[PATCH 13/17] OvmfPkg/PvScsiDxe: Setup requests and completions rings

["Liran Alon" <liran.alon@oracle.com>]

These rings are shared memory buffers between host and device in which
a cyclic buffer is managed to send request descriptors from host to
device and receive completion descriptors from device to host.

Note that because device may be constrained by IOMMU or guest may be run
under AMD SEV, we make sure to map these rings to device by using
PciIo->Map().

Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=2567
Reviewed-by: Nikita Leshenko <nikita.leshchenko@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
---
 OvmfPkg/PvScsiDxe/PvScsi.c | 235 +++++++++++++++++++++++++++++++++++++
 OvmfPkg/PvScsiDxe/PvScsi.h |  17 +++
 2 files changed, 252 insertions(+)

diff --git a/OvmfPkg/PvScsiDxe/PvScsi.c b/OvmfPkg/PvScsiDxe/PvScsi.c
index fb2407d2adb2..c3f5d38f3d30 100644
--- a/OvmfPkg/PvScsiDxe/PvScsi.c
+++ b/OvmfPkg/PvScsiDxe/PvScsi.c
@@ -16,6 +16,7 @@
 #include <Library/UefiBootServicesTableLib.h>
 #include <Library/UefiLib.h>
 #include <Protocol/PciIo.h>
+#include <Protocol/PciRootBridgeIo.h>
 
 #include "PvScsi.h"
 
