diff options
Diffstat (limited to 'drivers/hv')
| -rw-r--r-- | drivers/hv/channel.c | 160 |
1 files changed, 140 insertions, 20 deletions
diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c index 1cbe8fc931fc..45267b6d069e 100644 --- a/drivers/hv/channel.c +++ b/drivers/hv/channel.c @@ -36,6 +36,99 @@ static unsigned long virt_to_hvpfn(void *addr) } /* + * 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. */ @@ -160,7 +253,8 @@ EXPORT_SYMBOL_GPL(vmbus_send_modifychannel); /* * 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; @@ -173,7 +267,7 @@ static int create_gpadl_header(void *kbuffer, u32 size, 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 - @@ -200,10 +294,10 @@ static int create_gpadl_header(void *kbuffer, u32 size, 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; @@ -254,8 +348,8 @@ static int create_gpadl_header(void *kbuffer, u32 size, * 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, @@ -281,10 +375,10 @@ static int create_gpadl_header(void *kbuffer, u32 size, 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; } @@ -297,15 +391,20 @@ nomem: } /* - * 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; @@ -319,7 +418,7 @@ int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer, 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; @@ -400,6 +499,21 @@ cleanup: 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, @@ -438,10 +552,11 @@ 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; @@ -462,7 +577,13 @@ static int __vmbus_open(struct vmbus_channel *newchannel, 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) @@ -556,7 +677,6 @@ int vmbus_open(struct vmbus_channel *newchannel, } EXPORT_SYMBOL_GPL(vmbus_open); - /* * vmbus_teardown_gpadl -Teardown the specified GPADL handle */ |