diff options
Diffstat (limited to 'OvmfPkg/Library')
| -rw-r--r-- | OvmfPkg/Library/VirtioLib/VirtioLib.c | 135 | ||||
| -rw-r--r-- | OvmfPkg/Library/VirtioLib/VirtioLib.inf | 2 |
2 files changed, 127 insertions, 10 deletions
diff --git a/OvmfPkg/Library/VirtioLib/VirtioLib.c b/OvmfPkg/Library/VirtioLib/VirtioLib.c index f0328ef4cd..6ed977cd10 100644 --- a/OvmfPkg/Library/VirtioLib/VirtioLib.c +++ b/OvmfPkg/Library/VirtioLib/VirtioLib.c @@ -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>
@@ -276,6 +278,39 @@ 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.
This function implements the following sections from virtio-0.9.5:
@@ -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;
}
diff --git a/OvmfPkg/Library/VirtioLib/VirtioLib.inf b/OvmfPkg/Library/VirtioLib/VirtioLib.inf index cfd93a2c2c..fb5897a88e 100644 --- a/OvmfPkg/Library/VirtioLib/VirtioLib.inf +++ b/OvmfPkg/Library/VirtioLib/VirtioLib.inf @@ -29,6 +29,8 @@ OvmfPkg/OvmfPkg.dec
[LibraryClasses]
+ BaseLib
BaseMemoryLib
DebugLib
MemoryAllocationLib
+ UefiBootServicesTableLib
|