pRxNetDescriptor CParaNdisRX::CreateRxDescriptorOnInit()
{
//For RX packets we allocate following pages
// 1 page for virtio header and indirect buffers array
// X pages needed to fit maximal length buffer of data
// The assumption is virtio header and indirect buffers array fit 1 page
ULONG ulNumPages = m_Context->MaxPacketSize.nMaxDataSizeHwRx / PAGE_SIZE + 2;
pRxNetDescriptor p = (pRxNetDescriptor)ParaNdis_AllocateMemory(m_Context, sizeof(*p));
if (p == NULL) return NULL;
NdisZeroMemory(p, sizeof(*p));
p->BufferSGArray = (struct VirtIOBufferDescriptor *)
ParaNdis_AllocateMemory(m_Context, sizeof(*p->BufferSGArray) * ulNumPages);
if (p->BufferSGArray == NULL) goto error_exit;
p->PhysicalPages = (tCompletePhysicalAddress *)
ParaNdis_AllocateMemory(m_Context, sizeof(*p->PhysicalPages) * ulNumPages);
if (p->PhysicalPages == NULL) goto error_exit;
for (p->PagesAllocated = 0; p->PagesAllocated < ulNumPages; p->PagesAllocated++)
{
p->PhysicalPages[p->PagesAllocated].size = PAGE_SIZE;
if (!InitialAllocatePhysicalMemory(&p->PhysicalPages[p->PagesAllocated]))
goto error_exit;
p->BufferSGArray[p->PagesAllocated].physAddr = p->PhysicalPages[p->PagesAllocated].Physical;
p->BufferSGArray[p->PagesAllocated].length = PAGE_SIZE;
}
//First page is for virtio header, size needs to be adjusted correspondingly
p->BufferSGArray[0].length = m_Context->nVirtioHeaderSize;
//Pre-cache indirect area addresses
p->IndirectArea.Physical.QuadPart = p->PhysicalPages[0].Physical.QuadPart + m_Context->nVirtioHeaderSize;
p->IndirectArea.Virtual = RtlOffsetToPointer(p->PhysicalPages[0].Virtual, m_Context->nVirtioHeaderSize);
p->IndirectArea.size = PAGE_SIZE - m_Context->nVirtioHeaderSize;
if (!ParaNdis_BindRxBufferToPacket(m_Context, p))
goto error_exit;
return p;
error_exit:
ParaNdis_FreeRxBufferDescriptor(m_Context, p);
return NULL;
}
pRxNetDescriptor CParaNdisRX::CreateRxDescriptorOnInit()
{
//For RX packets we allocate following pages
// 1 page for virtio header and indirect buffers array
// X pages needed to fit maximal length buffer of data
// The assumption is virtio header and indirect buffers array fit 1 page
ULONG ulNumPages = m_Context->MaxPacketSize.nMaxDataSizeHwRx / PAGE_SIZE + 2;
pRxNetDescriptor p = (pRxNetDescriptor)ParaNdis_AllocateMemory(m_Context, sizeof(*p));
if (p == NULL) return NULL;
NdisZeroMemory(p, sizeof(*p));
p->BufferSGArray = (struct VirtIOBufferDescriptor *)
ParaNdis_AllocateMemory(m_Context, sizeof(*p->BufferSGArray) * ulNumPages);
if (p->BufferSGArray == NULL) goto error_exit;
p->PhysicalPages = (tCompletePhysicalAddress *)
ParaNdis_AllocateMemory(m_Context, sizeof(*p->PhysicalPages) * ulNumPages);
if (p->PhysicalPages == NULL) goto error_exit;
p->BufferSGLength = 0;
while (ulNumPages > 0)
{
// Allocate the first page separately, the rest can be one contiguous block
ULONG ulPagesToAlloc = (p->BufferSGLength == 0 ? 1 : ulNumPages);
while (!ParaNdis_InitialAllocatePhysicalMemory(
m_Context,
PAGE_SIZE * ulPagesToAlloc,
&p->PhysicalPages[p->BufferSGLength]))
{
// Retry with half the pages
if (ulPagesToAlloc == 1)
goto error_exit;
else
ulPagesToAlloc /= 2;
}
p->BufferSGArray[p->BufferSGLength].physAddr = p->PhysicalPages[p->BufferSGLength].Physical;
p->BufferSGArray[p->BufferSGLength].length = p->PhysicalPages[p->BufferSGLength].size;
ulNumPages -= ulPagesToAlloc;
p->BufferSGLength++;
}
//First page is for virtio header, size needs to be adjusted correspondingly
p->BufferSGArray[0].length = m_Context->nVirtioHeaderSize;
ULONG indirectAreaOffset = ALIGN_UP(m_Context->nVirtioHeaderSize, ULONGLONG);
//Pre-cache indirect area addresses
p->IndirectArea.Physical.QuadPart = p->PhysicalPages[0].Physical.QuadPart + indirectAreaOffset;
p->IndirectArea.Virtual = RtlOffsetToPointer(p->PhysicalPages[0].Virtual, indirectAreaOffset);
p->IndirectArea.size = PAGE_SIZE - indirectAreaOffset;
if (!ParaNdis_BindRxBufferToPacket(m_Context, p))
goto error_exit;
return p;
error_exit:
ParaNdis_FreeRxBufferDescriptor(m_Context, p);
return NULL;
}
