_establish_gpadl(newchannel,
- page_address(newchannel->ringbuffer_page),
- (send_pages + recv_pages) << PAGE_SHIFT,
- &newchannel->ringbuffer_gpadlhandle);
+ err = __vmbus_establish_gpadl(newchannel, HV_GPADL_RING,
+ page_address(newchannel->ringbuffer_page),
+ (send_pages + recv_pages) << PAGE_SHIFT,
+ newchannel->ringbuffer_send_offset << PAGE_SHIFT,
+ &newchannel->ringbuffer_gpadlhandle);
if (err)
goto error_clean_ring;
open_msg->openid = newchannel->offermsg.child_relid;
open_msg->child_relid = newchannel->offermsg.child_relid;
open_msg->ringbuffer_gpadlhandle = newchannel->ringbuffer_gpadlhandle;
- open_msg->downstream_ringbuffer_pageoffset = newchannel->ringbuffer_send_offset;
+ /*
+ * The unit of ->downstream_ringbuffer_pageoffset is HV_HYP_PAGE and
+ * the unit of ->ringbuffer_send_offset (i.e. send_pages) is PAGE, so
+ * here we calculate it into HV_HYP_PAGE.
+ */
+ open_msg->downstream_ringbuffer_pageoffset =
+ hv_ring_gpadl_send_hvpgoffset(send_pages << PAGE_SHIFT);
open_msg->target_vp = hv_cpu_number_to_vp_number(newchannel->target_cpu);
if (userdatalen)
}
EXPORT_SYMBOL_GPL(vmbus_open);
-
/*
* vmbus_teardown_gpadl -Teardown the specified GPADL handle
*/
projects / linux.git / commitdiff