> -----Original Message----- > From: Greg KH [mailto:gregkh@xxxxxxxxxxxxxxxxxxx] > Sent: Monday, December 15, 2014 11:34 AM > To: KY Srinivasan > Cc: linux-kernel@xxxxxxxxxxxxxxx; devel@xxxxxxxxxxxxxxxxxxxxxx; > olaf@xxxxxxxxx; apw@xxxxxxxxxxxxx; jasowang@xxxxxxxxxx > Subject: Re: [PATCH 1/1] Drivers: hv: vmbus: Support a vmbus API for > efficiently sending page arrays > > On Mon, Dec 15, 2014 at 12:33:47PM -0800, K. Y. Srinivasan wrote: > > Currently, the API for sending a multi-page buffer over VMBUS is > > limited to a maximum pfn array of MAX_MULTIPAGE_BUFFER_COUNT. > This > > limitation is not imposed by the host and unnecessarily limits the > > maximum payload that can be sent. Implement an API that does not have > this restriction. > > > > Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx> > > --- > > drivers/hv/channel.c | 44 > ++++++++++++++++++++++++++++++++++++++++++++ > > include/linux/hyperv.h | 31 +++++++++++++++++++++++++++++++ > > 2 files changed, 75 insertions(+), 0 deletions(-) > > > > diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c index > > c76ffbe..18c4f23 100644 > > --- a/drivers/hv/channel.c > > +++ b/drivers/hv/channel.c > > @@ -686,6 +686,50 @@ > EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer); > > /* > > * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet > > * using a GPADL Direct packet type. > > + * The buffer includes the vmbus descriptor. > > + */ > > +int vmbus_sendpacket_mpb_desc(struct vmbus_channel *channel, > > + struct vmbus_packet_mpb_array *desc, > > + u32 desc_size, > > + void *buffer, u32 bufferlen, u64 requestid) { > > + int ret; > > + u32 packetlen; > > + u32 packetlen_aligned; > > + struct kvec bufferlist[3]; > > + u64 aligned_data = 0; > > + bool signal = false; > > + > > + packetlen = desc_size + bufferlen; > > + packetlen_aligned = ALIGN(packetlen, sizeof(u64)); > > + > > + /* Setup the descriptor */ > > + desc->type = VM_PKT_DATA_USING_GPA_DIRECT; > > + desc->flags = > VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED; > > + desc->dataoffset8 = desc_size >> 3; /* in 8-bytes grandularity */ > > + desc->length8 = (u16)(packetlen_aligned >> 3); > > + desc->transactionid = requestid; > > + desc->rangecount = 1; > > + > > + bufferlist[0].iov_base = desc; > > + bufferlist[0].iov_len = desc_size; > > + bufferlist[1].iov_base = buffer; > > + bufferlist[1].iov_len = bufferlen; > > + bufferlist[2].iov_base = &aligned_data; > > + bufferlist[2].iov_len = (packetlen_aligned - packetlen); > > + > > + ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, > > +&signal); > > + > > + if (ret == 0 && signal) > > + vmbus_setevent(channel); > > + > > + return ret; > > +} > > +EXPORT_SYMBOL_GPL(vmbus_sendpacket_mpb_desc); > > + > > +/* > > + * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet > > + * using a GPADL Direct packet type. > > */ > > int vmbus_sendpacket_multipagebuffer(struct vmbus_channel *channel, > > struct hv_multipage_buffer > *multi_pagebuffer, diff --git > > a/include/linux/hyperv.h b/include/linux/hyperv.h index > > 08cfaff..8615b0d 100644 > > --- a/include/linux/hyperv.h > > +++ b/include/linux/hyperv.h > > @@ -57,6 +57,18 @@ struct hv_multipage_buffer { > > u64 pfn_array[MAX_MULTIPAGE_BUFFER_COUNT]; > > }; > > > > +/* > > + * Multiple-page buffer array; the pfn array is variable size: > > + * The number of entries in the PFN array is determined by > > + * "len" and "offset". > > + */ > > +struct hv_mpb_array { > > + /* Length and Offset determines the # of pfns in the array */ > > + u32 len; > > + u32 offset; > > + u64 pfn_array[]; > > +}; > > Does this cross the user/kernel boundry? If so, they need to be __u32 and > __u64 variables. This does not cross user/kernel boundry. > > > + > > /* 0x18 includes the proprietary packet header */ > > #define MAX_PAGE_BUFFER_PACKET (0x18 + > \ > > (sizeof(struct hv_page_buffer) * \ > @@ -812,6 +824,18 @@ struct > > vmbus_channel_packet_multipage_buffer { > > struct hv_multipage_buffer range; > > } __packed; > > > > +/* The format must be the same as struct vmdata_gpa_direct */ struct > > +vmbus_packet_mpb_array { > > + u16 type; > > + u16 dataoffset8; > > + u16 length8; > > + u16 flags; > > + u64 transactionid; > > + u32 reserved; > > + u32 rangecount; /* Always 1 in this case */ > > + struct hv_mpb_array range; > > +} __packed; > > Same here. This is completely internal to the kernel. Regards, K. Y > > thanks, > > greg k-h _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