@@ -396,6 +397,209 @@ PvScsiSetPCIAttributes (
   return EFI_SUCCESS;
 }
 
+STATIC
+EFI_STATUS
+PvScsiAllocatePages (
+  IN PVSCSI_DEV     *Dev,
+  IN UINTN          Pages,
+  IN OUT VOID       **HostAddress
+  )
+{
+  return Dev->PciIo->AllocateBuffer (
+                       Dev->PciIo,
+                       AllocateAnyPages,
+                       EfiBootServicesData,
+                       Pages,
+                       HostAddress,
+                       EFI_PCI_ATTRIBUTE_MEMORY_CACHED
+                       );
+}
+
+STATIC
+VOID
+PvScsiFreePages (
+  IN PVSCSI_DEV     *Dev,
+  IN UINTN          Pages,
+  IN VOID           *HostAddress
+  )
+{
+  Dev->PciIo->FreeBuffer (
+                Dev->PciIo,
+                Pages,
+                HostAddress
+                );
+}
+
+STATIC
+EFI_STATUS
+PvScsiMapBuffer (
+  IN PVSCSI_DEV                     *Dev,
+  IN EFI_PCI_IO_PROTOCOL_OPERATION  PciIoOperation,
+  IN VOID                           *HostAddress,
+  IN UINTN                          NumberOfBytes,
+  OUT PVSCSI_DMA_DESC               *DmaDesc
+  )
+{
+  EFI_STATUS Status;
+  UINTN      BytesMapped;
+
+  BytesMapped = NumberOfBytes;
+  Status = Dev->PciIo->Map (
+                         Dev->PciIo,
+                         PciIoOperation,
+                         HostAddress,
+                         &BytesMapped,
+                         &DmaDesc->DeviceAddress,
+                         &DmaDesc->Mapping
+                         );
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  if (BytesMapped != NumberOfBytes) {
+    Status = EFI_OUT_OF_RESOURCES;
+    goto Unmap;
+  }
+
+  return EFI_SUCCESS;
+
+Unmap:
+  Dev->PciIo->Unmap (Dev->PciIo, DmaDesc->Mapping);
+  DmaDesc->Mapping = NULL;
+
+  return Status;
+}
+
+STATIC
+VOID
+PvScsiUnmapBuffer (
+  IN PVSCSI_DEV                 *Dev,
+  IN OUT PVSCSI_DMA_DESC        *DmaDesc)
+{
+  Dev->PciIo->Unmap (Dev->PciIo, DmaDesc->Mapping);
+}
+
+STATIC
+EFI_STATUS
+PvScsiAllocateSharedPages (
+  IN PVSCSI_DEV                     *Dev,
+  IN UINTN                          Pages,
+  IN EFI_PCI_IO_PROTOCOL_OPERATION  PciIoOperation,
+  OUT VOID                          **HostAddress,
+  OUT PVSCSI_DMA_DESC               *DmaDesc
+  )
+{
+  EFI_STATUS Status;
+
+  *HostAddress = NULL;
+  DmaDesc->Mapping = NULL;
+
+  Status = PvScsiAllocatePages (Dev, Pages, HostAddress);
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  Status = PvScsiMapBuffer (
+             Dev,
+             PciIoOperation,
+             *HostAddress,
+             Pages * EFI_PAGE_SIZE,
+             DmaDesc
+             );
+  if (EFI_ERROR (Status)) {
+    goto FreePages;
+  }
+
+  return EFI_SUCCESS;
+
+FreePages:
+  PvScsiFreePages (Dev, Pages, *HostAddress);
+  *HostAddress = NULL;
+
+  return Status;
+}
+
+STATIC
+VOID
+PvScsiFreeSharedPages (
+  IN PVSCSI_DEV                     *Dev,
+  IN UINTN                          Pages,
+  IN OUT VOID                       **HostAddress,
+  IN OUT PVSCSI_DMA_DESC            *DmaDesc
+  )
+{
+  if (*HostAddress) {
+      if (DmaDesc->Mapping) {
+        PvScsiUnmapBuffer (Dev, DmaDesc);
+        DmaDesc->Mapping = NULL;
+      }
+
+      PvScsiFreePages (Dev, Pages, *HostAddress);
+      *HostAddress = NULL;
+  }
+}
+
+STATIC
+EFI_STATUS
+PvScsiInitRings (
+  IN OUT PVSCSI_DEV *Dev
+  )
+{
+  EFI_STATUS                  Status;
+  PVSCSI_CMD_DESC_SETUP_RINGS Cmd;
+
+  Status = PvScsiAllocateSharedPages (
+             Dev,
+             1,
+             EfiPciIoOperationBusMasterCommonBuffer,
+             (VOID **)&Dev->RingDesc.RingState,
+             &Dev->RingDesc.RingStateDmaDesc
+             );
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+  ZeroMem (Dev->RingDesc.RingState, EFI_PAGE_SIZE);
+
+  Status = PvScsiAllocateSharedPages (
+             Dev,
+             1,
+             EfiPciIoOperationBusMasterCommonBuffer,
+             (VOID **)&Dev->RingDesc.RingReqs,
+             &Dev->RingDesc.RingReqsDmaDesc
+             );
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+  ZeroMem (Dev->RingDesc.RingReqs, EFI_PAGE_SIZE);
+
+  Status = PvScsiAllocateSharedPages (
+             Dev,
+             1,
+             EfiPciIoOperationBusMasterCommonBuffer,
+             (VOID **)&Dev->RingDesc.RingCmps,
+             &Dev->RingDesc.RingCmpsDmaDesc
+             );
+  if (EFI_ERROR (Status)) {
+      return Status;
+  }
+  ZeroMem (Dev->RingDesc.RingCmps, EFI_PAGE_SIZE);
+
+  ZeroMem (&Cmd, sizeof Cmd);
+  Cmd.ReqRingNumPages = 1;
+  Cmd.CmpRingNumPages = 1;
+  Cmd.RingsStatePPN =
+        ((UINT64) Dev->RingDesc.RingStateDmaDesc.DeviceAddress) >>
+        EFI_PAGE_SHIFT;
+  Cmd.ReqRingPPNs[0] =
+        ((UINT64) Dev->RingDesc.RingReqsDmaDesc.DeviceAddress) >>
+        EFI_PAGE_SHIFT;
+  Cmd.CmpRingPPNs[0] =
+        ((UINT64) Dev->RingDesc.RingCmpsDmaDesc.DeviceAddress) >>
+        EFI_PAGE_SHIFT;
+
+  return PvScsiWriteCmdDesc(Dev, PVSCSI_CMD_SETUP_RINGS, &Cmd, sizeof Cmd);
+}
+
 STATIC
 EFI_STATUS
 PvScsiInit (
@@ -425,6 +629,15 @@ PvScsiInit (
   if (EFI_ERROR (Status)) {
     return Status;
   }
+
+  //
+  // Init PVSCSI rings
+  //
+  Status = PvScsiInitRings (Dev);
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
   //
   // Populate the exported interface's attributes
   //
@@ -463,6 +676,28 @@ PvScsiUninit (
   IN OUT PVSCSI_DEV *Dev
   )
 {
+  //
+  // Free PVSCSI rings
+  //
+  PvScsiFreeSharedPages (
+    Dev,
+    1,
+    (VOID **)&Dev->RingDesc.RingCmps,
+    &Dev->RingDesc.RingCmpsDmaDesc
+    );
+  PvScsiFreeSharedPages (
+    Dev,
+    1,
+    (VOID **)&Dev->RingDesc.RingReqs,
+    &Dev->RingDesc.RingReqsDmaDesc
+    );
+  PvScsiFreeSharedPages (
+    Dev,
+    1,
+    (VOID **)&Dev->RingDesc.RingState,
+    &Dev->RingDesc.RingStateDmaDesc
+    );
+
   //
   // Restore PCI Attributes
   //
diff --git a/OvmfPkg/PvScsiDxe/PvScsi.h b/OvmfPkg/PvScsiDxe/PvScsi.h
index 5f611dbbc98c..6d23b6e1eccf 100644
--- a/OvmfPkg/PvScsiDxe/PvScsi.h
+++ b/OvmfPkg/PvScsiDxe/PvScsi.h
@@ -15,12 +15,29 @@
 #include <Library/DebugLib.h>
 #include <Protocol/ScsiPassThruExt.h>
 
+typedef struct {
+  EFI_PHYSICAL_ADDRESS DeviceAddress;
+  VOID                 *Mapping;
+} PVSCSI_DMA_DESC;
+
+typedef struct {
+  PVSCSI_RINGS_STATE   *RingState;
+  PVSCSI_DMA_DESC      RingStateDmaDesc;
+
+  PVSCSI_RING_REQ_DESC *RingReqs;
+  PVSCSI_DMA_DESC      RingReqsDmaDesc;
+
+  PVSCSI_RING_CMP_DESC *RingCmps;
+  PVSCSI_DMA_DESC      RingCmpsDmaDesc;
+} PVSCSI_RING_DESC;
+
 #define PVSCSI_SIG SIGNATURE_32 ('P', 'S', 'C', 'S')
 
 typedef struct {
   UINT32                          Signature;
   EFI_PCI_IO_PROTOCOL             *PciIo;
   UINT64                          OriginalPciAttributes;
+  PVSCSI_RING_DESC                RingDesc;
   UINT8                           MaxTarget;
   UINT8                           MaxLun;
   EFI_EXT_SCSI_PASS_THRU_PROTOCOL PassThru;
-- 
2.20.1