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OvmfPkg: librarize reusable bits from VirtioBlkDxe's SynchronousRequest()

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new VirtioLib functions:
- VirtioPrepare(): prepare for appending descriptors
- VirtioFlush(): submit descriptor chain and await host answer

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@13844 6f19259b-4bc3-4df7-8a09-765794883524
This commit is contained in:
jljusten
2012-10-12 18:54:35 +00:00
parent 7fcacd6c92
commit e371e7e545
4 changed files with 205 additions and 66 deletions
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135
OvmfPkg/Library/VirtioLib/VirtioLib.c
View File

@@ -15,9 +15,11 @@
**/
#include <IndustryStandard/Pci22.h>
#include <Library/BaseLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/DebugLib.h>
#include <Library/MemoryAllocationLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/VirtioLib.h>
@@ -274,6 +276,39 @@ VirtioRingUninit (
}
/**
Turn off interrupt notifications from the host, and prepare for appending
multiple descriptors to the virtio ring.
The calling driver must be in VSTAT_DRIVER_OK state.
@param[in out] Ring The virtio ring we intend to append descriptors to.
@param[out] Indices The DESC_INDICES structure to initialize.
**/
VOID
EFIAPI
VirtioPrepare (
IN OUT VRING *Ring,
OUT DESC_INDICES *Indices
)
{
//
// Prepare for virtio-0.9.5, 2.4.2 Receiving Used Buffers From the Device.
// We're going to poll the answer, the host should not send an interrupt.
//
*Ring->Avail.Flags = (UINT16) VRING_AVAIL_F_NO_INTERRUPT;
//
// Prepare for virtio-0.9.5, 2.4.1 Supplying Buffers to the Device.
//
Indices->HeadIdx = *Ring->Avail.Idx;
Indices->NextAvailIdx = Indices->HeadIdx;
}
/**
Append a contiguous buffer for transmission / reception via the virtio ring.
@@ -287,6 +322,9 @@ VirtioRingUninit (
request submission. It is the calling driver's responsibility to verify the
ring size in advance.
The caller is responsible for initializing *Indices with VirtioPrepare()
first.
@param[in out] Ring The virtio ring to append the buffer to, as a
descriptor.
@@ -303,6 +341,8 @@ VirtioRingUninit (
host only interprets it dependent on
VRING_DESC_F_NEXT.
In *Indices:
@param [in] HeadIdx The index identifying the head buffer (first
buffer appended) belonging to this same
request.
@@ -315,21 +355,96 @@ VirtioRingUninit (
VOID
EFIAPI
VirtioAppendDesc (
IN OUT VRING *Ring,
IN UINTN BufferPhysAddr,
IN UINT32 BufferSize,
IN UINT16 Flags,
IN UINT16 HeadIdx,
IN OUT UINT16 *NextAvailIdx
IN OUT VRING *Ring,
IN UINTN BufferPhysAddr,
IN UINT32 BufferSize,
IN UINT16 Flags,
IN OUT DESC_INDICES *Indices
)
{
volatile VRING_DESC *Desc;
Desc = &Ring->Desc[*NextAvailIdx % Ring->QueueSize];
Desc = &Ring->Desc[Indices->NextAvailIdx % Ring->QueueSize];
Desc->Addr = BufferPhysAddr;
Desc->Len = BufferSize;
Desc->Flags = Flags;
Ring->Avail.Ring[(*NextAvailIdx)++ % Ring->QueueSize] =
HeadIdx % Ring->QueueSize;
Desc->Next = *NextAvailIdx % Ring->QueueSize;
Ring->Avail.Ring[Indices->NextAvailIdx++ % Ring->QueueSize] =
Indices->HeadIdx % Ring->QueueSize;
Desc->Next = Indices->NextAvailIdx % Ring->QueueSize;
}
/**
Notify the host about appended descriptors and wait until it processes the
last one (ie. all of them).
@param[in] PciIo The target virtio PCI device to notify.
@param[in] VirtQueueId Identifies the queue for the target device.
@param[in out] Ring The virtio ring with descriptors to submit.
@param[in] Indices The function waits until the host processes
descriptors up to Indices->NextAvailIdx.
@return Error code from VirtioWrite() if it fails.
@retval EFI_SUCCESS Otherwise, the host processed all descriptors.
**/
EFI_STATUS
EFIAPI
VirtioFlush (
IN EFI_PCI_IO_PROTOCOL *PciIo,
IN UINT16 VirtQueueId,
IN OUT VRING *Ring,
IN DESC_INDICES *Indices
)
{
EFI_STATUS Status;
UINTN PollPeriodUsecs;
//
// virtio-0.9.5, 2.4.1.3 Updating the Index Field
//
MemoryFence();
*Ring->Avail.Idx = Indices->NextAvailIdx;
//
// virtio-0.9.5, 2.4.1.4 Notifying the Device -- gratuitous notifications are
// OK.
//
MemoryFence();
Status = VirtioWrite (
PciIo,
OFFSET_OF (VIRTIO_HDR, VhdrQueueNotify),
sizeof (UINT16),
VirtQueueId
);
if (EFI_ERROR (Status)) {
return Status;
}
//
// virtio-0.9.5, 2.4.2 Receiving Used Buffers From the Device
// Wait until the host processes and acknowledges our descriptor chain. The
// condition we use for polling is greatly simplified and relies on the
// synchronous, lock-step progress.
//
// Keep slowing down until we reach a poll period of slightly above 1 ms.
//
PollPeriodUsecs = 1;
MemoryFence();
while (*Ring->Used.Idx != Indices->NextAvailIdx) {
gBS->Stall (PollPeriodUsecs); // calls AcpiTimerLib::MicroSecondDelay
if (PollPeriodUsecs < 1024) {
PollPeriodUsecs *= 2;
}
MemoryFence();
}
return EFI_SUCCESS;
}